Self-compacting concrete containing untreated-mixed fly ash and rice husk ash, Part II: Hardened concrete characteristics

Abstract

We evaluated the fresh characteristics of self-compacting concrete (SCC) mixtures containing rice husk ash (RHA) and fly ash (FA). The rice husk ash was used as a fine aggregate replacement at levels of 0% and 25% and the fly ash was used as a cement replacement at levels of 0, 20, 40 or 60% by volume. Trials were conducted to determine the water content required to produce SCC mixtures with a slump flow of 70 ± 2.5 cm. The hardened properties tests including compressive strength and ultrasonic pulse velocity were measured at 3, 7, 28, 91 and 180 days. The results demonstrate that the optimum fly ash content was 20-40% and the optimum rice husk ash content was 25%, resulting in an optimum SCC mixture with the compressive strength of 30-40 MPa.