The effect of adding latex powder to cement/gypsum-based dry powder ready-mixed mortar


Redispersible latex powder has good redispersibility, redisperses into emulsion when in contact with water, and its chemical properties are almost identical to the initial emulsion. Adding dispersible emulsion latex powder to cement or gypsum-based dry powder ready-mixed mortar can improve various properties of the mortar, such as: improving the cohesion and cohesion of the material; reducing the water absorption and elastic modulus of the material; enhancing the material’s Flexural strength, impact resistance, wear resistance and durability; improve the construction performance of materials, etc.

Adding latex powder to cement mortar will form a highly flexible and elastic polymer network film, which will significantly improve the performance of the mortar, especially the tensile strength of the mortar will be greatly improved. When an external force is applied, due to the improvement of the overall cohesion of the mortar and the soft elasticity of the polymer, the occurrence of micro-cracks will be offset or slowed down. Through the influence of latex powder content on the strength of thermal insulation mortar, it is found that the tensile bond strength of thermal insulation mortar increases with the increase of latex powder content; the flexural strength and compressive strength have a certain degree with the increase of latex powder content. The degree of decline, but still meet the requirements of the wall exterior finish.

The cement mortar mixed with latex powder, its 28d bonding strength increases with the increase of latex powder content. With the increase of latex powder content, the bonding ability of cement mortar and old cement concrete surface is improved, which ensures its unique advantages for repairing cement concrete pavement and other structures. Moreover, the folding ratio of mortar increases with the increase of latex powder content, and the flexibility of surface mortar improves. At the same time, with the increase of latex powder content, the elastic modulus of mortar decreases first and then increases. On the whole, with the increase of ash accumulation ratio, the elastic modulus and deformation modulus of mortar are lower than those of ordinary mortar.

The study found that with the increase of the latex powder content, the cohesion and water retention of the mortar were significantly improved, and the working performance was optimized. When the amount of latex powder reaches 2.5%, the working performance of the mortar can fully meet the construction requirements. The amount of latex powder does not need to be too high, which not only makes the EPS insulation mortar too viscous and has low fluidity, which is not conducive to construction, but also increases the cost of mortar.

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