Heat evolution, strengths, and drying shrinkage of concrete containing high volume ground bagasse ash with different LOIs

Abstract

This research examines the feasibilities of extending the high level of ordinary Portland cement (OPC) substitution by ground bagasse ash (GBA) with different loss on ignitions (LOIs). Bagasse ash (BA) from a sugar mill was processed by floating in the water to have different LOIs values of 10 ± 2, 15 ± 2, and 20 ± 2 wt%. Then, BA was ground to have high fineness and substituted OPC at 50, 65, and 80 wt% of binder to cast high volume ground bagasse ash (HVGBA) concrete. Properties of HVGBA concretes namely, heat evolution, compressive strength, splitting tensile strength, elastic modulus, and drying shrinkage were investigated. The results showed that the use of HVGBA could reduce the peak temperature rise by 8–19 °C from control concrete (CT). The use of 50–65% replacement of GBA with 10–15% of LOI for concrete with OPC of 140–200 kg/m3 produced a compressive strength similar to CT concrete (OPC of 400 kg/m3) at 90 days. HVGBA concretes with different LOIs did not significantly affect splitting tensile strength and elastic modulus of concrete. All concretes incorporating HVGBA with different LOIs had higher drying shrinkages than CT concrete which increased with the increasing LOI and rate of cement replacement. The results also indicated that the high LOI (higher than 15%) of GBA affected mechanical properties of concrete at the early age, particularly at high substitution rate (65–80%). In contrast, GBA with higher LOI had a greater effect on lowering heat evolution, while the higher drying shrinkage was achieved than the concrete with low LOI (10–20%) of GBA. The results indicated that the use of HVGBA as a pozzolanic material had many benefits such as decreasing of disposal area, increasing of its value, reducing the cost of concrete production, and a good choice to reduce CO2 due to the reduction of cement consumption.