Study of the hot mix asphalt used in middle west region of Brazil

Flexible or asphalt pavements compose the Brazilian highway network, which have to promote security on traffic on the highways, to support the effects of changes in climate and to resist the traffic of vehicles. By this reasons, the structure of the pavement is particularly important and must be constituted by layers, which can distribute the loads into the structure, reducing the vertical load produced by the action of traffic and, consequently, providing protection to the subgrade. In the middle western Brazil, in the state of Goiás, there is not advanced studies on asphalt mixtures used in highways and in urban pavements, and there is not a technical scientific proofing that the local aggregates available in the region, is the best option considering the local conditions. Forward better conditions of infrastructure, it is proposed to develop more efficient asphalt mixtures for pavements, by submitting the mixtures through testing and analysis of mechanical strength, analyzing if the most used asphalts mixtures are satisfactory or not. The hot asphalt mixture are composed by aggregates and asphalt binders that are design in order to attend the parameters set in the projects according to demand and traffic types. In this research, it was proposed the study of three asphalt mixture design with different types of asphalt binders with the same aggregates origin in a specific grain size range. The binders used in this study are the conventional cement asphalt in the region, CAP 30/45 e 50/70 (Brazilian penetration grade), with low and medium penetration, respectively, and the polymer modified asphalt (AMP). The CAP 50/70 is the most used in the region considering the conventional binders, and right after we have the CAP 30/45. The characterization tests of the materials that composed the mixture are presented and their selection and characterization attended the standardized procedures and requirements by the brazilian department responsible for highway structures (DNIT). In a second stage, the design tests were performed, combining aggregates and binders in different rates, by the Marshall Mix Design Method using manual compression, until the great design was obtained. The laboratory tests were realized with this great design to obtain its mechanical properties, given by the tensile strength. This study presents that CAP 30/45 showed the best stability and tensile strength for the mixture with regional aggregates.