Estudo do comportamento mecânico de concretos produzidos a partir da substituição do agregado graúdo por resíduos.

Abstract

Civil construction demands a large amount of natural resources from extraction to completion of the work and after its demolition, generating large volumes of waste. The sector is responsible for around 30% of raw material consumption and 25% of waste emission on a global scale. Another potentially polluting sector is mining, for example the process of processing Kaolin where about 75% of the extracted material becomes waste. A viable destination for the reuse of construction and mining waste is the use of replacing natural aggregate as a raw material in making sustainable concrete. The objective of this work is to evaluate the mechanical behavior of an alternative concrete from the use of construction and demolition waste (RCD) and coarse kaolin waste (RCG) as a partial replacement of the coarse aggregate, checking the compliance with the required properties, in order to obtain an efficient performance when comparing to a conventional concrete. The strokes had replacements in proportions of 15%, 30% and 50% for the residues and were submitted to curing periods of 7, 14 and 28 days. Initially, the materials were characterized: granulometry, unit and specific mass, absorption and fineness modulus, after the specimens were molded, the mechanical tests of resistance to simple compression and traction by diametrical compression were carried out. The results show that the specimens with replacement of the RCD and RCG residues obtained similar and even higher resistance values in relation to conventional concrete. For concrete with RCD the specimens of the 15% line showed the highest strength reaching 21.6 MPa, being higher than the 30% line and the conventional one after 28 days of curing, however the line with the greatest aggregate replacement (RCD 50%) did not reach the resistance stipulated by the standard. As for concrete with RCG replacement, we found that the 15% trace also obtained the best strength values, reaching 27.28 MPa, being below the reference trace only after 28 days of curing. The feasibility of using waste as a substitute for natural aggregates is seen, since more than 80% of the tested compositions meet the standards, standards. In this way, its use provides economic advantages, in addition to avoiding the extraction of natural resources and the inappropriate disposal of this waste, promoting sustainability and a good relationship between civil construction and the environment.