Mechanical Performance of Natural Rubber Latex Modified Mortars

Abstract

Latex-modified concrete has great potential in construction industry. Various synthetic latexes such as styrene butadiene rubber, polyvinyl acetate, and acrylic emulsions are widely used in repair works, grouting, surface overlay works, etc., to impart ductility, increased strain at peak load, and enhanced energy absorption capability. Natural rubber latex can be an improved option in terms of performance and cost for producing the same efficiency of mortar/concrete in a sustainable manner. This paper aims to investigate the effect of natural rubber latex on flexural strength, water absorption, and sorptivity capacities of mortar modified with natural rubber latex. Dosage of latex used for the study varies from 0.5 to 2% by weight of cement for constant water to cement ratio. Influence of natural rubber latex on setting of cement paste is also investigated. Intertwining latex films resembling bridging effect and filling pore spaces are observed. Flexural strength can be improved more than 60% with the addition of natural rubber latex of 2%, due to the co-matrix formation by cement hydration and polymer film formation. Natural rubber latex increases the resistance to water capillary adsorption of mortar indicative of the enhanced durability of the modified concrete.