Investigation of Flexural Capacity of Concrete Containing Liquid Silicone Rubber

Despite the great use of concrete, tensile strength and low flexibility and brittleness are its weaknesses. Many solutions have been provided to eliminate the mentioned defects. In order to increase the flexibility of concrete in previous studies, crushed rubber tire particles have been added to concrete. Recycling car tires helps the environment and makes concrete much more flexible than regular concrete. In this research, silicone rubber has been replaced by 0%, 2%, 4%, 8%, 12.5%, 25%, and 50% of mineral aggregates. This rubber was initially in liquid form, which, after mixing with ordinary concrete, dispersed into the concrete texture and formed a uniform mixture, and this liquid rubber became a flexible solid after 24 hours. Concrete containing silicone rubber is a new composite with new properties, and in this research, it is called Hybrid Silicone Rubber Concrete (HSRC). Also, to evaluate the effect of aggregate size in making experimental specimens, two coarse to fine aggregate ratios of G/S = 0.7, 1.1 were considered. Flexural strength tests were performed on hardened concrete beam specimens. The results showed that, with increasing the amount of silicone rubber in concrete, flexural strength decreased and this percentage of strength reduction was compared with the percentage of reduction in compression and splitting tensile strength. It was found that the reduction of flexural strength was less than compression and splitting tensile strength. Larger deformation was observed during all tests when the concentration of silicone rubber increased. It was observed that the higher the amount of silicone rubber in the specimens, the less noise and the less separation of aggregates with which the failure of the specimens was associated.