Influência da densidade máxima teórica na dosagem de misturas asfálticas

Abstract

The theoretical maximum specific gravity (Gmm) is a parameter required for the calculation of the aggregate effective specific gravity, asphalt absortion, effective asphalt content and air voids content (Vv), within the design of a hot mix asphalt. From the Gmm and the bulk specific gravities of the aggregates and the compacted mixture, one can determine the volumetric characteristics and the bitumen content of an asphalt mixture. Different procedures to determine the Gmm can lead to different values, also affecting the volumetric parameters. In Brazil, Gmm is determined indirectly from the mixture composition and the relative densities of its constituents. Besides the calculation of Gmm, two laboratory procedures are investigated for its determination: (i) ASTM D 2041, which uses a vacuum pump and (ii) method using kerosene. The differences in the Gmm values obtained by different procedures are discussed, evaluating the influence of these differences in the volumetric parameters and, consequently, in the choice of the optimum asphalt content. Finally, the mechanical behavior of the resultant mixtures is evaluated by the tensile strength and resilient modulus.