One of the most important physical and mechanical properties of soil-concrete is the compressive strength. To this end we carried out a study of soil-concrete strength depending on its curing conditions and percentage of cement. For our study we used loam soil with the plasticity index of I-p = 12.3, Portland cement of type I, ground limestone with the specific surface of 4500 cm(2)/g, polycarboxylate based superplasticizer C-3 and water for mixing. A mathematical model for determining the compressive strength of soil-concrete depending on the percentage of cement and the curing period is developed. This proposed mathematical model is advisable to apply for assessment of the compressive strength of soil-cement massive layer after the urgent repair of under-road pipelines, as well as where soil-concrete is used to strengthen the structure's base.