In the ongoing debate over whether concrete or asphalt is the best pavement for our roads and highways, a new study from Applied Research Associates gives the nod to concrete. The president of the Ready Mixed Concrete Association of Ontario weighs in.
In the ongoing debate over which pavement material is best for our roads and highways — concrete or asphalt — a new study gives the nod to concrete.
While that conclusion doesn’t surprise the executive at the Ready Mixed Concrete Association of Ontario (RMCAO), the third-party report goes further than previous initiatives in its analysis of the two competitive materials.
“It details cross-section design comparisons of concrete versus asphalt, identifies the maintenance and repair schedules as well as clearly identifying lifecycle cost,” says John Hull, president of RMCAO.
In a nutshell, it addresses both long and short-term cost efficiencies and establishes the lifecycle cost advantage of concrete pavement, he says.
The report was released at the Ontario Road Builders’ Association conference in Toronto earlier this year.
How is its software program different than CANPav, software released last year by the RMCAO that tabulated a 10-30 per cent savings of concrete over asphalt on first costs alone?
“CANPav simply allows comparisons — the user inputs their own design numbers etc.,” says Hull, adding that an upgraded version of CANPav reflecting the ARA report will be released soon.
The current study’s software called Mechanistic Empirical Pavement Design Guide (MEPDG) takes detailed traffic data, environmental data and material properties of concrete, asphalt and base/subbase materials to evaluate the performance of identified asphalt and concrete structures over a 25-year design life, he says.
The MEPDG is intended as a resource for municipal engineers and roadway consulting engineers.
The report was done by Applied Research Associates, Inc. (ARA), an international consulting firm, for the RMCAO and the Cement Association of Canada (CAC).
“Many consultants will identify with MEPDG,” says Hull. “Pavements are designed primarily based on soils, traffic and materials — this will offer a clear comparison.”
The ARA report is focused on pavement designs for arterial and collector roads, many of which are under the purview of the province’s Ministry of Transportation. Hull hopes that the findings will persuade MTO to reconsider its rule to allow only asphalt pavement bids on roadways.
“Right now they (MTO) restrict any competitive materials from bidding or even being tendered as an alternate.”
“Responsible municipal politicians and staff realize they must look beyond short-term expediency to deliver value to their communities,” say CAC president and CEO Michael McSweeney.
“Concrete pavement is not only more durable than asphalt, it can help municipalities reduce their greenhouse gas emissions and it provides other sustainable benefits like reduced aggregate demand, savings in truck fuel, and reduced energy consumption over the life of the pavement,” McSweeney says.
The RMCAO has been pressuring the MTO to allow concrete pavement bids since the late 1990s, a time when the ministry agreed to redo its lifecycle cost assessment.
That assessment’s conclusions, favouring concrete over a 50-year life cycle, prompted the government to call nine alternate bids, all of which were won by concrete over asphalt.
So why isn’t concrete pavement commonplace? Hull believes it is simply fear of change.
“This report will provide answers to questions and roadblocks that some (government officials) come up with — proof that designs are compared on an equivalent basis, an identified maintenance schedule and a life cycle cost.”
Hull admits that concrete won’t win over asphalt on every contract.
“Asphalt is installed with two or three layers on top of aggregate base and sub base. Many think that a fast fix is better than a long-term fix.”
The report, titled Methodology for the Development of Equivalent Pavement Design Matrix for Municipal Roadways, is available on both the RMCAO’s and the CAC’s websites.
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