Modelling the pre-yield behaviour of soils using isotropic hardening models is a difficult task. One-surface elasto-plastic models can predict the post-yield behaviour but fail to reproduce the pre-yield behaviour of soils, even if a non-linear elastic law is adopted. The complexity is increased when artificial cement is added to the soil, as the level of cementation influences the characteristics of the specific mixture. Models based on bounding surface plasticity are able to reproduce the experimentally observed smooth transition from purely elastic to fully plastic state. The model proposed in the present paper represents the extension of an existing model for cemented soil, reformulated in a two-surface bounding plasticity framework. The model is calibrated against a set of triaxial tests performed over an artificially cemented soil. The results of the calibration are compared against the corresponding one-surface model, emphasising the improved performance of the new model in the small strain domain.