A study on the effects crumb rubber and fiber on the mechanical properties of self-compacting concrete

Destruction and deterioration of concrete is highly dependent on the formation of cracks and micro-cracks resulted from loading, or environmental influences. Heat and humidity changes in the cement paste form micro-cracks that are concentrated on the surface of coarse grains. As the influence of loading and environmental issues increases, the micro-cracks merge and form cracks that ultimately spread in the concrete body. Using different fibers in the concrete and fabricating fiber concrete is an effective step in preventing the spread of micro-cracks and cracks, and improving the tensile strength.In the present experimental study, the effect of crumb rubber and various metal and glass fibers is investigated on mechanical properties (Compressive strength, tensile strength and modulus of elasticity), rheology (L-BOX, current slump, T50 and funnel V), and the water absorption of self-compacting concrete.To this end, 27 mix designs including mixtures of metal fiber and crumb rubber, glass fiber and crumb rubber, and metal and glass fiber. Metal fibers with 0.1, 0.2, and 0.3% by volume, and glass fibers with 0.1, 0.15, and 0.2% by volume were used. Moreover, crumb rubber was used for volume replacement of sand (0, 4, and 8%). Results show that optimal properties of fiber improve the mechanical properties of self-compacting concrete. Thus, in the mixture containing 0.2% metal fiber tensile strength had increased 29.3% compared to the control sample, due to the fibers’ role in controlling cracks.

کلیدواژه ها:

self-compacting concrete (SCC) ، fiber ، crumb rubber ، mechanical properties