Effect of Rubber Powder on the Flexibility of Cement-Based Materials
Release Time:
2021-09-27
Source:
Redispersible Latex Powder
Effect of Rubber Powder on the Flexibility of Cement-Based Materials
Re-dispersible latex powder improves the flexural strength and bond strength of mortar because it forms a polymer film on the surface of the mortar particles. This film contains pores, which are subsequently filled by the mortar matrix, thereby reducing stress concentrations and allowing the material to undergo creep under external loads without fracturing. Furthermore, after cement hydration, the mortar develops a rigid skeletal structure; within this skeleton, the polymer network acts as a compliant joint, much like biological tissues. The polymer film can be likened to joints and ligaments, thus ensuring the elasticity and toughness of the rigid framework.
In polymer-modified cement mortar systems, a continuous and intact polymer film is interwoven with the cement paste and sand particles, resulting in a denser and more homogeneous mortar matrix. At the same time, the polymer film fills capillaries and voids, forming an elastic network throughout the material. Consequently, the polymer film effectively transmits both compressive stress and tensile strain. The polymer film can bridge shrinkage cracks at the polymer–mortar interface, promoting crack healing and enhancing the mortar’s impermeability and cohesive strength. Moreover, the presence of highly flexible and highly elastic polymer domains improves the mortar’s flexibility and elasticity, imparting cohesion and dynamic behavior to the otherwise rigid skeletal structure. Under external loading, the enhanced flexibility and elasticity delay the propagation of microcracks, allowing them to develop only when higher stresses are applied. The interconnected polymer regions also exert a restraining effect on the coalescence of microcracks into through-cracks. Therefore, redispersible latex powder increases both the failure stress and the failure strain of the material.
