Road Talk

Ministry Tests New De-icing Product

A potential benefit that may result from the use of Thawrox^TM would be the reduced need to modify existing salt spreaders to include pre-wet tanks, as no liquid is required to be added to the product.

This winter, the Ministry of Transportation (MTO) began testing a new de-icing product in the Huntsville area. The product, called Thawrox^TM, contains rock salt, magnesium chloride and a viscosity modifier that adheres the product to the road. The trials compare Thawrox^TM salt against existing pre-wetting treatments to determine whether the product’s performance makes it a suitable candidate as an alternate source of road salt.

The magnesium chloride in the product enables it to react faster with moisture than regular untreated sodium chloride road salt, preventing snow and ice from bonding to the pavement. Thawrox^TM is promoted as a product that can be used at lower temperatures. However, because of the product’s rapid reaction rate, it is used up quicker, leaving snow more susceptible to being refrozen into ice at extremely cold temperatures if a more rigorous salt distribution schedule is not adopted to offset the side effects.

Ministry best practices in winter maintenance recommend that road salt be applied at temperatures no colder than -18 degrees Celsius and under ideal conditions—such as minimal traffic and permitting weather—because road salt becomes less effective as temperatures drop below the recommended threshold. The Thawrox^TM trials are being simulated under the same standards.

Trials commenced in January and continue until the end of the winter season. They are being conducted out of the Huntsville patrol yard by John Ballantine, patrol maintenance technician and project lead. The test site designates 11.9 km on Highway 11 north of the patrol yard for Thawrox^TM and 11.9 km south for pre-wetted salts. Pre-wetted road salt is used as a control to help evaluate Thawrox^TM’s performance. To ensure that testing conditions are as equal as possible, both products are being used at the same application rate.

Many Thawrox^TM product trials in Ontario have been positive. The ministry wishes to determine whether the product will be able to perform at least on par with current pre-wetting systems, adhere to the road surface and work faster than regular untreated salt.

A potential benefit that may result from the use of Thawrox^TM would be the reduced need to modify existing salt spreaders to include pre-wet tanks, as no liquid is required to be added to the product. This could reduce costs incurred to optimize MTO’s salt spreaders for pre-wetting treatments.

If results are favourable, the ministry could consider Thawrox^TM as an alternative source when applying road salt on the highway. Look for Thawrox^TM pilot results in a future Road Talk article.

For more information about pre-wetting, please refer to the Winter 2006 issue of Road Talk.

For more information about the Thawrox^TM test trials, contact:

• Jim Young, Maintenance Operations Analyst, Highway Standards Branch, at (905) 704-2976.

State-of-the-Art Technology for Highway 11 Runaway Truck Ramp

Layout of the new Thibeault Hill runaway truck ramp.

Runaway truck ramp dragnet system.

A new state-of-the-art runaway truck ramp was recently constructed on Highway 11 at Thibeault Hill in North Bay, where transport trucks descend into a busy commercial area of the city. This is the only runaway truck ramp on the Ontario provincial highway system.

A runaway truck ramp was first constructed at this location in 1994 in response to a recommendation from a coroner’s inquest.

The original 1994 runaway truck ramp was built with arrestor bed technology, which used a bed of gravel to stop trucks experiencing brake failure. While this technology did work very well, it required operators to enter the runaway truck ramp as they began their descent into the city. This meant that operators had to anticipate brake issues before they arose. It was also less effective during winter months.

The new runaway truck ramp features a dragnet system, which uses a series of cables held apart by metal spreaders that form a net to catch a runaway truck or bus. The system consists of seven nets attached to a series of energy absorbers similar to the system used to stop airplanes when landing on aircraft carriers.

The energy absorbers are anchored into a concrete barrier and contain a spool of coiled steel alloy tape, which is wound through a series of offset steel pins within the absorber. These components are used to dissipate the energy of the runaway vehicle and bring it safely to a stop. Drivers will experience braking forces similar to a hard traffic stop.

Since the dragnet system requires less distance to stop a vehicle, operators now have more time to determine the presence of a brake issue before committing to the runaway truck ramp as they descend into the city. The new ramp starts 140 metres from the bottom of the hill, compared to 370 metres for the former gravel ramp. Also, the new system is more effective in the winter and requires less maintenance.

As part of the new runaway truck ramp project, the ministry also constructed a brake check area about 2 km north of Thibeault Hill. This area provides commercial vehicle operators with a safe spot to inspect their vehicles before entering the city.

