Le Programme d’implantation de rues piétonnes et partagées (PIRPP) a été lancé en janvier 2015 par la Direction des Transports du Service des infrastructures, de la voirie et des transports de la Ville de Montréal. La Ville de Montréal a choisi de se positionner en soutenant la marche, un mode de transport durable qui présente de grands avantages pour l’individu comme pour l’environnement urbain. Le Programme d’implantation de rues piétonnes et partagées vise à soutenir techniquement et financièrement les 19 arrondissements dans la réalisation de projets de piétonnisation.
Despite the current economic downturn throughout Western Canada, the Province of Saskatchewan has been growing at an unprecedented rate, and the bedroom-community cities of Warman and Martensville, north of Saskatoon have mirrored that growth. As a result, Highway 11 and 12 corridors travelling adjacent to these cities have been the subject of several planning studies over the last 5-10 years. These studies have indicated a need for interchanges at both Warman on Highway 11 at Highway 305 and Martensville at Main Street/Township Road 384. Therefore, the Ministry of Highways and Infrastructure (MHI) in Saskatchewan has decided to proceed with plans to construct interchanges at both locations. The interchanges will address safety and economic development requirements for the Highway 11 and Highway 12 corridors north of Saskatoon. This project represents the first phase in addressing the larger transportation infrastructure needs in the Saskatoon region. Funding from the Federal Government, along with a provincial contribution, enabled the project to become a reality as a design-build project. MHI and ISL Engineering and Land Services Ltd. (ISL), as the Owner’s Engineer, have joined forces to prepare design-build documents for these interchanges with construction starting in 2017 and completion by 2019. Although, the steps taken to undertake a design-build project are well documented by several jurisdictions, numerous different examples exist for the preparation of design-build documentation. Saskatchewan has undertaken this task by combining parts of the Ontario, British Columbia and Alberta models, which have resulted in a robust model that has used a Fairness Monitor to ensure transparency throughout the Qualification and Proposal Request processes, and an Independent Certifier, which combines the normal duties of this independent body with a Road Safety Auditor. A “bucket” system has been developed for contract deficiencies, whereby negative points are accumulated by the Design-Builder resulting in financial penalties when the bucket is full. This paper examines the amount of work involved in incorporating these unique requirements into clauses in the design-build agreement.
Alberta Transportation and the Owner’s Engineering Consultant Team recently began the Alternate Delivery of Highway (Commercial) Safety Rest Areas (SRA) project. The intent of this project is to develop commercial SRA (CSRA) at no (or minimal) cost to government by having sites operated through an agreement with private developer(s) for a specified time period. Fourteen initial sites on government owned land have been shortlisted with the study team working to determine the feasibility of developing these sites, which are located on National Highway System corridors including Highway 1 (Trans-Canada), Highway 2 (Queen Elizabeth II), Highway 16 (Yellowhead) and Highway 63 (Fort McMurray/Athabasca Oil Sands access). The project requires the team to establish standards for provision of commercial services, conduct a jurisdictional scan of other agencies, develop functional plans and a business case for those sites pursued under this project, and administer the project through to construction. The project is currently in the functional planning phase of the work, which focuses on understanding the physical and economic strength of each site to support commercial development interests. The viability of the project is largely contingent on having sufficient traffic volumes that will bring in adequate revenue streams for potential development partners throughout the concession period. As such, it is important to establish policies and standards that will provide safe, convenient, comfortable and efficient rest areas to entice road users to utilize these facilities. Site enhancement opportunities (i.e., use of branding techniques to highlight surrounding regional and/or topographic features; provision of additional recreational features; amalgamation with tourism) will be sought for each site to customize these to local, regional and national travel demand needs. Sustainability measures are also being considered that meet green initiatives and support future travel requirements such as electric car charging and truck electrification. This presentation will address many of the initial considerations made during this first work phase regarding the economic/market factors that influence the viability of introducing commercial development to highway rest areas, site design and layout factors (building and site size, commercial amenities, user amenities, parking allowances, and fueling opportunities), and transportation design factors (roadside or median placement, traffic circulation, parking layout and access management). It will also address other items of interest to practitioners including sustainability, branding, legislation, emerging design and policy issues, and investment demands.
