Mae ether cellwlos, yn cael ei ddefnyddio'n helaeth mewn morter. As a kind of etherified cellulose,ether cellwlos
With the continuous development of world's construction industry and the continuous deepening of building materials research, the commercialization of mortar has become an irresistible trend. Due to the many advantages that traditional mortar does not have, the use of commercial mortar has become more common in large and medium-sized cities in my country. Fodd bynnag, mae gan forter masnachol lawer o broblemau technegol o hyd.
In this paper, the important admixtures in mortar, cellulose ether and admixture are used in the mortar, and the comprehensive influence law of the two components in the mortar on the fluidity and strength of the mortar is summarized through experiments. By changing the type and amount of cellulose ether and admixtures in the test, the influence on the fluidity and strength of the mortar was observed (in this paper, the test gelling system mainly adopts a binary system). Compared with HPMC, CMC is not suitable for thickening and water retention treatment of cement-based cementitious materials. HPMC can significantly reduce the fluidity of slurry and increase the loss over time at low dosage (below 0.2%). Reduce the strength of the mortar body and reduce the compression-to-fold ratio. Mae gofynion hylifedd a chryfder cynhwysfawr, cynnwys HPMC yn O. 1% yn fwy priodol. O ran admixtures, mae lludw hedfan yn cael effaith benodol ar gynyddu hylifedd y slyri, ac nid yw dylanwad powdr slag yn amlwg. Although silica fume can effectively reduce bleeding, the fluidity can be seriously lost when the dosage is 3%. . Ar ôl ystyried cynhwysfawr, daethpwyd i'r casgliad pan ddefnyddir lludw hedfan mewn morter strwythurol neu wedi'i atgyfnerthu â gofynion caledu cyflym a chryfder cynnar, ni ddylai'r dos fod yn rhy uchel, mae'r dos uchaf tua 10%, a phan fydd yn cael ei ddefnyddio ar gyfer bondio mortar, it is added to 20%. ‰ can also basically meet the requirements; considering factors such as the poor volume stability of mineral powder and silica fume, it should be controlled below 10% and 3% respectively. The effects of admixtures and cellulose ethers were not significantly correlated and had independent effects.
Trwy'r gwaith uchod, mae'r papur hwn yn dod i rai casgliadau damcaniaethol ac ymarferol gyda gwerth cyfeirio penodol.
1.1morter nwyddau
Cyflwyno morter masnachol
Yn niwydiant deunyddiau adeiladu fy ngwlad, mae concrit wedi cyflawni lefel uchel o fasnacheiddio, ac mae masnacheiddio morter hefyd yn mynd yn uwch ac yn uwch, yn enwedig ar gyfer morterau arbennig amrywiol, mae angen gweithgynhyrchwyr sydd â galluoedd technegol uwch i sicrhau'r gwahanol forterau. The performance indicators are qualified. Commercial mortar is divided into two categories: ready-mixed mortar and dry-mixed mortar. Mae morter cymysg parod yn golygu bod y morter yn cael ei gludo i'r safle adeiladu ar ôl cael ei gymysgu â dŵr gan y cyflenwr ymlaen llaw yn unol â gofynion y prosiect, tra bod y gwneuthurwr morter â chymysgedd sych yn cael ei wneud gan y gwneuthurwr morter trwy gymysgu sych a phecynnu deunyddiau smentitious, aggregates and additives according to a certain ratio. Add a certain amount of water to the construction site and mix it before use.
Traditional mortar has many weaknesses in use and performance. For example, the stacking of raw materials and on-site mixing cannot meet the requirements of civilized construction and environmental protection. In addition, due to on-site construction conditions and other reasons, it is easy to make the quality of mortar difficult to guarantee, and it is impossible to obtain high performance. morter. Compared with traditional mortar, commercial mortar has some obvious advantages. First of all, its quality is easy to control and guarantee, its performance is superior, its types are refined, and it is better targeted to engineering requirements. European dry-mixed mortar has been developed in the 1950s, and my country is also vigorously advocating the application of commercial mortar. Shanghai has already used commercial mortar in 2004. With the continuous development of my country's urbanization process, at least in the urban market, it will be inevitable that commercial mortar with various advantages will replace traditional mortar.
Although commercial mortar has many advantages over traditional mortar, there are still many technical difficulties as mortar. High fluidity mortar, such as reinforcement mortar, cement-based grouting materials, etc., have extremely high requirements on strength and work performance, so the use of superplasticizers is large, which will cause serious bleeding and affect the mortar. Comprehensive performance; and for some plastic mortars, because they are very sensitive to the loss of water, it is easy to have a serious decrease in workability due to the loss of water in a short time after mixing, and the operation time is extremely short: In addition, for In terms of bonding mortar, the bonding matrix is often relatively dry. During the construction process, due to the insufficient ability of the mortar to retain water, a large amount of water will be absorbed by the matrix, resulting in local water shortage of the bonding mortar and insufficient hydration. Mae'r ffenomen y mae'r cryfder yn lleihau a'r grym gludiog yn lleihau.
In response to the above questions, an important additive, cellulose ether, is widely used in mortar. As a kind of etherified cellulose, cellulose ether has affinity for water, and this polymer compound has excellent water absorption and water retention ability, which can well solve the bleeding of mortar, short operation time, stickiness, etc. Insufficient knot strength and many other problemau.
In addition, admixtures as partial substitutes for cement, such as fly ash, granulated blast furnace slag powder (mineral powder), silica fume, etc., are now more and more important. Gwyddom fod y rhan fwyaf o'r admixtures yn sgil-gynhyrchion diwydiannau fel pŵer trydan, mwyndoddi dur, mwyndoddi ferrosilicon a silicon diwydiannol. If they cannot be fully utilized, the accumulation of admixtures will occupy and destroy a large amount of land and cause serious damage. environmental pollution. On the other hand, if admixtures are used reasonably, some properties of concrete and mortar can be improved, and some engineering problems in the application of concrete and mortar can be well solved. Felly, mae cymhwysiad eang admixtures yn fuddiol i'r amgylchedd a'r diwydiant. yn fuddiol.
1.2Etherau cellwlos
Mae ether cellwlos (ether seliwlos) yn gyfansoddyn polymer gyda strwythur ether a gynhyrchir trwy etheriad seliwlos. Mae pob cylch glucosyl mewn macromoleciwlau seliwlos yn cynnwys tri grŵp hydrocsyl, grŵp hydrocsyl cynradd ar y chweched atom carbon, grŵp hydrocsyl eilaidd ar yr ail a'r trydydd atomau carbon, ac mae'r hydrogen yn y grŵp hydrocsyl yn cael ei ddisodli gan grŵp hydrocarbon i gynhyrchu ether seliwlos hydrocarbon deilliadau. thing. Mae cellwlos yn gyfansoddyn polymer polyhydroxy nad yw'n hydoddi nac yn toddi, ond gellir toddi seliwlos mewn dŵr, gwanhau toddiant alcali a thoddydd organig ar ôl etheriad, ac mae ganddo thermoplastigedd penodol.
Mae ether cellwlos yn cymryd seliwlos naturiol fel deunydd crai ac yn cael ei baratoi trwy addasu cemegol. Fe'i dosbarthir yn ddau gategori: ïonig a di-ïonig ar ffurf ïoneiddiedig. It is widely used in chemical, petroleum, construction, medicine, ceramics and other industries. .
Dosbarthu etherau seliwlos ar gyfer adeiladu
3. According to different solubility, it is divided into water-soluble (such as hydroxyethyl cellulose) and organic solvent solubility (such as ethyl cellulose), etc. The main application type in dry-mixed mortar is water-soluble cellulose, while water -Suluble Cellwlos mae wedi'i rannu'n fath ar unwaith ac oedi math diddymu ar ôl triniaeth ar yr wyneb.
1. Ar ôl i'r ether seliwlos yn y morter gael ei doddi mewn dŵr, mae'r gweithgaredd arwyneb unigryw yn sicrhau bod y deunydd smentitious yn cael ei wasgaru'n effeithiol ac yn unffurf yn y system slyri, a gall ether seliwlos, fel colloid amddiffynnol, “grynhoi” gronynnau solet, felly , a lubricating film is formed on the outer surface, and the lubricating film can make the mortar body have good thixotropy. Hynny yw, mae'r gyfrol yn gymharol sefydlog yn y cyflwr sefydlog, ac ni fydd ffenomenau niweidiol fel gwaedu neu haenu sylweddau golau a thrwm, sy'n gwneud y system morter yn fwy sefydlog; Tra yn y cyflwr adeiladu cynhyrfus, bydd yr ether seliwlos yn chwarae rôl wrth leihau cneifio'r slyri. Mae effaith ymwrthedd newidiol yn golygu bod gan y morter hylifedd a llyfnder da yn ystod y gwaith adeiladu yn ystod y broses gymysgu.
After the refined cotton is treated with alkali, methyl chloride is used as the etherifying agent to make cellulose ether through a series of reactions. The general substitution degree is 1. Melting 2.0, the degree of substitution is different and the solubility is also different. Yn perthyn i ether seliwlos nad yw'n ïonig.
2. Cellwlos hydroxyethyl (HEC)
It is prepared by reacting with ethylene oxide as an etherifying agent in the presence of acetone after the refined cotton is treated with alkali. The degree of substitution is generally 1.5 to 2.0. Mae ganddo hydrophilicity cryf ac mae'n hawdd ei amsugno lleithder.
Mae hydroxypropyl methylcellulose yn amrywiaeth seliwlos y mae ei allbwn a'i ddefnydd yn cynyddu'n gyflym yn ystod y blynyddoedd diwethaf. It is a non-ionic cellulose mixed ether made from refined cotton after alkali treatment, using propylene oxide and methyl chloride as etherifying agents, and through a series of reactions. The degree of substitution is generally 1.2 to 2.0. Mae ei briodweddau'n amrywio yn ôl cymhareb cynnwys methoxyl a chynnwys hydroxypropyl.
4. Carboxymethylcellulose (CMC)
Mae ether seliwlos ïonig yn cael ei baratoi o ffibrau naturiol (cotwm, ac ati) ar ôl triniaeth alcali, gan ddefnyddio sodiwm monocloroacetate fel asiant etherifying, a thrwy gyfres o driniaethau adweithio. The degree of substitution is generally 0.4–d. 4. Effeithir yn fawr ar ei berfformiad gan raddau'r amnewidiad.
Yn eu plith, y trydydd a'r pedwerydd math yw'r ddau fath o seliwlos a ddefnyddir yn yr arbrawf hwn.
1.2.4 Statws Datblygu'r Diwydiant Ether Cellwlos
my country is the world's largest producer and consumer of cellulose ether, with an average annual growth rate of more than 20%. According to preliminary statistics, there are about 50 cellulose ether production enterprises in China. The designed production capacity of the cellulose ether industry has exceeded 400,000 tons, and there are about 20 enterprises with a capacity of more than 10,000 tons, mainly located in Shandong, Hebei, Chongqing and Jiangsu. , Zhejiang, Shanghai a lleoedd eraill. Yn 2011, roedd gallu cynhyrchu CMC Tsieina tua 300,000 tunnell. With the increasing demand for high-quality cellulose ethers in the pharmaceutical, food, daily chemical and other industries in recent years, the domestic demand for other cellulose ether products other than CMC is increasing. Yn fwy, mae gallu MC/HPMC tua 120,000 tunnell, ac mae gallu HEC tua 20,000 tunnell. Mae PAC yn dal i fod yn y cam hyrwyddo a chymhwyso yn Tsieina. With the development of large offshore oil fields and the development of building materials, food, chemical and other industries, the amount and field of PAC are increasing and expanding year by year, with a production capacity of more than 10,000 tons.
1.3
An important conclusion about the water retention mechanism is that the rheological properties of the mortar are critical. Gellir gweld o ganlyniadau'r profion, ar gyfer morter cymysg sych gyda chymhareb sment dŵr sefydlog a chynnwys admixture, yn gyffredinol mae gan berfformiad cadw dŵr yr un rheoleidd-dra â'i gysondeb. Fodd bynnag, ar gyfer rhai etherau seliwlos, nid yw'r duedd yn amlwg; Yn ogystal, ar gyfer etherau startsh, mae patrwm cyferbyniol. Nid gludedd y gymysgedd ffres yw'r unig baramedr ar gyfer pennu cadw dŵr.
Canfu Laetitia National, Patrice Potion, et al., Gyda chymorth graddiant caeau pylsog a thechnegau MRI, fod yr ymfudiad lleithder ar ryngwyneb morter a swbstrad annirlawn yn cael ei effeithio gan ychwanegu ychydig bach o CE. The loss of water is due to capillary action rather than water diffusion. Moisture migration by capillary action is governed by substrate micropore pressure, which in turn is determined by micropore size and Laplace theory interfacial tension, as well as fluid viscosity. Mae hyn yn dangos mai priodweddau rheolegol toddiant dyfrllyd CE yw'r allwedd i berfformiad cadw dŵr. However, this hypothesis contradicts some consensus (other tackifiers like high molecular polyethylene oxide and starch ethers are not as effective as CE).
3. Effeithir ar gryfder y bond gan baru powdr CE a rwber. When the CE film cannot prevent the evaporation of moisture at the interface of the tile and the mortar, the adhesion under high temperature curing decreases.
4. Dylid ystyried cydgysylltu a rhyngweithio CE a phowdr polymer gwasgaredig wrth ddylunio cyfran y morter gludiog ar gyfer teils.
Lschmitzc yr Almaen. Soniodd J. Dr. H (A) CKER yn yr erthygl fod gan HPMC a HEMC mewn ether seliwlos rôl hanfodol iawn wrth gadw dŵr mewn morter cymysg sych. In addition to ensuring the enhanced water retention index of cellulose ether, it is recommended to use modified Cellulose ethers are used to improve and improve the working properties of mortar and the properties of dry and hardened mortar.
1.3.2Cyflwyniad byr o ymchwil ddomestig ar gymhwyso ether seliwlos i forter
Professor Ma Baoguo from Wuhan University of Technology pointed out that cellulose ether has obvious retardation effect, and can affect the structural form of hydration products and the pore structure of cement slurry; Mae ether cellwlos yn cael ei adsorbed yn bennaf ar wyneb gronynnau sment i ffurfio effaith rwystr benodol. It hinders the nucleation and growth of hydration products; on the other hand, cellulose ether hinders the migration and diffusion of ions due to its obvious viscosity increasing effect, thereby delaying the hydration of cement to a certain extent; cellulose ether has alkali stability.
Jian Shouwei from Wuhan University of Technology concluded that the role of CE in mortar is mainly reflected in three aspects: excellent water retention capacity, influence on mortar consistency and thixotropy, and adjustment of rheology. CE not only gives mortar good working performance, but also To reduce the early hydration heat release of cement and delay the hydration kinetic process of cement, of course, based on the different use cases of mortar, there are also differences in its performance evaluation methods .
CE modified mortar is applied in the form of thin-layer mortar in daily dry-mix mortar (such as brick binder, putty, thin-layer plastering mortar, etc.). Mae'r strwythur unigryw hwn fel arfer yn cyd -fynd â cholli dŵr cyflym y morter. At present, the main research focuses on the face tile adhesive, and there is less research on other types of thin-layer CE modified mortar.
Su Lei from Wuhan University of Technology obtained through the experimental analysis of the water retention rate, water loss and setting time of the mortar modified with cellulose ether. Mae maint y dŵr yn gostwng yn raddol, ac mae'r amser ceulo yn hir; when the amount of water reaches O. After 6%, the change of water retention rate and water loss is no longer obvious, and the setting time is nearly doubled; ac mae'r astudiaeth arbrofol o'i gryfder cywasgol yn dangos pan fydd cynnwys ether seliwlos yn is na 0.8%, mae cynnwys ether seliwlos yn llai na 0.8%. The increase will significantly reduce the compressive strength; and in terms of the bonding performance with the cement mortar board, O. Below 7% of the content, the increase of the content of cellulose ether can effectively improve the bonding strength.
Yuan Wei and Qin Min of Xinjiang Building Materials Research Institute conducted the test and application research of cellulose ether in foamed concrete. The test results show that HPMC improves the water retention performance of fresh foam concrete and reduces the water loss rate of hardened foam concrete; Gall HPMC leihau colli cwymp concrit ewyn ffres a lleihau sensitifrwydd y gymysgedd i dymheredd. ; HPMC will significantly reduce the compressive strength of foam concrete. Under natural curing conditions, a certain amount of HPMC can improve the strength of the specimen to a certain extent.
Li Yuhai of Wacker Polymer Materials Co., Ltd. pointed out that the type and amount of latex powder, the type of cellulose ether and the curing environment have a significant impact on the impact resistance of plastering mortar. Mae effaith etherau seliwlos ar gryfder effaith hefyd yn ddibwys o'i gymharu â chynnwys polymer ac amodau halltu.
