Effect of aggregate shape properties and binder's adhesiveness to aggregate on results of compression and tension/compression tests on hot mix asphalt

摘要

The mechanical behavior of hot mix asphalt is affected by their constituent properties, i.e., aggregate and asphalt binder properties. The loading path used in laboratory testing is also a factor that may influence results. The objective of this work was to investigate the effect of aggregate particle shape properties and texture, as well as of the aggregate-binder adhesion, on different tests used to evaluate mixture resistance: indirect tensile strength in axial compression (ITS); moisture-induced damage- modified Lottman; uniaxial repeated load permanent deformation-Flow number (FN); dynamic modulus, both at compression and at tension/compression; and tension/compression fatigue life. The Aggregate Image Measurement System was used for analyzing aggregate particle shape properties. Asphalt Bond Strength test results were used as an indicator of aggregate-binder adhesion. The results indicate that the binder is relatively more important for tension/compression tests, while aggregate properties are relatively more important for compression tests. For the latter, the higher the load applied in the test, the greater the importance of the aggregate to the mixture result, which is expected since this favors interlocking. ITS and FN results appear to be strongly affected by aggregate sphericity and texture. Dynamic modulus at compression depends more on aggregate shape properties, while fatigue life is more influenced by aggregate-binder adhesion.