Warm mix asphalt (WMA) is a technology that has seen widespread growth in Canada since its introduction to North America in 2002. Since this technology is relatively new, there are still concerns about how these asphalt mixtures will perform over long-term, especially regarding resistance to moisture damage. Moisture damage is the primary driver for the deterioration of asphalt in the field, and can also exacerbate existing life-cycle stresses and cause premature failure. The wide range of different techniques being used for this technology makes it difficult to make broad generalizations, as some seem to perform much better than others in a laboratory setting. With this in mind, a study comparing the results from plant produced WMA against a known hot Mix Asphalt (HMA) will provide useful information on what can be expected from the mixes currently in use. This study compared a WMA mix using a 0.3% Evotherm M1 additive and an HMA mix produced by a local provider in New Brunswick. These asphalt mixtures were prepared using the same locally sourced binder and aggregate. The WMA mix performed well compared to the control HMA mix in a Modified Lottman Test; both had tensile strength ratio (TSR) values above the minimum of 75%, and it was found that there is no difference between the WMA and HMA Tensile Strengths. Additional testing on the performance of the mixtures using the Hamburg Wheel rutting test was performed, and the mechanical response of the mixtures was characterized using the Dynamic Modulus Test. Additionally, the impact on the life cycle and a comparison using the Mechanistic-Empirical Design Method were analyzed and no difference was found in long-term performance of WMA and HMA.
Bovaird Drive is a key east-west arterial in the Region of Peel, with traffic volumes of approximately 5500 AADT. Just west of Heritage Road, a tributary to the Credit River crosses Bovaird Drive through a 14m deep culvert with three distinct segments, including a 20m long 75 year +/- old masonry structure, and two newer sections – a 20m long cast-in-place concrete box culvert, and a larger 60m long cast-in-place concrete box culvert. Both the first and second segments were structurally deficient and required removal and replacement. A 2m vertical internal drop between the first and second culvert sections impeded fish passage. Extensive consultation was undertaken with the Department of Fisheries and Oceans Canada (DFO), Ministry of Natural Resources and Forestry (MNRF), and Credit Valley Conservation (CVC) to develop a design that would meet the requirements for hydraulic passage and environmental permitting. The approved designed, tendered and constructed culvert involved 20,000 m3 of earth excavation to expose the deficient portion of the culvert, removal of 40m of the existing deficient culvert and replacement with a 20m long x 1.2m wide by 2.8m high precast concrete box structure, installation of wooden fish baffles within the culvert to improve passage for large-bodied fish, reconstruction of the upstream portion of the tributary for approximately 65m using a pool-step configuration, temporary realignment of Bovaird Drive (reduced to one lane in each direction and with lanes shifted to the south), roadside protection, construction of temporary access roads into the valley to facilitate construction equipment movement, and reforestation of the disturbed area with 400+ trees and 450+ shrubs. The culvert was over 14m deep which required movement of a large volume of earth by heavy excavation equipment. Careful consideration was required for protection of the natural environment. As required by agencies, the final construction must improve the ability for fish to travel upstream. The new 20m long precast culvert created a 4m difference between the existing tributary and the new culvert invert. Fish passage was achieved through an innovative approach which utilized a fish baffle system within the existing culvert, followed by a pool-step channel, connecting the existing channel to the new culvert in the shortest distance possible, while allowing the fish to jump from pool to pool. Finally, and most importantly, the structurally deficient sections of the existing culvert were removed and replaced. This not only ensures continued operation of a key arterial roadway, but also has improved the ability of the Credit River Tributary to function as a healthy and vibrant natural system.
Saskatchewan’s Ministry of Highways and Infrastructure (SMHI) has replaced the visual assessment method for collecting pavement condition information with data measured using the Laser Crack Measuring System (LCMS). Pavement bleeding, stone pick outs, ravelling, wheel path rutting, bumps & dips and all types of pavement cracking have been incorporated into the Saskatchewan pavement asset management system. The paper discusses how the field calibration site and testing fit into the overall project. The site was set up to understand repeatability of the categorization and severity of each measured distress. The design, construction and results from the field calibration site are discussed. Analysis of multiple measurements taken at the site was used to modify and fine tune the metrics developed for the Pavement Asset Management System. The paper includes: An over view of the LCMS integration project; Design, set up and operation of a field calibration site for surface distress measured by the LCMS including cracking, bleeding, potholes, delamination, pick outs and ravelling; Findings from the analysis of the calibration testing; Improvements that will be incorporated into the next cycle of data collection.
