Laboratory Testing of Self-Healing Polymer Modified Asphalt Mixtures Containing Recycled Asphalt Materials (RAP/RAS)

Sharareh Shirzad,Marwa M Hassan,Louay N Mohammad,Max A Aguirre,Samuel Cooper,Ioan I Negulescu,H Sadek

doi:10.1051/matecconf/201927103003

Sharareh Shirzad, Marwa M Hassan + Show 5 more

Open Access

https://doi.org/10.1051/matecconf/201927103003

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Abstract

The objective of this study was to evaluate the efficiency of an innovative light-induced self-healing polymers in enhancing the durability of asphalt mixtures and improving its self-healing properties. Mixtures were prepared using two different binders, with and without recycled materials, and self-healing polymer. Results showed that the addition of recycled asphalt material to mixtures prepared with an unmodified binder negatively affected the healing recovery at room temperature. Furthermore, Self-healing properties of the mixtures were improved by increasing the healing temperature. The addition of 5% self-healing polymer to the control mixture, followed by UV light exposure resulted in an increase in self-healing properties of the mixtures prepared with PG 67-22 binder. Semi-Circular Bending (SCB) test results showed that the incorporation of self-healing polymer and 48 h of UV light exposure improved the cracking resistance. Loaded-Wheel Test (LWT) results showed that the self-healing polymer caused an increase in the rut depth of the samples prepared with an unmodified binder. However, the final rut depth was less than the acceptable rutting performance. Thermal-Stress Restrained Specimen Test (TSRST) test results showed that self-healing polymer improved the low temperature cracking performance of the mixtures.

Highlights

Asphalt binder has self-healing properties, which can be defined as the ability to restore its original properties
For samples conditioned at room temperature, the recovery ratio of the control mixture was improved from 38% to 72% due to addition of self-healing polymer
The present study evaluated the effects of the addition of recycled asphalt materials (5% RAS, and 20%RAP) and a light-activated self-healing polymer (5%) on the mechanical performance of asphalt mixtures

Summary

Introduction

Asphalt binder has self-healing properties, which can be defined as the ability to restore its original properties. Using innovative self-healing techniques, fatigue cracking resistance of the pavement may be improved by accelerating the rate of crack healing. Different self-healing techniques such as rejuvenators, encapsulated rejuvenators [1, 2], induction heating [3], and nanoparticles [4] were examined to improve self-healing of asphalt mixtures. Polymer additives have been used in the asphalt pavement industry to improve pavement’s performance against fatigue cracking, thermal cracking, and rutting. Combining self-healing and polymer modification, a UV light activated self-healing polymer was examined in this study to improve the mechanical performance and selfhealing abilities of asphalt pavement containing recycled asphalt materials (RAS/RAP). The initiation and propagation of micro-cracks due to excessive loading and aging of asphalt binder leads to breakage of various bonds in the chemical structure of self-healing polymer, producing free radicals. The unstable free radicals would recombine through exposure to UV light, seal the microcracks, and stop crack propagation [5, 6]

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