Shear strength of epoxy-modified reinforced concrete beams

Epoxy-modified concrete (EMC) is made by partially replacing ordinary Portland cement with epoxy by weight. The present research is concerned with the shear behavior of epoxy-modified reinforced concrete (EMRC) beams. To study the response characteristics and failure mechanisms, a comprehensive experimental program was carried out on eighteen simply supported over-reinforced EMRC beams. All beams were made from EMC with 70 MPa as compressive strength. The testing variables include epoxy weight ratio, shear span-to-effective depth ratio, and stirrups ratio. Compared to non-epoxy concrete beams, EMCR beams exhibit less deformation, higher shear capacity at cracking and ultimate levels, and more displacement ductility. EMRC beams containing higher epoxy content tend to produce less propagated, less widened, and more spread cracks. In addition, nonlinear finite element analysis was performed in order to predict the load–deflection curves of tested beams. Finally, proposed design equation was proposed to predict the ultimate shear capacity of EMRC beams, and a comparative study was made with ACI Code. The predicted results of finite element and design studies correlated well with measured results.