Fourth Cycle of Pavement Research at the Pennsylvania Transportation Research Facility. Volume 5. Open-Graded Permeable Subbases at the Pavement Durability Research Facility

摘要

A pavement subbase should be capable of rapidly draining infiltrated moisture while maintaining stability under traffic loads. Six subbases have been incorporated into experimental pavement sections. The subbase materials have been examined both in the laboratory and in situ. Permeability was measured in the laboratory to evaluate the drainage capability of each material. The gradation and the degree of compaction were varied to measure these effects on permeability. The measurements were compared with the results of similar studies conducted by other researchers. The results of this research were used to develop a suggested gradation specification for a free-draining subbase aggregate. The performance of different open-graded materials and filters was monitored in the field. A gradation for open-graded subbase, based on laboratory permeability measurements and field performance, was recommended.