Miller Paving Limited was the prime contractor for the new runaway truck ramp and brake check area. The dragnet system itself was manufactured by Entwistle Company from Hudson, Massachusetts and was distributed locally by Powell Contracting Limited.

The new runaway truck ramp and the brake check area became operational on December 19, 2008. A demonstration of the dragnet system will take place in June. The results of the trial will also be presented in a report and a high-speed video.

Improvements to the Thibeault Hill Runaway Truck Ramp reflect the government's continuing commitment to research and innovation as a means to improve road safety.

Please keep up with Road Talk for a follow-up article on the results of the Thibeault Hill Runaway Truck Ramp dragnet system.

For more information, please contact:

• Jim Bucci, Senior Project Engineer, Engineering, at (705) 497-5450.

Salt Storage Structure an Award Winner

Innovative salt storage facility located in Goderich, Ontario, was recently honoured with an Excellence in Storage Award

Ontario’s Ministry of Transportation (MTO) recognizes that good storage and handling practices for road salt and de-icing materials can reduce their ecological impact and help protect the environment. The ministry’s best practices in road salt and de-icing liquids emphasize proper handling and storage through quality standards, effective management, training programs, and guidelines. MTO also builds contained storage and loading facilities for de-icing materials to reduce the environmental impact of road salt, while ensuring employee and community safety.

A particularly innovative salt storage facility located in Goderich, Ontario, was recently honoured with an Excellence in Storage Award in recognition of its excellent housekeeping and operating procedures by the Salt Institute, a North American salt industry trade association which advocates the responsible use of salt in applications. A plaque honouring the achievement was presented to Larry Dickinson, Facilities Co-ordinator for West Region at the International Public Works Congress and Equipment last year.

The Goderich salt storage facility manages salt, sand and de-icing liquids indoors. The facility also uses a number of preventative measures to reduce the risk of contamination to the surrounding environment. For example, loaders are able to access salt and sand stockpiles without leaving the facility, so little moisture is tracked into stockpile areas. Water used to wash winter maintenance equipment is captured and processed through an oil/water separator to prevent hydrocarbons from infiltrating the environment. A space-saving secondary containment system for de-icing liquids has been designed to capture more than the capacity of the tank should it fail, and is protected to avoid collisions with maintenance equipment. The secondary containment system consists of a liquid storage tank placed inside a larger poly tank. A submersible pump positioned at the top of the storage tank is used to draw excess de-icing liquid from the storage tank into the spreader units.

Other features of the Goderich facility include:

• A drive-through system to allow safe and efficient traffic flow in and out of the facility.
• The retrofitting of the storage facility as a full addition to the existing sand storage structure.
• The accommodation of a site constraint from being in proximity with a local airport, limiting structure height to a maximum of 30 feet.
• Multiple entrances that enable a stacking unit to be used for stockpiling salt and sand prior to the winter season.
• Enough storage capacity for a winter season.
• If additional salt is required during the winter season, it is delivered by a tandem trailer that is able to dump material inside the facility. .

These benefits are augmented by MTO’s documented standards for material handling. While all loading and unloading operations occur indoors, formal procedures are in place for material clean up in the event of an outdoor spill. Policies also require the cleanup of loading and spreading equipment after each storm event, and a detailed safety program maintains employee safety.

The Goderich facility and its award from the Salt Institute reflect MTO’s ongoing commitment to improve upon best management practices in the storage and handling of de-icing materials, and to minimize the environmental impact of patrol yards across the province.

For related articles, please see the Winter 2006 and Winter 2008 issues of Road Talk.

For more information, please contact:

• John Roberto, Maintenance Officer, Highway Standards Branch, at (905) 704-2973.

MRO's First pervious Concrete Pavement Trial

Construction of Pervious Concrete Pavement Parking Lot

Completed Pervious Concrete Parking Lot

In an effort to reduce the size of our ecological footprint, MTO is trying an emerging green technology: pervious pavements. Pervious pavements allow water to percolate through the pavement and into the subgrade—a unique and effective design that addresses important environmental concerns. They offer a functional surface suitable for many low speed applications, such as parking lots and walkways.

Pervious pavements provide several benefits to more effective land use, including less interference with the water table, lowered impact to vegetation, decreased effect on ambient surface temperatures and reduced need for pavement drainage. The concrete used is typically a low slump, open graded mix consisting of Portland cement, coarse aggregate, admixtures, water, and little or no fine aggregate. A high void content (15 to 25%) and the presence of inter-connected pores result in a free-draining pavement layer that allows water to drain directly into the subgrade, replenishing the groundwater and potentially reducing the need for storm water management devices such as ponds and/or swales. Better passage of water and air through the pavement and into the ground supplies the root systems of adjacent vegetation, enhancing roadside vegetation growth. Furthermore, compared to regular pavements, pervious pavements also produce a lower heat island, lessening surface and ambient temperature increases associated with land surface modification in urban areas.

