ABSTRACT
Warm Mix Asphalt (WMA) is produced at lower temperature than Hot Mix Asphalt (HMA) and is more vulnerable to adhesive failures at the aggregate-binder interface. An innovative approach was employed to quantify this failure using direct tensile test. Three levels of conditioning were utilized namely; unconditioned, 1 Freeze-Thaw (F-T) cycle and 3 F-T cycles prior to testing. Percent adhesive failure was initially estimated using a 2-D image analysis and then further quantified using the 3-D image analysis. The statistical paired t-test showed that there was a significant difference between the results of 2-D and 3-D analysis. This concluded that the use of 3-D technique is a more precise method to quantify the adhesive failure caused by moisture infiltration. The results from the image analysis also showed that adhesive failures for mixtures prepared with polymer modified binders were lower than unmodified binders. The extent of failure also escalated with the number of F-T cycles.
