Soil-cement ratio and curing conditions as the factors of soil-concrete strength

Soil-concrete is widely used to strengthen the foundation footings, in the construction of roads and railways, as well as for the production of bricks and pavement tiles. One of the most important physical and mechanical properties of soil-concrete is the compressive strength. 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 Ip = 12.3, Portland cement of type I, ground limestone with the specific surface of 4500 cm2/g, polycarboxylate based superplasticizer and water for mixing. Curing of samples was carried out in air-humid condition in wet sawdust and also with the thermal-humid treatment in a steam chamber. It is experimentally established that the strength of soil-concrete depends not only on the ratio of clay aggregate and mineral binder, but also on the temperature and humidity conditions of curing. Additives of ground limestone and superplasticizer contribute to increase the compressive strength of soil-concrete. 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. © 2017 Trans Tech Publications.