Optimizing the evolution of strength for lime-stabilized rammed soil

In the present study, unconfined compressive strength (qu) 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/Liv) as the main parameter. η/Liv represents the volume of void influenced by compaction effort and lime volume. The evolution of qu 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/Liv parameter was modified to η/LivC using the adjustment exponent C (to make qu-η/Liv variation rates compatible). The results show that with the decrease of η/LivC,qu increases potentially and the optimized values of C were 0.14–0.18. The mechanical resistance data show similar trends between qu and η/LivC 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.