Studying the Mechanical Behavior and Strengthening of RCSACC after Exposure to Elevated Temperatures

Rapid calcium sulfoaluminate cement concrete (RCSACC) has received increased attention of late because it can be manufactured with less CO2 emissions than ordinary Portland cement. In previous studies, RCSACC performed poorly when subjected to elevated temperatures, to which fiber-reinforced concrete (FRC) is a potential alternative. This study investigated the impact of incorporating two types of fibers, i.e., copper-plated steel microfilament (CPM) and shear corrugated steel (SC), on the engineering, mechanical, and microstructural features of RCSACC after exposure to elevated temperatures. Pore size distribution, microstructure, and mechanical properties were tested after exposure to temperatures of 100, 200, and 300 °C. The content of each type of fibers represented 1% of the concrete. The results showed that the mechanical properties were affected by the addition of either type of steel fibers. Adding CPM or SC steel fibers could ensure an adequate resistance of RCSACC when exposed to high temperatures, in addition to improving its residual mechanical behavior, spalling resistance, and ductility after heating. Steel fibers contribute to enhancing both mechanical properties and resistance to heating effects. However, adding steel fibers also appears to increase microstructure damage with heat, reduce workability, entrap air and water, and reduce cracking related to drying shrinkage.