Influence of Ultraviolet Aging on Adhesion Performance of Warm Mix Asphalt Based on the Surface Free Energy Theory

Abstract

To explore the effect of ultraviolet (UV) aging on the adhesion properties of warm mix asphalt (WMA), WMA binders were prepared by adding Evotherm M1 and Sasobit into base asphalt. The base asphalt and two WMA binders were aged using a self-made UV aging box after a rolling thin-film oven test (RTFOT). As a comparison, pressure aging vessel (PAV) tests were performed for asphalt binders after RTFOT. The contact angles between the WMA binder and distilled water, glycerol, and formamide, before and after UV aging, were measured using the sessile drop method. On the basis of the surface free energy (SFE) theory, the SFE and its components, cohesion work, adhesion work, peeling work, and compatibility rate, before and after the UV aging of WMA, were obtained. The results show that the contact angle between WMA and water gradually increases with the degree of UV aging, which indicates that the aging increases the hydrophobicity of asphalt. After the RTFOT aging, UV aging at different times, and PAV aging, the SFE and its component, as well as cohesion work for all asphalt binders were reduced. The attenuation was severe after UV aging, followed by PAV aging and RTFOT aging. With the extension of UV aging time, the adhesion work, hot mix asphalt, and limestone aggregate compatibility rate gradually reduced, the peeling work increased, and the overall adhesion performance became poor. Under the aging effect of RTFOT and PAV, the Evotherm M1 WMA had the strongest anti-peeling ability, better compatibility, and the best adhesion. When the UV aging time of Sasobit WMA reached 100 h, the adhesion performance increased.

Surface Characteristics of Ageing Asphalt Binder Coupling Thermal Oxidation and Ultraviolet Radiation

“…Surface free energy refers to the work that a certain material does to create a new interface per unit area. The components of surface free energy are used to evaluate the adhesion between asphalt and aggregate ( 29 , 30 ), and the moisture damage resistance ( 31 ). Recently, AFM has been used to explore the surface microstructures, and topographical and mechanical (stiffness and adhesion) properties of asphalt binder ( 32 , 33 ).…”

Influence of Ultraviolet and Oxygen Coupling Aging on Rheological Properties and Functional Group Index of Warm Mix Asphalt Binder

“…Relevant studies have shown that UV light is the primary cause of the aging of asphalt pavement within the first four months after the pavement is laid [ 34 ]. Therefore, the indoor UV test in this paper simulated natural outdoor aging for four months.…”

Study on the Bond Performance Between Epoxy Asphalt and Cement

“…The reason is some short-chain hydrocarbons will undergo addition and polymerization reactions to generate long-chain compounds in the aging process of SBSmodified asphalt binder, which will convert aromatic fractions and colloids into asphalt [24] . The asphalt content in asphalt is higher, which means smaller the surface free energy is, resulting in the hardening and crispiness of SBS-modified asphalt [25] . Finally, the interface strength of the composite specimen decreases significantly.…”