Dry-mixed mortar is a combination of cementitious materials (cement, fly ash, slag powder, etc.), special graded fine aggregates (quartz sand, corundum, etc., and sometimes requires light Granules, expanded perlite, expanded vermiculite, etc.) and admixtures are uniformly mixed in a certain proportion, and then packed in bags, barrels or supplied in bulk in dry powder state as a building material.
There are many kinds of commercial mortar, including dry powder mortar for masonry, dry powder mortar for plastering, dry powder mortar for ground, special dry powder mortar for waterproofing, heat preservation and other purposes. To sum up, dry-mixed mortar can be divided into ordinary dry-mixed mortar (masonry, plastering and ground dry-mixed mortar) and special dry-mixed mortar. Special dry-mixed mortar includes: self-leveling floor mortar, wear-resistant floor material, inorganic caulking agent, waterproof mortar, resin plastering mortar, concrete surface protection material, colored plastering mortar, etc.
So many dry-mixed mortars require admixtures of different varieties and different mechanisms of action to be formulated through a large number of tests. Compared with traditional concrete admixtures, dry-mixed mortar admixtures can only be used in powder form, and secondly, they are soluble in cold water, or gradually dissolve under the action of alkalinity to exert their due effect.
Redispersible latex powder is usually a white powder with dry fluidity, with an ash content of about 12%, and the ash content mainly comes from the release agent. The typical particle size of polymer powder is about 0.08mm. Of course, this is the size of the emulsion particle aggregate. After redispersing in water, the typical particle size of the emulsion particle is 1~5um. The typical particle size of the emulsion particles used directly in the form of emulsion is generally about 0.2um, so the particle size of the emulsion formed by the polymer powder is relatively large. The main function is to increase the bonding strength of mortar, improve its toughness, deformation, crack resistance and impermeability, and improve the water retention and stability of mortar.
The polymer redispersible polymer powder currently used in dry powder mortar mainly includes the following types:
(1) styrene-butadiene copolymer;
(2) Styrene-acrylic acid copolymer;
(3) vinyl acetate homopolymer;
(4) polyacrylate homopolymer;
(5) Styrene acetate copolymer;
(6) Vinyl acetate-ethylene copolymer, etc., most of which are vinyl acetate-ethylene copolymer powder.
Post time: Mar-07-2023