Efeitos da adição de resíduos de gesso da indústria da construção nas propriedades mecânicas do concreto asfáltico usinado a quente.

Abstract

The heavy investment of public and private sectors in order to meet the growing brazilian demand for housing in recent years, has increased the use of gypsum as a building material due to its advantages of application and finishing. However, the waste generated from this material during the construction process does not have proper destination and, in most urban centers, such waste is disposed in landfills, dumps or unsuitable areas. The Brazilian legislation classifies the gypsum waste as a material for which the recycling technology is not yet available and prohibits its disposal in outdoor areas. In this context, this study addresses the issue and shows results on the use of gypsum waste from construction as a filler in hot mix asphalt. Tests including the characterization of aggregates, binder and gypsum waste were carried out. The study determined, by the Marshall design method, the design binder concentration of a mixture without gypsum waste and with 2% and 4% of waste in aggregates, which mixtures are in range "C" of DNIT's specification. For the mechanical characterization of the mixtures, specimens were molded according to the Marshall and Superpave methodologies. The mechanical tests utilized were Tensile Strength by Diametrical Compression, Resilient Modulus, determination of fatigue life by diametrical compression under controlled stress made of loading, wastage by Cantabro, moisture induced and permanent deformation by uniaxial compression under static load. The results showed that the addition of gypsum to a limited extent, reduces the binder consumption, meets the requirements specified by DNIT and improves the mechanical characteristics of the mixtures. It has been finally concluded that, the use of waste gypsum with a percentage in the order of 2% in hot mix asphalt, shows to be a technically feasible alternative for its disposal.