Experimental investigation of strength and temperature effect of rubberized concrete

Abstract

Concrete is weak in tension and it has very limited ductility. Plain cement concrete performs very poorly when it is exposed to repetitive load and impact load. Crumb rubber obtained from rubber wastes of transportation and engineering sector can be added to concrete to improve the ductility and crack-resisting property of concrete, although there is known to be some reduction in compressive and flexural strength of concrete. Based on this background, an experimental investigation on the effect of crumb rubber in plain cement concrete has been made. The study includes the effect of addition of crumb rubber in different percentage of fine aggregate on the workability and mechanical properties of concrete. Initially the particle size distribution of crumb rubber, fine aggregate and coarse aggregate are analysed. The mechanical properties like compressive strength, flexural strength, split tensile strength, strength under thermal exposure, stress-strain behaviour of rubberized concrete have been studied. Nominal size of 10mm coarse aggregates and nominal size of 2.36mm crumb rubber chips are used along with sand of Zone-II to prepare the rubberized concrete mixes. Superplasticizer has also been used to improve the workability. Ordinary Portland cement (OPC) has been used and as a result, initial strength gain of 7 days has been found to be noteworthy. The crumb rubber chips are used in surface-dry condition without any surface treatment. Four different mixes have been prepared with M25 and M35 grades each, having 0%, 5%, 10% and 15% crumb rubber chips. Workability and compressive strength tests have been performed with both M25 and M35 grade mixes while split tensile strength, flexural strength, stress-strain study and study of temperature tests have been performed with M25 grade mixes. It is noted that the strength of rubberized concrete has been reduced but its toughness increases in proportion to the increasing rubber content which means the rubberized concrete has more strain energy storing capacity in comparison to the controlled mix concrete. Under thermal exposure, rubberized concrete has shown desired results which have established the fact that the crumb rubber induced in concrete is able to sustain high temperature exposure.