Yin Qingli of AkzoNobel Specialty Chemicals (Shanghai) Co., Ltd. used Bermocoll PADl, a specially modified polystyrene board bonding cellulose ether, for the experiment, which is especially suitable for the bonding mortar of EPS external wall insulation system. Gall Bermocoll PADL wella'r cryfder bondio rhwng morter a bwrdd polystyren yn ychwanegol at holl swyddogaethau ether seliwlos. Even in the case of low dosage, it can not only improve the water retention and workability of the fresh mortar, but also can significantly improve the original bonding strength and water-resistant bonding strength between the mortar and the polystyrene board due to the unique anchoring technoleg. . However, it cannot improve the impact resistance of mortar and the bonding performance with polystyrene board. Er mwyn gwella'r priodweddau hyn, dylid defnyddio powdr latecs ailddarganfod.
Zhang Lin and others of Shantou Special Economic Zone Longhu Technology Co., Ltd. have concluded that, in the bonding mortar of the expanded polystyrene board thin plastering external wall external thermal insulation system (ie Eqos system), it is recommended that the optimum amount of rubber powder be 2.5% is the limit; Mae gludedd isel, ether seliwlos wedi'i addasu'n fawr yn help mawr i wella cryfder bond tynnol ategol morter caledu.
Astudiodd Prifysgol Fuzhou, Huang Lipin et al, ddopio ether cellwlos methyl hydroxyethyl ac ethylen. Priodweddau ffisegol a morffoleg drawsdoriadol morter sment wedi'i addasu o bowdr latecs copolymer asetad finyl. It is found that cellulose ether has excellent water retention, water absorption resistance and outstanding air-entraining effect, while the water-reducing properties of latex powder and the improvement of the mechanical properties of mortar are particularly prominent. Effaith addasu; ac mae ystod dos addas rhwng polymerau.
Through a series of experiments, Chen Qian and others from Hubei Baoye Construction Industrialization Co., Ltd. proved that extending the stirring time and increasing the stirring speed can give full play to the role of cellulose ether in the ready-mixed mortar, improve the ymarferoldeb y morter, a gwella'r amser cynhyrfus. Bydd cyflymder rhy fyr neu rhy araf yn gwneud y morter yn anodd ei adeiladu; choosing the right cellulose ether can also improve the workability of ready-mixed mortar.
Astudiodd Ma Baoguo o Brifysgol Technoleg Wuhan ac eraill effeithiau gwahanol dosau o emwlsiwn styren-acrylig, powdr polymer gwasgaredig, ac ether methylcellwlos hydroxypropyl ar y defnydd o ddŵr, cryfder bond a chadernid morter plastro tenau. , found that when the content of styrene-acrylic emulsion was 4% to 6%, the bond strength of mortar reached the best value, and the compression-folding ratio was the smallest; the content of cellulose ether increased to O. At 4%, the bond strength of mortar reaches saturation, and the compression-folding ratio is the smallest; when the content of rubber powder is 3%, the bonding strength of mortar is the best, and the compression-folding ratio decreases with the addition of rubber powder. trend.
Qiu Yongxia of Beijing Wanbo Huijia Science and Trade Co., Ltd. found that with the increase of the viscosity of cellulose ether, the water retention rate of the mortar increased; Po fân y gronynnau o ether seliwlos, y gorau y bydd y dŵr yn cadw; Po uchaf yw cyfradd cadw dŵr ether seliwlos; Mae cadw dŵr ether seliwlos yn gostwng gyda'r cynnydd yn nhymheredd y morter.
Zhang Bin of Tongji University and others pointed out in the article that the working characteristics of modified mortar are closely related to the viscosity development of cellulose ethers, not that the cellulose ethers with high nominal viscosity have obvious influence on the working characteristics, because they are mae maint y gronynnau hefyd yn effeithio arno. , dissolution rate and other factors.
Zhou Xiao and others from the Institute of Cultural Relics Protection Science and Technology, China Cultural Heritage Research Institute studied the contribution of two additives, polymer rubber powder and cellulose ether, to the bond strength in NHL (hydraulic lime) mortar system, and found that Y syml oherwydd crebachu gormodol calch hydrolig, ni all gynhyrchu cryfder tynnol digonol gyda'r rhyngwyneb carreg. Gall swm priodol o bowdr rwber polymer ac ether seliwlos wella cryfder bondio morter NHL yn effeithiol a chwrdd â gofynion atgyfnerthu crair diwylliannol ac amddiffyn deunyddiau amddiffyn; Er mwyn ei atal mae'n cael effaith ar athreiddedd dŵr ac anadlu morter NHL ei hun a'r cydnawsedd â chreiriau diwylliannol gwaith maen. Ar yr un pryd, o ystyried perfformiad bondio cychwynnol morter NHL, mae'r swm ychwanegiad delfrydol o bowdr rwber polymer yn is na 0.5%i 1%, ac ychwanegu ether seliwlos y rheolir y swm ar oddeutu 0.2%.
1.4Ymchwil ar gymhwyso admixtures i forter gartref a thramor
Yn y diwydiant deunyddiau adeiladu, mae cymhwyso admixtures wedi bod yn helaeth iawn. Many cement varieties contain more or less a certain amount of admixtures. Among them, the most widely used ordinary Portland cement is added 5% in the production. ~20% admixture. In the production process of various mortar and concrete production enterprises, the application of admixtures is more extensive.
Ar gyfer cymhwyso admixtures mewn morter, mae ymchwil hirdymor ac helaeth wedi'i gynnal gartref a thramor.
1.4.1
P. Prifysgol California. JM Momeiro Joe IJ K. Wang et al. found that in the hydration process of the gelling material, the gel is not swelled in equal volume, and the mineral admixture can change the composition of the hydrated gel, and found that the swelling of the gel is related to the divalent cations in the gel . The number of copies showed a significant negative correlation.
Kevin J. o'r Unol Daleithiau. Folliard a Makoto Ohta et al. pointed out that the addition of silica fume and rice husk ash to the mortar can significantly improve the compressive strength, while the addition of fly ash reduces the strength, especially in the early stage.
Philippe Lawrence and Martin Cyr of France found that a variety of mineral admixtures can improve the mortar strength under the appropriate dosage. Nid yw'r gwahaniaeth rhwng gwahanol admixtures mwynau yn amlwg yng nghyfnod cynnar hydradiad. In the later stage of hydration, the additional strength increase is affected by the activity of the mineral admixture, and the strength increase caused by the inert admixture cannot simply be regarded as filling. effaith, ond dylid ei briodoli i effaith gorfforol cnewylliad amlhaenog.
1.4.2Cyflwyniad byr o ymchwil ddomestig ar gymhwyso admixtures i forter
Through experimental research, Zhong Shiyun and Xiang Keqin of Tongji University found that the composite modified mortar of a certain fineness of fly ash and polyacrylate emulsion (PAE), when the poly-binder ratio was fixed at 0.08, the compression-folding ratio of the Cynyddodd morter gyda mân a chynnwys lludw hedfan yn lleihau gyda'r cynnydd o ludw hedfan. It is proposed that the addition of fly ash can effectively solve the problem of high cost of improving the flexibility of mortar by simply increasing the content of polymer.
Wang Yinong of Wuhan Iron and Steel Civil Construction Company has studied a high-performance mortar admixture, which can effectively improve the workability of mortar, reduce the degree of delamination, and improve the bonding ability. It is suitable for masonry and plastering of aerated concrete blocks. .
Zhao Yujing of Shanghai Baosteel New Building Materials Co., Ltd. used the theory of fracture toughness and fracture energy to study the influence of mineral admixtures on the brittleness of concrete. Mae'r prawf yn dangos y gall yr admixture mwynol wella caledwch torri ac egni torri asgwrn morter ychydig; in the case of the same type of admixture, the replacement amount of 40% of the mineral admixture is the most beneficial to the fracture toughness and fracture energy.
Xu Guangsheng of Henan University pointed out that when the specific surface area of the mineral powder is less than E350m2/l [g, the activity is low, the 3d strength is only about 30%, and the 28d strength develops to 0~90% ; while at 400m2 melon g, the 3d strength It can be close to 50%, and the 28d strength is above 95%. From the perspective of basic principles of rheology, according to the experimental analysis of mortar fluidity and flow velocity, several conclusions are drawn: fly ash content below 20% can effectively improve mortar fluidity and flow velocity, and mineral powder in When the dosage is below 25%, the fluidity of the mortar can be increased but the flow rate is reduced.
Zhang Jianxin of Chongqing University and others found that by comprehensive modification of methyl cellulose ether, polypropylene fiber, redispersible polymer powder, and admixtures, a dry-mixed plastering mortar with good performance can be prepared. Mae gan y morter plastro sy'n gwrthsefyll crac sy'n gwrthsefyll crac ymarferoldeb da, cryfder bond uchel ac ymwrthedd crac da. Mae ansawdd drymiau a chraciau yn broblem gyffredin.
Ren Chuanyao of Zhejiang University and others studied the effect of hydroxypropyl methylcellulose ether on the properties of fly ash mortar, and analyzed the relationship between wet density and compressive strength. It was found that adding hydroxypropyl methyl cellulose ether into fly ash mortar can significantly improve the water retention performance of mortar, prolong the bonding time of mortar, and reduce the wet density and compressive strength of mortar. There is a good correlation between wet density and 28d compressive strength. O dan gyflwr dwysedd gwlyb hysbys, gellir cyfrifo'r cryfder cywasgol 28D trwy ddefnyddio'r fformiwla ffitio.
1.5
1.6Prif gynnwys ymchwil y papur hwn
2. By adding cellulose ethers and various mineral admixtures to high fluidity mortar and bonding mortar, explore their effects on compressive strength, flexural strength, compression-folding ratio and bonding mortar of high fluidity mortar and plastic mortar The law of influence on the tensile bond cryfder.
Pennod 2 Dadansoddiad o ddeunyddiau crai a'u cydrannau ar gyfer profi
2.1 Deunyddiau Prawf
Dewiswyd y powdr slag ffwrnais chwyth gronynnog gradd $ 95 o Shandong Jinan Luxin New Building Materials Co, Ltd.
2.1.3 lludw hedfan (fa)
Dewisir y lludw hedfan gradd II a gynhyrchir gan orsaf bŵer Jinan Huangtai, y mân (rhidyll sy'n weddill o ridyll twll sgwâr 459m) yw 13%, a'r gymhareb galw dŵr yw 96%.
2.1.5 Powdwr Latecs Ailddarganfod (JF)
2.1.7 Admixtures Eraill
2.1,8 tywod cwarts
Y powdr polycarboxylate o Suzhou Xingbang Chemical Building Materials Co, Ltd.) yw 1J1030, a'r gyfradd lleihau dŵr yw 30%.
2.1.10 tywod (au)
Defnyddir tywod canolig Afon Dawen yn Tai'an.
2.1.11 Agregau bras (g)
2.2 Dull Prawf
2.2.1 Dull prawf ar gyfer hylifedd slyri
Mae'r dulliau a'r canlyniadau prawf yn cael eu cyfrif yn ôl y dull prawf ar gyfer hylifedd past sment yn Atodiad A o "GB 50119.2003 Manylebau Technegol ar gyfer Cymhwyso Admixtures Concrit" neu ((GB/T8077-2000 Dull Prawf ar gyfer Homogenedd Admixtures Concrit ).
2.2.2 Dull prawf ar gyfer hylifedd morter hylifedd uchel
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Peiriant Profi Cywasgu Morter TYE-2000B, a gynhyrchwyd gan Wuxi Jianyi Instrument Machinery Co., Ltd .;
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Pennod 3. Effaith Ether Cellwlos ar Gludo Pur a Morter Deunydd Smentitious Deuaidd amrywiol Admixtures Mwynau
3.1 Amlinelliad o'r protocol arbrofol
1. puree. Mae ganddo fanteision greddf, gweithrediad syml a chywirdeb uchel, ac mae'n fwyaf addas ar gyfer canfod gallu i addasu'r admixtures fel ether seliwlos i'r deunydd gelling, ac mae'r cyferbyniad yn amlwg.
3.2.1 Cynllun Prawf ar gyfer Effaith Ether Seliwlos ar Hylifedd Gludo Sment Pur
Aiming at the influence of cellulose ether on the fluidity of the pure slurry, the pure cement slurry of the one-component cementitious material system was first used to observe the influence. Mae'r prif fynegai cyfeirio yma yn mabwysiadu'r canfod hylifedd mwyaf greddfol.
2. Cynnwys Ether Cellwlos
3. Amser gorffwys slyri
3.2.2 Canlyniadau Prawf a Dadansoddiad o Effaith Ether Cellwlos ar Hylifedd Gludo Sment Pur
(1) Canlyniadau profion hylifedd past sment pur wedi'i gymysgu â CMC
Dadansoddiad o ganlyniadau profion:
Comparing the three groups with the same standing time, in terms of initial fluidity, with the addition of CMC, the initial fluidity decreased slightly; Gostyngodd yr hylifedd hanner awr yn fawr gyda'r dos, yn bennaf oherwydd hylifedd hanner awr y grŵp gwag. It is 20mm larger than the initial (this may be caused by the retardation of PC powder): -IJ, the fluidity decreases slightly at 0.1% dosage, and increases again at 0.2% dosage .
Comparing the three groups with the same dosage, the fluidity of the blank group was the largest in half an hour, and decreased in one hour (this may be due to the fact that after one hour, the cement particles appeared more hydration and adhesion, Ffurfiwyd y strwythur rhyng-ronynnau i ddechrau, ac roedd y slyri yn ymddangos yn fwy. the fluidity of C1 and C2 groups decreased slightly in half an hour, indicating that the water absorption of CMC had a certain impact on the state; while at the content of C2, there was a large increase in one hour, indicating that the content of The effect of the retardation effect of CMC is dominant.
It can be seen that with the increase of the content of CMC, the phenomenon of scratching begins to appear, indicating that CMC has a certain effect on increasing the viscosity of the cement paste, and the air-entraining effect of CMC causes the generation of swigod aer.
(2) Canlyniadau profion hylifedd past sment pur wedi'i gymysgu â HPMC (gludedd 100,000)
Dadansoddiad o ganlyniadau profion:
From the line graph of the effect of standing time on fluidity, it can be seen that the fluidity in half an hour is relatively large compared with the initial and one hour, and with the increase of the content of HPMC, the trend is weakened. At ei gilydd, nid yw colli hylifedd yn fawr, gan nodi bod gan HPMC gadw dŵr yn amlwg i'r slyri, a chael effaith arafu benodol.
It can be seen from the observation that the fluidity is extremely sensitive to the content of HPMC. In the experimental range, the larger the content of HPMC, the smaller the fluidity. Yn y bôn, mae'n anodd llenwi'r mowld côn hylif ar ei ben ei hun o dan yr un faint o ddŵr. Gellir gweld, ar ôl ychwanegu HPMC, nad yw'r golled hylifedd a achosir gan amser yn fawr ar gyfer y slyri pur.
Dadansoddiad o ganlyniadau profion:
As far as observation is concerned, according to the overall trend of the change of fluidity with time, the half-hour retarding effect of HPMC (150,000) is obvious, while the effect of -4, is worse than that of HPMC (100,000) .
3.3 Prawf Dylanwad Ether Cellwlos Ar Hylifedd Slyri Pur Deunyddiau Smentitious Aml-gydran
The fly ash and slag powder in the mineral admixture are replaced by the same amount of internal mixing method, and the mixing levels are 10%, 20% and 30%, that is, the replacement amount is 30g, 60g and 90g. Fodd bynnag, o ystyried dylanwad gweithgaredd uwch, crebachu a nodi, rheolir y cynnwys mygdarth silica i 3%, 6%, a 9%, hynny yw, 9G, 18G, a 27g.
3.3.1 Cynllun Prawf ar gyfer Effaith Ether Cellwlos ar Hylifedd Slyri Pur y Deunydd Cementious Deuaidd
(1) Canlyniadau profion hylifedd cychwynnol y deunydd deuaidd slyri pur wedi'i gymysgu â CMC ac admixtures mwynau amrywiol.
Gellir gweld y gellir cynyddu hylifedd cychwynnol y slyri pur ar dos isel o bowdr mwynol, ac nid yw gwella hylifedd yn amlwg mwyach pan fydd y dos yn uwch na 20%. Ar yr un pryd, faint o CMC yn O. Ar 1%, mae'r hylifedd ar y mwyaf.
Gellir gweld o hyn bod cynnwys mygdarth silica yn gyffredinol yn cael effaith negyddol sylweddol ar hylifedd cychwynnol y slyri. At the same time, CMC also slightly reduced the fluidity.
It can be seen that the improvement of the fluidity of fly ash for half an hour is relatively effective at low dosage, but it may also be because it is close to the flow limit of the pure slurry. Ar yr un pryd, mae gan CMC ostyngiad bach mewn hylifedd o hyd.
