Effect of low VMA in hot mix asphalt on load-related cracking resistance

•Load-related cracking resistance was evaluated for HMA mixes with low VMA.•Three approaches were used: DCSE, |E∗|sin φ, and M-E PDG cracking models.•Results indicated that reduction in VMA leads to increase in cracking potential.•Low VMA asphalt mixes can be utilized in pavements with low traffic volumes. Voids in mineral aggregate (VMA) is an important parameter in hot mix asphalt (HMA) mix design. It is believed that a minimum VMA requirement is necessary to ensure adequate binder content and durability for HMA. This paper investigates the effect of lower than typically acceptable VMA on the load-related cracking resistance of four dense-graded asphalt mixes. The mixes were prepared with three aggregate types: limestone, sandstone, and granite. Three different approaches were used to evaluate the cracking resistance of the mixes: the dissipated creep strain energy (DCSE), the fatigue parameter (|E∗|sin φ), and the mechanistic-empirical pavement design guide (M-E PDG) cracking models. The indirect resilient modulus (Mr), indirect tensile strength (ITS), and dynamic modulus (E∗) tests were performed on the mixes. Finite element analysis was used together with the M-E PDG cracking models to predict the expected longitudinal and alligator cracking performance of the mixes when used in a typical pavement structure. Both DCSE and (|E∗| sin φ) results showed that lower VMA decreases the cracking resistance of the mixes. DCSE parameter decreased by 50%, while |E∗| sin φ increased by 12%, for a 3.8% reduction in VMA. The analysis results of M-E PDG cracking models were consistent with the experimental findings. The predicted longitudinal cracking increased by 73%, while the alligator cracking increased by 24% for the same reduction in VMA.