Evaluation of Asphalt Mixtures Containing Metallic Fibers from Recycled Tires to Promote Crack-Healing

Abstract

This paper reports part of an international research project with the long-term aim of developing more sustainable asphalt mixture with crack-healing properties by the addition of recycled metallic waste from industrial sources. Specifically, this article presents an evaluation of the physical, thermophysical, and mechanical properties of asphalt mixtures with metallic fiber obtained from recycled tires for crack-healing purposes. Detailed results on the crack-healing of asphalt mixtures will be reported in a second article. Results showed a small reduction on the bulk density and increase in the air voids content was quantified with increasing fiber contents. The experimental results showed that mixing and compaction was more difficult for higher fiber contents due to less space for the bitumen to freely flow and fill the voids of the mixtures. Computed tomography (CT) results allowed to identify clustering and orientation of the fibers. The samples were electrically conductive, and the electrical resistivity decreased with the increase of the fiber content. Fiber content had a direct effect on the indirect tensile stiffness modulus (ITSM) and strength (ITS) that decreased with increasing temperature for mixtures and with increase in fiber content. However, the indirect tensile strength ratio (ITSR) was within acceptable limits. In short, results indicate that fibers from recycled tires have a potential for use within asphalt mixtures to promote crack-healing.

Applications of Synthetic, Natural, and Waste Fibers in Asphalt Mixtures: A Citation-Based Review

“…However, the citations for document of González and Norambuena-Contrera were 56 and 45, respectively. González et al [ 188 ] assessed the performance of hot mix asphalt incorporating amended bitumen with different proportions of metallic fibers of 1.5, 2.5, and 3.5% by bitumen volume. The findings of the study demonstrated that the higher the dosage of fiber, the higher the air void content, clustering, and electrical conductivity.…”

The Effect of Adding Steel Fibers and Graphite on Mechanical and Electrical Behaviors of Asphalt Concrete

“…The found results are in accord with previous research. The research of González et al (2020) found that when the steel fibers increase, the electrical resistivity increases [28].…”

“…Adding fibers improve rut resistance, activate multifunctional applications [21][22][23][24][25][26] and increase crack resistance by fatigue and crack resistance by bending [5,27]. Many previous studies on the electrical conductivity of conducting asphalt concrete showed that conductivity is proportional to the fiber amount added [5,28]. Graphite is one of the most common carbon additives with the most stable crystalline structure.…”

Electrical and mechanical behaviors of conductor asphalt concrete by the addition of steel fibers

“…It has been demonstrated in numerous studies on the electrical conductivity of conductive bituminous mixes that the conductivity is inversely related to the amount of added fibers [5,28].…”