Oxidative aging of epoxy asphalt

Abstract

Oxidative aging is responsible for the irreversible asphalt stiffening and embrittlement leading to asphalt pavements of increased susceptibility to fatigue and thermal cracking. In recent years, various flexible binders have been introduced in asphalt industry to produce long-life pavements and the epoxy asphalt binders are among them. Nevertheless, in-depth understanding of the oxidative aging mechanism of epoxy asphalt binders and binding systems is still needed to enable reliable predictions of material degradation through service life. In this research, the compositional and rheological changes of epoxy asphalt, with and without filler, were analysed by means of Fourier Transform Infrared spectroscopy and Dynamic Shear Rheometer. Especially, kinetics (Arrhenius) parameters of epoxy asphalt have been determined by tracking the chemical composition changes. Oxidation of carbon species in epoxy asphalt is compositional dependent, and low values of activation energy accompany in low values of reaction rate are shown by adding epoxy in asphalt. Furthermore, the epoxy asphalt mastics (binders with filler) have been subjected to rheological testing to evaluate the stiffening effect as oxidation proceeds. Increase of modulus over a wide range of frequencies, decrease of frequency dependency of modulus of epoxy asphalt and shifting of phase angle to lower values are some important observations noticed as well. Overall, oxidation in epoxy asphalt materials occurs slowly yielding to oxygen-resistant binders when epoxy compounds are incorporated in asphalt binders.

Application of Epoxy‐Asphalt Composite in Asphalt Paving Industry: A Review with Emphasis on Physicochemical Properties and Pavement Performances

“…Sulfoxide compound contents were showed to be the most effective parameter for the evaluation of oxidative-controlled curing for EA [58]. In addition, a period of rapid decrease of carbonyl and sulfoxide compounds under isothermal oxidation conditioning indicated epoxy curing, whereas a period of constant increase of both compounds after curing indicated oxidative aging [125].…”

Effect of recycling agents on rheological properties of epoxy bitumen

“…Epoxy-asphalt binder is a type of thermosetting binder designed for flexible pavements. Despite the inherently brittle and poorly cracking resistant thermosetting epoxy resins, this binder cures to a rubbery system (Apostolidis et al, 2020b;Herrington & Alabaster, 2008;Kang et al, 2010;Luo et al, 2015;Widyatmoko et al, 2006;Xiao et al, 2011;Youtcheff et al, 2006). Shell Oil Company originally developed the epoxy-asphalt binder in the 1960s as a material with superior resistance to jet fuel damage.…”

“…The epoxy-asphalt binder, or epoxy binder, has been diluted with a conventional bitumen to balance the cost and performance. This idea has been already adopted as well as a feasible method to produce epoxy materials under longer operational time windows (Apostolidis et al, 2018(Apostolidis et al, , 2020a(Apostolidis et al, , 2020bApostolidis, Liu, van de Ven, et al, 2019;Herrington & Alabaster, 2008;Huang et al, 2020;Wu et al, 2017;Yao et al, 2019). Laboratory studies indicated a significant decrease in stiffness and elasticity of epoxy-asphalt materials could be obtained by reducing the proportion of epoxy binder in bitumen (Apostolidis et al, 2020b;.…”

“…This idea has been already adopted as well as a feasible method to produce epoxy materials under longer operational time windows (Apostolidis et al, 2018(Apostolidis et al, , 2020a(Apostolidis et al, , 2020bApostolidis, Liu, van de Ven, et al, 2019;Herrington & Alabaster, 2008;Huang et al, 2020;Wu et al, 2017;Yao et al, 2019). Laboratory studies indicated a significant decrease in stiffness and elasticity of epoxy-asphalt materials could be obtained by reducing the proportion of epoxy binder in bitumen (Apostolidis et al, 2020b;. Economic analyses have also shown that a diluted version of an epoxy binder with a 25:75 wt ratio of epoxy and bitumen is a sound investment for open-graded mixes reducing the resurfacing budget 1/6 of its current level (estimate based on 40-year service life) (Alabaster et al, 2017).…”

An Attempt to Track Two Grades of Road Bitumen from Different Plants Using Fourier Transform Infrared Spectroscopy

“…Therefore, many studies have focused on anti-ageing to find lasting solutions for thermochemical stability [ 14 , 16 ]. One of the modern solutions is the introduction of epoxy-based compounds as anti-ageing technologies for bituminous materials [ 15 , 19 , 20 ].…”