Expansividade de misturas de solos em camada de base de aterro sanitário: um estudo de caso no semiárido paraibano

Abstract

The base layer, commonly called liner, has great relevance for environmental protection in landfills, being responsible for inhibiting the migration of pollutants to the subsoil and the environment. Soil mixtures are widely used in the manufacture of these elements when the soil of the region does not provide enough characteristics to ensure the correct functioning of the liners. In this context, bentonite is a viable option because it allows the improvement of some geotechnical characteristics. However, it is indicated to analyze the expansivity of these mixtures due to the expansive characteristic of this soil. Therefore, this work proposes an evaluation of the expansive potential of three soil mixtures in the proportions of 5%, 15% and 25% of bentonite, for use in liners, having as an experimental field the Landfill of Campina Grande - PB, located in the Brazilian semiarid region, bringing together geotechnical, chemical and mineralogical aspects. To this end, tests of geotechnical and physical characterization, pH, CTC, organic matter, DRX, EDX were carried out, as well as the edometric test to evaluate the expansion index. From the analysis of the results, it was inferred that the expansion index of the mixtures was low, which contributed to the fact that the bentonite in its natural state is of the calcium type. Furthermore, the proportion of 25% is the most suitable for use in sanitary landfill liners with similar characteristics, because in addition to the acceptable expansion analysis, it is presented as the closest content to those recommended in other works in the same study area, to meet the parameter of soil permeability.