Multi-scale rheological properties of municipal solid waste fly ash-asphalt mastic materials

In order to promote the resource utilization of the byproducts of municipal solid waste incineration in asphalt pavement materials, this study selected different types of waste incineration fly ash as fillers and prepared waste fly ash-asphalt mastic materials. The Brookfield viscosity test was used to investigate the variation in apparent viscosity of the waste fly ash-asphalt mastic at different temperatures. The dynamic shear rheological test was employed to study the effects of fly ash content on the viscoelastic properties of asphalt under different frequencies. The low-temperature bending beam rheological test was used to analyze the changes in creep stiffness and creep rate of the waste fly ash-asphalt mastic. Based on this, the rotating film oven aging test was conducted to investigate the mass loss and softening point increment of the waste fly ash-asphalt mastic. The results indicated that the small particle size and developed pore structure of fly ash contributed to the adsorption of asphalt components, enhancing the volume of the mastic. As the fly ash content increased, its specific surface area also increased, further promoting the increase in the viscosity of the asphalt mastic. Under low-temperature conditions, the asphalt mastic became more prone to hardening and brittleness, which resulted in poorer low-temperature cracking resistance, consistent with the ductility results.