OAPC seminar explores asphalt pavement production

A roster of guest speakers turned the spotlight on a list of projects, programs, and ideas to improve the production of asphalt pavements at the Ontario Asphalt Pavement Council’s (OAPC) recent fall seminar.

Helping to disseminate the message of continuous product performance was Imperial Oil’s Americas Asphalt Technical Advisor, Chris Campbell.

He travelled from the oil refinery’s Sarnia, Ont. facility to give a summary of a first-ever asphalt technical symposium jointly conducted by the company and OAPC and in that city last June. Planning for the event began in late 2018.

Approximately 30 representatives from the Ministry of Transportation, academia, suppliers, road contractors, researchers, refineries and other industry players participated in the symposium which had a broad range of objectives including sharing knowledge of new technology, discussing ways to improve quality, and identifying technical topics, he said.

“A survey was distributed to gauge success and there were positive reviews for moving ahead,” said Campbell, citing a number of respondent recommendations such as the need to harmonize owner specifications.

And the organizers are moving ahead with plans now underway for a second symposium to be held this June. The location has not yet been determined, he said.

A second speaker, and one who has spoken at past seminars, was the Asphalt Institute’s Canadian Regional Engineer, Amma Wakefield who spoke about life cycle cost analysis (LCCA).

In a presentation titled Another Look at Life Cycle Cost Analysis for Asphalt Pavements, she built the case for using LCCA’s on road projects by explaining what exactly it is, why it’s important, and how it can be best employed.

“Government transportation agencies are constantly faced with important financial decisions when planning new or rehabilitated road projects and have to answer critical questions such as the initial investment, how much funds are needed to maintain the pavement, and what materials should be used.”

Answers to those questions may require a life cycle cost analysis which, as she explained, is a full in-depth evaluation of a pavement’s life cycle or “time value of money concept”

A successful LCCA is comprised of six critical elements: the initial analysis period when the owner is considering a project; the performance period which is the time span a newly constructed or rehabilitated pavement will need maintenance or rehabilitation; the upfront construction and long-term maintenance costs; the terminal value which is the pavement’s value at the end of is serviced life; the discount rate to determine the present value of future costs; and the costs incurred by motorists using roads under construction.

In all six there are a number of best practices to be considered, said Wakefield, citing, as just one example, vehicle operating costs and drive delay costs because of construction zone detours.

Although a LCCA was not used, a test project in the State of South Dakota is a good example of the benefits of long-term comparative analysis planning, said Wakefield, who called the project : The Tale of Two Pavements.

In the early 1970s the state reconstructed the westbound lane and built a new eastbound lane for a low volume rural interstate highway—but used different materials for both. Concrete was used for the eastbound lane, while the thick layer hot mix asphalt was used for the westbound one.

In 2018 the cost of reconstructing the concrete eastbound lane was pegged at $34 million, while the estimated cost of rebuilding the HMA lane was $5.8 million, she pointed out.

“The project showed two things: thick asphalt pavements do last long, and at a significantly lower cost if an LCCA is considered.”

A number of resources are available to assist owners with LCCA planning including the Perpetual Pavement & Recycling Alliance’s comprehensive Build a Better Network (www.roadresource.com), she said.

Just some of the information on the multi-layered and multi-tab web page includes breakdowns of pavement conditions and primary distress factors, different highway and road conditions, a photo tool to explore solutions to those conditions, and recommendations on the best treatments.

In a third presentation OAPC technical director Doubra Ambaiowei underscored the critical need for proper pavement density and provided pointers on the best practices required to meet that target. The key is compaction, he said.

“The performance of any asphalt is significantly influenced by the degree of compaction which is the process in which the volume of asphalt mixture is reduced, leading to an increase in material density.”

In addition to those three speakers, an update on Ontario’s Ministry of Transportation initiatives was delivered by Gelu Vasiliu, head of its bituminous section.