Semester

Summer

Date of Graduation

2013

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

The objective of this study was to develop a test method and testing device for measuring the bond strength between pavement layers. The research evaluated tack coat materials and mix designs for the West Virginia Department of Highways. The project included a laboratory and a field phase. For the laboratory work, 9.5 mm and 19 mm NMAS mix designs were evaluated. NTSS-1HM and SS-1h tack coats were evaluated. Two surface conditions were simulated; the interface was either cut HMA or milled HMA. Also, the effect of the AASHTO T-283 conditioning was evaluated as a subsidiary to the laboratory testing.;In the laboratory phase, initial testing concluded that compaction effort affected bond strength. Also it was found that the cut face and new HMA face of the sample exhibit different bond strengths. The effect of changing the NMAS from 9.5 mm to 19 mm did increase the bond strength, but not to a significant level. The cut faced samples exhibited higher bond strengths than the milled samples on average. The bond strengths of samples with or without tack coat were not statistically different. For milled and cut faced samples, the NTSS-1HM was superior to SS-1h. Emulsion set time from 0.25 to 2.0 hours was statistically significant for both milled and cut faced samples. The difference in bond strength between the AASHTO T283 conditioning and the non-conditioned samples was found to be statistically significant.;The laboratory study was augmented with field cores on an gas availableh basis. In August 2012 the WV DOH sent 11 cores to NCAT for bond strength testing. Two tack coats were evaluated, Ultrafuse and CSS-1h. The Ultrafuse was applied at rates of 0.08, 0.13, 0.18 gal/yd2 and the CSS-1h was unspecified. The Ultrafuse was superior to CSS-1h. The Ultrafuse applied at 0.08 gal/yd2 exhibited the highest average bond strengths. Six cores were extracted from I-64 in Dunbar West Virginia. Three cores tested at 77°F . exhibited bond average bond strengths of 136 psi, two cores tested at 71°F. exhibited bond strengths of 196 psi, and one core tested at 19. exhibited a bond strength of greater than 350 psi.

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