Efeito do tipo e da proporção de fíler no comportamento do mástique asfáltico

Abstract

The road system is the most important modal in the Brazil and the asphalt pavements of this system must meet the demands of traffic, weather and provide comfort and safety to the user. The useful life of this type of structure depends on the correct choice of materials, thickness and stiffness of each layer for a given boundary condition. The mechanical response of asphalt mixtures is influenced by the asphalt mastic, which is defined as the mix between the filler and the asphalt binder. The mastic acts by altering the void volume in the mineral aggregate, the lubrication between the larger particles and, consequently, the compaction characteristics and the asphalt content of the mixtures. The filler is characterized by being the portion that passes through the sieve nº. 200, which acts in the asphalt mixture filling the voids and activating the mastic and changing some characteristics of asphalt binders such as viscosity, elasticity and thermal susceptibility. The relationship between the benefits of filler addition and the amount of material in the mix is not linear, as high amounts of filler negatively affect the workability, flexibility and durability of the asphalt mix. In this context, the main objective of this work was to analyze the effects of different types of filers on the behavior of asphalt mastics. For this, physical tests were performed to evaluate the characteristics of the binder and of the mastics. The tests were made with basalt powder and metakaolin for 0.6 and 1.2 filler/asphalt. It can be seen that the additions of the fillers acted making the mastic more rigid, more viscous, less elastic and less susceptible to temperature. In addition, metakaolin had a greater effect on asphalt binder behavior than basalt powder derived binder.