Análise da influência do resíduo da lama de marmoraria como elemento de substituição parcial do cimento nas propriedades do concreto

Abstract

Economic activities and productive processes developed in society have contributed to the generation of waste. Regarding the processing of ornamental rocks, especially in the cutting phase and polishing carried out by equipment wet, a type of residue called marble slurry or abrasive slurry is generated consisting of the powder mix of different types of rock, water and residues of abrasive elements. This volume of waste is showing a significant increase on the construction demand and the large participation of brazilian companies in the domestic and international markets in the production and export of ornamental rocks. Consequently, many marble companies continue discarding their waste irregularly or without due appropriate treatment, with no provision for use or reuse, usually in industrial or grounded landfills in underground locations, polluting the soil and water, and when dry this residue becomes fine powder being harmful to human health. However, one of the problems in some municipalities relates to the disposal of waste in this sense, the work comes to analyze the influence of the use of the residue of marble slurry (powder) in the mass of concrete (without structural purposes) as a substitute partial weight of cement. Several studies have been developed for the use of the residue of ornamental and has motivated the search for viable alternative technologies and their application as raw material in construction. Thus, four mixtures of concrete containing marble slurry including the feature of reference, were prepared and evaluated the influence of residue on the mechanical properties and the durability parameters in aged 3, 7, 14, 28, 60, 91, 120 and 180 days through mechanical resistance, modulus of elasticity, surface and volume resistivity, by immersion and capillary water absorption and workability. The experimental methodology is grounded in trials relating fineness, physics analysis, mineralogical, thermogravimetric and pozzolanic activity of the residue. In this regard, the samples were prepared with Portland cement CPV ARI artificial medium sand, gravel 1 and w/c ratio of 0.53. The study aimed to investigate the effect of the addition of mud marble powder content of 10%, 20% and 30% in the same proportion to the replacement of cement weight. The results indicate that the application of the residue in the mixtures did not influence considerably on some properties, indicating that 20% of marble powder slurry can be used as partial replacement of cement weight. However, from 20% residue in partial replacement of cement may compromise the technical characteristics of the mixture and affect some properties of fresh and hardened concrete. In accordance with the durability, the influence of residue seems not impair the surface and volume resistivity, even showing a decrease with the increase of the residue percentage content of the mixtures. There was a correlation between effective values of mechanical resistance and electrical resistivity and modulus of elasticity, but it can say that the strength of concrete and water absorption are inversely related. However, this residue slurry collected in the marble company tank is formed by different types of rocks and showed a gain strength above 25 MPa at 28 days for the mixtures containing 10% and 20%. Thus, the use of waste contribute to sustainable development, contributing to the reduction of cement consumption, as well as providing a better final destination to the residue.