Study on performance of a novel asphalt mixture containing strength and morphology controlled artificial aggregates

The examinations of numerical simulations and investigations on basic behaviors and technical properties of asphalt mixture remained great challenges because of the uncontrolled and varied morphologies of natural coarse aggregates. The traditional ceramsite aggregates were generally associated with weaker skeleton contact and inferior cohesion characteristics because they were porous and spherical. In this study, two kinds of strength and morphology controlled coarse artificial aggregates (AAs) were produced with solid wastes including fly ash and bauxite residues based on 3D printing technology. After sintering, the coarse AAs were applied to prepare three kinds of artificial aggregate asphalt mixtures (AAAMs). The service performance of AAAMs was measured and compared to natural aggregate asphalt mixtures (NAAMs). Coefficient of variation (CV) values and paired sample t-test were applied to evaluate the impact of coarse AAs morphology. The result revealed that AAAMs exhibited superior lightweight characteristic, whose bulk specific gravity decreased by 10% approximately when compared to NAAMs. Except for residual strength ratio (RSR) of RG2-20-L, coarse AAs exerted positive effects on the improvement of moisture damage resistance and thermal sensitivity resistance including rutting resistance and low-temperature cracking resistance. The service performance of AAAMs could meet the technical requirements of specification and construction. CV values of AAAMs were smaller than that of NAAMs, demonstrating that the AAs with identical morphology eliminated the variability of testing results and providing a scientific base for examinations of numerical simulations. Results of paired sample t-tests reported that there was notable effect of AAs morphology on the performance of AAAMs.