Comparison study of modified asphalt by different coal liquefaction residues and different preparation methods

The performance of four coal liquefaction residues (CLRs) in modification of petroleum paving asphalts were investigated. The 40–55 penetration grade modified asphalts were made. ASTM D5710-95 specifications were used to evaluate the modified asphalts. The influence of chemical composition and preparation methods were studied. The results indicate that the performance of CLR mainly depends on the amount and type of its miscible fraction that can dissolve or melt into the base asphalt. The addition of different CLRs in the base asphalt by a conventional hot mixing method results in the similar changes with respect to the softening point and penetration. However, it leads to the different change in ductility. The morphology analysis of the modified asphalt shows that the immiscibles from CLR are dispersed or suspended as single or clustered particles in the continuous asphalt phase. The miscibles of CLR in the base asphalt are active ingredients participating in the modification. The amount and the average molecular weight of CLR’s tetrahydrofuran solubles have a close relationship with its performance. The dissolution or dispersion of CLR can be greatly improved with the help of solvent.

► The dispersion of CLR can be greatly improved with the help of solvent.
► The performance of CLR mainly depend on the amount and type of miscibles that can dissolve or melt into the base asphalt.
► The amount and average molecular weight of THF solubles have a close relationship with the performance of the CLR.