Moisture damage analysis based on adhesive failure in asphalt mixtures

ABSTRACT

This study explored a unique digital image analysis technique to quantify the adhesive failure (AF) in asphalt mixtures subjected to indirect tensile testing and different levels of aging and moisture conditions. Using the tensile strength ratio (TSR) in conjunction with AF, this study grouped asphalt mixture’s moisture resistance into three zones as high (TSR > 80%), moderate (70% < TSR < 80%), and low (TSR < 70%). Asphalt mixtures with AF less than 10% were grouped as highly resistant to moisture damage. Likewise, the asphalt mixtures with AF between 10%–15% were grouped as moderate and AF more than 15% was classified as asphalt mixtures with a low resistance to moisture intrusion. The association of fracture energy (FE) with proposed zones of moisture susceptibility was evaluated. The asphalt mixtures with FE higher than 5200 J/m² was found to be highly resistant to moisture damage (AF<10%). Whereas asphalt mixtures with FE lower than 3300 J/m² were less resistant (AF>15%) to moisture damage. Further, the percent loss in the coating on loose asphalt mixtures subjected to boiling water test agreed with the proposed AF limits. The findings showed that AF would help screen the moisture damage susceptible asphalt mixture stringently when used in conjunction with TSR and FE.

KEYWORDS:

• Moisture susceptibility
• aging
• adhesive failure
• image analysis
• fracture energy

Disclosure statement

No potential conflict of interest was reported by the author(s).