Test Methods to Quantify Cracking Resistance of Asphalt Binders and Mixtures

Monday, March 1, 2021 - 16:15

Incorporating cracking tests and criteria in binder acceptance, mix design, and construction quality control (QC and quality assurance (QA) offer a way to improve pavement performance. The objective of this research is to identify and, if necessary, refine binder and mixture tests capable of addressing asphalt cracking in Minnesota asphalt pavements. The tests/criteria selected for evaluation are the IDEAL-CT and the DCT for asphalt mixtures, and the ∆Tc and the G-R parameter for binders. These tests are relatively simple to perform in standard agency and contractor laboratories, require minimal time to perform and produce results, are repeatable and reproducible, and provide a distinction between brittle and ductile behavior. Additionally, binders are tested using the multiple stress creep recovery procedure to characterize their elastic recovery. Mixtures and binders from projects constructed in the 2018 and 2019 construction seasons are tested using these methods. It is found that all the mixtures and binders exhibit good cracking resistance. The mixture results from 2018 are robust for periods of up to two weeks after mixing and molding, but the mixing and molding needs to take place at the same time for both QC and QA samples as reheating QA samples will lead to a degradation in cracking resistance. The main conclusion from the 2019 mixture testing is that cracking resistance is directly related to asphalt content. Binder testing shows that all of the sources used possess good aging properties. The full report can be downloaded from the Minnesota Department of Transportation web site at https://www.dot.state.mn.us/research/reports/2021/202102.pdf


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