Development of Macrocracking Master Curves of Asphalt Mixtures

Abstract

Fracture energy from semicircular bending tests is commonly used to measure the fracture resistance of asphalt mixtures. A study was conducted to develop master curves for the macrocracking of asphalt mixtures. The study examined four testing temperatures, five loading rates, two binder types, and two nominal maximum aggregate sizes (NMASs). Fracture energy was captured at different loading rates and temperatures, and a preliminary master curve was built using the dynamic modulus master curve approach. However, the initial plot of fracture energy versus reduced loading rate did not show a consistent trend. Instead, a parabolic shape was found in the local fracture energy when increasing the loading rate, and peak values were plotted for each temperature to produce the master curve for the macrocracking of asphalt mixtures. The maximum fracture energy was unique for each combination of NMAS and asphalt binder type and occurred at a specific temperature, indicating a new methodology for classifying the cracking resistance of asphalt mixtures: macrocracking master curves. Maximum values fell between typical low-temperature and intermediate-temperature fracture testing, highlighting a gap in understanding regarding macrocracking behavior.