Development of a Performance-Based Approach to Asphalt Emulsion Selection for Cold In-Place Recycling Applications

Abstract

Asphalt emulsions are currently selected based on material classification. These properties do not predict performance and provide the same classification to emulsions that behave quite differently in the field. Therefore, this research developed a performance-based approach to asphalt emulsion selection for cold in-place recycling (CIR) applications. The performance period was broken down into three categories: workability, compactibiltiy, and cohesion gain. Superpave Gyratory Compactor (SGC) metrics, the loose triaxial-, raveling-, direct shear-, and compacted triaxial tests were used to quantify the behavior of three CSS-1h asphalt emulsions. It was found that the final density and the CIR workability engergy index SGC compaction metrics showed the most promise, whereas the Dongre workability test was found to have potential. The loose triaxial test was able to distinguish the performance of the three asphalt emulsion at 100 and 200 kPa confining pressures, but the results were not consistent with viscosity measurements. The raveling test showed high levels of variability, whereas the direct shear- and compacted triaxial tests showed similar trends and were able to distinguish between the three emulsions. Finally, for all tests, curing samples at 10°C is recommended.