Estudo da influência das propriedades dos agregados sobre o comportamento à fadiga e autorregeneração de matrizes de agregados finos

Abstract

Fatigue cracking is one of the most common types of distress in asphalt pavements. Each asphalt concrete constituent's characteristics and interactions are relevant to identifying its resistance to fatigue cracking. Also, for the selection of materials, it is essential to consider not only the capacity of the material to resist fatigue but also its ability to heal. Materials that exhibit self-healing capacity can prolong the overall asphalt concrete fatigue life. Most studies on the self-healing of bituminous materials are performed in the binder scale. However, this characteristic can be dependent on binder-aggregate interactions. Thus, the present work aims to evaluate the fatigue cracking strength and self-healing capacity of four Fine Aggregate Matrices (FAMs). The same binder was used in all FAMs, and each mixture used a different natural aggregate, among them, two granitic, one basaltic and the other micaxistic. The methodology consists of: (i) dosages of FAMs using different natural aggregates; (ii) verification of the variables existing between the FAMs and their constituent materials; (iii) verification of the influence of aggregates on the stiffness and elasticity of FAMs produced with different aggregates, through the experimental determination of their viscoelastic properties; (iv) verification of the influence of the aggregate on the self healing characteristic of the FAMs, by the experimental determination of the recovered integrity, using time-scan rheological tests with insertion of rest periods. Among the characterization of the aggregates, differences in the chemistry and mineralogy of all the aggregates were identified, in addition to the basaltic aggregate presenting a higher content of fines due to its crushing process. These variables were confronted with the results of self-healing and fatigue, concluding that there is a complex relationship of the properties of the aggregates in these characteristics. The FAM composed of micaxistic aggregate presented the highest rigidity, and its fatigue life drops more significantly with the increase of applied stress. As for self-regeneration, it is believed that the chemistry of each aggregate may have influenced the relationship between adhesive and cohesive cracks, impacting on binder movement