(2) Canlyniadau profion hylifedd cychwynnol y deunydd deuaidd slyri pur wedi'i gymysgu â HPMC (gludedd 100,000) ac amryw admixtures mwynau
From this, it can be seen that the reduction of the fluidity of silica fume is more obvious in the large dosage range, and in addition, the silica fume has obvious improvement effect on bleeding in the test. At the same time, HPMC has an obvious effect on the reduction of fluidity (especially in the range of high dosage (0.1% to 0.15%). In terms of the influencing factors of fluidity, silica fume and HPMC play a key role, and Arall mae'r admixture yn gweithredu fel addasiad bach ategol.
It can be seen that, in general, the effect of the three admixtures on the fluidity is similar to the initial value. Pan fydd y mygdarth silica mewn cynnwys uchel o 9% a chynnwys HPMC yn O. Yn achos 15%, roedd y ffenomen na ellid casglu'r data oherwydd cyflwr gwael y slyri , indicating that the viscosity of silica fume and HPMC increased significantly at higher dosages. Compared with CMC, the viscosity increasing effect of HPMC is very obvious.
From this, it can be seen that HPMC (150,000) and HPMC (100,000) have similar effects on the slurry, but HPMC with high viscosity has a slightly larger decrease in fluidity, but it is not obvious, which should be related to the dissolution of HPMC. Mae gan y cyflymder berthynas benodol. Among the admixtures, the effect of fly ash content on the fluidity of the slurry is basically linear and positive, and 30% of the content can increase the fluidity by 20,-,30mm; The effect is not obvious, and its improvement effect on bleeding is limited; even at a small dosage level of less than 10%, silica fume has a very obvious effect on reducing bleeding, and its specific surface area is nearly two times larger than that of cement. order of magnitude, the effect of its adsorption of water on the mobility is extremely significant.
Mae'r drydedd ran yn crynhoi dylanwad HPMC (150,000) ac admixtures ar hylifedd mwydion pur mewn hanner awr, sy'n gyffredinol yn debyg i gyfraith dylanwad y gwerth cychwynnol. It can be found that the increase of fly ash on the fluidity of pure slurry for half an hour is slightly more obvious than the increase of initial fluidity, the influence of slag powder is still not obvious, and the influence of silica fume content on fluidity yn dal yn amlwg iawn. In addition, in terms of the content of HPMC, there are many phenomena that cannot be poured out at high content, indicating that its O. 15% dosage has a significant effect on increasing viscosity and reducing fluidity, and in terms of fluidity for half Awr, o'i gymharu â'r gwerth cychwynnol, gostyngodd O. O. O. Gostyngodd hylifedd 05% HPMC yn amlwg.
3.4 Arbrawf ar effaith ether seliwlos ar hylifedd morter hylifedd uchel pur wedi'i seilio ar sment
3.4.1 Cynllun Prawf ar gyfer Effaith Ether Seliwlos ar Hylifedd Morter Ffeiliad Uchel Pur sy'n Sement Pur
Defnyddio morter hylifedd uchel i arsylwi ar ei effaith ar ymarferoldeb. Y prif fynegai cyfeirio yma yw'r prawf hylifedd morter cychwynnol a hanner awr.
1 math o etherau seliwlos,
2 dos o ether seliwlos,
3 Amser sefyll morter
3.4.2 Canlyniadau Profion a Dadansoddiad o Effaith Ether Cellwlos ar Hylifedd Morter Ffedwaith Uchel Pur sy'n Seiliedig ar Sment
Crynodeb a dadansoddiad o ganlyniadau profion:
Comparing the three groups with the same standing time, in terms of initial fluidity, with the addition of CMC, the initial fluidity decreased slightly, and when the content reached O. At 15%, there is a relatively obvious decrease; Mae ystod ostyngol yr hylifedd gyda chynnydd y cynnwys mewn hanner awr yn debyg i'r gwerth cychwynnol.
2. Symptom:
Theoretically speaking, compared with clean slurry, the incorporation of aggregates in mortar makes it easier for air bubbles to be entrained into the slurry, and the blocking effect of aggregates on bleeding voids will also make it easier for air bubbles or bleeding to be retained. In the slurry, therefore, the air bubble content and size of the mortar should be more and larger than that of the neat slurry. On the other hand, it can be seen that with the increase of the content of CMC, the fluidity decreases, indicating that CMC has a certain thickening effect on the mortar, and the half-hour fluidity test shows that the bubbles overflowing on the surface cynyddu ychydig. , which is also a manifestation of the rising consistency, and when the consistency reaches a certain level, the bubbles will be difficult to overflow, and no obvious bubbles will be seen on the surface.
(2) Canlyniadau profion hylifedd morter sment pur wedi'i gymysgu â HPMC (100,000)
Dadansoddiad o ganlyniadau profion:
Gellir gweld o'r ffigur, gyda chynnydd yng nghynnwys HPMC, bod yr hylifedd yn cael ei leihau'n fawr. O'i gymharu â CMC, mae HPMC yn cael effaith tewychu gryfach. The effect and water retention are better. From 0.05% to 0.1%, the range of fluidity changes is more obvious, and from O. After 1%, neither the initial nor half-hour change in fluidity is too large.
Dadansoddiad o ganlyniadau profion:
3.5.
Mae morter hylifedd uchel yn dal i gael ei ddefnyddio i arsylwi ar ei ddylanwad ar hylifedd. Y prif ddangosyddion cyfeirio yw'r canfod hylifedd morter cychwynnol a hanner awr.
(1) Cynllun Prawf Hylifedd Morter gyda Deunyddiau Smentitious Deuaidd wedi'u Cymysgu â CMC ac Admixtures Mwynau Amrywiol
(1) Canlyniadau profion hylifedd cychwynnol morter smentitious deuaidd wedi'i gymysgu â CMC ac amrywiol admixtures
O ganlyniadau profion hylifedd cychwynnol, gellir dod i'r casgliad y gall ychwanegu lludw hedfan wella hylifedd morter ychydig; Pan fydd cynnwys powdr mwynol yn 10%, gellir gwella hylifedd morter ychydig; ac mae mygdarth silica yn cael mwy o effaith ar hylifedd, yn enwedig yn yr ystod o amrywiad cynnwys 6% ~ 9%, gan arwain at ostyngiad mewn hylifedd o tua 90mm.
Canlyniadau Prawf Hylif Hanner Awr o Forter Smentitious Deuaidd wedi'u Cymysgu â CMC ac Admixtures Amrywiol
From the test results of the fluidity in half an hour, it can be concluded that the effect of the content of admixture and CMC is similar to the initial one, but the content of CMC in the mineral powder group changes from O. 1% to O. Mae'r newid 2% yn fwy, ar 30mm.
In terms of the loss of fluidity over time, fly ash has the effect of reducing the loss, while the mineral powder and silica fume will increase the loss value under high dosage. Mae'r dos 9% o fume silica hefyd yn achosi i'r mowld prawf beidio â chael ei lenwi ynddo'i hun. , the fluidity cannot be accurately measured.
Canlyniadau Prawf Hylif Hanner Awr o Forter Smentitious Deuaidd wedi'i gymysgu â HPMC (gludedd 100,000) ac amryw admixtures
It can still be concluded through experiments that the addition of fly ash can slightly improve the fluidity of mortar; Pan fydd cynnwys powdr mwynol yn 10%, gellir gwella hylifedd morter ychydig; The dosage is very sensitive, and the HPMC group with high dosage at 9% has dead spots, and the fluidity basically disappears.
The content of cellulose ether and silica fume are also the most obvious factors affecting the fluidity of mortar. Mae effaith HPMC yn amlwg yn fwy nag effaith CMC. Gall admixtures eraill wella colli hylifedd dros amser.
(3) Canlyniadau profion hylifedd cychwynnol morter smentitious deuaidd wedi'i gymysgu â HPMC (gludedd o 150,000) ac amrywiol admixtures
Canlyniadau Prawf Hylif Hanner Awr Morter Smentitious Deuaidd wedi'u Cymysgu â HPMC (Gludedd 150,000) ac Admixtures Amrywiol
Gellir dod i'r casgliad o hyd trwy arbrofion y gall ychwanegu lludw hedfan wella hylifedd morter ychydig; when the content of mineral powder is 10%, the fluidity of mortar can be slightly improved: silica fume is still very effective in solving the bleeding phenomenon, while the Fluidity is a serious side effect, but is less effective than its effect in clean slurries .
A large number of dead spots appeared under the high content of cellulose ether (especially in the table of half-hour fluidity), indicating that HPMC has a significant effect on reducing the fluidity of mortar, and mineral powder and fly ash can improve the loss o hylifedd dros amser.
3.5 Crynodeb y Bennod
1. Gan gymharu prawf hylifedd past sment pur yn gynhwysfawr wedi'i gymysgu â thri ether seliwlos, gellir gweld hynny
2. The water retention effect of HPMC is obvious, and it has a significant influence on the state, and the fluidity decreases significantly with the increase of the content. Mae'n cael effaith benodol i gael aer, ac mae'r tewychu yn amlwg. Bydd 15% yn achosi swigod mawr yn y slyri, sy'n sicr o fod yn niweidiol i'r cryfder. Gyda'r cynnydd o gludedd HPMC, cynyddodd colli hylifedd slyri sy'n dibynnu ar amser ychydig, ond nid yn amlwg.
1. The influence law of the three cellulose ethers on the fluidity of the slurry of the binary cementitious system of various mineral admixtures has the characteristics similar to the influence law of the fluidity of the pure cement slurry. Nid yw CMC yn cael fawr o effaith ar reoli gwaedu, ac mae'n cael effaith wan ar leihau hylifedd; Gall dau fath o HPMC gynyddu gludedd slyri a lleihau hylifedd yn sylweddol, ac mae'r un â gludedd uwch yn cael effaith fwy amlwg.
4. O ran colli hylifedd hanner awr, mae gwerth colli lludw hedfan yn llai, ac mae gwerth colli'r grŵp sy'n ymgorffori mygdarth silica yn fwy.
5. In the respective variation range of the content, the factors affecting the fluidity of the slurry, the content of HPMC and silica fume are the primary factors, whether it is the control of the bleeding or the control of the flow state, it is yn gymharol amlwg. The influence of mineral powder and mineral powder is secondary, and plays an auxiliary adjustment role.
3. Yn cynhwysfawr o gymharu prawf hylifedd morter sment pur wedi'i gymysgu â thri ether seliwlos, gellir gweld hynny
Fel y gwelir:
1. The influence law of three cellulose ethers on the fluidity of multi-component cementitious material mortar is similar to the influence law on the fluidity of pure slurry. Nid yw CMC yn cael fawr o effaith ar reoli gwaedu, ac mae'n cael effaith wan ar leihau hylifedd; two kinds of HPMC can increase the viscosity of mortar and reduce fluidity significantly, and the one with higher viscosity has a more obvious effect.
2. Ymhlith yr admixtures, mae gan ludw hedfan rywfaint o welliant ar hylifedd cychwynnol a hanner awr y slyri glân; Nid oes rheoleidd -dra amlwg i ddylanwad powdr slag ar hylifedd y slyri glân; although the content of silica fume is low, its The unique ultra-fineness, fast reaction and strong adsorption make it have a great reduction effect on the fluidity of the slurry. Fodd bynnag, o'i gymharu â chanlyniadau profion past pur, canfyddir bod effaith admixtures yn tueddu i wanhau.
5. Bydd swigod ar wyneb y morter gyda hylifedd o fwy na 250mm, ond yn gyffredinol nid oes gan y grŵp gwag heb ether seliwlos swigod na dim ond ychydig bach o swigod, sy'n dangos bod gan ether seliwlos aer-entraining penodol effect and makes the slurry viscous. In addition, due to the excessive viscosity of the mortar with poor fluidity, it is difficult for the air bubbles to float up by the self-weight effect of the slurry, but is retained in the mortar, and its influence on the strength cannot be ignored.
Pennod 4 Effeithiau etherau seliwlos ar briodweddau mecanyddol morter
4.1 Prawf Cryfder Cywasgol a Flexural Morter Hylif Uchel
4.1.1 Prawf Dylanwad ar gryfder cywasgol a flexural morter hylifedd uchel sy'n seiliedig ar sment pur
Early strength analysis: In terms of flexural strength, CMC has a certain strengthening effect, while HPMC has a certain reducing effect; O ran cryfder cywasgol, mae gan ymgorffori ether seliwlos gyfraith debyg â'r cryfder flexural; Mae gludedd HPMC yn effeithio ar y ddau gryfder. Nid yw'n cael fawr o effaith: o ran y gymhareb plygu pwysau, gall y tri ether seliwlos leihau'r gymhareb plygu pwysau yn effeithiol a gwella hyblygrwydd y morter. Among them, HPMC with a viscosity of 150,000 has the most obvious effect.
(2) Canlyniadau profion cymharu cryfder saith diwrnod
Seven-day strength analysis: In terms of flexural strength and compressive strength, there is a similar law to the three-day strength. Compared with the three-day pressure-folding, there is a slight increase in the pressure-folding strength. Fodd bynnag, gall cymhariaeth data'r un cyfnod oedran weld effaith HPMC ar leihau'r gymhareb plygu pwysau. yn gymharol amlwg.
(3) wyth ar hugain diwrnod o ganlyniadau profion cymharu cryfder
Dadansoddiad cryfder wyth ar hugain diwrnod: O ran cryfder flexural a chryfder cywasgol, mae deddfau tebyg i'r cryfder tridiau. Mae'r cryfder flexural yn cynyddu'n araf, ac mae'r cryfder cywasgol yn dal i gynyddu i raddau. Mae cymhariaeth data'r un cyfnod oedran yn dangos bod HPMC yn cael effaith fwy amlwg ar wella'r gymhareb plygu cywasgu.
4.1.2 Prawf Dylanwad o Gryfder Cywasgol a Flexural Admixture Mwynau Morter Hylif Uchel
According to the test of the fluidity of pure slurry and mortar mixed with admixtures in the previous chapter, it can be seen that the fluidity of silica fume is obviously deteriorated due to the large water demand, although it can theoretically improve the density and strength to i raddau. , especially the compressive strength, but it is easy to cause the compression-to-fold ratio to be too large, which makes the mortar brittleness feature remarkable, and it is a consensus that silica fume increases the shrinkage of the mortar. At the same time, due to the lack of skeleton shrinkage of coarse aggregate, the shrinkage value of mortar is relatively large relative to concrete. For mortar (especially special mortar such as bonding mortar and plastering mortar), the biggest harm is often shrinkage. For cracks caused by water loss, strength is often not the most critical factor. Therefore, silica fume was discarded as the admixture, and only fly ash and mineral powder were used to explore the effect of its composite effect with cellulose ether on the strength.
In this experiment, the proportion of mortar in 4.1.1 was used, and the content of cellulose ether was fixed at 0.1% and compared with the blank group. Lefel dos y prawf admixture yw 0%, 10%, 20%a 30%.
4.1.2.2 Canlyniadau Profion Cryfder Cywasgol a Flexural a Dadansoddiad o Forter Hylif Uchel
It can be seen from the compressive strength test value that the 3d compressive strength after adding HPMC is about 5/VIPa lower than that of the blank group. Yn gyffredinol, gyda'r cynnydd yn faint o admixture a ychwanegir, mae'r cryfder cywasgol yn dangos tuedd sy'n lleihau. . In terms of admixtures, the strength of the mineral powder group without HPMC is the best, while the strength of the fly ash group is slightly lower than that of the mineral powder group, indicating that the mineral powder is not as active as the cement, and its incorporation will slightly reduce the early strength of the system. The fly ash with poorer activity reduces the strength more obviously. The reason for the analysis should be that the fly ash mainly participates in the secondary hydration of cement, and does not contribute significantly to the early strength of the mortar.
It can be seen from the flexural strength test values that HPMC still has an adverse effect on the flexural strength, but when the content of the admixture is higher, the phenomenon of reducing the flexural strength is no longer obvious. Efallai mai'r rheswm yw effaith cadw dŵr HPMC. The water loss rate on the surface of the mortar test block is slowed down, and the water for hydration is relatively sufficient.
It can be seen that for the compressive strength of 7d, the adverse effects of the admixtures are no longer obvious. The compressive strength values are roughly the same at each admixture dosage level, and HPMC still has a relatively obvious disadvantage on the compressive strength. effaith.
Gellir gweld bod yr admixture yn cael effaith andwyol o ran y gymhareb indentation. With the increase of the amount of the admixture, the indentation ratio gradually increases, that is, the mortar is brittle. Yn amlwg, gall HPMC leihau'r gymhareb gwaith cywasgu a gwella disgleirdeb morter.
