Properties of reactive powder concrete containing different combinations of fly ash and metakaolin

Reactive powder concrete (RPC) is a special type of concrete that has excellent properties, especially compressive strength. However, one of the disadvantages of RPC is that it has a high cement content, which can reach 1000 kg/m3. Because of the high cost of producing cement and the greenhouse gas emissions associated with its manufacture, researchers have resorted to investigating alternatives to cement, including supplementary cementitious materials. Accordingly, this research aims to produce environmentally friendly RPC in which 50% of the cement was replaced by metakaolin (MK) and fly ash (FA) combinations. To achieve the aim of the study, three RPC mixtures: 10MK + 40FA, 15MK + 35FA, and control mixture (without replacement) were cast. The fresh and mechanical properties tests were performed. The results showed that the combination of MK and FA improved the fresh properties of RPC, while the hardening properties were decreased.