Composite Pavements: A Technical and Economic Analysis During the Pavement Type Selection Process

In most road infrastructure networks, the two prevalent types of pavements considered during the pavement type selection (PTS) process are flexible and rigid. Thus, these two structures are the most commonly constructed in the road industry. A consideration of a different pavement alternative is proposed in this study. Composite pavements, which are in essence a combination of a rigid base overlaid with a hot-mix asphalt (HMA) surface course, have the potential to meet the technical and economic requirements that are sought in the PTS process. For that reason, technical and economic evaluations were performed to justify the consideration of composite pavement systems in the PTS process.

At the technical level, composite pavement design guidelines from various transportation agencies were obtained and followed to design their respective composite pavement structures. A mechanistic analysis based on the multi-layer linear elastic theory was performed on different composite structures to understand the behavior they present when compared to traditional pavements. In addition, distresses affecting composite pavements such as fatigue (bottom-up and top-down) cracking, rutting, and reflective cracking were modeled and investigated using sensitivity analyses. At the economic level, a deterministic life cycle cost analysis (LCCA) based on Virginia Department of Transportation (VDOT) guidelines was performed. This LCCA compared two proposed composite pavements (one with a cement-treated base [CTB] and the other with a continuously reinforced concrete pavement [CRCP] base) to traditional flexible and rigid pavement structures. Furthermore, sensitivity analyses involving discount rates and traffic volumes were performed to investigate their effect on the present worth (PW) computation of the four pavement alternatives. Results from this study suggest that composite pavements have both the technical and economic potential to be considered during the PTS process.