Characterization and Valorization of Two Algerian Bentonites in the Waterproofing Systems

摘要

The interest in environment has recently considerably grown, and its protection is now included in the continuous action of the governments and the industries. In Algeria, the different types of waste are currently produced in almost 3.000 illegal dumps, occupying approximately 150.000 hectares. To overcome this problem, waterproofing sites prove the most appropriate solution. It is a geotechnical method to guard against the action of water by narrowing the flow of water through a surface in a given time. The site’s waterproofing technique, in the landfills sites, is nowadays a very necessary condition to protect the environment, which requires the use of appropriate materials. This work deals within the valorization of local materials (sand and bentonite), in the waterproofing technique of the technical landfills site “TLS”. To this end, two types of bentonites from the west of Algeria are used. In order to achieve an optimal mixture, ensuring good performance in terms of hydraulic conductivity, durability and shear strength, mixtures based of sand at different concentrations of bentonite, at compact state are prepared and studied. This study showed that a low permeability of mixture (sand/bentonite) can be achieved with introducing 8% of a calcium bentonite, against 6% of a sodium bentonite. The latter presents a great adsorption capacity and a self healing ability, compared to calcium bentonite. This gives a good sustainability against climate variations of mixture based on sodium bentonite. This mixture has also confered a good mechanical behavior, expressed by the recorded, reduction of the friction angle (Φ) and the increase of the cohesion (C). Therefore it represents an optimal mixture for waterproofing systems, due to its economical and ecological advantages.