Análise do efeito de agentes rejuvenescedores encapsulados na autorregeneração da mistura asfáltica.

Abstract

Self-healing is a characteristic of asphalt materials to reverse the cracking process, resuming its initial characteristics, when subjected to a damage. Although this phenomenon occurs naturally, it is associated with internal factors (chemical properties, free surface energy and volumetric properties) and external factors (time, temperature, damage and loading level, aging and humidity). Based on these factors, to occur naturally, long periods of time would be required to recover from damage caused, for example, by fatigue in the layer of an asphalt coating. Thus, mechanisms for accelerating self-healing are needed. This work evaluated the use of fatty acid (AGS) and sludge (BS) from soybean oil as rejuvenating agents encapsulated by the ionotropic alginate gelation procedure in the presence of calcium. The rejuvenators were chosen based on their technical potential and because it is a waste with low added economic value. Four types of capsules were produced: C/BS0,1 and C/BS0,2 (composed of soybean dregs); C/AGS0,1 and C/AGS0,2 (composed of fatty acid). The rejuvenator/water ratio varied between 0.1 and 0.2. Initially, the properties of the capsules obtained through their equivalent diameter, uniformity and compressive strength were evaluated. These were added to the mixture at a content of 0.6%. After that, the effect of this addition on void volume, indirect tensile strength, induced moisture

damage, stiffness, permanent deformation and fatigue life was evaluated. Finally, the self- regeneration of the mixtures with and without capsules was evaluated using the Semicircular

Bending Test - SCB, using dynamic loading and a 24-hour rest period. The capsules presented resistance and uniformity that enable their use. The additions did not significantly affect the void volume, they showed beneficial effects on the resilience module, fatigue life and moisture damage, but reduced the resistance to permanent deformation and tensile, also showing reductions in the strength test performed by the static SCB. All samples increased the percentage of regeneration with values of 169%, 72%, 109% and 90% for mixtures with capsules C/BS0,1; C/BS0,2; C/AGS0,1 e C/AGS0,2, respectively, while for the mixture without capsules this value reached 62%. In view of this, the technical applicability of fatty acid and soybean oil sludge for use as an encapsulated rejuvenator in addition to asphalt mixtures stands out.