Citation

Allen GJ, Peters RI. Transp. Res. Rec. 1981; 821: 1-4.

Copyright

(Copyright © 1981, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

There has been a growing emphasis, particularly in the past seven to eight years, on the placement of what have become known as open-graded asphaltic concrete friction courses (ACFCs). Such placement is as a final, or wearing, course for asphaltic concrete pavements and is used not only for highways but for airport runways as well. It was replaced in July 1976 that 47 states have now tried some type of open-graded mix and that 20 or 25 states are continuing this type of surfacing on a regular basis. The following performance aspects of proper ACFC design, construction, and maintenance, based on observations made over the past 25 years, are discussed: (a) Although the film coatings on particles in an open-graded ACFC are larger than those in dense-graded designs, a planned maintenance program that requires a fog seal of rejuvenators and/or combined asphalt rejuvenators every two of three years is essential (service life is affected by the lack of such a program); (b) an open-graded ACFC has the ability to hide surface reflective cracking, and it also provides space for subsequent fog seals of rejuvenating agents to retard cracking; (c) since an open-graded ACFC is sensitive to bitumen quantity, temperatures, and hauling distances, consideration should be given to control of the construction season; (d) adequate sealing of the existing pavement surface prior to placement of an open-graded ACFC is essential; and (e) under high traffic volumes and speeds, an open-graded ACFC facilitates the handling of traffic during construction and reduces the splashing effects of surface water.