Influence of thermal cycles and high-temperature exposures on the residual strength of hybrid steel/glass fiber-reinforced self-consolidating concrete

Abstract

Although using steel fiber has been efficiently studied to mitigate the thermal damages of concrete samples exposed to high-temperature exposure, however reducing the workability is the primary concern of researchers. Accordingly, the present study aims to investigate the effect of glass and hybrid steel/glass fibers on compensating the workability and improving the thermal resistance of SCC mixtures, which was not precisely investigated by the literature. SCC specimens with various types of fibers, different packing factors (1.12 & 1.14), different sand-to-all aggregate ratios (0.50 & 0.57), and SCC grades (M40 & M80) were considered in the present study. Also, two thermal damages of thermal cycles at 200 °C (1, 3, 14, and 28 cycles) and high-temperature exposure (200 °C, 400 °C, and 600 °C) were selected. Concrete resistivity, ultrasonic pulse velocity (UPV), and concrete compressive strength are the tests considered in the present study. Results indicate that hybrid steel/glass fiber-reinforced SCC specimens have considerably higher thermal resistance as compared to single steel and glass fiber-reinforced ones. Accordingly, using glass fiber in combination with steel fiber in SCC can considerably compensate for the workability reduction along with reducing strength loss due to thermal cycles and high-temperature exposure.