The replacement of the actual Champlain Bridge crossing the Saint-Lawrence River at the height of Montréal and Brossard in the province of Quebec, Canada was tendered as a PPP project. The design of the new bridge required extensive geotechnical investigations in order to use construction techniques adapted to the timeline specified in the contract. Firstly, innovating investigation techniques that were used to determine the sound rock level for the installation of the pier foundation footings for the main bridge will be presented. Secondly, large scale in situ tests, using an Osterberg cell which were carried out to optimize the caissons design of the main tower will be described. Finally, the results of these investigations will be presented and the construction techniques put in place in order to allow quality control during construction of the foundations.
A major incident on a 400-series highway in the Greater Toronto Area has the potential to result in significant costs related to delay with respect to both passenger and commercial travel. Such incidents might involve collisions requiring police investigation or truck roll-overs, fires, or major spills, and could result in partial or full highway closures over multiple hours. In addition, significant delay would be anticipated on “diversion” routes used by drivers to circumvent the incident, as well as delay incurred during the system recovery period once the highway has been re-opened. Since traffic flows on major highways can range from 5,000 vehicles/hour to between 10,000 and 15,000 vehicles per hour over much of the typical day, the total delay cost from a single incident can run into the millions of dollars without even considering the implications for the broader economy. The Ministry of Transportation of Ontario (MTO) is in the process of reviewing response strategies to major incidents in two contexts. First, prior to the 2015 Pan Am/ParaPan Am Games, the Ministry developed traffic management plans to address major incidents affecting the highways accommodating the temporary High-Occupancy Vehicle (HOV) lanes implemented for the Games. These plans were designed to be more proactive than ambient incident response protocols. The use of the plans on several occasions during the Games created a generally favourable impression of the potential to reduce the impacts of traffic incidents. Secondly, the potential benefit associated with reducing the amount of time required to clear truck roll-overs and similar incidents has been investigated. We also note that ongoing expansion of the use of advanced traffic management systems (ATMS) by the Ministry enhances the toolbox available for incident-related traffic management. This paper describes the process used to develop more pro-active traffic management protocols for major incidents and provides an evaluation of some of the potential benefits of reducing the time required to clear truck roll-over incidents.
Longitudinal edge cracking is a widespread and costly safety concern for northern regulators, such as Yukon Highways and Public Works. The exact cause of longitudinal edge cracking in northern, low volume highways is not well understood. There are many factors that may be linked to cracking such as weak materials under the side slope toe, differential frost heave, oversteepened side slopes, concentration of moisture in road edge materials, and climate change. In an effort to prevent edge cracking in its low volume pavements, the Yukon Government partnered with FPInnovations and TenCate in 2015 and 2016 to construct two, instrumented, thin pavement test sites on the Campbell Highway near Watson Lake, Yukon. The test pavements were reinforced with a new geosynthetic product; instrumentation installed above and below the geotextile monitored roadbed moisture content and temperature. Mirafi® H2Ri is a high strength, woven, geotextile with hygroscopic, hydrophilic, and wicking properties that promote rapid drainage. It is anticipated that the geotextile will help prevent edge cracking by interrupting capillary rise from the subgrade, draining excess moisture from thawing layers, providing additional structural support, and confining road edge materials. Additional benefits may include the mitigation of rutting, cracking and pot holes associated with excess roadbed moisture. Activities in 2015 comprised site construction, and monitoring of moisture and temperature trends. The shoulders of the test pavement sections were consistently wetter than near centerline before and after paving. The geotextile, installed at the subbase-subgrade interface, reduced moisture in the subbase of both test pavements by up to 3%. In 2016, activities included continuing to evaluate roadbed moisture control by the geosynthetic, and assessing how well the new pavement design controls edge cracking and other pavement distresses. This innovative research will provide knowledge to owners, designers, and maintainers of low volume northern roads about road construction solutions to mitigate pavement distress, improve safety, and decrease maintenance costs.
