Influência da adição de bentonita em misturas alternativas para a utilização em barreiras impermeabilizantes de aterros sanitários

• Autor(a) principal: Martins, Ligia Abreu
• Data de Publicação: 2017
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/9500
• topic: Landfill; Impermeable barriers; Zeolite; Bentonite; Hydraulic conductivity; Shear strength; Aterro sanitário; Camada impermeabilizante; Zeólita; Bentonita; Condutividade hidráulica; Resistência ao cisalhamento; Engenharia Civil; Aterro sanitário; Impermeabilização; Resistência ao cisalhamento; Bentonita; Zeólitos; 624

One of the relevant issues about the geotechnical behavior of sanitary and industrial landfills is the integrity and performance of impermeable barriers throughout the useful life of these containment systems. In this context, it is noted that some questions about permeability, shear strength, the effect of solutions percolation and the integrity of impermeable barriers have been discussed for some time. At a national level, the works of Lukiantchuki (2007), Camargo (2012) and Morandini (2015) can be quoted. Nevertheless, due to the heterogeneity of the soil and the country's great extension, these issues have not been satisfactorily resolved in Brazil. In this context, it is relevant that, in the face of increasingly severe environmental policies, industries have been led to adopt procedures for a better removal of toxic elements from effluents. To the possible to avoid major environmental impacts and to minimize the risk of contamination for soil and groundwater under waste containment systems, zeolite, minerals as adsorptive material used in permeable reactive barriers for remediation of groundwater contaminated by heavy metals, can be used as alternative material in constructions of landfill bottom liners. For these analysis, this research project intends to evaluate the influence of adding bentonite for the improvement of a tropical soil of the Espírito Santo State and adding natural zeolite of clinoptilolite type with the purpose of using it in impermeable barriers. The permeability and the shear strength, along with the expansion of the materials, were evaluated in the pure state and in the alternative mixtures in bentonite percentages of 3%, 5%, 7% and 9%. To determine the conductivity hydraulic the laboratory test involves flexible wall permeameter. The shear strength was evaluated by means of uniaxial compression test with compacted soil. In order to reach better results, California bearing ratio (CBR) and confined expansion tests have been made. The addition of bentonite considerably reduced the hydraulic conductivity of the local soil and the zeolite. The results indicate that, for all alternative mixtures, the hydraulic conductivity showed adequate values for the construction of impermeable barriers. Regarding the resistance to uniaxial compression test, all pure soil mixtures and only the 3% bentonite zeolite blend reached acceptable values for use in compacted landfill layers. As for the CBR, both materials presented acceptable values and the pure zeolite and its mixtures exceeded the local values of the soil.