Low-Temperature and Fatigue Properties of Asphalt Binders Modified with Crumb Rubber from Discarded Tires and Recycled Low-Density Polyethylene

Abstract

The addition of virgin polymers to asphalt binders is a technique widely used in the asphalt paving industry, because this approach helps improve the performance and extends the longevity of asphalt pavements. In recent years, modification of asphalt binders with polymeric waste has received a lot of attention from asphalt industry experts, due to economic and environmental benefits. This paper aims at evaluating the rheological characteristics at low and intermediate temperatures of a performance grade (PG) 64-22 asphalt binder modified with crumb rubber (CR) from discarded tires and recycled low-density polyethylene (RPE) from post-industrial sources, with the following component proportions by percentage of mass: 86≤binder≤100, 0≤RPE≤4, and 0≤CR≤10. To achieve this objective, a series of rheological tests were performed, namely: linear amplitude sweep, Superpave performance grading, and frequency sweep. The results indicated that the modifiers increased the fatigue resistance of the asphalt binders. The addition of 4% RPE had a worsening effect on the low-temperature performance of the asphalt binder. Nevertheless, with the hybrid modification with CR, the binder’s low-temperature performance was restored. Furthermore, the modifiers improved the asphalt binder’s temperature susceptibility, based on |G*| data from master curves.