A Systematic Review on the Interfacial Asphalt-Aggregate Adhesion with Emphasis on Measuring Devices and Tensile Strength Influencing Parameters

Bonding strength between asphalt binder and aggregate is one of the major factors considered when developing flexible pavements. The bonding strength refers to the average tensile stress at the point of failure, which is often referred to as the pull-off tensile strength (POTS). Globally, flexible pavements have been utilized for decades. They are the predominant type of pavement in most of the world’s regions, but their durability and utilization diminish over time due to the buildup of distress. These concerns may emerge due to several circumstances, including poor construction and quality control, unsuitable materials, or insufficient design. Failure may also result from other factors, including water infiltrations, temperature changes (freezing-thawing cycles), asphalt oxidation, and inadequate bonding between asphalt binder and aggregate. Hence, this research focuses on the effect of the bond strength between asphalt binder and aggregate and the factors that affect it. Investigating the variables and measuring techniques for bond strength at the asphalt-aggregate interface is essential to providing extended service life and safe roadways. To this end, there has been an appeal for this study, which primarily entails a thorough literature review to highlight a few important points for the researchers and asphalt pavement engineers regarding factors affecting bond strength and testing methods. Accordingly, this study aims to fill the void in the existing literature, which frequently focuses on a single factor, by providing a detailed overview of asphalt-aggregate bond strength, thus providing extensive knowledge of this essential element in the asphalt mix design industry.