Desenvolvimento e caracterização de concreto com incorporação de resíduos de marmoraria

Abstract

Advocated by environmental sustainability, the current concern across the planet refers to the final destination of solid waste generated by various production processes, especially industrial ones, which in their stages of the production chain, generate intermediate waste considered environmental liabilities. Recycling and the use of such waste have been encouraged and are included as one of the great alternatives to reduce such impacts on the environment, in addition to reducing the growing consumption of raw materials in natura imposed by the production demand. In this context, the residual powder from the processing of ornamental rock sawdust is a major concern for companies and environmental agencies, due to the large amount of waste generated, which is often deposited irregularly in landfills, vacant lots and other urban and rural areas, causing harm to society and the environment. This study aimed to develop the production of concrete with the incorporation of marble waste from the processing of conventional ornamental rock sawdust, replacing the natural sand aggregate. The physical properties of the conventional raw materials were obtained, as well as the physical, chemical and mineralogical characterization of the waste collected for processing, as well as the mechanical and microstructural characteristics of the concrete produced. Cylindrical test specimens measuring 15 cm in diameter and 20 cm in height were molded with partial replacement of the fine aggregate by marble waste at levels of 10%, 20%, 30% and the resistance to simple axial compression at ages of 7 and 28 days, determination of the modulus of elasticity, water absorption level and microscopic analysis of the concretes developed were determined. It was observed that the replacement of fine aggregate by marble waste made it possible to obtain concrete with properties that meet the normative parameters, highlighting the increase in mechanical strength in the percentage in the mix with 20% replacement of fine aggregate at 28 days, as well as an increase in the modulus of elasticity, and a reduction in water absorption. The scanning electron microscope (SEM) images revealed a reduction in porosity in the concrete mix with 20% replacement of the concrete mix, and the formation of hydrated calcium silicates and the formation of ettringite in the crystallographic phase. The results indicate the viability of using marble waste as a partial replacement for natural sand.