FREITAS, R. D.; http://lattes.cnpq.br/6479019111717415; FREITAS, Rodrigo Dias.
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.
