Influence of CaCO3 Whiskers and PVA Fibers on the Flexural Properties of Steel Fiber–Reinforced Cementitious Composites

Abstract

Multiscale fiber hybridization is an essential method for enhancing and toughening cement-based materials. In this study, the influence of the content of calcium carbonate whiskers (CW) and polyvinyl alcohol (PVA) fibers on the flexural properties of cementitious composites containing 1.5% by volume steel fibers was investigated by using the hybridization of CW, PVA fibers, and steel fibers based on the four-point bending notched test. The distribution characteristics of PVA fibers and steel fibers in multiscale hybrid fiber-reinforced cementitious composites (MFRC) were analyzed and evaluated using backscattered electron imaging (BSE). The results demonstrated that the addition of an appropriate amount of CW and PVA fibers effectively improved the flexural performance of steel fiber–reinforced cementitious composites and promoted a more uniform distribution of steel fibers within the matrix. The MFRC with 1% by volume CW, 0.3% by volume PVA fiber, and 1.5% by volume steel fiber (C1P03S15) exhibited the highest flexural toughness coefficient (σb) and fiber dispersion coefficient (γ), which increased by 46.2% and 81.4%, respectively, compared to the control group without CW. Furthermore, a strong correlation between σb and γ was observed through fitting, indicating the potential for guiding practical engineering applications.