Monitoring the temperature gradient of pavement structure layers and its effect on the structural behaviour helped to establish a fundamental understanding of the magnitude and impact of these variations on the pavement response to different loading conditions. The performance of pavements clearly reveals the need to properly measure the distribution of stresses and strains within road layers over a period of time taking into account the effect of extreme temperatures. The adverse effects of traffic speed during hot weather conditions on the structural behaviour of the flexible pavement are briefly discussed and possible recommendations to overcome these effects. Structural data including stresses and strains were collected under the action of external loads applied by a calibrated test trucks. To mimic the effect temperature extreme events on the flexible pavements, the study was carried out on flexible roads immediately after the construction at 51o C (truck impact test) and 44o C (truck creep test) and after one year at normal operating temperature (20o C). The field results showed unprecedented high stress and strain levels caused by low asphalt stiffness when the asphalt mat temperature is above a normal operating temperature. Traffic-induced stresses and strains transmitted through the asphalt concrete layer to unbound materials of the asphalt concrete are directly influenced by the stiffness. The impact test using a truck speed lower than 25 km/h resulted in a very high truck pressure impact. This study confirmed that most of pavement performance problems occurred at locations where buses frequently stopped and areas close to traffic signals. This finding highlighted the importance of traffic speed impact, extreme hot weather events and the interaction of both.
Canada’s first High Occupancy Toll (HOT) Lanes were a key government transportation commitment publicly announced in December 2015 and introduced to Ontario on September 15, 2016. The HOT pilot program and supporting retail and distribution system was developed and delivered in less than nine months as an online service. MTO and ServiceOntario collaborated to simultaneously develop policy, performance measures and program design, including an online digital retail service. This successful team approach ensured a key government priority was delivered within a compressed timeframe while introducing a new business model for digital services. Typically, to deploy an online service of this nature, it takes 12 to 18 months to deliver. The HOT Lanes Pilot Branch, Policy and Planning Division, Ministry of Transportation Ontario (MTO) is nominated for TAC’s Sustainable Urban Transportation Award for the development and implementation of Canada’s first High Occupancy Toll (HOT) Lane.
Located immediately east of Toronto, Ontario, the Regional Municipality of Durham includes 7 area municipalities with a total geographical area of approximately 2,590 square kilometres and a combined population of approximately 650,000 people. Situated in the highly developed and populated economic centre of Ontario, known as the Golden Horseshoe, Durham Region is expected to grow to an estimated population target of 970,000 by the year 2031. This growth will bring higher traffic volumes including buses and heavy trucks, which should be designed for in today’s road reconstruction projects. As part of its commitment to continually improve its service excellence, Durham Region is exploring innovative approaches to pavement design and road rehabilitation that could extend the life of its roadways and reduce overall lifecycle costs of the network. In line with this initiative, a pilot project was undertaken to reconstruct the intersection of Harwood Avenue and Bayly Street (Regional Road 22) in the Town of Ajax using a jointed plain concrete pavement design instead of a conventional asphalt pavement design. This paper provides an overview of the pilot project, highlighting key differences between concrete pavement design and traditional asphalt pavement design, and discusses construction considerations and lessons learned. This paper also outlines the construction staging that was followed and a traffic impact assessment undertaken by the Centre for Pavement and Transportation Technology (CPATT) at the University of Waterloo.
