Utilização de resíduos de construção civil em concreto de alto desempenho

Abstract

Civil construction and demolition waste, also known as CDW, is material resulting from construction work, renovations, demolitions and repairs to structures. This waste can originate from the remains of beams and pillars. There is a significant increase in CDW in cities due to the high demand for urban infrastructure and consequently, a growing impact on the environment due to its inadequate disposal, causing soil, water and air pollution. Using CDW as fine aggregate in high-performance concrete (HPC) is a sustainable way to avoid this impact. The objective of this research was to verify the potential for reuse of recycled aggregate in high-performance concrete. The mixture used was 1: 0,2: 1,5: 0,3 (cement: microsilica: fine aggregate: water/cement ratio) and 3% superplasticizing additive in relation to the cement content, which was used as CP V-ARI. Thus, the results obtained with the partial replacement (5, 10 and 15%) of the fine aggregates that make up the concrete, showed satisfactory results in their use in HPC, when compared with the reference (0% replacement). In the analysis of tensile strength in flexion, there was an increase in resistance from 7 to 28 days, from 10,8 MPa to 12,2 MPa, which made the 5% sample equivalent to the reference (12,2 MPa). The remaining replacements, 10% and 15%, presented statistically compatible results, respectively 11,0 MPa and 10,3 MPa). This same line of statistical compatibility was followed in the compressive strength results (with 5% corresponding to 95,6% of the reference, 10% corresponding to 93,6% and 15% to 86,9%). The most appropriate proportion, identified in this study, was the replacement of 5% of fine aggregate with CDW, because it was closer to the reference value, the other proportions also reached acceptable levels for their application in high-performance concrete.