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Red Hill Parkway was lauded for using paving technology that raised internal concerns at MTO

Red Hill Parkway was lauded for using paving technology that raised internal concerns at MTO

Documents released by the Red Hill Valley Inquiry tell a story of how a particular paving technique that had been in limited use in Ontario, was promoted by the manager in charge of the design of the Red Hill Valley Parkway, and how that technique later came under question by MTO. Gary Moore, who had been involved in the Red Hill project from 1988 until its completion was looking for a road design that would be capable of handling large traffic volumes and one that would outlast typical paving. He settled on a technique known as Stone Mastic Asphalt (SMA) developed in Germany in the 1960s, where a high percentage of coarse aggregate particles are mixed with the bitumen. It provides a durable surfacing material, suitable for heavily trafficked roads.

Settling on a design

Moore first raised the issue in 2003 with then Red Hill Valley manager Chris Murray, suggesting SMA was stronger, more durable, and more skid-resistant than typical pavements. In early 2005, Moore discussed the SMA possibility with Dr. Ludomir Uzarowski, a paving expert working for the consultants Golder and Associates. Uzarowski was subsequently engaged to conduct a feasibility study on SMA.

Within weeks, Moore and Uzarowski were collaborating on a paper to be presented to an industry conference that described the benefits of SMA as part of a road construction technique called perpetual pavement design, writing, “The advanced asphalt technology and materials used in the perpetual pavement design will allow the pavement structure to last 50 years with only periodic surface course replacements and without any major pavement rehabilitation.”

By early 2006 the use of SMA was confirmed for the Red Hill Project. A tender call went out in April 2006 and Dufferin Construction was the successful bidder. The discussion then turned to the exact mix of asphalt to be used. Dufferin wanted to use aggregate from a Quebec quarry that was not on the MTO’s list of preferred suppliers, but MTO did not have jurisdiction over the Hamilton project. It was agreed to continually test the Quebec product to make sure it was meeting specifications. There was some back and forth over the mixture to be used, and Dufferin commenced paving at the end of May 2007; but two weeks later Golder who had been hired by the city to oversee the pavement specs, said they had not approved Dufferin’s asphalt mix.

Whatever the issue with Dufferin, Moore and Uzarowski continued to promote the project through publication of an article titled, “Perpetual Pavements: Twenty Years in the Making.”

Test failed

A test strip of asphalt that Dufferin laid down on July 25 did not pass muster. Uzarowski noted in a memo, “Dufferin Construction should be aware the test strip has not been approved and the paving (using SMA) will be at their entire risk.” On the same day Uzarowski was made aware the Ontario Ministry of Transportation had concerns about friction on projects where it had employed SMA. MTO set up an SMA task force to explore the issue.

On August 13, 2007 Dufferin had completed the paving of the Red Hill Expressway using SMA. A week later test results were received that showed a third of the test samples taken were unacceptable. Uzarowski produced a memo reading, “how should we inform the client that 9 out of 28 SMA samples are rejectable? By now Dufferin had pulled out and taken down their asphalt plant. Meanwhile another trade paper article praising the project was released. On November 3, 2007 the Red Hill Valley Parkway official opening ceremony took place.

Promoting the project

Moore and Uzarowski continued to promote SMA presenting two papers at the 2008 Annual Conference of the Transportation Association of Canada, one called “Innovative, Comprehensive Design and Construction of Perpetual Pavement on the Red Hill Valley Parkway in Hamilton”. In June 2008 the Red Hill Creek Parkway captured the “Project of the Year Award” at a ceremony at the Chateau Laurier hotel in Ottawa.

Two weeks before Dufferin had completed paving the RHCE, the MTO had conducted friction testing on the road at the invitation of Dr. Uzarowski. MTO had been concerned about friction on SMA pavement since 2005. There was a robust internal debate at MTO over whether there was a skid problem or not with SMA. MTO was concerned that imposing a moratorium on SMA would be a problem because the paving industry had invested in plant modifications to accommodate SMA and a number of contracts had been let that called for its use.

Ministry of Transportation concerns

By June of 2007 MTO became aware that Hamilton was using SMA on the red Hill. Dr. Uzarowski had contacted the ministry and according to an MTO memo, “expressed concern regarding the proposed use of SMA on a City of Hamilton project (Red Hill Creek Expressway) where the contractor has submitted a mix design using a Quebec source (Demix Varennes) – the aggregate is not on the Ministry’s DSM.

The MTO conducted further testing on the RCEon October 16, 2007. The results showed the skid resistance on the Red Hill was 33.8. An MTO memo commented, “The friction number of 30 is an approximation of the (approaching worst condition) friction value used to determine minimum stopping distances in the Geometric Design Standards for Ontario Highways. The number 30 is a minimum friction number to be considered safe, low 20 is considered unsafe.”

MTO continued to test friction on the Red Hill every year except 2013. A 2014 test of the Red Hill prompted an MTO official to note in a memo, ”4 lanes of the Parkway were tested a few days ago. Performance shows friction levels continue to drop.”. The accompanying figures showed the friction levels had dropped roughly 20 percent from 2008 just after the road opened, and 2014.

Shortly afterwards MTO suspended the use of SMA pending further exploration of alternatives to improve friction; this included sand blasting the surface, grinding it, even running over it with studded tired to give it more grip.

Setting a friction standard

Since MTO had not set a friction standard it spent much of 2014 considering setting one. Staff recommended setting the lower limits at FN 35. But one MTO staffer noted, “Recommended HMA frictional requirement: : If you go to FN of 35 (100km/hr), some traps will have a problem with this from what I have seen based on data I have such as the Red Hill Ck xway.” There were also concerns expressed about legal action if the Province was explicit about picking a number.

It will be up to the Red Hill Enquiry to determine whether the road design and friction issues alone, accounted for the high number of fatal accidents that occurred on the highway, or to what degree speed combined with weather conditions also contributed to the accidents.

What is known that since the entire road was repaved, years ahead of its scheduled re-paving and since the speed limit was lowered to 80 kmh, there has been a decrease in accidents.

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