Caracterização dos resíduos de demolições em bairros de Maceió/AL para reaproveitamento como agregado em camadas do pavimento urbano

Abstract

The prolonged extraction of rock salt in underground caverns in Maceió-AL has resulted in soil subsidence, cracks in buildings, and surface instability, affecting the neighborhoods of Mutange, Bom Parto, Pinheiro, Bebedouro, and Farol, as well as the Mundaú Lagoon. This situation led to the evacuation of more than 40,000 people and large-scale demolitions, generating a significant volume of demolition waste (DW). Given this scenario, it is essential to seek sustainable alternatives for reusing these materials, contributing to the reduction of environmental, social, and economic impacts. This study investigates the technical feasibility of using recycled aggregate (RA) from these demolitions as a material for urban pavement layers. Three samples were evaluated: pure RA (100% DW), soil from the Mutange hillside (100% SM), and a mixture of 85% RA with 15% SM. The research included the physical, mechanical, chemical, mineralogical, and environmental characterization of the materials, with laboratory tests on particle size distribution, Atterberg limits, compaction, direct shear strength, California Bearing Ratio (CBR), Los Angeles abrasion, X-ray diffraction (XRD), scanning electron microscopy (SEM), and leaching and solubilization analyses. The results indicated that RA has suitable properties for use in subgrade reinforcement and sub-base layers, although its application in base layers requires granulometric improvements and stabilization. Environmental analysis demonstrated that the evaluated materials do not pose a contamination risk, meeting regulatory limits. The proposed approach aligns with the National Solid Waste Policy (PNRS) and the principles of the circular economy, promoting efficient DW management and encouraging sustainable practices in the construction sector.