Concretos com substituição parcial do cimento pelo resíduo do beneficiamento de rochas ornamentais: análise quanto à ação de íons cloreto.

Abstract

As a result of population growth, improved living conditions, rising consumption levels and growing industrialization in developing countries, it is estimated that concrete production will show significant growth over the coming decades. The concrete production process accounts for approximately 5% of the world's CO2 emissions, a significant pollutant in the environment. Based on these concepts, this work evaluated the influence of the partial replacement of the Portland cement by the ornamental rock residue (RBRO) on concrete compressive strength, capillary absorption, immersion absorption and chloride ion penetration in natural environments in cities of Pelotas and Rio Grande. In addition, the penetration of chloride ions in a laboratory environment was investigated. The residue was characterized mineralogically by X-ray diffraction (XRD), X-ray fluorescence (EDX) and physically by X-ray diffraction (XRD) tests. laser particle size and specific mass tests. A trace of reference concrete produced with CP V-ARI cement was adopted from the IPT / EPUSP method. The residue was used in proportions of 5%, 7.5%, 10% and 12,5% of mass substitution to the cement. The results treated by statistical analysis indicate the possibility of replacing up to 7.5% of the cement by RBRO, simultaneously meeting the criteria of resistance to compression, water absorption and chloride ion penetration, generating a concrete with adequate resistance to Brazilian standards and with possibility of structural use. In this substitution content there was an increase in mechanical resistance, decrease in permeability and a lower penetration of chloride ions, due to the process of pore refinement promoted by the RBRO.