How is the stripping of asphalt from aggregates typically tested?

The boiling water test is a standard method for evaluating the stripping of asphalt from aggregates. This test involves immersing asphalt-coated aggregates in boiling water for a specified period of time, then assessing how much of the asphalt film has detached from the aggregate surfaces. The effectiveness of the adhesive bond between the asphalt and the aggregate can be indicated by the amount of asphalt that remains on the aggregate after the treatment. This method provides a practical approach to simulate the effects of moisture on the asphalt-aggregate bond and helps determine the durability of the asphalt mix in conditions where moisture could cause stripping.

In contrast, the blending test assesses the compatibility and adhesion characteristics of different asphalt binder and aggregate types, rather than evaluating stripping directly. Visual inspection may offer qualitative insights but lacks the rigorous methodology needed for definitive results. Measuring pH levels does not directly correlate with the stripping phenomenon; rather, it pertains to the chemical properties of materials and could be relevant in different contexts but not specifically for testing asphalt stripping. Therefore, the boiling water test is the best-known practice for determining the effectiveness of the asphalt bond to the aggregate under adverse conditions.