United States Department of Transportation
i
Effects of an Uncrushed Base Layer on Pavement Performance Final Report
-
1987-06-01
[PDF-1.32 MB]
Details:
-
Creators:
-
Corporate Creators:
-
Corporate Contributors:
-
Subject/TRT Terms:
-
Publication/ Report Number:
-
Resource Type:
-
Geographical Coverage:
-
TRIS Online Accession Number:00472587
-
Corporate Publisher:
-
Abstract:In 1974, the Alaska Department of Highways decided to save money and fuel by removing the base course and placing the asphalt concrete surface directly on the surface of the Glenn Highway Widening project. The original two lanes had been constructed with a crushed base course in 1969, thus providing an excellent comparison of the performance of the two bases. Laboratory testing showed that the uncrushed base (subbase) was uniformly graded with a maximum size of 2 inches with 37 percent aggregate fracture while the crushed base was uniformly graded with a maximum size of 1 inch with an 85 percent aggregate fracture. Base course resilient modulus was back calculated from FWD readings and subsequently measured in the laboratory. Contrary to previous research and experience in crushed and uncrushed gravel, the uncrushed base course performed better than the crushed base course: the resilient modulus was higher and the permanent deformation was lower. The uncrushed base is apparently superior because of a larger maximum particle size and greater maximum density. An analysis of the future performance of the roadway with equal thickness of asphalt indicates that the pavement over the uncrushed base would have a longer life than the pavement over the crushed base by 54%.
-
Format:
-
Funding:
-
Collection(s):
-
Main Document Checksum:
-
Download URL:
-
File Type:
