Effect of mixing ratio on fire resistance of cement mortar with polypropylene fiber and polymer

Polymer cement mortar is commonly used as a repair material for reinforced-concrete (RC) structures owing to its high resistance to degradation factors, except for high-temperature environments. Here, the fire resistance of fiber-mixed polymer cement mortar was evaluated according to the polymer content and polypropylene (PP) fiber length and content to identify the optimal mix for ensuring adequate fire resistance of polymer cement mortar. Furthermore, a 3-h fire resistance test was conducted on specimens with different moisture content. The probability of spalling increased with increasing moisture content and polymer content and decreased with increasing length and content of PP fibers. •Fire resistance of fiber-mixed polymer cement mortar was evaluated.•Polymer content and polypropylene fiber length and content were varied.•3-h fire resistance test was conducted on specimens with varying moisture content.•Spalling increased with moisture and polymer contents.•Spalling decreased with polypropylene fiber length and content.