DURABILITY PERFORMANCE OF NATURAL RUBBER LATEX MODIFIED CONCRETE

Abstract

Deterioration of concrete due to chemical aggression normally through transporting agents is a serious menace to the two major qualities of concrete; strength and durability. This paper reports the findings of a study conducted to assess the effect of natural rubber latex on resistance to the ingress of sodium sulphate (Na2SO4) and moisture into hardened concrete. Two principal categories of concrete (normal and modified) involving different grades and sizes were developed. Concentrated natural rubber latex was used in this study. The quantity of the latex was varied from 0 – 5% and 0 – 10% latex/water ratio (L/w) for the chemical resistance and water absorptions respectively. A simulated aggressive medium containing 2.5% Na2SO4 serves as the curing environment for the chemical detections. Results have shown that attack due to Na2SO4 and moisture absorptions are seriously influenced by the amount of latex added into the mix and period of exposure. It is further comprehended that the general moisture ingress is significantly affected by concrete grade. In fact, within the time frame considered in this work, the optimum amount of concentrated latex for maximum resistance to Na2SO4 penetrations is 1.5% (L/w) while for minimum water absorption is 5% (L/w). The outcome of the work therefore, identifies and indicates the level of efficiency and importance of using appropriate quantity of latex concentrate in the modification process of normal concrete, especially in the areas of sulphates attack and water ingress.