| Abstract: | Researchers conducted a laboratory test program to evaluate the durability and wear characteristics of aggregates commonly used for seal coat construction. They also sampled commonly used seal coat binders from construction projects and tested the binders in the laboratory to evaluate their propensity for flushing characteristics. Field test sections consisting of many of the commonly used binders were evaluated for performance in terms of bleeding and aggregate loss. Some of the limestone aggregates, which normally perform poorly in terms of Micro-Deval, performed better than expected in the new test methods employed in this study. While the polymer modified binders overall performed at a higher level, the test section with the highest score happened to be an unmodified binder (AC-10). There are many factors that can influence the performance of seal coats, and material selection is only one. If constructed properly and if the roadway is a good candidate, unmodified binders may perform very well. For higher volume facilities, it still seems that polymer modified binders are likely to give better success. For lower volume facilities, most of the laboratory and field data point to polymer modified materials ensuring better performance. To assist inselecting materials, 0-6747-P1, Guidelines for TxDOT in Selecting Seal Coat Materials was developed as part of this project. |
|---|