Evaluation of pore structure and its influence on permeability and moisture damage in asphalt concrete

Abstract

This study evaluates the pore structure of asphalt concrete (AC) samples by measuring the different components of pore space and their contributions to permeability and moisture damage. Three components of the total pore space namely permeable, dead-end and isolated pores are quantified using tracer test, which is a combination of permeameter and salt concentration measuring meter. Permeable pores become impermeable if an AC sample is compacted below 5% air voids. Permeable pores increase with an increase in sample radius. It is observed from this study that the permeable pore has a good correlation with permeability, whereas total pore shows a poor correlation with permeability. The effects of permeable and dead-end pores on moisture damage of asphalt concrete are evaluated using a moisture induced sensitivity testing device and the AASHTO T 283 method. It is observed that permeable and dead-end pores do not contribute to moisture damage of AC samples.