It can be seen that from the 28d compressive strength, the admixture has played a more obvious beneficial effect on the later strength, and the compressive strength has been increased by 3-5MPa, which is mainly due to the micro-filling effect of the admixture and the pozzolanic substance. The secondary hydration effect of the material, on the one hand, can utilize and consume the calcium hydroxide produced by cement hydration (calcium hydroxide is a weak phase in the mortar, and its enrichment in the interface transition zone is detrimental to the strength), Mae cynhyrchu mwy o gynhyrchion hydradiad, ar y llaw arall, yn hyrwyddo gradd hydradiad sment a gwneud y morter yn fwy trwchus. Mae HPMC yn dal i gael effaith andwyol sylweddol ar y cryfder cywasgol, a gall y cryfder gwanhau gyrraedd mwy na 10MPA. Er mwyn dadansoddi'r rhesymau, mae HPMC yn cyflwyno rhywfaint o swigod aer yn y broses gymysgu morter, sy'n lleihau crynoder y corff morter. Dyma un rheswm. Mae HPMC yn hawdd ei adsorbed ar wyneb gronynnau solet i ffurfio ffilm, gan rwystro'r broses hydradiad, ac mae'r parth trosglwyddo rhyngwyneb yn wannach, nad yw'n ffafriol i gryfder.
Gellir gweld, o safbwynt y gymhareb lleihau cywasgiad, bod HPMC yn gyffredinol o fudd i leihau'r gymhareb lleihau cywasgu a gwella caledwch y morter. Mewn un grŵp, gyda'r cynnydd yn faint o admixtures, mae'r gymhareb ail-adolygu cywasgu yn cynyddu. Analysis of the reasons shows that the admixture has obvious improvement in the later compressive strength, but limited improvement in the later flexural strength, resulting in the compression-refraction ratio. gwelliant.
4.2 Profion Cryfder Cywasgol a Flexural o Fortar wedi'i Bondio
In order to explore the influence of cellulose ether and admixture on the compressive and flexural strength of bonded mortar, the experiment fixed the content of cellulose ether HPMC (viscosity 100,000) as 0.30% of the dry weight of the mortar. ac o'i gymharu â'r grŵp gwag.
It can be seen from the experiment that HPMC is obviously unfavorable in terms of the 28d compressive strength of the bonding mortar, which will cause the strength to decrease by about 5MPa, but the key indicator for judging the quality of the bonding mortar is not the cryfder cywasgol, felly mae'n dderbyniol; Pan fydd y cynnwys cyfansawdd yn 20%, mae'r cryfder cywasgol yn gymharol ddelfrydol.
Gellir gweld o'r arbrawf, o safbwynt cryfder flexural, nad yw'r gostyngiad cryfder a achosir gan HPMC yn fawr. Efallai bod gan y morter bondio hylifedd gwael a nodweddion plastig amlwg o'i gymharu â morter hylif uchel. The positive effects of slipperiness and water retention effectively offset some of the negative effects of introducing gas to reduce compactness and interface weakening; Nid yw admixtures yn cael unrhyw effaith amlwg ar gryfder flexural, ac mae data grŵp lludw hedfan yn amrywio ychydig.
Gellir gweld o'r arbrofion, cyn belled ag y mae'r gymhareb lleihau pwysau yn y cwestiwn, yn gyffredinol, mae cynnydd y cynnwys admixture yn cynyddu'r gymhareb lleihau pwysau, sy'n anffafriol i galedwch y morter; HPMC has a favorable effect, which can reduce the pressure-reduction ratio by O. 5 above, it should be pointed out that, according to "JG 149.2003 Expanded Polystyrene Board Thin Plaster External Wall External Insulation System", there is generally no mandatory requirement for the compression-folding ratio in the detection index of the bonding mortar, and the compression-folding ratio is mainly It is used to limit the brittleness of the plastering mortar, and this index is only used as a reference for the flexibility of the bonding morter.
In order to explore the influence law of the composite application of cellulose ether and admixture on the bond strength of bonded mortar, refer to "JG/T3049.1998 Putty for Building Interior" and "JG 149.2003 Expanded Polystyrene Board Thin Plastering Exterior Walls" Insulation System ", gwnaethom gynnal prawf cryfder bond y morter bondio, gan ddefnyddio'r gymhareb morter bondio yn Nhabl 4.2.1, a thrwsio cynnwys ether seliwlos HPMC (gludedd 100,000) i 0 o bwysau sych y morter .30% , a'i gymharu â'r grŵp gwag.
4.3.1 Cynllun Prawf Cryfder Bond Morter Bond
4.3.2 Canlyniadau Prawf a Dadansoddiad o Gryfder Bond Morter Bond
It can be seen from the experiment that the groups added with HPMC are significantly better than the blank group, indicating that HPMC is beneficial to the bonding strength, mainly because the water retention effect of HPMC protects the water at the bonding interface between the mortar and Y bloc prawf morter sment. The bonding mortar at the interface is fully hydrated, thereby increasing the bond strength.
(2) Canlyniadau profion cryfder bond 14D o forter bondio a bwrdd polystyren estynedig
4.4 Crynodeb o'r Bennod
1. For high fluidity mortar, with the increase of age, the compressive-fold ratio has an upward trend; the incorporation of HPMC has an obvious effect of reducing the strength (the decrease in the compressive strength is more obvious), which also leads to The decrease of the compression-folding ratio, that is, HPMC has obvious help to the improvement of mortar toughness . In terms of three-day strength, fly ash and mineral powder can make a slight contribution to the strength at 10%, while the strength decreases at high dosage, and the crushing ratio increases with the increase of mineral admixtures; in the seven-day strength, The two admixtures have little effect on the strength, but the overall effect of fly ash strength reduction is still obvious; O ran y cryfder 28 diwrnod, mae'r ddau admixtures wedi cyfrannu at gryfder, cywasgol a chryfder ystwyth. Both were slightly increased, but the pressure-fold ratio still increased with the increase of the content.
Pennod 5 Dull ar gyfer darogan cryfder cywasgol morter a choncrit
5.1 Theori Cryfder Feret
The advantage of this formula is that the grout concentration, which correlates with concrete strength, has a well-defined physical meaning. Ar yr un pryd, mae dylanwad cynnwys aer yn cael ei ystyried, a gellir profi cywirdeb y fformiwla yn gorfforol. Y rhesymeg dros y fformiwla hon yw ei bod yn mynegi gwybodaeth bod cyfyngiad ar y cryfder concrit y gellir ei gael. Yr anfantais yw ei fod yn anwybyddu dylanwad maint gronynnau agregau, siâp gronynnau a math agregau. When predicting the strength of concrete at different ages by adjusting the K value, the relationship between different strength and age is expressed as a set of divergences through the coordinate origin. The curve is inconsistent with the actual situation (especially when the age is longer). Of course, this formula proposed by Feret is designed for the mortar of 10.20MPa. It cannot fully adapt to the improvement of concrete compressive strength and the influence of increasing components due to the progress of mortar concrete technology.
It is considered here that the strength of concrete (especially for ordinary concrete) mainly depends on the strength of the cement mortar in the concrete, and the strength of the cement mortar depends on the density of the cement paste, that is, the volume percentage o'r deunydd smentitious yn y past.
The theory is closely related to the effect of void ratio factor on strength. However, because the theory was put forward earlier, the influence of admixture components on concrete strength was not considered. O ystyried hyn, bydd y papur hwn yn cyflwyno'r cyfernod dylanwad admixture yn seiliedig ar y cyfernod gweithgaredd ar gyfer cywiro rhannol. At the same time, on the basis of this formula, an influence coefficient of porosity on concrete strength is reconstructed.
5.2 Cyfernod Gweithgaredd
The activity coefficient, Kp, is used to describe the effect of pozzolanic materials on the compressive strength. Obviously, it depends on the nature of the pozzolanic material itself, but also on the age of the concrete. The principle of determining the activity coefficient is to compare the compressive strength of a standard mortar with the compressive strength of another mortar with pozzolanic admixtures and replacing the cement with the same amount of cement quality (the country p is the activity coefficient test. Use surrogate canrannau). The ratio of these two intensities is called the activity coefficient fO), where t is the age of the mortar at the time of testing. If fO) is less than 1, the activity of pozzolan is less than that of cement r. Conversely, if fO) is greater than 1, the pozzolan has a higher reactivity (this usually happens when silica fume is added).
Generally, granulated blast furnace slag powder Kp=0.95～1.10, fly ash Kp=0.7-1.05, silica fume Kp=1.00～1.15. Rydym yn cymryd yn ganiataol bod ei effaith ar gryfder yn annibynnol ar sment. Hynny yw, dylid rheoli mecanwaith yr adwaith pozzolanig gan adweithedd y pozzolan, nid gan gyfradd dyodiad calch hydradiad sment.
5.3 Dylanwadu ar Gyfernod Admixture ar Gryfder
5.4 Dylanwadu ar gyfernod y defnydd o ddŵr ar gryfder
5.5 Dylanwadu ar gyfernod cyfansoddiad agregau ar gryfder
According to the views of professors PK Mehta and PC Aitcin in the United States, in order to achieve the best workability and strength properties of HPC at the same time, the volume ratio of cement slurry to aggregate should be 35:65 [4810] Because of the general plasticity and fluidity The total amount of aggregate of concrete does not change much. Cyn belled â bod cryfder y deunydd sylfaen agregau ei hun yn cwrdd â gofynion y fanyleb, anwybyddir dylanwad cyfanswm yr agreg ar y cryfder, a gellir pennu'r ffracsiwn annatod cyffredinol o fewn 60-70% yn unol â gofynion y cwymp .
It is theoretically believed that the ratio of coarse and fine aggregates will have a certain influence on the strength of concrete. As we all know, the weakest part in concrete is the interface transition zone between aggregate and cement and other cementitious material pastes. Therefore, the final failure of common concrete is due to the initial damage of the interface transition zone under stress caused by factors such as load or temperature change. caused by the continuous development of cracks. Therefore, when the degree of hydration is similar, the larger the interface transition zone is, the easier the initial crack will develop into a long through crack after stress concentration. That is to say, the more coarse aggregates with more regular geometric shapes and larger scales in the interface transition zone, the greater the stress concentration probability of the initial cracks, and the macroscopically manifested that the concrete strength increases with the increase of the coarse aggregate cymhareb. lleihau. However, the above premise is that it is required to be medium sand with very little mud content.
Mae gan y gyfradd tywod ddylanwad penodol hefyd ar y cwymp. Felly, gall y gyfradd tywod gael ei rhagosod yn ôl y gofynion cwymp, a gellir ei phennu o fewn 32% i 46% ar gyfer concrit cyffredin.
Mae maint ac amrywiaeth admixtures ac admixtures mwynau yn cael eu pennu gan gymysgedd treial. In ordinary concrete, the amount of mineral admixture should be less than 40%, while in high-strength concrete, silica fume should not exceed 10%. Ni ddylai faint o sment fod yn fwy na 500kg/m3.
Y sment yw E042.5 sment a gynhyrchir gan Lubi Cement Factory, Laiwu City, Talaith Shandong, a'i ddwysedd yw 3.19/cm3;
Mae'r lludw hedfan yn lludw pêl gradd II a gynhyrchir gan orsaf bŵer Jinan Huangtai, a'i gyfernod gweithgaredd yw O. 828, ei ddwysedd yw 2.59/cm3;
Mae gan dywod afon sych Taian ddwysedd o 2.6 g/cm3, dwysedd swmp o 1480kg/m3, a modwlws mân o MX = 2.8;
Mae Jinan Ganggou yn cynhyrchu carreg falu sych 5-'25mm gyda dwysedd swmp o 1500kg/m3 a dwysedd o tua 2.7∥cm3;
The water-reducing agent used is a self-made aliphatic high-efficiency water-reducing agent, with a water-reducing rate of 20%; the specific dosage is determined experimentally according to the requirements of slump. Paratoi treial o goncrit C30, mae'n ofynnol i'r cwymp fod yn fwy na 90mm.
2. Ansawdd Tywod
3. Penderfynu ar ffactorau dylanwad pob dwyster
4. Gofynnwch am y defnydd o ddŵr
5. Mae'r dos o asiant lleihau dŵr yn cael ei addasu yn unol â gofyniad cwymp. Y dos yw 1%, ac mae ma = 4kg yn cael ei ychwanegu at yr offeren.
7. Ar ôl cymysgu treial, gall fodloni'r gofynion cwymp. Y cryfder cywasgol 28D mesuredig yw 39.32MPA, sy'n cwrdd â'r gofynion.
1 Cyfernod Dylanwad Admixture Concrit
3 Dylanwadwch ar gyfernod cyfansoddiad agregau
4 Cymhariaeth wirioneddol. Gwirir bod y dull rhagfynegiad cryfder 28D o goncrit wedi'i wella gan y cyfernod gweithgaredd a theori cryfder Feret yn cytuno'n dda â'r sefyllfa wirioneddol, a gellir ei defnyddio i arwain paratoi morter a choncrit.
Pennod 6 Casgliad a Rhagolwg
2. Among the admixtures, the initial and half-hour fluidity of fly ash on the clean slurry and mortar has been improved to a certain extent. The 30% content of the clean slurry test can be increased by about 30mm; hylifedd y powdr mwynol ar y slyri glân a'r morter nid oes rheol ddylanwad amlwg; Er bod cynnwys mygdarth silica yn isel, mae ei ultra-pennau unigryw, adwaith cyflym, ac arsugniad cryf yn gwneud iddo gael effaith ostyngol sylweddol ar hylifedd slyri glân a morter, yn enwedig wrth ei gymysgu â 0.15 pan %hpmc, bydd yna Ffenomen na ellir llenwi'r côn marw. O'i gymharu â chanlyniadau profion y slyri glân, darganfyddir bod effaith yr admixture yn y prawf morter yn tueddu i wanhau. O ran rheoli gwaedu, nid yw lludw hedfan a phowdr mwynol yn amlwg. Gall mygdarth silica leihau faint o waedu yn sylweddol, ond nid yw'n ffafriol i leihau hylifedd a cholled morter dros amser, ac mae'n hawdd lleihau'r amser gweithredu.
Rhan II Priodweddau Mecanyddol Morter
1. Ar gyfer morter hylifedd uchel, gyda'r cynnydd mewn oedran, mae tuedd ar i fyny ar y gymhareb falu; the addition of HPMC has a significant effect of reducing the strength (the decrease in the compressive strength is more obvious), which also leads to the crushing The decrease of the ratio, that is, HPMC has obvious help to the improvement of mortar toughness. In terms of three-day strength, fly ash and mineral powder can make a slight contribution to the strength at 10%, while the strength decreases at high dosage, and the crushing ratio increases with the increase of mineral admixtures; in the seven-day strength, The two admixtures have little effect on the strength, but the overall effect of fly ash strength reduction is still obvious; O ran y cryfder 28 diwrnod, mae'r ddau admixtures wedi cyfrannu at gryfder, cywasgol a chryfder ystwyth. Cynyddwyd y ddau ychydig, ond roedd y gymhareb plygu pwysau yn dal i gynyddu gyda chynnydd y cynnwys.
2. Ar gyfer cryfder cywasgol a flexural 28D y morter wedi'i fondio, pan fydd y cynnwys admixture yn 20%, mae'r cryfderau cywasgol ac ystwythol yn well, ac mae'r admixture yn dal i arwain at gynnydd bach yn y gymhareb cywasgol-i-blygu, gan adlewyrchu ei effect on the mortar. Adverse effects of toughness; HPMC leads to a significant decrease in strength.
3. Regarding the bond strength of bonded mortar, HPMC has a certain favorable effect on the bond strength. The analysis should be that its water retention effect reduces the loss of water in the mortar and ensures more sufficient hydration. The bond strength is related to the admixture. Nid yw'r berthynas rhwng y dos yn rheolaidd, ac mae'r perfformiad cyffredinol yn well gyda morter sment pan fydd y dos yn 10%.
4. Nid yw CMC yn addas ar gyfer deunyddiau smentitious sy'n seiliedig ar sment, nid yw ei effaith cadw dŵr yn amlwg, ac ar yr un pryd, mae'n gwneud y morter yn fwy brau; while HPMC can effectively reduce the compression-to-fold ratio and improve the toughness of mortar, but it is at the expense of a substantial reduction in compressive strength.
cael effaith annibynnol.
1. Cyfernod dylanwadu Mineral
3. Ffactor dylanwadu ar gyfansoddiad agregau
This paper mainly studies the fluidity and mechanical properties of the clean paste and mortar of the binary cementitious system. The effect and influence of the joint action of multi-component cementitious materials need to be further studied. In the test method, mortar consistency and stratification can be used. Astudir effaith ether seliwlos ar gysondeb a chadw dŵr morter yn ôl graddfa ether seliwlos. In addition, the microstructure of mortar under the compound action of cellulose ether and mineral admixture is also to be studied.
