Evaluation of the performance of lime and cement treated base layers in unpaved roads

Mechanical properties of road subgrades and pavement layers, which consequently result in better performance, both in paved and unpaved roads. In this study, both laboratory experiments and finite element analysis were conducted to evaluate the performance of lime and cement treated base layers on soft clay subgrade. To achieve this, a number of mixtures with different lime and cement contents were defined and modelled, using finite element software, namely PLAXIS, as base layers under different loadings. The models were then analysed and compared in terms of vertical deformation under loads and the maximum applicable load. Analytical and numerical modelling of lime and cement treated soils require a number of soil parameters, which are usually obtained from expensive and time-consuming laboratory experiments. An alternative method was proposed in this study, in which the soil parameters required for the finite element analysis were obtained from the unconfined compressive strength tests, and estimated using the estimating functions available in available literature. The results of this study have showed that the application of the mixture with the highest modulus of elasticity for a base layer does not necessarily result in a pavement with the greatest bearing capacity. Rather, a correspondence should exist between the stiffness of the subgrade and that of the base layer.