Natural rubber latex for the development of high performance cement mortar

Performance enhanced concrete and mortar with cost-effective and renewable materials are essential for sustainable construction. The use of synthetic polymeric latexes in construction applications is quite common. The use of natural polymers like natural rubber latex (NRL) with very low embodied energy compared to synthetic latexes has become essential in the construction industry. This study attempts to develop a high-performance mortar using natural rubber latex. The effect of natural rubber latex addition (from 0.5 to 2% by weight of cement) on the flow, strength, and durability of mortar is investigated. Challenges in the concrete modified with natural rubber latex are addressed by the inclusion of defoamer. The influence of defoamer in reducing the air entrainment of NRL-modified mortar is studied and the optimum percentage of defoamer to be incorporated in modified mortar is suggested. Macroscopic and microscopic images have confirmed the formation of latex film and network formation in the mortar which explains the improvement in mechanical properties and durability of NRL-modified mortar compared to the reference mortar without latex. The effect of natural rubber latex incorporation on mortar mixture composition and interactions on strength parameters has been verified by ANOVA at 5% significance level. NRL increases the flexural strength capacity and causes a significant reduction in permeable porosity (58%) and sorptivity (86.4%), demonstrating its huge potential in terms of durability properties. The results indicate that natural rubber latex-modified mortar can be effectively utilized for field applications, particularly those exposed to aggressive environments and repair works.