Mae ether cellwlos bellach yn un o gydrannau admixture anhepgor gwahanol forterau. Mae ei effaith cadw dŵr da yn ymestyn amser gweithredu'r morter, yn gwneud i'r morter gael thixotropi da, ac yn gwella caledwch y morter. It is convenient for construction; and the application of fly ash and mineral powder as an industrial waste in mortar can also create great economic and environmental benefits
1.1
Yn niwydiant deunyddiau adeiladu fy ngwlad, mae concrit wedi cyflawni lefel uchel o fasnacheiddio, ac mae masnacheiddio morter hefyd yn mynd yn uwch ac yn uwch, yn enwedig ar gyfer morterau arbennig amrywiol, mae angen gweithgynhyrchwyr sydd â galluoedd technegol uwch i sicrhau'r gwahanol forterau. The performance indicators are qualified. Commercial mortar is divided into two categories: ready-mixed mortar and dry-mixed mortar. Mae morter cymysg parod yn golygu bod y morter yn cael ei gludo i'r safle adeiladu ar ôl cael ei gymysgu â dŵr gan y cyflenwr ymlaen llaw yn unol â gofynion y prosiect, tra bod y gwneuthurwr morter â chymysgedd sych yn cael ei wneud gan y gwneuthurwr morter trwy gymysgu sych a phecynnu deunyddiau smentitious, aggregates and additives according to a certain ratio. Add a certain amount of water to the construction site and mix it before use.
Traditional mortar has many weaknesses in use and performance. For example, the stacking of raw materials and on-site mixing cannot meet the requirements of civilized construction and environmental protection. In addition, due to on-site construction conditions and other reasons, it is easy to make the quality of mortar difficult to guarantee, and it is impossible to obtain high performance. morter. Compared with traditional mortar, commercial mortar has some obvious advantages. First of all, its quality is easy to control and guarantee, its performance is superior, its types are refined, and it is better targeted to engineering requirements. European dry-mixed mortar has been developed in the 1950s, and my country is also vigorously advocating the application of commercial mortar. Shanghai has already used commercial mortar in 2004. With the continuous development of my country's urbanization process, at least in the urban market, it will be inevitable that commercial mortar with various advantages will replace traditional mortar.
Although commercial mortar has many advantages over traditional mortar, there are still many technical difficulties as mortar. High fluidity mortar, such as reinforcement mortar, cement-based grouting materials, etc., have extremely high requirements on strength and work performance, so the use of superplasticizers is large, which will cause serious bleeding and affect the mortar. Comprehensive performance; and for some plastic mortars, because they are very sensitive to the loss of water, it is easy to have a serious decrease in workability due to the loss of water in a short time after mixing, and the operation time is extremely short: In addition, for In terms of bonding mortar, the bonding matrix is often relatively dry. During the construction process, due to the insufficient ability of the mortar to retain water, a large amount of water will be absorbed by the matrix, resulting in local water shortage of the bonding mortar and insufficient hydration. Mae'r ffenomen y mae'r cryfder yn lleihau a'r grym gludiog yn lleihau.
In response to the above questions, an important additive, cellulose ether, is widely used in mortar. As a kind of etherified cellulose, cellulose ether has affinity for water, and this polymer compound has excellent water absorption and water retention ability, which can well solve the bleeding of mortar, short operation time, stickiness, etc. Insufficient knot strength and many other problemau.
In addition, admixtures as partial substitutes for cement, such as fly ash, granulated blast furnace slag powder (mineral powder), silica fume, etc., are now more and more important. Gwyddom fod y rhan fwyaf o'r admixtures yn sgil-gynhyrchion diwydiannau fel pŵer trydan, mwyndoddi dur, mwyndoddi ferrosilicon a silicon diwydiannol. If they cannot be fully utilized, the accumulation of admixtures will occupy and destroy a large amount of land and cause serious damage. environmental pollution. On the other hand, if admixtures are used reasonably, some properties of concrete and mortar can be improved, and some engineering problems in the application of concrete and mortar can be well solved. Felly, mae cymhwysiad eang admixtures yn fuddiol i'r amgylchedd a'r diwydiant. yn fuddiol.
1.2Etherau cellwlos
Mae ether cellwlos (ether seliwlos) yn gyfansoddyn polymer gyda strwythur ether a gynhyrchir trwy etheriad seliwlos. Mae pob cylch glucosyl mewn macromoleciwlau seliwlos yn cynnwys tri grŵp hydrocsyl, grŵp hydrocsyl cynradd ar y chweched atom carbon, grŵp hydrocsyl eilaidd ar yr ail a'r trydydd atomau carbon, ac mae'r hydrogen yn y grŵp hydrocsyl yn cael ei ddisodli gan grŵp hydrocarbon i gynhyrchu ether seliwlos hydrocarbon deilliadau. thing. Mae cellwlos yn gyfansoddyn polymer polyhydroxy nad yw'n hydoddi nac yn toddi, ond gellir toddi seliwlos mewn dŵr, gwanhau toddiant alcali a thoddydd organig ar ôl etheriad, ac mae ganddo thermoplastigedd penodol.
Mae ether cellwlos yn cymryd seliwlos naturiol fel deunydd crai ac yn cael ei baratoi trwy addasu cemegol. Fe'i dosbarthir yn ddau gategori: ïonig a di-ïonig ar ffurf ïoneiddiedig. It is widely used in chemical, petroleum, construction, medicine, ceramics and other industries. .
Dosbarthu etherau seliwlos ar gyfer adeiladu
3. According to different solubility, it is divided into water-soluble (such as hydroxyethyl cellulose) and organic solvent solubility (such as ethyl cellulose), etc. The main application type in dry-mixed mortar is water-soluble cellulose, while water -Suluble Cellwlos mae wedi'i rannu'n fath ar unwaith ac oedi math diddymu ar ôl triniaeth ar yr wyneb.
1. Ar ôl i'r ether seliwlos yn y morter gael ei doddi mewn dŵr, mae'r gweithgaredd arwyneb unigryw yn sicrhau bod y deunydd smentitious yn cael ei wasgaru'n effeithiol ac yn unffurf yn y system slyri, a gall ether seliwlos, fel colloid amddiffynnol, “grynhoi” gronynnau solet, felly , a lubricating film is formed on the outer surface, and the lubricating film can make the mortar body have good thixotropy. Hynny yw, mae'r gyfrol yn gymharol sefydlog yn y cyflwr sefydlog, ac ni fydd ffenomenau niweidiol fel gwaedu neu haenu sylweddau golau a thrwm, sy'n gwneud y system morter yn fwy sefydlog; Tra yn y cyflwr adeiladu cynhyrfus, bydd yr ether seliwlos yn chwarae rôl wrth leihau cneifio'r slyri. Mae effaith ymwrthedd newidiol yn golygu bod gan y morter hylifedd a llyfnder da yn ystod y gwaith adeiladu yn ystod y broses gymysgu.
After the refined cotton is treated with alkali, methyl chloride is used as the etherifying agent to make cellulose ether through a series of reactions. The general substitution degree is 1. Melting 2.0, the degree of substitution is different and the solubility is also different. Yn perthyn i ether seliwlos nad yw'n ïonig.
2. Cellwlos hydroxyethyl (HEC)
It is prepared by reacting with ethylene oxide as an etherifying agent in the presence of acetone after the refined cotton is treated with alkali. The degree of substitution is generally 1.5 to 2.0. Mae ganddo hydrophilicity cryf ac mae'n hawdd ei amsugno lleithder.
Mae hydroxypropyl methylcellulose yn amrywiaeth seliwlos y mae ei allbwn a'i ddefnydd yn cynyddu'n gyflym yn ystod y blynyddoedd diwethaf. It is a non-ionic cellulose mixed ether made from refined cotton after alkali treatment, using propylene oxide and methyl chloride as etherifying agents, and through a series of reactions. The degree of substitution is generally 1.2 to 2.0. Mae ei briodweddau'n amrywio yn ôl cymhareb cynnwys methoxyl a chynnwys hydroxypropyl.
4. Carboxymethylcellulose (CMC)
Mae ether seliwlos ïonig yn cael ei baratoi o ffibrau naturiol (cotwm, ac ati) ar ôl triniaeth alcali, gan ddefnyddio sodiwm monocloroacetate fel asiant etherifying, a thrwy gyfres o driniaethau adweithio. The degree of substitution is generally 0.4–d. 4. Effeithir yn fawr ar ei berfformiad gan raddau'r amnewidiad.
Yn eu plith, y trydydd a'r pedwerydd math yw'r ddau fath o seliwlos a ddefnyddir yn yr arbrawf hwn.
1.2.4 Statws Datblygu'r Diwydiant Ether Cellwlos
my country is the world's largest producer and consumer of cellulose ether, with an average annual growth rate of more than 20%. According to preliminary statistics, there are about 50 cellulose ether production enterprises in China. The designed production capacity of the cellulose ether industry has exceeded 400,000 tons, and there are about 20 enterprises with a capacity of more than 10,000 tons, mainly located in Shandong, Hebei, Chongqing and Jiangsu. , Zhejiang, Shanghai a lleoedd eraill. Yn 2011, roedd gallu cynhyrchu CMC Tsieina tua 300,000 tunnell. With the increasing demand for high-quality cellulose ethers in the pharmaceutical, food, daily chemical and other industries in recent years, the domestic demand for other cellulose ether products other than CMC is increasing. Yn fwy, mae gallu MC/HPMC tua 120,000 tunnell, ac mae gallu HEC tua 20,000 tunnell. Mae PAC yn dal i fod yn y cam hyrwyddo a chymhwyso yn Tsieina. With the development of large offshore oil fields and the development of building materials, food, chemical and other industries, the amount and field of PAC are increasing and expanding year by year, with a production capacity of more than 10,000 tons.
1.3
An important conclusion about the water retention mechanism is that the rheological properties of the mortar are critical. Gellir gweld o ganlyniadau'r profion, ar gyfer morter cymysg sych gyda chymhareb sment dŵr sefydlog a chynnwys admixture, yn gyffredinol mae gan berfformiad cadw dŵr yr un rheoleidd-dra â'i gysondeb. Fodd bynnag, ar gyfer rhai etherau seliwlos, nid yw'r duedd yn amlwg; Yn ogystal, ar gyfer etherau startsh, mae patrwm cyferbyniol. Nid gludedd y gymysgedd ffres yw'r unig baramedr ar gyfer pennu cadw dŵr.
Canfu Laetitia National, Patrice Potion, et al., Gyda chymorth graddiant caeau pylsog a thechnegau MRI, fod yr ymfudiad lleithder ar ryngwyneb morter a swbstrad annirlawn yn cael ei effeithio gan ychwanegu ychydig bach o CE. The loss of water is due to capillary action rather than water diffusion. Moisture migration by capillary action is governed by substrate micropore pressure, which in turn is determined by micropore size and Laplace theory interfacial tension, as well as fluid viscosity. Mae hyn yn dangos mai priodweddau rheolegol toddiant dyfrllyd CE yw'r allwedd i berfformiad cadw dŵr. However, this hypothesis contradicts some consensus (other tackifiers like high molecular polyethylene oxide and starch ethers are not as effective as CE).
3. Effeithir ar gryfder y bond gan baru powdr CE a rwber. When the CE film cannot prevent the evaporation of moisture at the interface of the tile and the mortar, the adhesion under high temperature curing decreases.
4. Dylid ystyried cydgysylltu a rhyngweithio CE a phowdr polymer gwasgaredig wrth ddylunio cyfran y morter gludiog ar gyfer teils.
Lschmitzc yr Almaen. Soniodd J. Dr. H (A) CKER yn yr erthygl fod gan HPMC a HEMC mewn ether seliwlos rôl hanfodol iawn wrth gadw dŵr mewn morter cymysg sych. In addition to ensuring the enhanced water retention index of cellulose ether, it is recommended to use modified Cellulose ethers are used to improve and improve the working properties of mortar and the properties of dry and hardened mortar.
1.3.2Cyflwyniad byr o ymchwil ddomestig ar gymhwyso ether seliwlos i forter
Professor Ma Baoguo from Wuhan University of Technology pointed out that cellulose ether has obvious retardation effect, and can affect the structural form of hydration products and the pore structure of cement slurry; Mae ether cellwlos yn cael ei adsorbed yn bennaf ar wyneb gronynnau sment i ffurfio effaith rwystr benodol. It hinders the nucleation and growth of hydration products; on the other hand, cellulose ether hinders the migration and diffusion of ions due to its obvious viscosity increasing effect, thereby delaying the hydration of cement to a certain extent; cellulose ether has alkali stability.
Jian Shouwei from Wuhan University of Technology concluded that the role of CE in mortar is mainly reflected in three aspects: excellent water retention capacity, influence on mortar consistency and thixotropy, and adjustment of rheology. CE not only gives mortar good working performance, but also To reduce the early hydration heat release of cement and delay the hydration kinetic process of cement, of course, based on the different use cases of mortar, there are also differences in its performance evaluation methods .
CE modified mortar is applied in the form of thin-layer mortar in daily dry-mix mortar (such as brick binder, putty, thin-layer plastering mortar, etc.). Mae'r strwythur unigryw hwn fel arfer yn cyd -fynd â cholli dŵr cyflym y morter. At present, the main research focuses on the face tile adhesive, and there is less research on other types of thin-layer CE modified mortar.
Su Lei from Wuhan University of Technology obtained through the experimental analysis of the water retention rate, water loss and setting time of the mortar modified with cellulose ether. Mae maint y dŵr yn gostwng yn raddol, ac mae'r amser ceulo yn hir; when the amount of water reaches O. After 6%, the change of water retention rate and water loss is no longer obvious, and the setting time is nearly doubled; ac mae'r astudiaeth arbrofol o'i gryfder cywasgol yn dangos pan fydd cynnwys ether seliwlos yn is na 0.8%, mae cynnwys ether seliwlos yn llai na 0.8%. The increase will significantly reduce the compressive strength; and in terms of the bonding performance with the cement mortar board, O. Below 7% of the content, the increase of the content of cellulose ether can effectively improve the bonding strength.
Yuan Wei and Qin Min of Xinjiang Building Materials Research Institute conducted the test and application research of cellulose ether in foamed concrete. The test results show that HPMC improves the water retention performance of fresh foam concrete and reduces the water loss rate of hardened foam concrete; Gall HPMC leihau colli cwymp concrit ewyn ffres a lleihau sensitifrwydd y gymysgedd i dymheredd. ; HPMC will significantly reduce the compressive strength of foam concrete. Under natural curing conditions, a certain amount of HPMC can improve the strength of the specimen to a certain extent.
Li Yuhai of Wacker Polymer Materials Co., Ltd. pointed out that the type and amount of latex powder, the type of cellulose ether and the curing environment have a significant impact on the impact resistance of plastering mortar. Mae effaith etherau seliwlos ar gryfder effaith hefyd yn ddibwys o'i gymharu â chynnwys polymer ac amodau halltu.
Yin Qingli of AkzoNobel Specialty Chemicals (Shanghai) Co., Ltd. used Bermocoll PADl, a specially modified polystyrene board bonding cellulose ether, for the experiment, which is especially suitable for the bonding mortar of EPS external wall insulation system. Gall Bermocoll PADL wella'r cryfder bondio rhwng morter a bwrdd polystyren yn ychwanegol at holl swyddogaethau ether seliwlos. Even in the case of low dosage, it can not only improve the water retention and workability of the fresh mortar, but also can significantly improve the original bonding strength and water-resistant bonding strength between the mortar and the polystyrene board due to the unique anchoring technoleg. . However, it cannot improve the impact resistance of mortar and the bonding performance with polystyrene board. Er mwyn gwella'r priodweddau hyn, dylid defnyddio powdr latecs ailddarganfod.
Zhang Lin and others of Shantou Special Economic Zone Longhu Technology Co., Ltd. have concluded that, in the bonding mortar of the expanded polystyrene board thin plastering external wall external thermal insulation system (ie Eqos system), it is recommended that the optimum amount o bowdr rwber fod yn 2.5% yw'r terfyn; Mae gludedd isel, ether seliwlos wedi'i addasu'n fawr yn help mawr i wella cryfder bond tynnol ategol morter caledu.
Astudiodd Prifysgol Fuzhou, Huang Lipin et al, ddopio ether cellwlos methyl hydroxyethyl ac ethylen. Priodweddau ffisegol a morffoleg drawsdoriadol morter sment wedi'i addasu o bowdr latecs copolymer asetad finyl. It is found that cellulose ether has excellent water retention, water absorption resistance and outstanding air-entraining effect, while the water-reducing properties of latex powder and the improvement of the mechanical properties of mortar are particularly prominent. Effaith addasu; ac mae ystod dos addas rhwng polymerau.
Through a series of experiments, Chen Qian and others from Hubei Baoye Construction Industrialization Co., Ltd. proved that extending the stirring time and increasing the stirring speed can give full play to the role of cellulose ether in the ready-mixed mortar, improve the ymarferoldeb y morter, a gwella'r amser cynhyrfus. Bydd cyflymder rhy fyr neu rhy araf yn gwneud y morter yn anodd ei adeiladu; choosing the right cellulose ether can also improve the workability of ready-mixed mortar.
