Cutback asphalt is asphalt that has been diluted to reduce it's flow temperature and make it easier to transport and apply. Once mixed with aggregate and laid in place, the diluent evaporates, curing (hardening) the asphalt into place.

Different intermediates can be used as diluents depending upon how quickly the asphalt needs to cure (harden): naphtha for a rapid cure, kerosene for a medium cure, and gas oil for a slow cure.