Performance of Strain hardening cementitious composite as strengthening and protective overlay in flexural members

Abstract

Strain-hardening cementitious composites (SHCC) are advanced type of cement-based composite materials having superior crack control and tensile properties. Owing to such characteristics, SHCC can be used for strengthening and crack-width control of structural members. This paper presents a study on the flexural response of reinforced concrete (RC) beams with different overlays of SHCC. The work consists of RC-SHCC overlay beams, in which SHCC overlays of different thicknesses (15% and 30% of beam height, plus cover) and reinforcement ratios (0% and 0.4%) were cast at the bottom of the RC beams. The performance of the RC-SHCC overlay beams was compared with control RC beams having concrete overlays of similar parameters. A series of eight laboratory-scale control and composite beam specimens were tested under four-point bending test. From the experimental results, it was observed that RC-SHCC overlay beams showed improved flexural capacity and crack control as compared to that of control beams. The beams with unreinforced SHCC overlays showed significant improvement at service stage, while beams with reinforced SHCC overlays showed significant improvement at peak stage. The SHCC overlay beams without reinforcement have showed improved ductility as compared to control beams with concrete overlays. Additionally, the SHCC overlays performed as a protective layer for controlling the crack widths in the composite beams.