Abstract
In this paper, since there are no grading specification on gap-grading for base course materials for road at present, we studied the mechanical properties of gap-grading base course materials, based on many laboratory CBR test results, comparing to the mechanical properties of continuous grading materials, and clarified that the mechanical properties of gap-grading materials are not inferior to those of continuous grading materials. Further, studying the application of gap-grading materials to base course materials for road in detail, we specified and showed the gradation range of gap-grading materials applicable to base course materials and subbase course materials. Besides we also described matters to be attended to when gap-grading materials are used.
