Experimental investigation on flexural properties of directional steel fiber reinforced rubberized concrete

Abstract

Incorporating rubber and steel fiber into concrete can avoid brittle failure of the concrete under complex stress condition and improve its flexural performance. The present study aims to investigate the synergistic effect of the rubber and steel fiber on the mechanical strengths, flexural toughness and strain field characteristics of the steel fiber reinforced rubberized concrete (SFRRC). Accordingly, a series of mechanical tests in terms of compressive, tensile splitting and flexural tests were conducted on 13 groups concrete specimens proportioned with different rubber volume content, steel fiber volume fraction and orientation of steel fiber. In addition, digital image correlation (DIC) technology was applied to analyze the process of crack propagation and strain field distribution of cracks of the concrete in the flexural tests. Experimental results suggested that rubber could enhance the residual strength f150 (maximum increase of 128.8%) of steel fiber reinforced concrete (SFRC) in the flexural tests, but caused a negative effect on its flexural strength. Furthermore, steel fiber and the orientation of steel fiber promoted the flexural strength, crack resistance and flexural toughness while decreased the strain value of cracks of the SFRRC. The maximum toughness indexes T150 of the directional SFRRC was 11.14 times of that of the rubberized concrete. Consequently, the coexistence of the rubber and steel fiber is conducive to improving the flexural performance of the SFRRC.