Improvement of expansive soil characteristics stabilized with sawdust ash, high calcium fly ash and cement

The purpose of this study is to investigate the individual and admixed effects of sawdust ash (SDA) and high calcium fly ash (HCFA) on the geotechnical characteristics of expansive soil (ES). The effectiveness of these pozzolanic materials was examined, particularly tests of their physical and mechanical characteristics and the potential of enhancing expansive soil (ES). The mixing ratio for ES stabilization was adopted as 70:30 by fixed dry weight, based on the HCFA/SDA mixture plasticity and strength. Cement was added to the optimal ratio in varying amounts (1%, 0.5%) to increase the HCFA reactivity. The results reveal that increasing the mixture and cement content enhanced ES properties while lowering the liquid limit (LL) and plasticity index (PI). The plastic limit (PL) has shown an increasing trend and the optimum water content (OMC), whereas the maximum dry density (MDD) decreased. It was found that the addition of 1% cement to 10% HCFA-SDA combination provides maximum strength improvement to (ES) that would help to maximize the use of HCFA-SDA to reduce the swelling characteristics of ES in the field.