To test the pavement’s performance over time, MTO has designed and constructed its first pervious concrete pavement. A commuter parking lot adjacent to Highway 401 approximately 50 km west of Toronto near Milton has served as a test site since 2007.

The test site consists of five layers: the bottom layer is composed of silty sand subgrade. Directly on top of this layer rests select subgrade material, followed by an additional 200 mm of granular base material. Above the granular base material sits approximately 100 mm of open graded clear stone. Finally, 240 mm of pervious concrete forms the uppermost layer to complete the pervious concrete pavement.

The contractor, Facca Incorporated, placed the pervious concrete and underlying granular materials, while Dufferin Concrete was subcontracted for the material design and supply of the pervious concrete. The contractor used a Bid-Well bridge deck finishing machine to lay down a majority of the pervious concrete pavement. The contractor chose to use razorback screed (an air driven steel truss) to construct the final length of the pavement, due to restricted access for construction vehicles.

Trial results will be used to develop an industry standard for pervious concrete pavement. MTO will continue to monitor the pervious pavement test site to evaluate the performance and environmental benefits of pervious pavements for some time.

This technology may provide the ministry with another tool for building more environmentally friendly low volume pavements in Ontario.

For more information, please contact:

• Chris Raymond, Senior Pavement Design Engineer, at (416) 235-3513.
  
  
• Linda Fischer, Head, Planning and Environmental, at (416) 235-5488.
  
  
• Maria Bianchin, Senior Concrete Engineer, at (416) 235-3710.

Now you see us; now you don't - Burlington Bay Skyway Joint Replacement Goes Unnoticed by Bridge Users

New bridge joint being lowered into position during overnight replacement.

New bridge joint being installed overnight.

For most drivers in Ontario, it seems as though there are two driving seasons: winter and construction. During the construction season, drivers may face traffic congestion and time delays due to highway maintenance or repair. Construction traffic conditions and delays can be frustrating for drivers trying to reach their destinations on time.  However, repairs on the Burlington Bay Skyway were completed with little disruption to the travelling public.

The replacement project for the six modular joints of the Burlington Bay Skyway was a very innovative solution. The project proceeded with little disturbance to traffic and to drivers who were hardly aware of the construction. The replacement project occurred over six months with construction planned for select time slots each week to avoid congestion and delays.
The Niagara bound Burlington Bay Skyway in Hamilton, originally constructed in 1983, is a vital link connecting people and goods from Toronto through Niagara to New York State.  The skyway is two and half kilometres long, only 87 metres shorter than the Golden Gate Bridge in San Francisco.  The Niagara bound lanes of traffic travel over six modular expansion joints. These joints have a life expectancy of 20 - 30 years and are designed to expand in the summer and contract in the winter.

In 2007, Central Region engineers and maintenance staff concluded that the 23 - 24 year old joints needed complete replacement. But with an annual traffic volume of 70,000 vehicles (20% of which are commercial trucks), reducing the lanes on the skyway during the replacement of these joints was expected to cause a delay of up to an hour during peak traffic times. To work around this issue, traffic engineers conducted further research to determine that Friday, Saturday and Sunday night traffic volumes were relatively light. If construction was carried out then, detours of traffic to local roads during those times would eliminate traffic congestion.

To meet this construction schedule, structural engineers broke the work into smaller tasks that could be completed within short 10-hour weekend night construction windows (30 hours per week). Structural engineers designed a cover plate system which allowed traffic over partially constructed joints when work was not being performed.

There was minor construction from Monday to Friday, keeping the skyway’s four lanes open most of the week and preserving the speed limit. The bridge was closed on Friday night after 9 pm, and traffic diverted to a local road underneath the skyway. While the bridge was closed, the cover plates were lifted to allow work, such as removing existing joints, installing new joints, or pouring concrete. By Saturday morning, the bridge was re-opened and then the process was repeated on Saturday and Sunday night. After six months of construction, all six joints were replaced.

The replacement of expansion joints on bridges without - or with minimal - interruption of traffic is a major challenge to engineers and contractors.  As the contract progressed, the contractor’s familiarity with the project and the cover plates improved future mitigation of traffic impacts.  Communication with the media to report accurate bridge lane opening/closing times also decreased driver frustration with the project.

