There are several questions that are not well understood with respect to the long-term stability characteristics of lime-treated expansive soils in spite of being used as a conventional technique to improve the properties of expansive soils. This paper examines the long-term stability characteristics of FoCa bentonite soil (FoCa represents the first two letters of the two towns between which this type of soil is excavated: Fourgues and Cahaignes) using 4% lime treatment. The long-term stability characteristics referred to as durability in the paper were interpreted taking into account the influence of wetting–drying and freezing-thawing cycles on key engineering properties which include swelling and strength behavior of both untreated and lime-treated FoCa. In addition, leaching tests were carried out to study the Ca2+ ions and pH concentration changes of the percolating water from both treated and untreated compacted expansive soil specimens analyze the permanence of the clay treatment. Finally, to highl...

The aim of this paper is to find out new alternative materials that respond to sustainable development criteria. For this purpose, an original utilization of straw for the design of lightweight aggregate concretes is proposed. Four types of straw were used: three wheat straws and a barley straw. In the present study, the morphology and the porosity of the different straw aggregates was studied by SEM in order to understand their effects on the capillary structure and the hygroscopic behavior. The physical properties such as sorption-desorption isotherms, water absorption coefficient, pH, electrical conductivity and thermo-gravimetric analysis were also studied. As a result, it has been found that this new vegetable material has a very low bulk density, a high water absorption capacity and an excellent hydric regulator. The introduction of the straw in the water tends to make the environment more basic; this observation can slow carbonation of the binder matrix in the presence of the straw.