Optimizing the evolution of strength for lime-stabilized rammed soil

In the present study, unconfined compressive strength (q_u) values of two lime-treated soils (soil 1 and 2) with curing times of 28 d, 90 d and 360 d were optimized. The influence of void/lime ratio was represented by the porosity/volumetric lime content ratio (η/L_iv) as the main parameter. η/L_iv represents the volume of void influenced by compaction effort and lime volume. The evolution of q_u was analyzed for each soil using the coefficient of determination as the optimization parameter. Aiming at providing adjustments to the mechanical resistance values, the η/L_iv parameter was modified to $\eta /L_{\text{iv}}^C$ using the adjustment exponent C (to make q_u-η/L_iv variation rates compatible). The results show that with the decrease of $\eta /L_{\text{iv}}^C,$ q_u increases potentially and the optimized values of C were 0.14–0.18. The mechanical resistance data show similar trends between q_u and $\eta /L_{\text{iv}}^C$ for the studied silty soil-ground lime mixtures, which were cured at ambient temperature (23 ± 2) °C with different curing times of 28–360 d. Finally, optimized equations were presented using the normalized strengths and the proposed optimization model, which show 6% error and 95% acceptability on average.