Paving: Does thicker mean better?
Surface asphalt is expected to last 10 to 20 years if laid at a depth of at least 50 millimetres. Linda Gyulai talks to the city about what went wrong on some projects.
The city of Montreal says it intended to do “short-term” repaving when it awarded $18 million in roadwork contracts on sections of an eight-kilometre stretch of Notre Dame St. E. between 2004 and 2012.
After two weeks of waiting for the city of Montreal to explain why sections of Notre Dame E. and another artery, Côte des Neiges Rd., were repaved multiple times in the mid-2000s, The Gazette got answers Wednesday. But some of the city’s answers raised other questions.
On Notre Dame E., where the city awarded $16 million in contracts in 2004, 2005 and 2006, a city spokesman, Philippe Sabourin, said the city repaved a 50-millimetre-thick surface layer of asphalt along sections of the road as a temporary measure because the city expected the Quebec government to announce a $1.5-billion project to rebuild and “moder nize” Notre Dame E., a high-traffic artery and truck route, as an urban boulevard.
As a result, the repaving work was not intended to last the 10 to 15 years that repav- ing work is normally meant to last, Sabourin said. Notre Dame E. has been considered heavily degraded for years.
However, for other jurisdictions The Gazette contacted, 40 to 50 millimetres is a standard depth for repaving hightraffic arteries, and lasts 10, 15 or 20 years.
Moreover, the work on Notre Dame E. apparently didn’t last beyond even two years in some spots.
The city’s contracts called for repaving the intersection at Notre Dame E. and Ste. Catherine St. E. in both 2004 and 2005, as well as the redesign of the intersection in 2005. The contracts also called for the redesign of the intersection at Notre Dame E. and Dickson St. in 2004 — which had been redesigned in 1998 as well — and the repaving of the intersection in 2004 and again in 2006.
The city issued another $2-million repaving contract for parts of Notre Dame E. in 2012, in which three of the four sections to be repaved were included in the repaving contracts the city awarded in 2004 and 2005.
The 2012 contract said the repaving work was “preventive” maintenance until the province gives a green light to the Notre Dame E. “modernization” project, which remains at a standstill. The repaving work is expected to become necessary again.
However, the contracts in 2004, 2005 and 2006 did not describe the repaving work as stopgap.
In fact, if the city intended a temporary repaving j ob on Notre Dame E., it’s unclear why the breakdown of work for the contract the
The contracts in 2004, 2005 and 2006 did not describe the repaving work as stopgap.
city awarded in 2006 calls for repaving a 40-millimetre depth of the asphalt base on a portion of the area targeted in the contract, plus 50 millimetres of surface asphalt, for a total of 90 millimetres.
The plans and specifications for the 2012 “maintenance” contract did not call for any of the asphalt base to be redone. And while the city refused The Gazette’s request last week for an interview with a bureaucrat in the city’s infrastructure depart- ment, a division chief in the department spoke to 98.5 FM radio host Paul Arcand on Wednesday.
The division chief, Benoît Champagne, said it cost the city about the same to repave parts of Notre Dame E. three times temporarily than to repave it properly once.
However, every repaving contract involves a cost to mark the pavement, redirect traffic during the construction work, and remove the surface level of asphalt so new asphalt can be laid. It also includes laboratory and engineering costs.
In 2004, for example, a civil service report to the city executive committee said the engineering work was budgeted for $200,000 on top of the roadwork contract.
A March 2009 study by Transport Quebec found that congestion on Montreal streets costs the economy $1.42 billion in terms of lost time, wages and fuel. The Société de transport de Montréal estimates another $1.42 billion is lost because of delays caused by roadwork and accidents on Montreal streets. The Transport Quebec study used 2003 as the reference year.
Meanwhile, on Côte des Neiges, Sabourin said watermain repair work in 2006 and again in 2009 in the same section of road near Queen Mary Rd. was to address different pipes.
The city was aware of a problem with the principal water main in 2006 when it cut open the road to repair a secondary water main, he said. But it couldn’t close the principal water main because of broken valve chambers, he said. Repairing the valve chambers would have entailed shutting off water to buildings around it for a few days to a few weeks, Sabourin said. The city went back in 2009, built a secondary water main to maintain water distribution to buildings and then repaired the principal water main, he said.
But while the city knew it would go back to fix the principal water main — which was also known to be antiquated in 2006, Sabourin said — it nevertheless called for “permanent” road repair at the completion of the initial water-main repair in the 2006 contract. The plans called for rebuilding the concrete base, plus a 60-millimetre-thick asphalt base and a 50-millimetre-thick asphalt surface.
And while laying 50 milli- metres of asphalt is a “short term” fix on Notre Dame St. E. in Montreal, it lasts 15 to 20 years on an artery in Quebec City or in Ottawa.
On a typical resurfacing job in Ottawa, the thickness that is removed and replaced on the surface of an arterial road is between 40 millimetres and 50 millimetres and the repaving job lasts 15 to 20 years, the city said through its media-relations office. In Quebec City, the city removes and repaves 40 millimetres of surface asphalt on damaged roads, spokesperson Jacques Perron said. Otherwise, the city repaves the top 20- to 25-millimetre layer of asphalt every 15 years, he said.
Meanwhile, the standards vary within Montreal.
A spokesperson for Transport Quebec said the average thickness of the surface asphalt on Décarie Expressway, a provincial roadway, is, in fact, 71 millimetres, slightly more than an engineer with the transport department told The Gazette earlier in the week. Yet the city repaved 85 millimetres on Côte des Neiges Rd. between Forest Hill and Decelles Aves. in 2009.