In this paper, mechanical and thermal properties of compressed earth blocks stabilized (soil–sand dune–cement) with and without aggregates of cork have been studied, with the use of some models that predict thermal conductivity for comparison of experimental results. The first part highlights the influence of the percentage by weight of cement and of sand dune on the maximum dry density, optimum moisture content and mechanical resistance. The results showed that mass content of 30% sand dune and 12% cement significantly improves these properties more in the wet conditions than dry, and therefore gives the optimal mixture (58% of soil–30% of sand dune –12% of cement). However, the composite materials used for building must present sufficient mechanical strength to be suitable for constructions. For that the optimal composition has undergone a static compaction (2.5–5–7.5–10 MPa) thus showing further improvement on the same properties. Incorporating the aggregates of cork (3/8) in the optimal mixture, improves significantly the thermal performance with little influence of compaction, while remaining within the range of acceptable strength. Lastly the study was extended to the search for theory capable of predicting the effective thermal conductivity of a dry blend considered like a two-phase system, which shows that linear model and some theoretical models give the best concordance with experimental results.