High-strength rice husk ash concrete incorporating quarry dust fine aggregates

An experimental investigation was undertaken to evaluate the mechanical properties of highstrength concrete (HSC) when sand was partially replaced with quarry dust as fine aggregates. Rice husk ash (RHA) was used as cement replacement in the HSC mixes, produced with water-binder ratio of 0.38 to achieve 60MPa at 28 days. During the trial mixes stage, sand was substituted with quarry dust from 10% to 40% in the HSC containing 10% RHA. The mix containing 20% quarry dust was chosen as the optimum to undergo further evaluation of their mechanical properties. Compressive strength, modulus of rupture, dynamic modulus of elasticity and ultrasonic pulse velocity were evaluated up to 1 year, whereas the initial surface absorption was measured on the 28th and 56th day. While the substitution of sand with quarry dust in the HSC mixes does contribute to some minor negative effects in mechanical properties, these outcomes can be compensated with cement replacement materials such as RHA, and coupled with a good mix design.