Effect of dry desulfurization ash as a filler on asphalt pavement performance

This study aims to explore the feasibility of using dry flue gas desulphurization ash (DFGDA) as a filler in asphalt pavements. Two DFGDA materials were added into the base asphalt with different mineral powder proportions to prepare asphalt mastic and mixture, and the pure mineral powder asphalt mastic and mixture were used as the blank control group to evaluate the properties of DFGDA-doped asphalt mastic and mixture. The results show that the addition of DFGDA can improve the high-temperature rheological property and reduce the low-temperature rheological property of asphalt mastic; similarly, the high-temperature stability of asphalt mixture can be greatly improved, while its low-temperature performance and water stability are reduced; despite these decreases, all outcomes still meet the requirements of relevant specifications. No chemical reactions are observed between DFGDA and asphalt, indicating that the physicochemical properties of fillers are responsible for the change in the properties of DFGDA-doped slurry and mixture. Notably, the DFGDA-added asphalt mixture does not bring additional negative effects to the environment. Based on cost analysis, the high-quality use of DFGDA in asphalt mixture can save direct material costs of about $920,000 per 100 kilometers of asphalt road construction. In summary, the application of DFGDA in the asphalt mixture can not only meet the basic performance requirements of asphalt pavements but also greatly save material costs and protect the environment.