Análise do processo de autorregeneração de misturas asfálticas incorporadas com agentes rejuvenescedores encapsulados

Abstract

In view of the numerous distresses presented in asphalt pavements, specifically those observed in the coating layer, the incorporation of capsules containing rejuvenating agents in the asphalt mixtures appears as an alternative for the closure of cracks caused by fatigue. This material is composed of a nucleus, generally oily, surrounded by a polymeric membrane of sodium alginate obtained from the ionotropic gelling reaction in the presence of calcium chloride. The crack closure process, called self-healing, occurs from the moment the crack present in the pavement reaches the capsule, enabling the release of oil. The phenomenon partially restores the mechanical properties and promotes a reduction in the viscosity of the asphalt binder, which is drained through the cracks, thus initiating the wetting process, so that finally, the structure is continuous again. Several materials and parameters have been studied to assess the self-healing capacity. That said, the aim of this study is to evaluate the influence of the addition of capsules on asphalt mixtures, so three types of mixtures were studied: the GI, reference, the GII, containing soybean oil capsules, and the GIII, containing capsules of residual oils from the frying process in the kitchen. The mechanical properties of the asphalt mixtures were studied, as well as the self-healing through mechanical tests of static and dynamic loading. In order to evaluate the influence of the addition of capsules on the mechanical properties of asphalt mixtures, four tests were carried out: Indirect tensile strength, Resilient modulus, fatigue life and Permanent deformation in static Creep. The evaluation of self-healing, that is, the recovery of the mechanical strength of the mixture, was carried out by means of Self-healing with static loading, Self-healing with dynamic loading and Self-healing with static loading via two cycles of loading/ healing. According to statistical analysis, the addition of capsules did not affect the tensile strength and permanent deformation, while it reduced the resilient modulus and fatigue life. In all self-healing tests, in general, both the GII and GIII mixtures showed positive results when compared to the reference mixture, with the mixture with soybean oil capsules showing the best result. In this context, it is evident this self-healing method is promising for increasing the useful life of asphalt coatings.