Effect of Different Levels of Moisture Intrusion on the Dynamic Modulus and Tensile Properties of Dense Graded Hot Mix Asphalt Using a Cyclic Moisture Induced Stress Tester

Moisture intrusion can potentially result in the degradation of the adhesive bonds between the aggregate and mastic, and cohesive bonds within the mastic resulting in deterioration in mechanical performance of asphalt concrete pavements. The motivation for this research was to characterize the variations in such mechanical properties in asphalt mixes when subjected to cyclic moisture intrusion. Each permutation of the experiment design was subjected to moisture conditioning using a Moisture Induced Stress Tester (MIST) at three different levels; 500 cycles, 5000 cycles, and 10000 cycles. Additionally, dynamic modulus tests and indirect tensile tests were performed on both unconditioned and moisture conditioned specimen to identify the influence of cyclic moisture on the mechanical properties of the continuum. The analysis of the indirect tensile tests underscores the role of moisture to increase the degree of nonlinearity of the asphalt specimen. Additionally, the loss in stiffness properties evidenced by the reduction in the dynamic modulus values of moisture conditioned specimen were more prominent at lower loading rates in the dynamic modulus tests. This study can provide valuable insights on the dynamic variations of the pore water pressure in asphalt mixes and its relevance to the mechanical performance of dense graded asphalt mixes.