Materiais compósitos à base de cimento com adições de vidro cominuído como agregado fino para aplicação na construção civil

Abstract

The civil construction sector, when compared to the others, is the one that most consumes sand, a natural raw material, in the formulation of the various ceramic compositions. Due to the constant increase in demand for this material, this natural resource has become increasingly scarce; Furthermore, the extraction of natural sand is responsible for considerable damage to the environment. It is known that the amount of solid waste generated in the world represents a major problem regarding the environmental aspect, mainly due to its disposal, often done incorrectly, as is the case of glass waste, dumped in open dumps. . This work aimed to study the influence of replacing natural sand with glass powder from waste from long neck bottles in reactive powder concrete formulations, comparing the results obtained with a reference formulation. For this, the preparation and characterization of the raw materials to be used in the concrete formulations (cement, microsilica, quartz powder, sand and ground glass) was initially carried out, setting as the maximum diameter of the aggregate to be used in the formulation the value of 0.6mm and the minimum diameter of 0.075mm. The X-ray fluorescence technique (FRX) proved that long neck bottles are composed of conventional soda-lime glasses; the morphology of the aggregates was analyzed using Optical Microscopy, indicating that the glass particles are angular and lamellar, with a low degree of sphericity, while the particles of natural sand are sub-rounded with a high degree of sphericity, which directly influences the packing of the aggregates. particles and the final mechanical properties. For the reference formulation (without replacing the sand) and other formulations containing replacement of the natural aggregate (sand) with glass powder from waste from long neck bottles in the fractions of 12.5; 25; 50; 75 and 100%, the water/cement ratio (w/c) was set at 0.3% by mass, and specimens in a cylindrical shape with dimensions of 100mm in height and 50mm in diameter were molded and cured. Physical and mechanical tests were performed. The reference formulation presented superior performance to the other formulations studied, referring to compressive strength, the formulation of 100% replacement of sand by glass was the formulation that presented the best values of compressive strength in relation to the other substitutions. The mechanical strength at 28 days decreased as the replacement of sand by glass was lower, the formulations with 12.5% and 25% replacement showed the lowest values of mechanical strength. The physical tests (water absorption and void index) showed that, in relation to water absorption, the concrete with 100% replacement obtained the best result, followed by the reference formulations and 75% replacement and the formulation of 12.5 % showed the lowest performance. Regarding the void index, the best results were found in the reference formulation and in the 100% and 75% substitutions, and the lowest performance was in the 12.5% formulation.