Dab tsi yog hom retarders?

Retarders yog cov tshuaj additives uas ua rau qeeb qhov chaw los yog hardening ntawm cov cement. Lawv tau siv rau hauv cov ntawv thov pob zeb uas qhov kev ncua sij hawm yog qhov xav tau, xws li thaum huab cua kub, lossis thaum xav tau kev sib txuas ntxiv lossis sijhawm tso kawm. Muaj ntau ntau hom retarders muaj, txhua tus muaj nws tus kheej cov khoom thiab cov txiaj ntsig. Nov yog qee qhov ntau yam ntawm retarders:

1. Organic Acids: Organic acids xws li citric, tartaric, thiab gluconic acid feem ntau yog siv los ua retarders hauv cov khoom siv cement. Lawv ua hauj lwm los ntawm reacting nrog dawb lime nyob rau hauv cov cement, uas slows down lub hydration txheej txheem. Organic acid retarders feem ntau tsis muaj tshuaj lom thiab biodegradable, ua rau lawv xaiv ib puag ncig zoo.
2. Qab Zib: Cov piam thaj xws li qabzib, sucrose, thiab fructose kuj tuaj yeem siv los ua cov khoom qab zib hauv cov khoom siv cement. Lawv ua haujlwm los ntawm kev khi rau saum npoo ntawm cov cement, uas ua rau cov txheej txheem hydration qeeb. Qab zib retarders feem ntau siv ua ke nrog lwm cov retarders los muab lub sij hawm tswj ntau dua.
3. Inorganic ntsev: Inorganic ntsev xws li borax, zinc sulfate, thiab sodium silicate feem ntau yog siv los ua retarders hauv cov ntaub ntawv cement. Lawv ua haujlwm los ntawm kev tsim cov yeeb yaj kiab nyias ntawm cov cement hais, uas ua rau cov txheej txheem hydration qeeb. Inorganic ntsev retarders feem ntau yog siv ua ke nrog cov organic acid los yog qab zib retarders los muab lub sij hawm zoo sib xws thiab kwv yees ntau dua.
4. Lignosulfonates: Lignosulfonates yog ntuj polymers uas tau los ntawm cov ntoo pulp. Lawv feem ntau yog siv los ua retarders hauv cov khoom siv cement, vim lawv ua haujlwm los ntawm kev khi rau saum npoo ntawm cov cement hais thiab ua rau cov txheej txheem hydration qeeb. Lignosulfonate retarders feem ntau ua tau zoo nyob rau hauv high-alumina cement dua li Portland cement zoo tib yam.
5. Hydroxycarboxylic Acids: Hydroxycarboxylic acids xws li gluconic thiab citric acid feem ntau yog siv los ua retarders hauv cov khoom siv cement. Lawv ua haujlwm los ntawm chelate cov calcium ions dawb hauv cov cement, uas ua rau cov txheej txheem hydration qeeb. Hydroxycarboxylic acid retarders feem ntau yog siv ua ke nrog rau lwm cov retarders los muab lub sij hawm zoo sib xws thiab kwv yees ntau dua.
6. Polycarboxylate Ether (PCE) Superplasticizers: PCE superplasticizers feem ntau yog siv los ua retarders hauv cov ntawv thov pob zeb uas xav tau sijhawm ncua sijhawm. Lawv ua hauj lwm los ntawm dispersing cov cement hais thiab txo qhov nro ntawm cov dej, uas slows down lub hydration txheej txheem. PCE retarders feem ntau yog siv ua ke nrog lwm cov superplasticizers los muab lub sijhawm teem sijhawm zoo sib xws.

Hauv kev xaus, retarders yog ib qho tseem ceeb ntawm cov khoom siv cement, vim tias lawv muab lub sijhawm tswj xyuas ntau dua thiab tuaj yeem pab txhim kho kev ua haujlwm ntawm cov khoom siv. Hom retarder siv yuav nyob ntawm qhov kev thov tshwj xeeb thiab lub sijhawm xav tau, nrog rau cov khoom ntawm cov cement thiab lwm yam khoom siv ntxiv. Los ntawm kev xaiv qhov zoo ntawm retarder, cov neeg cog lus thiab engineers tuaj yeem xyuas kom meej tias lawv cov khoom siv cement muaj zog, ruaj khov, thiab ua haujlwm zoo nyob rau lub sijhawm.