Mechanical behavior and durability of latex modified mortars

This article summarizes the results of an experimental program developed on latex-modified mortars. Fluidity tests, compressive strength tests, flexural strength tests, water absorption tests, adhesion tests on clay bricks and cementitious substrates were carried out. The test bodies were prepared by the pre-wetting method with different latex contents while partially substituting Portland cement by two types of latex: Styrene-Butadiene (SBR) and Styrene Acrylic (SA). In addition, samples of ordinary mortars are made in parallel as references.

The experimental results showed that the substitution of cement in mortars produced a notable improvement on fluidity and adhesion. In the case of clay substrates, a cohesive failure in the support above 10% substitution has been reported; whereas the rupture is always at the interface for all the mixtures tested on cementitious substrates. An improvement was also noted on the flexural tensile strength beyond 60 days. On the other hand, the compressive strength of the polymer mortars decreased with the substitution rate of cement for all the maturities studied. As for the absorption of water, the results show a clear reduction in the percentage of water absorption by increasing the substitution rate.