THE DURABILITY ASPECTS AND BOND STRENGTH OF RUBBERCRETE CONTAINING NANO SILICA

Crumb rubber is product from the processed waste scrap tire which is non-biodegradable and threat to environment. One of common usage of crumb rubber is production of concrete containing crumb rubber or rubbercrete. Rubbercrete contribute a lot of benefits such low density, good thermal resistivity, and high ductility. Adverse effect of rubbercrete strength of the concrete is decreased as percentage of crumb rubber added increased. This is due to physical properties of crumb rubber that repels water make the adhesion between cement and aggregate decreased. Nano silica is widely used nowadays and found can increase the compressive strength of concrete. Nanosilica works as filler in the empty spaces in the concrete particles. It acts as nucleation of the hydrated products resulting in the improvement of concrete hydration rate of the concrete proving in the high early strength of concrete containing nano silica. Thus nano silica is proven can improve the transition zone between aggregates and cement paste. Hence, in this research, we believe by adding nano silica in the rubbercrete, the nano silica will overcome the problem of decreasing in strength of rubbercrete as a matter of fact, creating a concrete that have both high ductile properties and high strength. In these studies, 0, 5, 10, 15, and 20 weights % of rubber crumbs with respect to fine aggregate is added to the concrete. The type of w/c used for the concrete containing crumb rubber is 0.41, 0.57 and 0.68 accordingly. For increasing the concrete compressive strength, 1, 3 and 5% of nano silica were introduced to the rubber containing concrete with respect to cementitios material. For the concrete containing nano silica and crumb rubber the w/c ratio used only 0.57. The mixture schemes for measuring the 28 day compressive strengths and bond strength were performed according to ACI standard. After that the durability aspect and bond strength of the concrete were tested according to BS EN 12393 and ASTM C234 1999. Result show that by adding nano silica in the concrete mixture containing crumb rubber, it counterpart the weakness of cubbercrete which low in strength. The porosity and permeability of the concrete also decrease by adding nano silica in the rubbercrete.