Research on the Mechanical Strengths and the Following Corrosion Resistance of Inner Steel Bars of RPC with Rice Husk Ash and Waste Fly Ash

Abstract

In this paper, the slump flow and mechanical strengths (compressive and flexural strengths) of the reactive powder concrete (RPC) with rice husk ash (RHA) and waste fly ash (WFA) were investigated. The following corrosion resistance of steel bars-reinforced specimens was researched. The ultrasonic sound, the mass loss rate, the electrical resistance, and the electrical resistance time history curves were determined to reflect the corrosion resistance of steel bars. The influence of NaCl freeze–thaw cycles and dry–wet alternations was considered. Results showed that the addition of RHA and WFA demonstrated a negative effect on the fluidity of fresh RPC. The fluidity of fresh RPC with WFA was lower. Moreover, RHA and WFA could effectively improve the mechanical strengths of hardened RPC, and the enhancing effect of RHA was higher. The increasing dosage of RHA could improve the corrosion resistance of steel bars in RPC when the specimens were exposed to the environment of NaCl freeze–thaw cycles and dry–wet alternations. However, when WFA was added, the effect was the opposite. The steel bars in RPC corroded more seriously when the specimens were exposed to the environment of NaCl dry–wet alternations than the environment of NaCl freeze–thaw cycles.