Mechanical properties of PVA fiber reinforced cementitious composites (PVA-FRCC) after high temperature

PVA fiber reinforced cementitious composites (PVA-FRCC) exhibit superior mechanical properties and are widely utilized in engineering applications. However, the investigations into their behaviors at high temperatures are limited. Given that these materials are potentially exposed to elevated temperatures in specific applications, it is crucial to study their performance under such conditions. This study investigates the appearance, mass, compressive strength, flexural strength, and uniaxial tensile properties of PVA-FRCC after exposure to high temperatures (200 °C, 400 °C, 600 °C, and 800 °C) for 1 h. Degradation curves and equations for the mechanical properties of PVA-FRCC post-high temperature exposure were developed, and the underlying mechanisms were explored through XRD and thermogravimetric analysis. The results indicate that the performance of the specimens decreases significantly after high temperature exposure. As temperature increases, the mass loss rate gradually rises, accompanied by corresponding decreases in compressive strength, flexural strength, and ultimate tensile strength. After exposure to 800 °C, the mass loss rate reaches 19.1 %, and the compressive strength, flexural strength, and ultimate tensile strength decrease by 66.7 %, 68.2 %, and 86.4 %, respectively, compared to the reference. The decomposition of Ca(OH) 2 , C-S-H, and CaCO 3 within the material, along with fiber melting at different temperature ranges, leads to pore formation within the matrix, resulting in the deterioration of material properties.