Fourteen reclaimed asphalt pavement (RAP) mixtures designed with different combinations of RAP sources, contents (up to 40%) and mixture conditioning levels were evaluated to determine the maximum allowable amount of RAP material in surface courses without jeopardizing pavement cracking performance. Extracted RAP binder was blended with virgin polymer-modified asphalt (PMA) binder at various RAP binder replacement ratios. All blends behaved effectively as PMA binder as they met the multiple stress creep recovery (MSCR) % recovery requirement, and in addition they had satisfactory binder fracture energy density (FED) values. RAP gradation was found to significantly affect the fracture properties of RAP mixtures as it controls the distribution of RAP binder and potentially the degree of blending between virgin and RAP binder. Increased RAP content resulted in stronger (i.e., higher tensile strength) but more brittle (i.e., lower failure strain and lower mixture fracture energy) mixtures. However, after long-term oven aging (LTOA) plus cyclic pore pressure conditioning (CPPC) which was used to simulate long-term field aging conditioning, all RAP mixtures still exhibited dissipated creep strain energy to failure (DCSEf) values above 0.75 kJ/m3 and energy ratio (ER) values well above 1.0, indicating acceptable cracking performance. It must be emphasized that all RAP mixtures had good gradation characteristics as they all met Superpave design criteria and dominant aggregate size range and the interstitial component (DASR-IC) requirements. Therefore, satisfactory inclusion of up to 40% RAP was acceptable for well-designed PMA mixtures.
As the temperature of an asphalt pavement drops to below freezing point, the asphalt material starts to lose its ductility, and consequently, the asphalt mixture becomes more susceptible to cracking. The disk-shaped compact tension [DC(T)] fracture test has been used to quantify the fracture properties of asphalt concrete at subzero temperatures for more than a decade. The Asphalt Institute laboratory has successfully utilized the DC(T) test in several research studies. As a result of these studies, a valuable database has been gathered which represents the sensitivity of the DC(T) test, and exhibits how the test is capable of capturing the effects of various factors on the performance of asphalt mixtures at low temperatures. This paper briefly presents the findings from some of these studies. The paper presents the response of the DC(T) test to the variations in several factors relative to asphalt pavements including the crude source of the asphalt binder, aging of the asphalt mixture, deficiency in the in-place density, pavement temperature, using a warm-mix agent, using RAP and RAS materials, and chip sealing as a preservation method. The test proved to be well capable of capturing the variations in these factors; therefore, it can be utilized by pavement managers to assess changes in specimens from asphalt pavements over time to help determine if any maintenance or rehabilitation action is required. Furthermore, the test can be used to evaluate laboratory-made mixtures and ascertain if they would perform satisfactorily in their designated environmental conditions.
For current asphalt paving practice, many unconventional asphalt binders and additives have been introduced. Through physical and chemical interactions with base binders, these modifications usually affect the binder and mix strength and fracture properties as well as stiffness. However, the currently used binder grading system is based on the low temperature stiffness and relaxation behavior as measured using the Bending Beam Rheometer (BBR). The absence of strength and fracture properties in the asphalt binder grading process may result in inaccurate prediction of field performance. Five PG grade asphalt binders including unmodified, polyphosphoric acid (PPA) modified and styrene-butadiene-styrene (SBS) modified binders were tested using the BBR and the Asphalt Binder Cracking Device (ABCD). Asphalt mixes prepared with these five binders were also tested with a revised Asphalt Concrete Cracking Device (ACCD) test procedure. The test results showed improved strength and fracture resistance characteristics for SBS modified asphalt binders in the ABCD test and mixtures in the ACCD test, resulting in better performance than that predicted by the BBR low temperature PG grade. However, the PPA modified asphalt binder and the corresponding mixture exhibited worse performance in the ABCD and ACCD tests, respectively, than that predicted by the BBR low temperature PG grade, which may be attributed to the poor fracture resistance.
Low temperature cracking is a critical distress form and is heavily influenced by the relaxation and strength capabilities of the material. These properties are related to the stiffness through principles of viscoelasticity. Recently, there is elevated pressure on decisions made by pavement and materials engineers to produce the longest lasting, most resourceful pavement systems possible to optimize monetary and non-renewable resource usage. The primary objectives of this study are to: 1) assess the value of a parameter which can describe low temperature cracking resistance by using dynamic modulus ( E* ) and phase angle (delta) of the mixture and laboratory-measured performance; 2) present shape parameters of a mixture master curve that are directly related to the relaxation spectra, which is expected to play a pivotal role in low temperature distress resistance with aging; 3) define failure lines in Black Space which correspond with laboratory-measured performance and operate under a well-understood basis reinforced by the literature; and 4) provide agencies with a tool to aid in the movement towards a performance-based mixture design, acceptance, or rehabilitation decision-making system. An analysis of the mixture master curve is done to establish parameters which describe the relaxation spectra and aging potential of materials. A mixture-based Black Space parameter is presented based on results from the E* master curve construction and the thermal stress restrained specimen test. This approach holds promise, but must be calibrated with a robust database before serious implementation considerations are made. Future work will look to determine a common stiffness condition to better define the failure threshold and to identify possible alternatives to the modified Glover- Rowe function used in this study. Further evaluation is also needed to optimize the temperature-frequency combination of the Black Space parameter itself and ensure a condition is specified that can be captured by test equipment an owner agency or contractor may possess as part of a performance-based specification framework.
