Abstract Manager

The 407 ETR Concession Company operates an annual concrete grinding program for the purpose of increasing highway pavement friction for a safer and quieter ride. This process uses a constant spray of cooling water to protect the diamond grinding blades from overheating damage. This process produces a slurry byproduct, which is referred to as Concrete Grinding Residue (CGR). Concrete debri is identified as a regulated waste material under Ontario Regulation 347. The 407 ETR had previously spent $850,000 annually to dewater and deliver approximately 500 truckloads of CGR to a quarry rehabilitation site located 200 kms from the grinding areas. In 2018, twenty-nine (29) CGS slurry samples were collected during the 407 ETR concrete grinding operations. Standard environmental laboratory test results triggered waste disposal requirements due to high pH levels, which typically ranged from between 11 and 12. However, alternative agricultural test methods determined that the plant-available pH levels did not exceed this standard. This finding allowed the Ontario Ministry of Environment Conservation and Parks (MECP) to issue the first mobile Environmental Compliance Approval (ECA) for beneficial reuse of the CGR as a berm construction material on highway right-of-way (ROW) lands. This berm has been constructed over the past three years, which provides a visual and sound barrier between the 407 ETR highway and residential neighbourhoods. Local beneficial reuse diverted approximately 2000 truckloads of CGR from waste disposal facilities, while also reducing the transportation carbon footprint as well.