Semester

Summer

Date of Graduation

2012

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Civil and Environmental Engineering

Committee Chair

John P. Zaniewski.

Abstract

Field permeability test using NCAT Permeameter were conducted at four project sites before and after the application of fog seal. Due to the fact that it is difficult to estimate the thickness of pavement tested, instead of permeability, the infiltration rate is calculated to estimate the effectiveness of fog seal on reducing the permeability of pavement.;Cores from I-79, I-64 and Route-19 projects were collected and sent to the WVUATL for bulk specific gravity (Gmb) measurements. According to AASHTO T 166, when the percent of water absorbed by the specimen exceeds 2%, AASHTO T 275 or T 331 should be used to determine the bulk specific gravity. There is a proposal to reduce this threshold to one percent which is supported by the data and analysis in this study. Paired student test, and a line of equality regression analysis were used to analyze the data provided by the contractor and collected in the WVUATL, the AASHTO T166 is proven to be repeatable, and CoreLok is a viable device for determining the Gmb and corresponding air voids of field cores. Based on density data from the I-79 project, provided by the contractor and WVDOH, the thin-lift gauge had smaller correction factors than standard nuclear gauges. Developing correction factors based on the ration of means may be better than using the difference of means methods which is currently used by the WVDOH.;Laboratory permeability tests were conducted on all field cores following Florida Testing Method 5-565. In general the permeability of the field cores on this project is consistent with the rule of thumb that permeability becomes an issue when the air voids of the sample are greater than eight percent. The regression model of the field cores permeability indicates that at eight percent air voids the permeability is about 80x10-5 cm/sec which is less than the recommended criteria of 100x10-5 cm/sec to 125x10-5 cm/sec.;In addition, eight HMA mixtures including 9.5 mm fine and coarse, 12.5 mm coarse, 19 mm fine and coarse, 25 mm fine, and 37.5 mm fine and coarse, were evaluated. For each mixture, gyratory compacted samples were produced and tested at target air voids contents of 4, 7, 9 and 11 percent, with two samples at each target. Laboratory permeability tests were performed to determine how air voids content, nominal maximum aggregate size, and aggregate gradation affect the permeability of HMA mixtures. The model developed by Vivar et al. was found to be suitable for data collected in this study, and new coefficients were suggested. The results of multi regression analysis indicated that air voids and nominal maximum aggregate size significantly affect the permeability, but aggregate gradation does not.;Comparing the permeability data from field cores and laboratory compacted pills, it is clear cores have higher permeability than laboratory compacted pills when the air voids are lower than approximately 10 percent, and the pills have a higher permeability at more than 10 percent air voids. This observation is consistent with previous research.

Download

Share

COinS