| 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 &... |
