Equations Controlling Tensile and Compressive Strength Ratio of Sedimentary Soil–Cement Mixtures under Optimal Compaction Conditions

AbstractMethodologies for dosing fine/coarse-grained soils with cement using the porosity/cement ratio (η/Civ) have mainly focused on the nonoptimal compaction conditions to calculate the split tensile and compressive strengths as well as the empirical relationships between both tests, neglecting the study on the optimal soil-cement mixes compaction conditions. Thus, this technical paper aims to determine the equations that control the empirical relationships between split tensile (STS or qt) and unconfined compressive strengths (UCS or qu) of a sedimentary soil improved with portland cement (PC) under optimal compaction conditions using the η/Civ ratio. The results showed a power increase of qt and qu with the curing time and the decrease of η/Civ ratio. In addition, it has been demonstrated that a relationship between tensile and compression might be defined using the η/Civ ratio adjusted to an exponent β=0.45, constant for all curing times. Therefore, the tensile/compression ratio obtained was 0.15, 0.16, and 0.17 for the 7th, 14th, and 28th days of cure, respectively. All qt and qu data were normalized (divided) into a single power increase function (93% acceptance with a 4.36% error) to find any mechanical resistance value with variables and molding conditions using the η/Civ0.45 ratio. Finally, the η/Civ ratio was a suitable parameter for dosing soil-cement mixes under optimal compaction conditions.