Otimização multivariada da substituição de agregados de resíduos de construção e demolição em concreto

Abstract

The construction industry is one of the largest industries in the world and is in a major generator of waste called waste from construction and demolition (RCD). The reuse of this waste is an important factor, both for the environment and for businesses, as they bring many problems due to the amount generated and substances that makes up as they are of different types of materials. Thus the aim of this study is to conduct a study to assess the possibility of reuse of this type of waste in concrete using an experimental design to optimize simultaneously the process variables and blending components. In this work, the concrete is composed of three components of mixtures, namely: cement, aggregate (coarse and kid) and water, and two process variables which are the particle size and the percentage of RCD replacing natural aggregate. Regression calculations and quadratic sums of ANOVA are presented. The linear-linear model is shown as it presents no lack of fit. Considering the level of the variable under study, the optimal condition with concrete RCD is: 0.30mm for the particle size of the RCD, 25% replacement of natural aggregate by the DCO with 15% cement, 77% aggregates and 8 % of water. The optimum conditions of mixture with 25% of RCD showed a resistance value of concrete compression exceeding 19 MPA, allowing its use in construction in precast and block pavers, concrete blocks, curbs, sidewalks, subfloors among other concrete artifacts that does not require structural function.