Performance evaluation of reactive powder concrete with polypropylene fibers at elevated temperatures

Reactive Powder Concrete (RPC) is a type of ultra-high strength concrete. Due to its dense microstructure, is vulnerable to explosive spalling at elevated temperatures. Remarkable application of RPC in special structures throughout the world has drawn the attention to understand the performance of RPC at elevated temperatures, which has not been investigated extensively yet. The main objective of this work was to evaluate the performance of RPC at elevated temperatures from 200 °C to 800 °C, by obtaining residual mechanical properties after exposure. The study aims to find an optimum fiber dosage for spalling protection of RPC. To improve the mechanical properties, RPC incorporating fiber dosage from 0.1% to 0.9% is studied. The thermal deterioration of RPC is assessed using ultrasonic pulse velocity, water absorption and sorptivity. Results shows that 0.1% fiber dosage is enough to control spalling of RPC up to 800 °C. To enhance the residual properties of RPC exposed to elevated temperatures, it is recommended to use fiber dosage of 0.5%. The study also includes microstructural analysis of RPC subjected to elevated temperatures, to assess and evaluate the formation of pores and cracks.