Key parameters dictating strength of lime/cement-treated soils

An effort is being carried out to develop dosage methodologies for improved soils based on a rational criterion, as in concrete technology, where the water/cement ratio plays a fundamental role in target strength assessment. This study aims to assess the strength-controlling parameters of a sandy lean clay treated with lime or cement, and to show that the void/cementitious material content ratio plays a fundamental role in target strength assessment. The controlling parameters evaluated were the amount of cementitious material, the porosity, the moisture content, and the void/ cementitious material ratio. A number of unconfined compression tests and suction measurements were carried out in the present work. The results show that the unconfined compressive strength (UCS) increased linearly (with a reduced strength gain rate) with lime content for soil-lime mixtures. A power function fits the UCS-cement relationship better for soil-cement mixtures. The UCS increased linearly with the reduction in porosity for soil-lime mixtures and exponentially for soil-cement mixtures. Finally, the porosity/volumetric cementitious material content is shown to be a good parameter in the evaluation of the unconfined compressive strength of the soil studied.