Study on the Application of Coal Tar Pitch in Middle Asphalt Layer of Shanxi Highway Project

In this study, the objective was to dedicate to the application of coal tar pitch in road engineering construction. The present application situation of the coal pitch was discussed. The asphalt and the asphalt mix were designed. Appropriate adjustment of the proportion of coal pitch and petroleum asphalt improved the technical indexes of asphalt. The optimal bitumen-aggregate ratio based on the closest skeleton-interlocking dense condition principle is selected. Results indicated that the mix with modified coal tar pitch and the designed optimal bitumen-aggregate ratio had good performances, involving high temperature stability, low temperature cracking resistance and water stability. Besides, it was also found that the construction temperature can be reduced by the warm mix asphalt additive decreasing the volatile of polycyclic aromatic hydrocarbon which was a carcinogenic substance in coal pitch. The conclusion of this paper is valuable for the further application of coal tar pitch.