Cost-Effectiveness and Performance of Overlay Systems in Illinois, Volume 2: Guidelines for Interlayer System Selection Decision When Used in HMA Overlays

摘要

In an effort to control reflective cracking in hot-mix asphalt (HMA) overlays placed over Portland Cement Concrete (PCC) pavements, several reflective crack control (RCC) systems, including interlayer systems, have been used. However, the cost-effectiveness of interlayer systems is still in doubt due their performance and additional costs. In this project, a decision making procedure to aid in the selection of cost-effective interlayer systems was developed. As a core step in evaluating the benefit-cost ratio (B/C) of interlayer systems, a user-friendly life-cycle cost analysis (LCCA) program, CIND (Cost-effective INterlayer system Decision program) was developed. Based on sensitivity analysis, a B/C prediction model was proposed, which takes into account a performance benefit ratio (PBR) parameter, a material cost ratio (MCR), and a construction time ratio (CTR). Using the B/C model, a table was developed which allows the user to determine the most cost-effective interlayer system in a rehabilitation project for a given equivalent single-axle load (ESAL) level, representative low temperature (TL), and existing concrete pavement joint spacing (JS). Finally, a decision making tree was constructed to simplify the process of determining the most cost-effective and compatible interlayer system for a given project. Depending on project significance and/or information availability, pavement engineers can select from one of three newly developed B/C evaluation tools (in order of sophistication): application tables, B/C prediction model, and the CIND computer program. Using these tools, it was found that B/C increases as PBR increases or MCR and CTR decrease. In general, System D is cost-effective in a wide range of ESALs and TL values; especially in a cold region with lower traffic volume. The application range is reduced with the increase of JS, however. System E is relatively cost-effective only in warm regions having higher traffic volume.