Mechanical Properties of Hybrid Steel–Glass Fiber-Reinforced Reactive Powder Concrete After Exposure to Elevated Temperatures.

Due to extremely dense microstructure, reactive powder concrete (RPC) shows poor performance at elevated temperatures owing to the development of high pore pressure that causes the deterioration of the material. By using fiber reinforcement, elevated temperature performance of RPC can be improved, as noted by many researchers. To this end, 3% volume fraction of four combinations of steel fiber (SF) and glass fiber (GF) [(3%, 0%), (2%, 1%), (1%, 2%), and (0%, 3%)] was used in RPC to study the change in residual mechanical properties of RPC after exposure to elevated temperatures. Three main mechanical properties, i.e., compressive strength, splitting tensile strength, and flexural strength properties, were studied. Experimental results showed that using 3% volume fraction of fibers (regardless of combination), explosive spalling of RPC was completely prevented. Hybrid fiber RPC with 2%SF–1%GF showed the maximum best mechanical performance at both elevated and normal temperatures. Single 3%SF–RPC performed significantly better than single 3%GF–RPC at both normal and elevated temperatures. A strong correlation existed between the normal temperature strength, residual strength, and exposure temperature. [ABSTRACT FROM AUTHOR]