The goal is to mitigate the water sensitivity of mixes using these materials. In hot-mix asphalt, the use of phosphoric acid-modified asphalt already shows promise. In subsequent years, materials deleterious to Portland cement concrete will be examined. Aggregates suspected of deleterious properties will be analyzed by physical, chemical, and petrographic properties. Most research aggregates will be characterized by the Aggregate Image Measurement System for shape, angularity, and texture. The Micro-Deval test can also be a tool to see how aggregates breakdown in the presence of water. Potential issues include Minus No. 200 minerals and size, aggregate surface chemistry and absorption, development of a better methylene blue test for active clays, and evaluation of surfacing aggregates.
Material characterization of minus No. 200 size materials on aggregates and their effect on the quality of bond at the aggregate surface both in asphalt and concrete mixtures.
Guidelines for the evaluation of the aggregate interface zone as affected by coatings, texture, minerals, and minus No. 200 fine materials. [Source: FHWA, PMSS Database (2013)]