The Main Components of Dry Mortar
Dry mortar is a semi-finished mortar product that is accurately mixed and evenly mixed with the raw materials at the factory. At the construction site, it only needs to be mixed with water. Because there are many types of dry mortar, it is widely used. One of its biggest features is that it can play a role of adhesion, decoration, protection, and lining with a thin layer. For example, the mortar with the function of adhesion mainly includes masonry mortar, tile adhesive mortar, grout mortar, and anchoring mortar; the mortar with the function of decorative effect mainly includes various plastering mortar, interior and exterior wall putty, colored decorative mortar, etc.; the mortar with the function of protection includes waterproof mortar, various corrosion-resistant mortar, self-leveling floor mortar, wear-resistant mortar, thermal insulation and heat preservation mortar, sound-absorbing mortar, repair mortar, mold-proof mortar, anti-mildew mortar, shielding mortar, etc. Therefore, its components are also relatively complex, which can be summarized as consisting of adhesive materials, fillers, mineral admixtures, pigments, and additives.
1. Adhesive materials. The commonly used adhesive materials for dry mortar are: Portland cement, ordinary Portland cement, high-alumina cement, calcium silicate cement, natural gypsum, lime, silica fume, and mixtures of these materials. Portland cement (usually Type I) or Portland cement white are the main adhesive materials. Special cement is often used in floor mortar. The proportion of binders in dry mixed mortar products ranges from 20% to 40% of the product quality.
2. Fillers. The main fillers used in dry mortar are: yellow sand, quartz sand, limestone, dolomite, expanded perlite, etc. These fillers are crushed, dried, and screened into three categories of coarse, medium, and fine. The particle sizes are: coarse fillers 4mm-2mm, medium fillers 2mm-0.1mm, and fine fillers less than 0.1mm. Very fine products require the use of fine stone powder and selected limestone as aggregate. Ordinary dry mortar can use crushed limestone or dried and screened sand as aggregate. If the sand quality is sufficient for high-quality structural concrete, it must meet the requirements for producing dry mixes. Producing reliable dry mortar requires accurate control of the particle size and feed ratio, which is achieved in a dry mortar automatic production line.
3. Mineral admixtures. The main mineral admixtures used in dry mortar are: industrial by-products, industrial waste, and some natural minerals, such as slag, fly ash, volcanic ash, fine silica stone powder, etc. These admixtures have a chemical composition mainly of calcium aluminum silicate hydrates with high reactivity and water hardening properties.
4. Additives. Additives are a key factor in dry mortar, the type, quantity, and compatibility of additives, as well as the relationship between additives, affect the quality and performance of dry mortar. To improve the workability and adhesion of dry mortar, enhance its crack resistance, reduce permeability, prevent segregation and bleeding, and improve its construction performance, reduce production costs. Such as polymeric powder adhesives, wood fibers, hydroxy methyl cellulose ether, hydroxypropyl methyl cellulose, modified polypropylene fibers, PVA fibers, and various types of superplasticizers.
