Estudo de misturas asfálticas mornas modificadas com adição da cera de abelha.

Abstract

In paving industry, the use of hot asphaltic mixtures contributes to emit greenhouse gases, as this type of mixture requires the use of high machining and compaction temperatures, achieved by burning chemical fuels, in order to guarantee workability to the mixture, stability and durability to the pavement. Therefore, emerged the technique of warm asphalt mixtures, as they are produced and compacted to lower temperatures used by hot mixtures. This is considered a less impactful alternative for environment, in the production of asphalt coatings. In order to produce warm mixtures, there are a variety of wax-based additives available in the Market, however, none use a natural wax as the main component. The aim of this study was to evaluate the potential for use of beeswax as an additive in the production of warm mixtures, based on the hypothesis that beeswax is a natural additive capable of reducing the viscosity of the binder and, consequently, the machining and compaction temperatures. Rheological and mechanical tests were carried out, based on three levels of beeswax: 1%, 3% and 5%, by mass of asphalt binder. In order to evaluate the effects of reducing the temperature of production and compaction and the influence of the incorporation of additives in the asphalt mixture, the following mechanical tests were performed: Tensile Strength, Resilience Module, Moisture Damage (Lottman), Flow Number, Dynamic Module and Fatigue Life. The binder modified with 5% beeswax shows a decrease in the machining temperature of 9°C, and 12°C in the compaction, which allows the reduction of the polluting gases and energy expenditure. However, there are still some gaps that need to be filled for the use of this type of additive in production of asphalt mixtures, such as the absence of a national standard that aborts, among other items, a specific methodology for determining temperatures of use and compaction for this type of mixture.