Combined use of untreated-waste rice husk ash and foundry sand waste in high-performance self-consolidating concrete

Abstract

High-performance self-consolidating concrete (SCC) has great potential for advanced applications in modern concrete construction. SCC has high-performance characteristics especially high flow when in its fluid state it is poured into complicated molds and passes congested reinforcing steel without either excessive segregation or bleeding. Thus, SCC can develop strong early- and long-term mechanical and durability properties. The focus of this study is the combined effects of using foundry sand waste (FDW) obtained from the process of casting automobile engine parts as a fine aggregate replacement for Type-I Portland cement (OPC) in the amounts of 30 and 50 wt% with untreated rice husk ash (RHA) obtained from a rice husk–based fuel electricity power plant to replace OPC in the amounts of 10 and 20 wt%. The SCC prepared with water-binder materials (OPC and/or RHA) at a ratio (w/b) of 0.35 and 0.45 and the targeted slump flow in SCC production (the measured slump flow must be in the range of 70.0 ± 2.5 cm. In this study, a comprehensive investigation is undertaken that includes tests to determine the SCC specimens' fresh, hardened, and durability properties. The results indicate that FDW used to replace OPC to the extent specified has a positive effect on the SCC with RHA, increases the required superplasticizer amount and setting times compared to those of the control SCC, and decreases the slump flow of SCC. The incorporation of RHA and FDW decreases the filling, passing ability, and segregation of SCC while increasing its durability. In summary, with 10 wt% RHA together with 30 wt% FDW, the RHA-FDW-SCC produced showed the highest compressive and splitting tensile strengths of all the specimens tested compared to conventional SCC and met the durability requirements for SCC.