Viabilidade da utilização de resíduos da construção civil em cobertura final de aterros sanitários

Abstract

The growing concern for the sustainable management of urban solid waste has driven more indepth analyses of the potential reuse of materials derived from construction and demolition waste. This study focuses on evaluating the recycled aggregate obtained from the processing of these residues, mixed with soil, aiming to use it as a substitute for natural aggregates in the final cover layers of sanitary landfills, with a specific focus on the municipality of Maceió. The research investigates the physical, chemical, and environmental characteristics of the processed demolition waste (DW), sourced from an area affected by soil subsidence that impacted five neighborhoods in Maceió, where building demolitions generated a significant amount of waste. The study analyzed the soil, the DW, and mixtures with different proportions: 85% DW + 15% soil, 70% DW + 30% soil, and 60% DW + 40% soil, with the latter demonstrating the best conditions across key parameters for cover layers. The parameters assessed include shear strength, erodibility, and hydraulic conductivity of the waste-soil mixtures, while chemical characterization, conducted through X-ray diffraction and scanning electron microscopy, identified the elements present in the samples. Environmental characterization involved leaching and solubilization tests, ensuring the material's reliability for soil use. The results indicate that the mixture containing 60% DW and 40% soil exhibits typical granular soil characteristics, with a maximum dry density of 1.68 g/cm³, an optimum moisture content of 17.35%, an internal friction angle of 24.56° under saturated conditions, and a permeability coefficient on the order of 10⁻⁶ cm/s. This material proved to be erodible, non-dispersive, classified as non-inert and non-hazardous, suggesting its viability for use in landfill cover layers and other potential applications in waste management.