Greater Sudbury is mulling over the idea of using old-fashioned road-resurfacing technology in an effort to save money and reduce emissions.

Council will vote today on a proposed pilot project that will see about 25 kilometres of four major roads resurfaced using hot in-place asphalt recycling.

The technology is an on-site, in-place method that rehabilitates deteriorated asphalt pavements—thereby minimizing the use of new materials. The process begins by heating the asphalt pavement surface, cutting away the surface material, mixing that material with a recycling agent, asphalt binder or new mix, and then laying down and paving the recycled mix in place.

Hot in-place recycling was popular in Ontario for a period of about 15 years—from the late 1980s through early 2000s. The Ministry of Transportation specified the method on many road projects before hot in-place contractors began to be consistently outbid by those offering mill and pave options.

The ministry has been including hot in-place asphalt recycling as an alternative in recent contract documents in an effort to re-establish the method in Ontario. Due to improvements in technology and experience with hot in-place recycling, the treatment is now becoming a competitive alternative to milling and paving with new asphalt.

New evidence suggests that current hot in-place technology uses about 35 percent less energy than conventional methods and emits fewer greenhouse gases than other methods.

Greater Sudbury hired consultants Wood Environment & Infrastructure Solutions and PNJ Engineering Inc to evaluate the suitability of using hot in-place methods in the city. The engineers’ study identified about 77 lane kilometres of local roads as suitable candidates for the procedure.

“In selection of road candidates to be considered for [hot in-place recycling], pavements need to be free of major structural distress such as structural cracking and excessive rutting,” says the city staff report. “Asphalt material testing of candidate road sections includes tests for asphalt cement content, asphalt cement penetration, and air voids to ensure compatibility with the proposed treatment.”

Those roads proposed for the pilot program in 2020 are MR35, from Clarabele Road to Big Nickel Road; The Kingsway, from Falconbridge Road to Levesque Street; Radar Road, from Skead Road to Pine Street Ridge; and, Bancroft Drive, from The Kingsway to Bellevue Avenue.

Council has allocated about $1.4 million for the work, and staff will issue a full report on the method before the end of the year—if the pilot project goes ahead.

"This pilot project will help determine if HIR is a cost-effective strategy within our community when considering factors such as existing road structure/asphalt material conditions and available contractors and equipment," the staff report said.