Sustainable cementitious blends for strength enhancement of Queensland dredged mud

Cement is commonly used as a stabilisation material in soft soil stabilisation. However, the use of cement can cause environmental issues as the production of cement results in high emission of CO2. Hence, it is essential to develop other suitable stabilisation materials to reduce the amount of cement used in the stabilisation of soft soil. Fly ash and DuraCrete® were investigated in this study to be used as partial replacements for traditional cement-only mixes. The behaviour of specimens stabilised using cement, fly ash, and DuraCrete (blended cement) under both Unconfined Compressive (UC) and Consolidated Isotropic Undrained (CIU) conditions, were investigated in this study. The experiment results proved that both fly ash and DuraCrete can be used as partial replacements of cement. Fly ash can provide the highest reduction in terms of percentage of cement. Meanwhile, DuraCrete is more cost effective, as a relatively smaller quantity of DuraCrete can replace a correspondingly larger amount of cement for a similar strength gain. The contribution of this research can provide engineers with alternative, more sustainable design mixes for soft soil stabilisation that can readily satisfy design strength requirements, while emitting relatively lesser CO2.