The development of the well-known Christensen-Anderson (CA) rheological model grew out of attempts to model the relaxation spectra of asphalt binders using a skewed logistic distribution function. For this reason, there are very strong relationships between the CA model parameters and the characteristics of relaxation spectra for asphalt binders. This paper presents a recently developed equation that allows direct and accurate calculation of the relaxation spectra from CA model parameters, demonstrating the nature of this relationship. Of the CA model/spectrum parameters, the most important in terms of describing overall behavior and potential performance is the R-value, which describes the shape and skewness of the spectrum. This parameter and other similar rheological parameters have been linked to various important aspects of asphalt binder behavior, including fatigue resistance, chemical composition and degree of oxidative aging. This makes the parameter R a potentially useful parameter for inclusion in asphalt binder specifications; although care must be taken in how it is determined to ensure that it is accurate, repeatable and reflects the performance characteristics of interest.
The determination of the rheological properties of the aged binder in reclaimed asphalt pavement (RAP) materials is a challenging problem. Conventionally, extraction and recovery are used to obtain the RAP binder for further experimental characterization; however, this procedure is not entirely reliable and accurate. Alternative and more precise approaches are based on asphalt mixture tests in combination with complex and sophisticated back-calculation methods which are costly and time consuming. In this paper a new and simple approach to estimate the rheological properties of RAP binder at intermediate temperature is proposed. This is based on Dynamic Shear Rheometer (DSR) tests performed on mortars, composed of a selected fine fraction of RAP and virgin binder, together with a new back-calculation solution. The properties of the bituminous blend of virgin and RAP binders are obtained through the manipulation of the Nielsen model equation to take into account the effects of frequency and temperature on mortar stiffness. The Voigt model is then used to estimate the complex modulus and the phase angle of the RAP binder from the complex modulus and the phase angle of the back-calculated binder blend.
This paper presents a simple, yet powerful method for simultaneously evaluating the high and low temperature performance of asphalt paving mixtures for the purpose of mixture design, evaluation, and forensic investigation. A performance-space diagram approach is described, with an emphasis on Hamburg-DC(T) plots presented in this paper. Specifically, a plot of Hamburg wheel tracking results, plotted in reverse order on the y-axis using an arithmetic scale, along with DC(T) fracture energy results, plotted on the x-axis, constitutes the Hamburg-DC(T) plot. Plotting candidate mixture designs, research results, etc., yields a surprising amount of insight towards mixture variables that affect overall performance. For instance, substitution of one straight-run binder grade for another results in a clear, predictable trade-off in the Hamburg-DC(T) performance space. Polymer modified grades, on the other hand, provide a more beneficial shift in the Hamburg-DC(T) space. The benefits of using this approach in the design of mixtures containing recycled asphalt mixture and recycled asphalt shingles are also presented. Effects of rejuvenators and the benefits of stone mastic asphalt designs are also demonstrated. Finally, a broad look at a large database of mixtures recently designed in Illinois is presented.
Mechanically stabilized earth (MSE) walls are a mature earth retention technology but concerns sometimes arise over who retains ultimate responsibility for wall design, quality assurance, asset management and repairs, and post-construction in-service monitoring, particularly if significant construction or performance problems occur. This guide provides owners, engineers, suppliers and contractors of MSE walls with practical guidance on the selection, design, construction, and inspection of these structures with a focus on public works projects. The guide was developed through reviews of published literature supplemented by a survey of industry stakeholders. It is not intended to reproduce the large volume of published design guidance and related information; rather the guide highlights aspects of the current state of practice in Canada and suggests modifications of current practice where deficiencies are apparent.