A mix-design development of self-compacting concrete in achieving structural durability

Self-compacting concrete (SCC) is a custom-blend formulation that does not require vibration or compaction before curing because it readily flows in every corner of a mould or formwork. Compared to conventional cement-based concrete, the workability of fresh SCC is defined by high filling capacity, obstruction-passing capability, and resistance to aggregate separation. Moreover, hardened SCC provides better mechanical properties which are required in earth retaining systems, retrofitting constructions, and column formworks. Experimental tests suggest that SCC mixed with rice husk ash (RHA) provides good compaction and high flowability with improved compressive strength and durability as it hardens. This present work highlights the implementation of mix proportions modified for RHA-SCC, combining fresh and hardened RHA-SCC properties in one nomogram adapted from Monteiro et al.’s study. The nomogram is developed using experimental data from 15 mixture designs of RHA-SCC. The adapted method is rooted on three classical ideas―Abram’s law for cured SCC, Lyse’s law for pre-hardened SCC, and Molinari’s law for cement-like contents. Results are compared to different strength-based mix-design studies with cement- and cement-like materials to discuss further the advantages and limitations of the present mix-design development. Also, a durability test via seawater immersion of the 28-day cured samples is done to determine the mass loss and relative strength after 30 cycles. This study aims to further improve the adapted method by comparing it to various mix designs, evaluating the long-term durability of RHA-SCC samples, and achieving adequate mechanical properties with low water demand. Lastly, the partial substitution of RHA produces a sustainable SCC and contributes to the circular economy.