Comparison of Fracture Cracking Parameters from Monotonic Loading Tests: Indirect Tension and Monotonic Overlay Tester Tests

Abstract

Cracking is one of the major structural distresses that occur in hot-mix asphalt (HMA) pavements and is undesirable. Cracking often leads to costly maintenance and rehabilitation activities. Various laboratory test methods, including the indirect tension (IDT) test, semicircular bend test, Texas Overlay Test (OT), and bending beam fatigue test, are typically used to characterize and quantify the resistance of HMA to cracking. Recently, the OT test in monotonic loading configuration was explored as a supplement or surrogate to the traditional repeated loading OT test for evaluating the cracking resistance potential of HMA mixes in the laboratory. The basic analysis parameters from the monotonic OT test include the tensile strength, failure tensile strain, fracture energy (FE), and FE index, which are essentially the same fracture parameters obtainable from the IDT test. In this study, the crack resistance potentials of 15 different HMA mixes were comparatively evaluated with two monotonic loading tests: the IDT and monotonic OT. Statistical analysis with analysis of variance and Tukey’s honestly significant difference methods was performed to characterize the test methods’ comparative potential to discriminate and screen mixes. For the mixes evaluated and the test conditions considered, the corresponding results indicate that the FE index was the most effective fracture parameter in capturing the test loading history and differentiating the crack resistance potential of the HMA mixes. The statistical comparisons between the IDT and monotonic OT tests showed plausible correlations for all the fracture parameters that were evaluated, with the FE index being the best.