Experimental Research on Properties of Fresh and Hardened Rubberized Concrete

In this study, the use of tire-rubber particles as a replacement for coarse aggregate in concrete is investigated. Rubber has replaced coarse aggregate at content levels of 25, 50, 75, and 100% in concrete by volume. Also, emulsified asphalt (EA) was used to improve the mechanical properties of rubberized concrete. Four different series of concrete mixtures were designed to investigate the effects of the water-cement (w/c) and EA-cement (EA/C) ratios on the properties of rubberized concrete. The slump, air content, dry unit weight, compressive strength, elasticity modulus, and flexural strength have been compared to the corresponding properties of controlled concrete. Consequently, an increase in rubber content leads to a decrease in slump and an increase in air content because of the rough surface of rubber. An increase in rubber content decreases compressive strength, elasticity modulus, and flexural strength because of its lower stiffness and poorer bonding between rubber and the paste matrix. In the case of equal levels of rubber particle content, the addition of EA greatly increases slump. However, the effects of EA on the properties of rubberized concrete, such as air content, strength, and elasticity modulus, are based on the EA/C ratio. A certain level of EA addition can improve the compressive and flexural strength of rubberized concrete. EA addition reduces the elasticity modulus of the concrete. Adding EA is a good way to improve the bonding between rubber particles and cement paste. (C) 2014 American Society of Civil Engineers.