Empirical Relationships with Unconfined Compressive Strength and Split Tensile Strength for the Long Term of a Lime-Treated Silty Soil

Fine-grained soils have a low load-bearing capacity that hinders their use in pavement construction, slope protection, or foundation support. Therefore, the chemical stabilization of a soil with the addition of lime is a viable technique that could enable its use in civil construction. Unconfined compressive strength (UCS) and split tensile strength tests were performed to evaluate the improvement of a soil with lime and the existing correlation between these two tests. This study aims to determine the empirical relationships between the split tensile strength ($q_t$) and UCS ($q_u$) of a silty soil artificially cemented with hydrated lime ($L$). To calculate the $q_t/q_u$ ratio, soil–lime specimens are molded by controlling the dry unit weight, lime content, porosity, and water content, followed by curing for 15, 30, 60, 90, and 180 days. The voids/lime relationship determined by the porosity/volumetric lime content ratio ($\eta /L_v$) plays an essential role in this study, and it is the principal parameter used to assess the increases in $q_t$ and $q_u$ and determine their empirical relationship. The results demonstrate that $q_t/q_u=0.16$ for all curing times (15–180 days), so that it is an overall constant relationship ($q_t/q_u$). Moreover, with the addition of 9% lime, maximum resistances of $q_t$ (700 kPa) and $q_u$ (3,750 kPa) are obtained for the soil–lime mixtures after 180 days of curing. Moreover, two dosage equations that can be used as mix design relationships are obtained to determine the $q_t$ and $q_u$ of the lime-treated soils.