Astudiodd Ma Baoguo o Brifysgol Technoleg Wuhan ac eraill effeithiau gwahanol dosau o emwlsiwn styren-acrylig, powdr polymer gwasgaredig, ac ether methylcellwlos hydroxypropyl ar y defnydd o ddŵr, cryfder bond a chadernid morter plastro tenau. , found that when the content of styrene-acrylic emulsion was 4% to 6%, the bond strength of mortar reached the best value, and the compression-folding ratio was the smallest; the content of cellulose ether increased to O. At 4%, the bond strength of mortar reaches saturation, and the compression-folding ratio is the smallest; when the content of rubber powder is 3%, the bonding strength of mortar is the best, and the compression-folding ratio decreases with the addition of rubber powder. trend.
Qiu Yongxia of Beijing Wanbo Huijia Science and Trade Co., Ltd. found that with the increase of the viscosity of cellulose ether, the water retention rate of the mortar increased; Po fân y gronynnau o ether seliwlos, y gorau y bydd y dŵr yn cadw; Po uchaf yw cyfradd cadw dŵr ether seliwlos; Mae cadw dŵr ether seliwlos yn gostwng gyda'r cynnydd yn nhymheredd y morter.
Zhang Bin of Tongji University and others pointed out in the article that the working characteristics of modified mortar are closely related to the viscosity development of cellulose ethers, not that the cellulose ethers with high nominal viscosity have obvious influence on the working characteristics, because they are mae maint y gronynnau hefyd yn effeithio arno. , cyfradd diddymu a ffactorau eraill.
Zhou Xiao and others from the Institute of Cultural Relics Protection Science and Technology, China Cultural Heritage Research Institute studied the contribution of two additives, polymer rubber powder and cellulose ether, to the bond strength in NHL (hydraulic lime) mortar system, and found that Y syml oherwydd crebachu gormodol calch hydrolig, ni all gynhyrchu cryfder tynnol digonol gyda'r rhyngwyneb carreg. Gall swm priodol o bowdr rwber polymer ac ether seliwlos wella cryfder bondio morter NHL yn effeithiol a chwrdd â gofynion atgyfnerthu crair diwylliannol ac amddiffyn deunyddiau amddiffyn; Er mwyn ei atal mae'n cael effaith ar athreiddedd dŵr ac anadlu morter NHL ei hun a'r cydnawsedd â chreiriau diwylliannol gwaith maen. Ar yr un pryd, o ystyried perfformiad bondio cychwynnol morter NHL, mae'r swm ychwanegiad delfrydol o bowdr rwber polymer yn is na 0.5%i 1%, ac ychwanegu ether seliwlos y rheolir y swm ar oddeutu 0.2%.
1.4Ymchwil ar gymhwyso admixtures i forter gartref a thramor
Yn y diwydiant deunyddiau adeiladu, mae cymhwyso admixtures wedi bod yn helaeth iawn. Many cement varieties contain more or less a certain amount of admixtures. Among them, the most widely used ordinary Portland cement is added 5% in the production. ~20% admixture. In the production process of various mortar and concrete production enterprises, the application of admixtures is more extensive.
Ar gyfer cymhwyso admixtures mewn morter, mae ymchwil hirdymor ac helaeth wedi'i gynnal gartref a thramor.
1.4.1
P. Prifysgol California. JM Momeiro Joe IJ K. Wang et al. found that in the hydration process of the gelling material, the gel is not swelled in equal volume, and the mineral admixture can change the composition of the hydrated gel, and found that the swelling of the gel is related to the divalent cations in the gel . The number of copies showed a significant negative correlation.
Kevin J. o'r Unol Daleithiau. Folliard a Makoto Ohta et al. pointed out that the addition of silica fume and rice husk ash to the mortar can significantly improve the compressive strength, while the addition of fly ash reduces the strength, especially in the early stage.
Philippe Lawrence and Martin Cyr of France found that a variety of mineral admixtures can improve the mortar strength under the appropriate dosage. Nid yw'r gwahaniaeth rhwng gwahanol admixtures mwynau yn amlwg yng nghyfnod cynnar hydradiad. In the later stage of hydration, the additional strength increase is affected by the activity of the mineral admixture, and the strength increase caused by the inert admixture cannot simply be regarded as filling. effaith, ond dylid ei briodoli i effaith gorfforol cnewylliad amlhaenog.
1.4.2Cyflwyniad byr o ymchwil ddomestig ar gymhwyso admixtures i forter
Through experimental research, Zhong Shiyun and Xiang Keqin of Tongji University found that the composite modified mortar of a certain fineness of fly ash and polyacrylate emulsion (PAE), when the poly-binder ratio was fixed at 0.08, the compression-folding ratio of the Cynyddodd morter gyda mân a chynnwys lludw hedfan yn lleihau gyda'r cynnydd o ludw hedfan. It is proposed that the addition of fly ash can effectively solve the problem of high cost of improving the flexibility of mortar by simply increasing the content of polymer.
Wang Yinong of Wuhan Iron and Steel Civil Construction Company has studied a high-performance mortar admixture, which can effectively improve the workability of mortar, reduce the degree of delamination, and improve the bonding ability. It is suitable for masonry and plastering of aerated concrete blocks. .
Zhao Yujing of Shanghai Baosteel New Building Materials Co., Ltd. used the theory of fracture toughness and fracture energy to study the influence of mineral admixtures on the brittleness of concrete. Mae'r prawf yn dangos y gall yr admixture mwynol wella caledwch torri ac egni torri asgwrn morter ychydig; in the case of the same type of admixture, the replacement amount of 40% of the mineral admixture is the most beneficial to the fracture toughness and fracture energy.
Xu Guangsheng of Henan University pointed out that when the specific surface area of the mineral powder is less than E350m2/l [g, the activity is low, the 3d strength is only about 30%, and the 28d strength develops to 0~90% ; while at 400m2 melon g, the 3d strength It can be close to 50%, and the 28d strength is above 95%. From the perspective of basic principles of rheology, according to the experimental analysis of mortar fluidity and flow velocity, several conclusions are drawn: fly ash content below 20% can effectively improve mortar fluidity and flow velocity, and mineral powder in When the dosage is below 25%, the fluidity of the mortar can be increased but the flow rate is reduced.
Zhang Jianxin of Chongqing University and others found that by comprehensive modification of methyl cellulose ether, polypropylene fiber, redispersible polymer powder, and admixtures, a dry-mixed plastering mortar with good performance can be prepared. Mae gan y morter plastro sy'n gwrthsefyll crac sy'n gwrthsefyll crac ymarferoldeb da, cryfder bond uchel ac ymwrthedd crac da. Mae ansawdd drymiau a chraciau yn broblem gyffredin.
Ren Chuanyao of Zhejiang University and others studied the effect of hydroxypropyl methylcellulose ether on the properties of fly ash mortar, and analyzed the relationship between wet density and compressive strength. It was found that adding hydroxypropyl methyl cellulose ether into fly ash mortar can significantly improve the water retention performance of mortar, prolong the bonding time of mortar, and reduce the wet density and compressive strength of mortar. There is a good correlation between wet density and 28d compressive strength. O dan gyflwr dwysedd gwlyb hysbys, gellir cyfrifo'r cryfder cywasgol 28D trwy ddefnyddio'r fformiwla ffitio.
1.6Prif gynnwys ymchwil y papur hwn
2. By adding cellulose ethers and various mineral admixtures to high fluidity mortar and bonding mortar, explore their effects on compressive strength, flexural strength, compression-folding ratio and bonding mortar of high fluidity mortar and plastic mortar The law of influence on the tensile bond cryfder.
Pennod 2 Dadansoddiad o ddeunyddiau crai a'u cydrannau ar gyfer profi
2.1 Deunyddiau Prawf
Dewiswyd y powdr slag ffwrnais chwyth gronynnog gradd $ 95 o Shandong Jinan Luxin New Building Materials Co, Ltd.
2.1.3 lludw hedfan (fa)
Dewisir y lludw hedfan gradd II a gynhyrchir gan orsaf bŵer Jinan Huangtai, y mân (rhidyll sy'n weddill o ridyll twll sgwâr 459m) yw 13%, a'r gymhareb galw dŵr yw 96%.
～Mynegai gweithgaredd 0.39m, 28D yw 108%, cymhareb galw dŵr yw 120%.
2.1.5 Powdwr Latecs Ailddarganfod (JF)
2.1.7 Admixtures Eraill
2.1,8 tywod cwarts
Y powdr polycarboxylate o Suzhou Xingbang Chemical Building Materials Co, Ltd.) yw 1J1030, a'r gyfradd lleihau dŵr yw 30%.
2.1.10 tywod (au)
Defnyddir tywod canolig Afon Dawen yn Tai'an.
2.1.11 Agregau bras (g)
2.2 Dull Prawf
2.2.1 Dull prawf ar gyfer hylifedd slyri
The test methods and results are calculated according to the test method for the fluidity of cement paste in Appendix A of “GB 50119.2003 Technical Specifications for the Application of Concrete Admixtures” or ((GB/T8077–2000 Test Method for Homogeneousness of Concrete Admixtures) .
2.2.2 Dull prawf ar gyfer hylifedd morter hylifedd uchel
Offer Prawf: JJ. Cymysgydd Morter Sment Math 5, wedi'i gynhyrchu gan Wuxi Jianyi Instrument Machinery Co., Ltd .;
Peiriant Profi Cywasgu Morter TYE-2000B, a gynhyrchwyd gan Wuxi Jianyi Instrument Machinery Co., Ltd .;
Mae dull canfod hylifedd morter yn seiliedig ar “JC. T 986-2005 Cement-based grouting materials” and “GB 50119-2003 Technical Specifications for the Application of Concrete Admixtures” Appendix A, the size of the cone die used, the height is 60mm, the inner diameter of the upper port is 70mm, the inner diameter of the lower port is 100mm, and the outer diameter of the lower port is 120mm, and the total dry weight of the mortar should not be less than 2000g each time.
Dylai canlyniadau profion y ddwy hylifedd gymryd gwerth cyfartalog y ddau gyfeiriad fertigol fel y canlyniad terfynol.
Prif Offer Prawf: WDL. Type 5 electronic universal testing machine, produced by Tianjin Gangyuan Instrument Factory.
Pennod 3. Effaith Ether Cellwlos ar Gludo Pur a Morter Deunydd Smentitious Deuaidd amrywiol Admixtures Mwynau
3.1 Amlinelliad o'r protocol arbrofol
1. puree. Mae ganddo fanteision greddf, gweithrediad syml a chywirdeb uchel, ac mae'n fwyaf addas ar gyfer canfod gallu i addasu'r admixtures fel ether seliwlos i'r deunydd gelling, ac mae'r cyferbyniad yn amlwg.
3.2.1 Cynllun Prawf ar gyfer Effaith Ether Seliwlos ar Hylifedd Gludo Sment Pur
Aiming at the influence of cellulose ether on the fluidity of the pure slurry, the pure cement slurry of the one-component cementitious material system was first used to observe the influence. Mae'r prif fynegai cyfeirio yma yn mabwysiadu'r canfod hylifedd mwyaf greddfol.
2. Cynnwys Ether Cellwlos
3. Amser gorffwys slyri
3.2.2 Canlyniadau Prawf a Dadansoddiad o Effaith Ether Cellwlos ar Hylifedd Gludo Sment Pur
(1) Canlyniadau profion hylifedd past sment pur wedi'i gymysgu â CMC
Dadansoddiad o ganlyniadau profion:
Comparing the three groups with the same standing time, in terms of initial fluidity, with the addition of CMC, the initial fluidity decreased slightly; Gostyngodd yr hylifedd hanner awr yn fawr gyda'r dos, yn bennaf oherwydd hylifedd hanner awr y grŵp gwag. It is 20mm larger than the initial (this may be caused by the retardation of PC powder): -IJ, the fluidity decreases slightly at 0.1% dosage, and increases again at 0.2% dosage .
Comparing the three groups with the same dosage, the fluidity of the blank group was the largest in half an hour, and decreased in one hour (this may be due to the fact that after one hour, the cement particles appeared more hydration and adhesion, Ffurfiwyd y strwythur rhyng-ronynnau i ddechrau, ac roedd y slyri yn ymddangos yn fwy. the fluidity of C1 and C2 groups decreased slightly in half an hour, indicating that the water absorption of CMC had a certain impact on the state; while at the content of C2, there was a large increase in one hour, indicating that the content of The effect of the retardation effect of CMC is dominant.
It can be seen that with the increase of the content of CMC, the phenomenon of scratching begins to appear, indicating that CMC has a certain effect on increasing the viscosity of the cement paste, and the air-entraining effect of CMC causes the generation of swigod aer.
(2) Canlyniadau profion hylifedd past sment pur wedi'i gymysgu â HPMC (gludedd 100,000)
Dadansoddiad o ganlyniadau profion:
From the line graph of the effect of standing time on fluidity, it can be seen that the fluidity in half an hour is relatively large compared with the initial and one hour, and with the increase of the content of HPMC, the trend is weakened. At ei gilydd, nid yw colli hylifedd yn fawr, gan nodi bod gan HPMC gadw dŵr yn amlwg i'r slyri, a chael effaith arafu benodol.
It can be seen from the observation that the fluidity is extremely sensitive to the content of HPMC. In the experimental range, the larger the content of HPMC, the smaller the fluidity. Yn y bôn, mae'n anodd llenwi'r mowld côn hylif ar ei ben ei hun o dan yr un faint o ddŵr. Gellir gweld, ar ôl ychwanegu HPMC, nad yw'r golled hylifedd a achosir gan amser yn fawr ar gyfer y slyri pur.
Dadansoddiad o ganlyniadau profion:
As far as observation is concerned, according to the overall trend of the change of fluidity with time, the half-hour retarding effect of HPMC (150,000) is obvious, while the effect of -4, is worse than that of HPMC (100,000) .
3.3 Prawf Dylanwad Ether Cellwlos Ar Hylifedd Slyri Pur Deunyddiau Smentitious Aml-gydran
The fly ash and slag powder in the mineral admixture are replaced by the same amount of internal mixing method, and the mixing levels are 10%, 20% and 30%, that is, the replacement amount is 30g, 60g and 90g. Fodd bynnag, o ystyried dylanwad gweithgaredd uwch, crebachu a nodi, rheolir y cynnwys mygdarth silica i 3%, 6%, a 9%, hynny yw, 9G, 18G, a 27g.
3.3.1 Cynllun Prawf ar gyfer Effaith Ether Cellwlos ar Hylifedd Slyri Pur y Deunydd Cementious Deuaidd
(1) Cynllun Prawf ar gyfer Hylifedd Deunyddiau Smentitious Deuaidd wedi'u Cymysgu â CMC ac Admixtures Mwynau Amrywiol.
(2) Cynllun Prawf ar gyfer Hylifedd Deunyddiau Smentitious Deuaidd wedi'u cymysgu â HPMC (gludedd 100,000) ac amryw admixtures mwynau.
.
.
Gellir gweld y gellir cynyddu hylifedd cychwynnol y slyri pur ar dos isel o bowdr mwynol, ac nid yw gwella hylifedd yn amlwg mwyach pan fydd y dos yn uwch na 20%. Ar yr un pryd, faint o CMC yn O. Ar 1%, mae'r hylifedd ar y mwyaf.
Gellir gweld o hyn bod cynnwys mygdarth silica yn gyffredinol yn cael effaith negyddol sylweddol ar hylifedd cychwynnol y slyri. At the same time, CMC also slightly reduced the fluidity.
Canlyniadau profion hylifedd hanner awr o ddeunydd smentitious deuaidd pur wedi'i gymysgu â CMC ac admixtures mwynau amrywiol.
It can be seen that the improvement of the fluidity of fly ash for half an hour is relatively effective at low dosage, but it may also be because it is close to the flow limit of the pure slurry. Ar yr un pryd, mae gan CMC ostyngiad bach mewn hylifedd o hyd.
(2) Canlyniadau profion hylifedd cychwynnol y deunydd deuaidd slyri pur wedi'i gymysgu â HPMC (gludedd 100,000) ac amryw admixtures mwynau
～0.15% o'r dos uchel.
From this, it can be seen that the reduction of the fluidity of silica fume is more obvious in the large dosage range, and in addition, the silica fume has obvious improvement effect on bleeding in the test. At the same time, HPMC has an obvious effect on the reduction of fluidity (especially in the range of high dosage (0.1% to 0.15%). In terms of the influencing factors of fluidity, silica fume and HPMC play a key role, and Arall mae'r admixture yn gweithredu fel addasiad bach ategol.
It can be seen that, in general, the effect of the three admixtures on the fluidity is similar to the initial value. Pan fydd y mygdarth silica mewn cynnwys uchel o 9% a chynnwys HPMC yn O. Yn achos 15%, roedd y ffenomen na ellid casglu'r data oherwydd cyflwr gwael y slyri , indicating that the viscosity of silica fume and HPMC increased significantly at higher dosages. Compared with CMC, the viscosity increasing effect of HPMC is very obvious.
