Asphalt modification with direct coal liquefaction residue based on benzaldehyde crosslinking agent

The modified asphalt was prepared via adding tetrahydrofuran soluble fraction of direct coal liquefaction residue (THFS) as modifier and benzaldehyde as crosslinking agent. Modification conditions such as mixing temperature, ratio of THFS and crosslinking agent to asphalt were studied. The optimal conditions are mixing temperature of 170 ℃, and THFS to asphalt ratio of 4%. The modified asphalt can get the better properties by using crosslinking agent. Characterizations of modified asphalt were analyzed by TG-FTIR, FT-IR and fluorescence microscope. Comparing with other asphalt the weight loss of modified asphalt which added benzaldehyde as crosslinking agent is lower. The modified asphalt with benzaldehyde as crosslinking agent has less CH₄ release than other samples and CH₄ was released at higher temperature. The involvement of benzaldehyde significantly enhances the stretching vibration of aliphatics (-CH₂-) of modified asphalt at 2 924 and 2 854 cm^-1 as well as the transmittance of the absorption peaks at 872, 810 and 746 cm^-1 representing benzene substituent, and a new absorption peak at 1 060 cm^-1 assigned to C-O-C stretching vibration. Moreover the new modified particle in the fluorescence microscope images indicates that the involvement of cross-linking agent may cause polycondensation of THFS and the matrix asphalt.