RETRACTED: Experimental study and theoretical modeling for the flexural property of multi-scale hybrid fiber reinforced SHCC

Abstract

The design of multi-scale hybrid fiber reinforced strain hardening cement-based composite (MsHySHCC) can enhance the mechanical characteristics of traditional PVA-SHCC and lower the cost. In this paper, a modified kind of MsHySHCC containing additional hooked steel fibers and CaCO 3 whiskers was designed. The flexural properties of the designed MsHySHCC thin-plate were studied by experimental and theoretical methods. The results indicated that partial substitution of PVA fibers by steel fibers and CaCO 3 whiskers improved the flexural behaviors of MsHySHCC. Although further decrease in the content of PVA fibers along with increase in the amount of steel fibers and CaCO 3 whiskers further improved the flexural bearing capacity of designed MsHySHCC, high flexural ductility could not be achieved. A semi-theoretical prediction model was derived to calculate the flexural behaviors of PVA-SHCC and MsHySHCC thin-plate. By comparing the theoretical results with the experimental results, it was found that this semi-theoretical model can adequately calculate and predict the characteristics of MsHySHCC's flexural load-deflection relationships. In order to verify the effectiveness of the designed MsHySHCC in structural strengthening application, hysteretic loop experiments of reinforced concrete (RC) columns strengthened by cast-in-place MsHySHCC thin-plate layer were also performed. The results showed that the RC column strengthened by designed MsHySHCC had a fuller hysteresis curve and skeleton curve, higher load bearing capacity, slower stiffness deterioration, higher ductility and better energy dissipation ability compared to un-strengthened column or high-strength mortar strengthened column.