The Importance of Water Retention of HPMC
April 24th 2024
HPMC manufacturer-How to Choose Construction Additives for Various Ready Mix Mortars to Better Improve the Performances?
Modified additives such as ready-mixed mortar additives, cellulose ethers, coagulant, redispersible polymer powder, air-entraining agents, early strength agents, water-reducing agents, etc., which are added separately according to the needs of the project, greatly improve the performance of ready-mixed mortars, physical and mechanical properties. The additives in these ready-mixed mortars are added to the ready-mixed mortar to make the quality of the ready-mixed mortar more stable and superior in performance.
The anionic surfactant contained in the ready-mixed mortar additive in projects can disperse the cement particles and release the free water encapsulated by the cement agglomerates, which fully diffuses the agglomerated cement clusters, completely hydrates, and achieves a compact structure and increases the mortar’s strength, improve impermeability, crack resistance and durability. The mortar mixed with ready-mixed mortar additives has good workability during operation, high water retention rate, strong adhesion, non-toxic, harmless, safe and environmentally friendly. It is suitable for the production of ordinary masonry, plastering, ground and waterproof mortar in ready-mixed mortar factories. It is used for the construction of concrete clay bricks, ceramsite bricks, hollow bricks, concrete blocks, and non-burning bricks in various industrial and civil buildings. Construction of internal and external wall plastering, concrete wall plastering, ground and roof leveling, waterproof mortar, etc.
In the ready-mixed mortar, cellulose ether is a main additive that has a very low addition amount, but can significantly improve the performance of the wet mortar and affect the construction performance of the mortar. Reasonable selection of cellulose ether of different varieties, different viscosities, different particle sizes, different degrees of viscosity and added amount will produce and exert a positive influence on the improvement of the performance of dry mortar.
The production of cellulose ether is mainly made by processing natural fibers through alkali dissolution, grafting reaction (etherification), washing, drying, and submerging. In the production of building materials, especially dry mortar, cellulose ether plays an irreplaceable role, especially in the production of special mortar (modified mortar), it is an indispensable and important part. Cellulose ether plays a role in water retention, thickening, delaying cement hydration power, and improving construction performance. The good water retention capacity makes the cement hydration more complete, can improve the wet tackiness of the wet mortar, increase the bonding strength of the mortar, and the time can be adjusted. The addition of cellulose ether to mechanical spraying mortar can improve the spraying or pumping performance of the mortar, as well as the structural strength. Therefore, cellulose ether is widely used as an important additive in ready-mixed mortar. The cellulose ethers used in ready-mixed mortar are mainly methyl hydroxyethyl cellulose ether and methyl hydroxypropyl cellulose ether. They hold more than 90% of the market share.
Redispersible polymer powder is a powdered thermoplastic resin produced by spray drying and subsequent processing of polymer emulsions. It is mainly used in construction, especially dry mortar to increase cohesion, cohesion and flexibility.
The role of the redispersible polymer powder in the mortar: the redispersible polymer powder forms a film after being dispersed and acts as a second adhesive to enhance the adhesion; the protective colloid is absorbed by the mortar system and will not be destroyed by water after the film is formed or disperse twice; the film-forming polymer resin is distributed in the entire mortar system as a reinforcing material, thereby increasing the cohesion of the mortar.
Redispersible polymer powder in wet mortar can improve construction performance, improve fluidity, increase thixotropy and sag resistance, improve cohesion, extend open time, enhance water retention, etc. It can improve the tensile strength after the mortar is cured. Tensile strength, increase bending strength, reduce elastic modulus, improve deformability, increase material compactness, increase wear resistance, increase cohesive strength, reduce carbonization depth, reduce material water absorption, and make materials have excellent hydrophobicity water and other effects.
Air-entraining agent, refers to the introduction of a large number of uniformly distributed micro-bubbles during the mortar mixing process, which can reduce the surface tension of the mixed water in the mortar, resulting in better dispersibility and reduced mortar mixing Additives for bleeding and segregation. In addition, the introduction of fine and stable air bubbles also improves construction performance. The amount of air introduced depends on the type of mortar and the mixing equipment used.
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