PERFORMANCE OF COLD IN-PLACE RECYCLING IN ONTARIO

In today's climate of environmental and economic constraints coupled with a limited aggregate supply, in-place recycling provides a feasible alternative to conventional pavement rehabilitation. Several state agencies have employed the cold in-place recycling (CIR) process for low-to-moderate traffic volume roads since the mid-1980s with reported favorable results. The Ministry of Transportation of Ontario was interested in determining whether these benefits could be realized on Ontario's highways. CIR consists of partial milling the existing pavement, processing the material to a suitable size, treating with an emulsion, and placing this recycled cold mix using conventional paving and compaction equipment. In the summer of 1990 the Ministry decided to use CIR on a major rehabilitation project. The location chosen was Highway 15, 40 km southwest of Ottawa. The ride on this road was considered uncomfortable, with major distresses consisting of extensive, moderate transverse and longitudinal wheel track cracking and slight rutting throughout the project length. The design details, construction procedures, mix test results, and pavement performance of this project are described. Conclusions and recommendations are made for further development of CIR in Ontario.