From this, it can be seen that HPMC (150,000) and HPMC (100,000) have similar effects on the slurry, but HPMC with high viscosity has a slightly larger decrease in fluidity, but it is not obvious, which should be related to the dissolution of HPMC. Mae gan y cyflymder berthynas benodol. Among the admixtures, the effect of fly ash content on the fluidity of the slurry is basically linear and positive, and 30% of the content can increase the fluidity by 20,-,30mm; The effect is not obvious, and its improvement effect on bleeding is limited; even at a small dosage level of less than 10%, silica fume has a very obvious effect on reducing bleeding, and its specific surface area is nearly two times larger than that of cement. order of magnitude, the effect of its adsorption of water on the mobility is extremely significant.
The third part summarizes the influence of HPMC (150,000) and admixtures on the fluidity of pure pulp in half an hour, which is generally similar to the influence law of the initial value. It can be found that the increase of fly ash on the fluidity of pure slurry for half an hour is slightly more obvious than the increase of initial fluidity, the influence of slag powder is still not obvious, and the influence of silica fume content on fluidity yn dal yn amlwg iawn. In addition, in terms of the content of HPMC, there are many phenomena that cannot be poured out at high content, indicating that its O. 15% dosage has a significant effect on increasing viscosity and reducing fluidity, and in terms of fluidity for half Awr, o'i gymharu â'r gwerth cychwynnol, gostyngodd O. O. O. Gostyngodd hylifedd 05% HPMC yn amlwg.
3.4 Arbrawf ar effaith ether seliwlos ar hylifedd morter hylifedd uchel pur wedi'i seilio ar sment
3.4.1 Cynllun Prawf ar gyfer Effaith Ether Seliwlos ar Hylifedd Morter Ffeiliad Uchel Pur sy'n Sement Pur
Defnyddio morter hylifedd uchel i arsylwi ar ei effaith ar ymarferoldeb. Y prif fynegai cyfeirio yma yw'r prawf hylifedd morter cychwynnol a hanner awr.
1 math o etherau seliwlos,
2 dos o ether seliwlos,
3 Amser sefyll morter
3.4.2 Canlyniadau Profion a Dadansoddiad o Effaith Ether Cellwlos ar Hylifedd Morter Ffedwaith Uchel Pur sy'n Seiliedig ar Sment
Crynodeb a dadansoddiad o ganlyniadau profion:
Comparing the three groups with the same standing time, in terms of initial fluidity, with the addition of CMC, the initial fluidity decreased slightly, and when the content reached O. At 15%, there is a relatively obvious decrease; Mae ystod ostyngol yr hylifedd gyda chynnydd y cynnwys mewn hanner awr yn debyg i'r gwerth cychwynnol.
2. Symptom:
Theoretically speaking, compared with clean slurry, the incorporation of aggregates in mortar makes it easier for air bubbles to be entrained into the slurry, and the blocking effect of aggregates on bleeding voids will also make it easier for air bubbles or bleeding to be retained. In the slurry, therefore, the air bubble content and size of the mortar should be more and larger than that of the neat slurry. On the other hand, it can be seen that with the increase of the content of CMC, the fluidity decreases, indicating that CMC has a certain thickening effect on the mortar, and the half-hour fluidity test shows that the bubbles overflowing on the surface cynyddu ychydig. , which is also a manifestation of the rising consistency, and when the consistency reaches a certain level, the bubbles will be difficult to overflow, and no obvious bubbles will be seen on the surface.
(2) Canlyniadau profion hylifedd morter sment pur wedi'i gymysgu â HPMC (100,000)
Dadansoddiad o ganlyniadau profion:
Gellir gweld o'r ffigur, gyda chynnydd yng nghynnwys HPMC, bod yr hylifedd yn cael ei leihau'n fawr. O'i gymharu â CMC, mae HPMC yn cael effaith tewychu gryfach. The effect and water retention are better. From 0.05% to 0.1%, the range of fluidity changes is more obvious, and from O. After 1%, neither the initial nor half-hour change in fluidity is too large.
Dadansoddiad o ganlyniadau profion:
3.5.
Mae morter hylifedd uchel yn dal i gael ei ddefnyddio i arsylwi ar ei ddylanwad ar hylifedd. Y prif ddangosyddion cyfeirio yw'r canfod hylifedd morter cychwynnol a hanner awr.
(1) Cynllun Prawf Hylifedd Morter gyda Deunyddiau Smentitious Deuaidd wedi'u Cymysgu â CMC ac Admixtures Mwynau Amrywiol
(1) Canlyniadau profion hylifedd cychwynnol morter smentitious deuaidd wedi'i gymysgu â CMC ac amrywiol admixtures
O ganlyniadau profion hylifedd cychwynnol, gellir dod i'r casgliad y gall ychwanegu lludw hedfan wella hylifedd morter ychydig; Pan fydd cynnwys powdr mwynol yn 10%, gellir gwella hylifedd morter ychydig; ac mae mygdarth silica yn cael mwy o effaith ar hylifedd, yn enwedig yn yr ystod o amrywiad cynnwys 6% ~ 9%, gan arwain at ostyngiad mewn hylifedd o tua 90mm.
Canlyniadau Prawf Hylif Hanner Awr o Forter Smentitious Deuaidd wedi'u Cymysgu â CMC ac Admixtures Amrywiol
From the test results of the fluidity in half an hour, it can be concluded that the effect of the content of admixture and CMC is similar to the initial one, but the content of CMC in the mineral powder group changes from O. 1% to O. Mae'r newid 2% yn fwy, ar 30mm.
In terms of the loss of fluidity over time, fly ash has the effect of reducing the loss, while the mineral powder and silica fume will increase the loss value under high dosage. Mae'r dos 9% o fume silica hefyd yn achosi i'r mowld prawf beidio â chael ei lenwi ynddo'i hun. , the fluidity cannot be accurately measured.
Canlyniadau Prawf Hylif Hanner Awr o Forter Smentitious Deuaidd wedi'i gymysgu â HPMC (gludedd 100,000) ac amryw admixtures
It can still be concluded through experiments that the addition of fly ash can slightly improve the fluidity of mortar; Pan fydd cynnwys powdr mwynol yn 10%, gellir gwella hylifedd morter ychydig; The dosage is very sensitive, and the HPMC group with high dosage at 9% has dead spots, and the fluidity basically disappears.
The content of cellulose ether and silica fume are also the most obvious factors affecting the fluidity of mortar. Mae effaith HPMC yn amlwg yn fwy nag effaith CMC. Gall admixtures eraill wella colli hylifedd dros amser.
(3) Canlyniadau profion hylifedd cychwynnol morter smentitious deuaidd wedi'i gymysgu â HPMC (gludedd o 150,000) ac amrywiol admixtures
Canlyniadau Prawf Hylif Hanner Awr Morter Smentitious Deuaidd wedi'u Cymysgu â HPMC (Gludedd 150,000) ac Admixtures Amrywiol
Gellir dod i'r casgliad o hyd trwy arbrofion y gall ychwanegu lludw hedfan wella hylifedd morter ychydig; when the content of mineral powder is 10%, the fluidity of mortar can be slightly improved: silica fume is still very effective in solving the bleeding phenomenon, while the Fluidity is a serious side effect, but is less effective than its effect in clean slurries .
A large number of dead spots appeared under the high content of cellulose ether (especially in the table of half-hour fluidity), indicating that HPMC has a significant effect on reducing the fluidity of mortar, and mineral powder and fly ash can improve the loss o hylifedd dros amser.
3.5 Crynodeb y Bennod
1. Gan gymharu prawf hylifedd past sment pur yn gynhwysfawr wedi'i gymysgu â thri ether seliwlos, gellir gweld hynny
2. The water retention effect of HPMC is obvious, and it has a significant influence on the state, and the fluidity decreases significantly with the increase of the content. Mae'n cael effaith benodol i gael aer, ac mae'r tewychu yn amlwg. Bydd 15% yn achosi swigod mawr yn y slyri, sy'n sicr o fod yn niweidiol i'r cryfder. Gyda'r cynnydd o gludedd HPMC, cynyddodd colli hylifedd slyri sy'n dibynnu ar amser ychydig, ond nid yn amlwg.
1. The influence law of the three cellulose ethers on the fluidity of the slurry of the binary cementitious system of various mineral admixtures has the characteristics similar to the influence law of the fluidity of the pure cement slurry. Nid yw CMC yn cael fawr o effaith ar reoli gwaedu, ac mae'n cael effaith wan ar leihau hylifedd; Gall dau fath o HPMC gynyddu gludedd slyri a lleihau hylifedd yn sylweddol, ac mae'r un â gludedd uwch yn cael effaith fwy amlwg.
4. O ran colli hylifedd hanner awr, mae gwerth colli lludw hedfan yn llai, ac mae gwerth colli'r grŵp sy'n ymgorffori mygdarth silica yn fwy.
5. In the respective variation range of the content, the factors affecting the fluidity of the slurry, the content of HPMC and silica fume are the primary factors, whether it is the control of the bleeding or the control of the flow state, it is yn gymharol amlwg. The influence of mineral powder and mineral powder is secondary, and plays an auxiliary adjustment role.
3. Yn cynhwysfawr o gymharu prawf hylifedd morter sment pur wedi'i gymysgu â thri ether seliwlos, gellir gweld hynny
Fel y gwelir:
1. The influence law of three cellulose ethers on the fluidity of multi-component cementitious material mortar is similar to the influence law on the fluidity of pure slurry. Nid yw CMC yn cael fawr o effaith ar reoli gwaedu, ac mae'n cael effaith wan ar leihau hylifedd; two kinds of HPMC can increase the viscosity of mortar and reduce fluidity significantly, and the one with higher viscosity has a more obvious effect.
2. Ymhlith yr admixtures, mae gan ludw hedfan rywfaint o welliant ar hylifedd cychwynnol a hanner awr y slyri glân; Nid oes rheoleidd -dra amlwg i ddylanwad powdr slag ar hylifedd y slyri glân; although the content of silica fume is low, its The unique ultra-fineness, fast reaction and strong adsorption make it have a great reduction effect on the fluidity of the slurry. Fodd bynnag, o'i gymharu â chanlyniadau profion past pur, canfyddir bod effaith admixtures yn tueddu i wanhau.
5. Bydd swigod ar wyneb y morter gyda hylifedd o fwy na 250mm, ond yn gyffredinol nid oes gan y grŵp gwag heb ether seliwlos swigod na dim ond ychydig bach o swigod, sy'n dangos bod gan ether seliwlos aer-entraining penodol effect and makes the slurry viscous. In addition, due to the excessive viscosity of the mortar with poor fluidity, it is difficult for the air bubbles to float up by the self-weight effect of the slurry, but is retained in the mortar, and its influence on the strength cannot be ignored.
Pennod 4 Effeithiau etherau seliwlos ar briodweddau mecanyddol morter
4.1 Prawf Cryfder Cywasgol a Flexural Morter Hylif Uchel
4.1.1 Prawf Dylanwad ar gryfder cywasgol a flexural morter hylifedd uchel sy'n seiliedig ar sment pur
Early strength analysis: In terms of flexural strength, CMC has a certain strengthening effect, while HPMC has a certain reducing effect; O ran cryfder cywasgol, mae gan ymgorffori ether seliwlos gyfraith debyg â'r cryfder flexural; Mae gludedd HPMC yn effeithio ar y ddau gryfder. Nid yw'n cael fawr o effaith: o ran y gymhareb plygu pwysau, gall y tri ether seliwlos leihau'r gymhareb plygu pwysau yn effeithiol a gwella hyblygrwydd y morter. Among them, HPMC with a viscosity of 150,000 has the most obvious effect.
(2) Canlyniadau profion cymharu cryfder saith diwrnod
Seven-day strength analysis: In terms of flexural strength and compressive strength, there is a similar law to the three-day strength. Compared with the three-day pressure-folding, there is a slight increase in the pressure-folding strength. Fodd bynnag, gall cymhariaeth data'r un cyfnod oedran weld effaith HPMC ar leihau'r gymhareb plygu pwysau. yn gymharol amlwg.
(3) wyth ar hugain diwrnod o ganlyniadau profion cymharu cryfder
Dadansoddiad cryfder wyth ar hugain diwrnod: O ran cryfder flexural a chryfder cywasgol, mae deddfau tebyg i'r cryfder tridiau. Mae'r cryfder flexural yn cynyddu'n araf, ac mae'r cryfder cywasgol yn dal i gynyddu i raddau. Mae cymhariaeth data'r un cyfnod oedran yn dangos bod HPMC yn cael effaith fwy amlwg ar wella'r gymhareb plygu cywasgu.
4.1.2 Prawf Dylanwad o Gryfder Cywasgol a Flexural Admixture Mwynau Morter Hylif Uchel
According to the test of the fluidity of pure slurry and mortar mixed with admixtures in the previous chapter, it can be seen that the fluidity of silica fume is obviously deteriorated due to the large water demand, although it can theoretically improve the density and strength to i raddau. , especially the compressive strength, but it is easy to cause the compression-to-fold ratio to be too large, which makes the mortar brittleness feature remarkable, and it is a consensus that silica fume increases the shrinkage of the mortar. At the same time, due to the lack of skeleton shrinkage of coarse aggregate, the shrinkage value of mortar is relatively large relative to concrete. For mortar (especially special mortar such as bonding mortar and plastering mortar), the biggest harm is often shrinkage. For cracks caused by water loss, strength is often not the most critical factor. Therefore, silica fume was discarded as the admixture, and only fly ash and mineral powder were used to explore the effect of its composite effect with cellulose ether on the strength.
In this experiment, the proportion of mortar in 4.1.1 was used, and the content of cellulose ether was fixed at 0.1% and compared with the blank group. Lefel dos y prawf admixture yw 0%, 10%, 20%a 30%.
4.1.2.2 Canlyniadau Profion Cryfder Cywasgol a Flexural a Dadansoddiad o Forter Hylif Uchel
It can be seen from the compressive strength test value that the 3d compressive strength after adding HPMC is about 5/VIPa lower than that of the blank group. Yn gyffredinol, gyda'r cynnydd yn faint o admixture a ychwanegir, mae'r cryfder cywasgol yn dangos tuedd sy'n lleihau. . In terms of admixtures, the strength of the mineral powder group without HPMC is the best, while the strength of the fly ash group is slightly lower than that of the mineral powder group, indicating that the mineral powder is not as active as the cement, and its incorporation will slightly reduce the early strength of the system. The fly ash with poorer activity reduces the strength more obviously. The reason for the analysis should be that the fly ash mainly participates in the secondary hydration of cement, and does not contribute significantly to the early strength of the mortar.
It can be seen from the flexural strength test values that HPMC still has an adverse effect on the flexural strength, but when the content of the admixture is higher, the phenomenon of reducing the flexural strength is no longer obvious. Efallai mai'r rheswm yw effaith cadw dŵr HPMC. The water loss rate on the surface of the mortar test block is slowed down, and the water for hydration is relatively sufficient.
It can be seen that for the compressive strength of 7d, the adverse effects of the admixtures are no longer obvious. The compressive strength values are roughly the same at each admixture dosage level, and HPMC still has a relatively obvious disadvantage on the compressive strength. effaith.
Gellir gweld bod yr admixture yn cael effaith andwyol o ran y gymhareb indentation. With the increase of the amount of the admixture, the indentation ratio gradually increases, that is, the mortar is brittle. Yn amlwg, gall HPMC leihau'r gymhareb gwaith cywasgu a gwella disgleirdeb morter.
It can be seen that from the 28d compressive strength, the admixture has played a more obvious beneficial effect on the later strength, and the compressive strength has been increased by 3-5MPa, which is mainly due to the micro-filling effect of the admixture and the pozzolanic substance. The secondary hydration effect of the material, on the one hand, can utilize and consume the calcium hydroxide produced by cement hydration (calcium hydroxide is a weak phase in the mortar, and its enrichment in the interface transition zone is detrimental to the strength), Mae cynhyrchu mwy o gynhyrchion hydradiad, ar y llaw arall, yn hyrwyddo gradd hydradiad sment a gwneud y morter yn fwy trwchus. Mae HPMC yn dal i gael effaith andwyol sylweddol ar y cryfder cywasgol, a gall y cryfder gwanhau gyrraedd mwy na 10MPA. Er mwyn dadansoddi'r rhesymau, mae HPMC yn cyflwyno rhywfaint o swigod aer yn y broses gymysgu morter, sy'n lleihau crynoder y corff morter. Dyma un rheswm. Mae HPMC yn hawdd ei adsorbed ar wyneb gronynnau solet i ffurfio ffilm, gan rwystro'r broses hydradiad, ac mae'r parth trosglwyddo rhyngwyneb yn wannach, nad yw'n ffafriol i gryfder.