This project demonstrated that construction can be completed on a high volume freeway without significant traffic disruption. The team’s creative approach, using extensive research, careful planning and meticulous scheduling, is a useful model for others planning repairs to busy roads where work zone delays or closures present major impacts to the movement of people and goods, and hence, the local economy.

For more information, please contact:

• John Lam, Senior Structural Engineer, Central Region, at (416) 235-5509.
  
  
• Joe Costantino, Area Contracts Engineer, Central Region, at (416) 235-3613.

MTO Mobile Radio Network a Success

The radio system is vital to traffic management at the MTO Burlington Compass Centre

MTO provides its highway maintenance contractors with portable board mount radios to coordinate highway operations and participate in provincial Road and Weather reports.

Since the 1960s, five government agencies—the Ministry of Transportation (MTO), Ministry of Health, Ministry of Natural Resources, Ontario Provincial Police and Corrections—relied upon five legacy networks for critical radio communications across Ontario. As equipment aged, and technical difficulties and reliability issues grew, Ontario began to look for upgrade solutions which would also ensure that these five public agencies would be able to exchange information seamlessly.

Originally, each agency managed its own communications network. These networks were not linked, limiting interoperability between the agencies. Furthermore, the networks were not able to handle high volumes of communication. Radio users attempting to contact other users on the network would often find themselves waiting to complete their call. This was unacceptable for agencies that required real time communication or needed to synchronize among themselves for operations, particularly in the event of an emergency where it was critical for an urgent message to be transmitted a soon as possible.

In June 1998, Ontario signed a fifteen-year contract with a major mobile radio communications company that would replace the separately existing mobile networks with a single trunking VHF radio system, unifying the agencies under one network. The network, called the Government Mobile Communications Network (GMCN), would consist of 180 repeater towers strategically placed for optimal communications along all major highways throughout Ontario. Since then, the unified radio network has proven to be extremely reliable and stable. Because of this arrangement, ministries have been able to share upgrade costs and resources, such as communication towers, instead of bearing costs on their own.

With GMCN, users across five agencies are divided into four zones, each one representing a specific region in the province. Within these zones many talkgroups exist, defined by the needs of each agency. Despite operating on the same network, users of one talkgroup do not interfere with the communications in another talkgroup. For instance, an MTO contract snow plow operator is able to communicate in the same geographic region as police officers and ambulance workers without any of the parties interfering with one another.

The network’s radios eliminate the need to change radio channels while driving as it automatically interconnects selected towers to enable wide area coverage, allowing operators to travel long stretches of highway in full radio contact. Towers are also equipped with multiple repeaters which permit many simultaneous communications transmissions, eliminating call queuing time and providing an almost instant means of communication. In this way, users are assured clear, reliable communications.

MTO road maintenance currently uses approximately 3,000 mobile radios across the province, including about 250 located at patrol yards and MTO regional offices. MTO Enforcement uses approximately 250 radios, most of which are vehicle repeaters, including approximately 40 located in Truck Inspection Stations.

GMCN enables radio communications among MTO staff and its highway maintenance service providers. MTO provides its highway maintenance contractors with portable board mount radios to coordinate highway operations and participate in provincial road and weather reports. These reports are communicated five times per day during winter months and posted on MTO’s website for media weather reporting and forecasting. The information can be found at http://www.mto.gov.on.ca/english/traveller.

Network coverage and reliability have tested extremely well since GMCN inauguration. Initial post-conversion test results of the new network were extremely positive. As the network expanded across the province over the first five years, it tested at a uniformly high level of performance. According to this past winter’s statistics, the network continues to maintain over 99% coverage and almost 100% reliability. Operators have been able to rely on the network for consistent operational and urgent communications.

The mobile network currently uses a mixture of analog and digital signals. It is expected that the next generation of the network will be a completely digital system. Voice-over Internet Protocol (VoIP) may be implemented to take advantage of substantial cost savings.  Another option also being considered is an open-architecture for the network that would increase technological flexibility.

MTO is currently working with the other ministries involved in evaluating new system enhancements as the current contract comes to a close in 2013.

For more information, please contact:

• Bill Caldwell, Government Mobile Communication Project (GMCP) & Service Manager, Transportation I & IT Cluster, at (905) 704-2790.
  
  
• George Kudrewaytch, IT Service Mgt Consultant, Transportation I & IT Cluster, at (905) 704-2795.