Lai, James S.

Tech Report

Final report

Georgia. Dept. of Transportation. Office of Materials & Research

The practice of placing an open-graded friction course (OGFC) or a porous European mix (PEM) directly on top of a conventional milled surface has rarely been done in Georgia due to concerns that this rehabilitation method could potentially cause delamination of the surface layer due to poor bonding between the OGFC/PEM layer and the conventional milled surface. This report presents the research study for evaluating the quality of two micro-milling operations (one on I-75 and one on I-95) designed to reduce the potential for these issues. Results obtained from the I-75 project indicated that based on four years of satisfactory performance of the PEM overlay the use of a 95-percentile ridge-to-valley texture depth (RVD) parameter as the threshold value for compliance with the correction 3.2 mm RVD acceptance requirement could be too restrictive. Alternatively, Mean RVD was tentatively adopted on the I-95 project for compliance with the correction 3.2 mm RVD acceptance criteria. The research team concluded that the ultimate decision for selecting an appropriate RVD parameter for compliance with the correction 3.2 mm RVD acceptance requirement should be based on the long-term performance of the OGFC/PEM layer placed on the micro-milled surface.

PDF

SPR00-0008-00-516

US Transportation Collection