Avaliação da angularidade de agregados miúdos de diferentes litologias para uso em pavimentação

Abstract

Aggregates are of great importance in the composition of asphalt concrete mixtures (AC) occupying a volume between 80 and 90% of the total volume, where angularity interferes with the performance of asphalt coatings. This research aims to evaluate the shape, angularity and surface texture of fine aggregates (such as stone dust and sand) by implementing the fine aggregate angularity test (FAA) at the Federal University of Santa Maria - RS. The fine aggregates to be used come from various locations in the state of Rio Grande do Sul, samples already studied of fine and coarse aggregates by other researchers, associating their physical characteristics, sphericity, angularity and surface texture and direct shear strength. It began with the implementation of equipment and collection of materials; the evaluation of the angularity of fine aggregates is obtained through the volume of uncompressed voids following ASTM C 1252/06. The test of visual analysis of angularity, sphericity and surface texture by microscope and AIMS (Aggregate Image Measurement System) according to the obtained results will be specified for use according to the traffic volume. The surface texture and angularity of the fine aggregates interfere with the direct shear strength. The polished, smooth texture, sphericity and rounded and elongated roundness / angularity aggregates did not resist the imposed normal stress. Taking into account only results obtained from the FAA test we cannot define which fine aggregates are most suitable, for high traffic volume asphalt mixtures should be analyzed and compared with the visual analysis by microscope.