May 10, 2012

Seminars aim to improve Ontario hot mix asphalt

KELLY LAPOINTE

staff writer

The Partners in Quality seminars currently happening throughout Ontario are some of the most important events of the years for the Ontario Hot Mix Producers Association (OHMPA), says the association president.

These collaborative seminars aim “to improve the quality of hot mix asphalt,” says association president Mike O’Connor.

As the Ministry of Transportation (MTO) has downloaded responsibilities for various roads onto municipalities, they have become involved in the seminars for the past three years and O’Connor said it’s an important partnership.

“They bring their concerns to us and we work them to resolve them,” he said. “We bring it to everyone and see how it’s working.”

One of the initiatives identified by the Municipal Liaison Committee in 2011 is to conduct research on ways to improve longitudinal joints in hot mix asphalt pavements, which O’Connor said is one of the biggest concerns for both municipalities and the MTO.

The conference will have a presentation about the recent Federal Highway Administration (FHWA) and Asphalt Institute (AI) study which has recommendations that cover many areas, from construction best practices to agency considerations. The study says improving joint performance has to be a collaboration between the agency and the contractors.

The four Partners in Quality seminars in the Greater Toronto Area, London, Ottawa and Sudbury will have presentations and updates from the OHMPA, the MTO, the Ontario Good Roads Association and the Canadian Council of Independent Laboratories (CCIL).

“I hope we’ll improve communication between partners so we can keep working as we do on an open and collaborative basis,” said O’Connor.

The MTO Bituminous section will report on the 2011 ERS results and inform the seminars on changes to be implemented in 2012 contracts, such as warranty specifications, pavements paid for by the square metre and new smoothness measurement requirements.

The MTO and OHMPA will update the conference on 2011 joint initiatives, including:

Asphalt Cement Acceptance Testing: Many different acceptance methods were tested to ensure high quality asphalt on MTO projects. They are introducing the multiple stress creep recovery test procedure, which the OHMPA said will likely be the acceptance methodology that moves forward.

Stone Mastic Asphalt was reapproved for use on high-traffic roads. It enhances the durability of pavements of 400 series highways and the new gritting procedure on SMA pavements will ensure improve early life (four to six weeks) pavement friction.

Due to supply issues, a number of Rubber Modified Asphalt trials were cancelled last year.

While rubber modified asphalt may be an environmentally acceptable way to eliminate a potential waste stream there are still challenges for its introduction into pavement, noted OHMPA.

Last year, MTO replaced about 10 per cent of hot-mix asphalt with warm-mix asphalt technologies, which reduces greenhouse gas emissions by lowering asphalt production temperatures.

This year, MTO has introduced a permissive specification to allow contractors to substitute warm-mix technologies for hot-mix technologies at their discretion.

In 2011, MTO and OHMPA worked together to improve road worker safety by introducing a new method for measuring the smoothness of newly constructed pavements.

MTO and OHMPA partnered to introduce the new Hot-on-Hot Paving Technology, which allows for thicker lifts of binder with an integrally applied surface course, allowing up to 170 millimetres of hot mix asphalt to be placed in one pass.

This technology results in economical pavements and should result in better performing pavements. Additional trials are expected for 2012 and they will continue to monitor last year’s trial.

O’Connor was pleased with the first seminar and said there was a good cross section of people who attended, including good representation by municipalities, MTO and a number of consultants.

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