Economic and Environmental Cost Analysis of Cold In-Place Recycling

The purpose of this study is to evaluate and quantify the construction costs, energy costs, and environmental benefits of using cold in-place recycling (CIR) as a pavement rehabilitation technique. For this study, the costs of using CIR mixes prepared using either asphalt emulsion (CIR-E) or foamed asphalt (CIR-F) were compared with conventional 5.1-cm (2-in.) hot-mix asphalt (HMA) mill and overlays. Three different costs were considered for the production of each pavement rehabilitation technique: (1) construction, (2) energy, and (3) environmental costs. To facilitate the cost comparisons, an equivalent pavement structural analysis was conducted between each pavement rehabilitation technique using a standard design method. The results of the study showed that initial construction costs of using CIR are less than the conventional HMA mill and overlay. The energy and environmental costs were also found to be much lower for CIR mixtures compared with the HMA mill and overlay, with energy savings of up to 63%. Overall, when considering all costs, the use of CIR has lower costs compared with traditional HMA overlays. Cost savings of approximately $34,000–$39,000 were observed when using CIR with HMA overlays, with a total cost savings between 41% and 47% over traditional HMA mill and overlays. This study gives an overall procedure for assessing the economic and environmental costs of different pavement rehabilitation techniques and provides further evidence of the cost benefits associated with CIR to practitioners.