A Laboratory Assessment of the Influence of Crumb Rubber in Hot Mix Asphalt with Recycled Steel Slag

Bruno Crisman, Giulio Ossich, Lorenzo De Lorenzi, Paolo Bevilacqua and Roberto Roberti
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Bruno Crisman: Department of Engineering and Architecture, University of Trieste, via Alfonso Valerio 6/2, 34127 Trieste, Italy
Giulio Ossich: Department of Engineering and Architecture, University of Trieste, via Alfonso Valerio 6/2, 34127 Trieste, Italy
Lorenzo De Lorenzi: Department of Engineering and Architecture, University of Trieste, via Alfonso Valerio 6/2, 34127 Trieste, Italy
Paolo Bevilacqua: Department of Engineering and Architecture, University of Trieste, via Alfonso Valerio 6/2, 34127 Trieste, Italy
Roberto Roberti: Department of Engineering and Architecture, University of Trieste, via Alfonso Valerio 6/2, 34127 Trieste, Italy

Sustainability, 2020, vol. 12, issue 19, 1-21

Abstract: To reduce thermal susceptibility and improve rutting and fatigue cracking resistance, increasingly more non-conventional additives and materials have been used in road pavement asphalt mixes in recent years. Non-conventional materials mainly include recycled materials, which reduce production costs and lead to environmental benefits related to their reuse. The aim of this research was to evaluate the influence of recycled tyre rubber in the production of asphalt concrete for road pavements built with recycled aggregates consisting of steel slag in relation to possible improvements in structural performance during operation (i.e., fatigue and rutting). Steel slag has a higher bulk specific gravity than natural aggregates, and it has a very porous surface that allows for a different interaction with the bitumen and the crumb rubber compared to traditional aggregates. To this end, two mixtures of asphalt concrete are compared. One was mixed with a modest percentage by weight of crumb rubber using the “dry” technique, and the other mixture did not contain crumb rubber. Indirect tensile and compression tests with cyclic loads were performed to determine the mechanical behaviour of the two mixtures at different temperatures and under different load frequencies. The results of this research indicate the better performance of the modified mixture with crumb rubber, which agrees with other experiments in the literature that have been made using natural aggregates. Furthermore, a significant increase in stiffness was found at high temperatures (up to 30%), a slight reduction (up to 8%) was found at low temperatures, and a reduction in permanent deformation was found under cyclic loads.

Keywords: crumb rubber; dry method; asphalt pavements; steel slag; mechanical properties; hot mix asphalt (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (5)

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