Avaliação do uso de agregados reciclados para a produção de blocos vazados

Abstract

With the constant evolution of Civil Construction, means of reuse of various residues has been expanding to the production of artifacts for the sector, contributing to reducing the scarcity of virgin raw materials, mainly as aggregates in cementitious matrices. Therefore, this work aims to evaluate the use of construction and demolition waste and residual heavy ash from thermoelectric plant as aggregates for the production of hollow blocks - Cobogó. For this, four types of mortars were analyzed, varying the type of aggregate. Only natural sand was used in the reference mortar, while the others were produced with construction and demolition waste (CDW), with heavy ash and with the composition of the two residues. The consistency and plasticity table test (Flow Table Test) was carried out in the fresh state. In addition, in the hardened state, tests were carried out on flexural tensile strength, compressive strength, water absorption, void ratios and specific mass. A qualitative comparative analysis of the main environmental impacts of the production of the produced blocks was also carried out. According to the results obtained, the mortar with CDW aggregate showed lower workability and the mortar with heavy ash aggregate showed a self-levelling characteristic. The compressive strength of mortars with residual aggregates, measured in cubic specimens, reached an average between 5.73 and 5.90 MPa. The produced blocks also registered satisfactory compressive strengths, between 21.01 and 26.29 MPa. However, the blocks with RCD aggregate and with mixed aggregates showed high levels of voids and water absorption. In addition, according to the comparative analysis of the main environmental impacts, compared to the mix containing traditional aggregate, the impacts generated on the environment are reduced with the use of recycled aggregates. In general, it was verified that it is feasible to use aggregates obtained from CDW and bottom ash for the production of hollow blocks.