Moisture stability improvement of asphalt mixture considering the surface characteristics of steel slag coarse aggregate: Fid-Bau Portal

Moisture stability improvement of asphalt mixture considering the surface characteristics of steel slag coarse aggregate

Chen, Zongwu / Gong, Zhenlong / Jiao, Yuyong / Wang, Yi / Shi, Kui / Wu, Jianchao

Abstract

Highlights • Weathered steel slag coarse aggregate (SSCA) was modified by spraying silicone resin. • SBS modified asphalt and cement were used to adjust the composition of mastic. • Surface product layer made weathered SSCA sensitive to freeze–thaw cycle damage. • Spraying silicone resin was effective in sealing the surface of weathered SSCA. • Combined use of SBS modified asphalt and some cement was recommended.

Abstract Weathering treatment is a necessary operation to ensure the volume stability of steel slag coarse aggregate (SSCA) in service. Some previous research proved that the surface of weathered SSCA can significantly affect the moisture resistance of steel slag based asphalt mixture. In this research, the surface characteristics of weathered SSCA and its effect process on the moisture stability of asphalt mixture were first determined. Then two corresponding measures, strengthening the surface of weathered SSCA by an improved organic modification method and enhancing the bonding performance between SSCA and asphalt mastic by adjusting the composition of asphalt mastic, were taken to improve the moisture stability of weathered SSCA based asphalt mixture. Results suggested that weathered SSCA was sensitive to freeze–thaw cycle damage, and the fracture of calcium carbonate product layer coating the surface of weathered SSCA should be responsible for it. The proposed two measures both play a positive role in raising the freeze–thaw cycle damage resistance of weathered SSCA based asphalt mixture. Considering the asphalt pavement may be faced to serious freeze–thaw damage environment in service, weathered SSCA or organic modified weathered SSCA was suggested to prepare asphalt mixture with SBS modified asphalt and some Portland cement. The recommended dosage of Portland cement was 50% of the total filler volume after considering the technology solutions commonly adopted in the actual construction of asphalt pavement in China.