Effect of substitution of wood shavings by barley straws on the physico-mechanical properties of lightweight sand concrete

The paper mainly aims to study the effect of the incorporation of barley straws and wood shavings on the physico-mechanical properties of sand concrete intended for the construction in arid zones. Basing on the study at fresh state, the experimental work has been firstly devoted to searching for optimal compositions of the composite. Then, a second study has focused on the physico-mechanical characterization of sand concrete without lignocellulosic materials. Finally, a special experimental program has been devoted to the study of sand concrete with lignocellulosic materials. The obtained results show that it is quite possible to develop a lightweight sand concrete by the incorporating, separately and in combination, of barley straws and wood shavings. Moreover, it has been noted that the combined addition of barley straws and wood shavings gives the best physico-mechanical results which were strongly confirmed by a microstructure study. With combined addition, the problem of shrinkage was relatively solved: decreases of about 11.76% and 39.02% were recorded in comparison with the cases where barley straws and wood shavings are taken separately. In addition, the thermal diffusivity has been reduced of about 35.47% with respect to the basic composition. Due to its higher deformability, the barley straw improves the toughness and ductility of sand concrete and reduces its dimensional variations. Indeed, the studied composites, offer to the local constructions important technical and economic interests: good thermal insulation and efficient energy saving and low cost of materials.