Gellir gweld, o safbwynt y gymhareb lleihau cywasgiad, bod HPMC yn gyffredinol o fudd i leihau'r gymhareb lleihau cywasgu a gwella caledwch y morter. Mewn un grŵp, gyda'r cynnydd yn faint o admixtures, mae'r gymhareb ail-adolygu cywasgu yn cynyddu. Analysis of the reasons shows that the admixture has obvious improvement in the later compressive strength, but limited improvement in the later flexural strength, resulting in the compression-refraction ratio. gwelliant.
4.2 Profion Cryfder Cywasgol a Flexural o Fortar wedi'i Bondio
In order to explore the influence of cellulose ether and admixture on the compressive and flexural strength of bonded mortar, the experiment fixed the content of cellulose ether HPMC (viscosity 100,000) as 0.30% of the dry weight of the mortar. ac o'i gymharu â'r grŵp gwag.
It can be seen from the experiment that HPMC is obviously unfavorable in terms of the 28d compressive strength of the bonding mortar, which will cause the strength to decrease by about 5MPa, but the key indicator for judging the quality of the bonding mortar is not the cryfder cywasgol, felly mae'n dderbyniol; Pan fydd y cynnwys cyfansawdd yn 20%, mae'r cryfder cywasgol yn gymharol ddelfrydol.
Gellir gweld o'r arbrawf, o safbwynt cryfder flexural, nad yw'r gostyngiad cryfder a achosir gan HPMC yn fawr. Efallai bod gan y morter bondio hylifedd gwael a nodweddion plastig amlwg o'i gymharu â morter hylif uchel. The positive effects of slipperiness and water retention effectively offset some of the negative effects of introducing gas to reduce compactness and interface weakening; Nid yw admixtures yn cael unrhyw effaith amlwg ar gryfder flexural, ac mae data grŵp lludw hedfan yn amrywio ychydig.
It can be seen from the experiments that, as far as the pressure-reduction ratio is concerned, in general, the increase of the admixture content increases the pressure-reduction ratio, which is unfavorable to the toughness of the mortar; HPMC has a favorable effect, which can reduce the pressure-reduction ratio by O. 5 above, it should be pointed out that, according to “JG 149.2003 Expanded Polystyrene Board Thin Plaster External Wall External Insulation System”, there is generally no mandatory requirement for the compression-folding ratio in the detection index of the bonding mortar, and the compression-folding ratio is mainly It is used to limit the brittleness of the plastering mortar, and this index is only used as a reference for the flexibility of the bonding morter.
4.3.1 Cynllun Prawf Cryfder Bond Morter Bond
4.3.2 Canlyniadau Prawf a Dadansoddiad o Gryfder Bond Morter Bond
It can be seen from the experiment that the groups added with HPMC are significantly better than the blank group, indicating that HPMC is beneficial to the bonding strength, mainly because the water retention effect of HPMC protects the water at the bonding interface between the mortar and Y bloc prawf morter sment. The bonding mortar at the interface is fully hydrated, thereby increasing the bond strength.
(2) Canlyniadau profion cryfder bond 14D o forter bondio a bwrdd polystyren estynedig
4.4 Crynodeb o'r Bennod
1. For high fluidity mortar, with the increase of age, the compressive-fold ratio has an upward trend; the incorporation of HPMC has an obvious effect of reducing the strength (the decrease in the compressive strength is more obvious), which also leads to The decrease of the compression-folding ratio, that is, HPMC has obvious help to the improvement of mortar toughness . In terms of three-day strength, fly ash and mineral powder can make a slight contribution to the strength at 10%, while the strength decreases at high dosage, and the crushing ratio increases with the increase of mineral admixtures; in the seven-day strength, The two admixtures have little effect on the strength, but the overall effect of fly ash strength reduction is still obvious; O ran y cryfder 28 diwrnod, mae'r ddau admixtures wedi cyfrannu at gryfder, cywasgol a chryfder ystwyth. Both were slightly increased, but the pressure-fold ratio still increased with the increase of the content.
Pennod 5 Dull ar gyfer darogan cryfder cywasgol morter a choncrit
Mae'n hysbys bod cryfder cywasgol yn ddangosydd pwysig ar gyfer deunyddiau sy'n seiliedig ar sment (concrit a morter) a ddefnyddir fel deunyddiau strwythurol. Fodd bynnag, oherwydd llawer o ffactorau sy'n dylanwadu, nid oes model mathemategol a all ragfynegi ei ddwyster yn gywir. Mae hyn yn achosi anghyfleustra penodol i ddylunio, cynhyrchu a defnyddio morter a choncrit. The existing models of concrete strength have their own advantages and disadvantages: some predict the strength of concrete through the porosity of concrete from the common point of view of the porosity of solid materials; Mae rhai yn canolbwyntio ar ddylanwad y berthynas cymhareb rhwymwr dŵr ar y cryfder. This paper mainly combines the activity coefficient of pozzolanic admixture with Feret's strength theory, and makes some improvements to make it relatively more accurate to predict the compressive strength.
Ym 1892, sefydlodd Feret y model mathemategol cynharaf ar gyfer darogan cryfder cywasgol. O dan y rhagosodiad o ddeunyddiau crai concrit penodol, cynigir y fformiwla ar gyfer darogan cryfder concrit am y tro cyntaf.
The advantage of this formula is that the grout concentration, which correlates with concrete strength, has a well-defined physical meaning. Ar yr un pryd, mae dylanwad cynnwys aer yn cael ei ystyried, a gellir profi cywirdeb y fformiwla yn gorfforol. Y rhesymeg dros y fformiwla hon yw ei bod yn mynegi gwybodaeth bod cyfyngiad ar y cryfder concrit y gellir ei gael. Yr anfantais yw ei fod yn anwybyddu dylanwad maint gronynnau agregau, siâp gronynnau a math agregau. When predicting the strength of concrete at different ages by adjusting the K value, the relationship between different strength and age is expressed as a set of divergences through the coordinate origin. The curve is inconsistent with the actual situation (especially when the age is longer). Of course, this formula proposed by Feret is designed for the mortar of 10.20MPa. It cannot fully adapt to the improvement of concrete compressive strength and the influence of increasing components due to the progress of mortar concrete technology.
It is considered here that the strength of concrete (especially for ordinary concrete) mainly depends on the strength of the cement mortar in the concrete, and the strength of the cement mortar depends on the density of the cement paste, that is, the volume percentage o'r deunydd smentitious yn y past.
The theory is closely related to the effect of void ratio factor on strength. However, because the theory was put forward earlier, the influence of admixture components on concrete strength was not considered. O ystyried hyn, bydd y papur hwn yn cyflwyno'r cyfernod dylanwad admixture yn seiliedig ar y cyfernod gweithgaredd ar gyfer cywiro rhannol. At the same time, on the basis of this formula, an influence coefficient of porosity on concrete strength is reconstructed.
5.2 Cyfernod Gweithgaredd
The activity coefficient, Kp, is used to describe the effect of pozzolanic materials on the compressive strength. Obviously, it depends on the nature of the pozzolanic material itself, but also on the age of the concrete. The principle of determining the activity coefficient is to compare the compressive strength of a standard mortar with the compressive strength of another mortar with pozzolanic admixtures and replacing the cement with the same amount of cement quality (the country p is the activity coefficient test. Use surrogate canrannau). The ratio of these two intensities is called the activity coefficient fO), where t is the age of the mortar at the time of testing. If fO) is less than 1, the activity of pozzolan is less than that of cement r. Conversely, if fO) is greater than 1, the pozzolan has a higher reactivity (this usually happens when silica fume is added).
For the commonly used activity coefficient at 28-day compressive strength, according to ((GBT18046.2008 Granulated blast furnace slag powder used in cement and concrete) H90, the activity coefficient of granulated blast furnace slag powder is in standard cement mortar The strength ratio a gafwyd trwy ddisodli 50% o sment ar sail y prawf; yn ôl (GBT1596.2005 lludw hedfan a ddefnyddir mewn sment a choncrit), ceir cyfernod gweithgaredd lludw hedfan ar ôl disodli sment 30% ar sail y morter sment safonol Prawf yn ôl “GB.T27690.2011 Ffug silica ar gyfer morter a choncrit”, cyfernod gweithgaredd mygdarth silica yw'r gymhareb cryfder a geir trwy ddisodli sment 10% ar sail prawf morter sment safonol.
Yn gyffredinol, powdr slag ffwrnais chwyth gronynnog kp = 0.95～1.10, lludw hedfan kp = 0.7-1.05, mygdarth silica kp = 1.00～
5.3 Dylanwadu ar Gyfernod Admixture ar Gryfder
5.4 Dylanwadu ar gyfernod y defnydd o ddŵr ar gryfder
5.5 Dylanwadu ar gyfernod cyfansoddiad agregau ar gryfder
According to the views of professors PK Mehta and PC Aitcin in the United States, in order to achieve the best workability and strength properties of HPC at the same time, the volume ratio of cement slurry to aggregate should be 35:65 [4810] Because of the general plasticity and fluidity The total amount of aggregate of concrete does not change much. Cyn belled â bod cryfder y deunydd sylfaen agregau ei hun yn cwrdd â gofynion y fanyleb, anwybyddir dylanwad cyfanswm yr agreg ar y cryfder, a gellir pennu'r ffracsiwn annatod cyffredinol o fewn 60-70% yn unol â gofynion y cwymp .
It is theoretically believed that the ratio of coarse and fine aggregates will have a certain influence on the strength of concrete. As we all know, the weakest part in concrete is the interface transition zone between aggregate and cement and other cementitious material pastes. Therefore, the final failure of common concrete is due to the initial damage of the interface transition zone under stress caused by factors such as load or temperature change. caused by the continuous development of cracks. Therefore, when the degree of hydration is similar, the larger the interface transition zone is, the easier the initial crack will develop into a long through crack after stress concentration. That is to say, the more coarse aggregates with more regular geometric shapes and larger scales in the interface transition zone, the greater the stress concentration probability of the initial cracks, and the macroscopically manifested that the concrete strength increases with the increase of the coarse aggregate cymhareb. lleihau. However, the above premise is that it is required to be medium sand with very little mud content.
Mae gan y gyfradd tywod ddylanwad penodol hefyd ar y cwymp. Felly, gall y gyfradd tywod gael ei rhagosod yn ôl y gofynion cwymp, a gellir ei phennu o fewn 32% i 46% ar gyfer concrit cyffredin.
Mae maint ac amrywiaeth admixtures ac admixtures mwynau yn cael eu pennu gan gymysgedd treial. In ordinary concrete, the amount of mineral admixture should be less than 40%, while in high-strength concrete, silica fume should not exceed 10%. Ni ddylai faint o sment fod yn fwy na 500kg/m3.
Y sment yw E042.5 sment a gynhyrchir gan Lubi Cement Factory, Laiwu City, Talaith Shandong, a'i ddwysedd yw 3.19/cm3;
Mae'r lludw hedfan yn lludw pêl gradd II a gynhyrchir gan orsaf bŵer Jinan Huangtai, a'i gyfernod gweithgaredd yw O. 828, ei ddwysedd yw 2.59/cm3;
Mae gan dywod afon sych Taian ddwysedd o 2.6 g/cm3, dwysedd swmp o 1480kg/m3, a modwlws mân o MX = 2.8;
Mae Jinan Ganggou yn cynhyrchu carreg falu sych 5-'25mm gyda dwysedd swmp o 1500kg/m3 a dwysedd o tua 2.7∥cm3;
The water-reducing agent used is a self-made aliphatic high-efficiency water-reducing agent, with a water-reducing rate of 20%; the specific dosage is determined experimentally according to the requirements of slump. Paratoi treial o goncrit C30, mae'n ofynnol i'r cwymp fod yn fwy na 90mm.
2. Ansawdd Tywod
3. Penderfynu ar ffactorau dylanwad pob dwyster
4. Gofynnwch am y defnydd o ddŵr
5. Mae'r dos o asiant lleihau dŵr yn cael ei addasu yn unol â gofyniad cwymp. Y dos yw 1%, ac mae ma = 4kg yn cael ei ychwanegu at yr offeren.
7. Ar ôl cymysgu treial, gall fodloni'r gofynion cwymp. Y cryfder cywasgol 28D mesuredig yw 39.32MPA, sy'n cwrdd â'r gofynion.
1 Cyfernod Dylanwad Admixture Concrit
3 Dylanwadwch ar gyfernod cyfansoddiad agregau
4 Cymhariaeth wirioneddol. Gwirir bod y dull rhagfynegiad cryfder 28D o goncrit wedi'i wella gan y cyfernod gweithgaredd a theori cryfder Feret yn cytuno'n dda â'r sefyllfa wirioneddol, a gellir ei defnyddio i arwain paratoi morter a choncrit.
Pennod 6 Casgliad a Rhagolwg
2. Among the admixtures, the initial and half-hour fluidity of fly ash on the clean slurry and mortar has been improved to a certain extent. The 30% content of the clean slurry test can be increased by about 30mm; hylifedd y powdr mwynol ar y slyri glân a'r morter nid oes rheol ddylanwad amlwg; Er bod cynnwys mygdarth silica yn isel, mae ei ultra-pennau unigryw, adwaith cyflym, ac arsugniad cryf yn gwneud iddo gael effaith ostyngol sylweddol ar hylifedd slyri glân a morter, yn enwedig wrth ei gymysgu â 0.15 pan %hpmc, bydd yna Ffenomen na ellir llenwi'r côn marw. O'i gymharu â chanlyniadau profion y slyri glân, darganfyddir bod effaith yr admixture yn y prawf morter yn tueddu i wanhau. O ran rheoli gwaedu, nid yw lludw hedfan a phowdr mwynol yn amlwg. Gall mygdarth silica leihau faint o waedu yn sylweddol, ond nid yw'n ffafriol i leihau hylifedd a cholled morter dros amser, ac mae'n hawdd lleihau'r amser gweithredu.
Rhan II Priodweddau Mecanyddol Morter
1. Ar gyfer morter hylifedd uchel, gyda'r cynnydd mewn oedran, mae tuedd ar i fyny ar y gymhareb falu; the addition of HPMC has a significant effect of reducing the strength (the decrease in the compressive strength is more obvious), which also leads to the crushing The decrease of the ratio, that is, HPMC has obvious help to the improvement of mortar toughness. In terms of three-day strength, fly ash and mineral powder can make a slight contribution to the strength at 10%, while the strength decreases at high dosage, and the crushing ratio increases with the increase of mineral admixtures; in the seven-day strength, The two admixtures have little effect on the strength, but the overall effect of fly ash strength reduction is still obvious; O ran y cryfder 28 diwrnod, mae'r ddau admixtures wedi cyfrannu at gryfder, cywasgol a chryfder ystwyth. Cynyddwyd y ddau ychydig, ond roedd y gymhareb plygu pwysau yn dal i gynyddu gyda chynnydd y cynnwys.
2. Ar gyfer cryfder cywasgol a flexural 28D y morter wedi'i fondio, pan fydd y cynnwys admixture yn 20%, mae'r cryfderau cywasgol ac ystwythol yn well, ac mae'r admixture yn dal i arwain at gynnydd bach yn y gymhareb cywasgol-i-blygu, gan adlewyrchu ei effect on the mortar. Adverse effects of toughness; HPMC leads to a significant decrease in strength.
3. Regarding the bond strength of bonded mortar, HPMC has a certain favorable effect on the bond strength. The analysis should be that its water retention effect reduces the loss of water in the mortar and ensures more sufficient hydration. The bond strength is related to the admixture. Nid yw'r berthynas rhwng y dos yn rheolaidd, ac mae'r perfformiad cyffredinol yn well gyda morter sment pan fydd y dos yn 10%.
4. Nid yw CMC yn addas ar gyfer deunyddiau smentitious sy'n seiliedig ar sment, nid yw ei effaith cadw dŵr yn amlwg, ac ar yr un pryd, mae'n gwneud y morter yn fwy brau; while HPMC can effectively reduce the compression-to-fold ratio and improve the toughness of mortar, but it is at the expense of a substantial reduction in compressive strength.
cael effaith annibynnol.
1. Cyfernod dylanwadu Mineral
3. Ffactor dylanwadu ar gyfansoddiad agregau
This paper mainly studies the fluidity and mechanical properties of the clean paste and mortar of the binary cementitious system. The effect and influence of the joint action of multi-component cementitious materials need to be further studied. In the test method, mortar consistency and stratification can be used. Astudir effaith ether seliwlos ar gysondeb a chadw dŵr morter yn ôl graddfa ether seliwlos. In addition, the microstructure of mortar under the compound action of cellulose ether and mineral admixture is also to be studied.
Mae ether cellwlos bellach yn un o gydrannau admixture anhepgor gwahanol forterau. Mae ei effaith cadw dŵr da yn ymestyn amser gweithredu'r morter, yn gwneud i'r morter gael thixotropi da, ac yn gwella caledwch y morter. It is convenient for construction; and the application of fly ash and mineral powder as an industrial waste in mortar can also create great economic and environmental benefits
Amser Post: Medi-29-2022