Transport Properties and Deicing Salt Resistance of Blended Ultrahigh-Performance Concrete

Abstract

Premature degradation of concrete, caused by frost damage, has been associated with inadequate transport properties and poor resistance to deicing salt. In this study, transport properties and deicing salt resistance of various kinds of ultrahigh-performance concrete (UHPC) containing Type V portland cement, fly ash, and microsilica were investigated. Seven combinations of cementitious materials (one reference, three binary, and three ternary) were used to batch UHPCs using a water-to-cementitious material ratio (w/cm) of 0.21. The aggregate-to-cementitious material ratio (Va/Vcm) of 1.20 was kept constant for all mixtures. The investigated transport properties included water absorption, volume of permeable voids, water penetration, rapid chloride penetration, and surface resistivity. The transport properties of the plain UHPCs were also compared to those of the corresponding steel fiber–reinforced UHPCs. The test results showed that the transport properties and deicing salt resistance of the studied binary and ternary UHPCs improved with the inclusion and increases in microsilica, replacing a portion of cement. The addition of steel fiber had a minor effect on strength and transport properties and a moderate increase in deicing salt resistance of the studied UHPCs. While rapid chloride penetration and surface resistivity tests were found appropriate to assess chloride transport through the studied plain UHPCs, both tests were deemed unsuitable for the companion steel fiber–reinforced UHPCs.