Characterization of mechanical behavior and mechanism of hybrid fiber reinforced cementitious composites after exposure to high temperatures

In this paper, we developed a novel hybrid fiber reinforced cementitious composites (HFRCCs) using steel fibers, polyvinyl alcohol (PVA) fibers and calcium carbonate whisker (CW) with high temperature resistance and cost-effectiveness. Mechanical and physical responses of HFRCCs after exposure to high temperature and roles of different fibers were particularly studied. The results showed that partially replacing PVA fibers by CW could reduce the deterioration of strengths and flexural toughness of HFRCCs before 600 °C because of significant nucleation effect and restraining cracking of CW. PVA fibers would melt above 200 °C and thus deteriorated the flexural and splitting tensile strengths, but less effective to compressive strengths. Steel fiber was most effective to increase the residual mechanical properties among these fibers because of its higher thermostability and strong bond with matrix. Generally, high temperature deteriorated the matrix and adversely affected the quality of fibers, which was mainly related to the different thermostability between fibers.