Influência da adesividade ligante-agregado nas propriedades de fratura de misturas asfálticas sujeitas ao dano por umidade

Abstract

The most recurrent problems in asphaltic are rutting, fatigue cracking, raveling due to the dislodgment of the aggregate materials, and potholes, and these damages are intensified with the presence of water. In addition, a worldwide concern is the use of natural materials from non-renewable sources, so it is necessary to search for sustainable alternatives. An alternative aggregate material is blast furnace slag from the steel industry. However, studies have shown that those materials have chemical, physical and thermodynamic characteristics that affect the binder-aggregate adhesion. Thus, it is necessary to broaden the understanding of the behavior of asphalt mixtures containing slag aggregates. Therefore, the aim of this research is to investigate the effects of the partial substitution of 25% of natural aggregates (AN) by air-cooled blast furnace slag (ACBFS) in asphalt mixtures, with and without the addition of fillers of different chemical compositions (hydrated lime, electrostatic precipitator (EP) powder, AN powder and ACBFS powder), checking the influence of the characteristics of each material on the fracture properties of asphalt mixtures subject to moisture damage. For this, specimens were subjected to induced moisture-damage and static semi-circular bending (SCB). The results indicated that mixtures with both aggregate compositions showed similar behaviors. The addition of hydrated lime provided greater rigidity to the mixtures and greater resistance to moisture damage. The addition of EP powder also promoted an improvement in the resistance to moisture damage of the mixtures and maintained the capacity of the samples to absorb energy, in addition to contributing to the ductility gain of the asphalt mixtures after moisture conditioning. It was realized that the steel aggregate can be a sustainable alternative and with great potential for the partial replacement of natural aggregates in asphalt mixtures as long as additions are incorporated to solve its deficiency in the adhesion to the asphalt binder.