Avaliação das propriedades de concretos utilizando areia residual do processo de extração do minério de ferro como agregado miúdo

Abstract

The construction and mining sectors have a significant social and environmental impact. One of the alternatives found to mitigate these problems is the use of mining tailings as a component in cementitious mixtures in civil construction. Binders and aggregates can be replaced with mining tailings in mortars and concrete, maintaining acceptable mechanical properties while reducing the consequences of extracting non-renewable raw materials for their production. This study aims to evaluate the physical and microstructural properties of concrete made with different proportions iron ore tailings as fine aggregate. Three independent variables were defined: the percentage of natural sand replacement, cement consumption, and curing age. The physical properties evaluated included compressive strength, modulus of elasticity, splitting tensile strength, absorption, and capillarity. The mixtures were defined and randomized using the software Statistica 12.0. The results were obtained through multiple regressions analyzed by Analysis of Variance (ANOVA) and the Response Surface Methodology (RSM). The findings showed that the only variable that significantly influenced compressive strength, splitting tensile strength, and modulus of elasticity was curing age. The variables natural sand replacement percentage and cement consumption were not significant for absorption but were significant for capillarity, with a decreasing trend in these properties within the 50% to 70% replacement range.