As part of bridge maintenance, evaluating deterioration in asphalt overlaid concrete bridge decks is crucial in determining the timing and nature of any maintenance. Chloride contamination caused by de-icing salt is one of the primary contributors to bridge deck deterioration. Early detection can trigger proactive maintenance rather than more expensive, reactive rehabilitation. Ground Penetrating Radar (GPR) technology is an efficient and reliable testing method that collects data to evaluate deterioration in asphalt overlaid concrete bridge decks. When comparing the results of the GPR evaluation to that of ASTM D6087 and traditional test methods (Chloride samples, AC resistance, and CSE), the results proved more accurate when compared to ASTM D6087, and correlated well with traditional methods. GPR can identify and quantify the chloride contamination by looking for reductions in the amplitude of the returning signal due to attenuation. Attenuation is affected by the conductivity (chloride content) of the concrete. The challenge is that the amplitude of the returning signal is also affected by geometric spreading of the signal. A method to account for geometric spreading (by normalizing the amplitude to the 90th percentile of the data) has been developed and is extensively used on bare concrete decks, but less work has been done on data correction for asphalt overlaid bridge decks. On asphalt overlaid bridge decks, the GPR signal must pass through both the asphalt and concrete, both of which have different electromagnetic material properties. Consequently, this produces less reliable results due to the addition of amplitude variability caused by inconsistent signal reflection at the asphalt/concrete interface. To address this, the amplitude was corrected for geometric spreading using the 90th percentile method and applying Fresnel's Law to correct for the variability in the asphalt/concrete interface reflection. A total of five structures in Ontario with asphalt overlays, waterproofing membranes, and epoxy rebar were tested in 2020 using GPR to determine chloride contamination. The results from the proposed GPR method were compared to the traditional test methods, and to the analysis method specified in ASTM D6087. The results of this GPR approach suggested that accounting for geometric spreading, in conjunction with interface reflection correction, not only correlates with the traditional test methods, but produces more accurate deterioration mapping than ASTM D6087. This increased accuracy allows for better decision making on the timing and nature of any recommended bridge repairs, leading to improved cost savings over the lifespan of the bridge.
In 2015, the Canadian government awarded a $4.3 Billion Design-Build contract to the Joint Venture (JV) team Signature on the Saint Lawrence (led by SNC-Lavalin) for the design and construction of one of the largest infrastructure projects in North America, Samuel de Champlain Bridge over Saint-Laurence River in Montreal. In addition to the new 3.5 km main bridge, the overall project involved the construction of tens of smaller bridges and over 20 retaining walls along the bridge approaches. The complexity of the project posed unique geotechnical challenges on many levels. One significant challenge was the construction of part of the alignment over an old landfill where the subsurface investigation indicated up to 9 m of waste solid. To assess the foundation material properties, settlement monitoring was performed during the design phase on a 7-m high temporary embankment, constructed on the existing fill, using numerous settlement platforms. The “consolidation” and strength parameters were then back calculated and used in the roadway embankment design. On the west approach, part of the new highway alignment was to be constructed over an existing 11x5 m COS collector with unknown structural condition, with the requirement not to apply additional load on the collector. Lightweight fill composed of expanded polystyrene was used for this purpose. Detailed numerical analysis of the stress-strain conditions was performed to optimize the design. Moreover, the presence of a thick liquefiable silty soil deposit, covering a large area along the alignment, led the geotechnical team to design the foundation system to withstand seismic loading induced during a 2% in 50-year return period. Furthermore, the rock formation at the site was known to exhibit relaxation (decrease in resistance) phenomenon for piles driven to refusal on bedrock. A thorough dynamic testing program was developed to carefully assess the nominal pile resistance. This paper addresses the issues encountered and concerns raised during the geotechnical design and how these were addressed and resolved. Design and construction procedures, challenges and solutions are discussed in detail.
Airfield aluminum matting systems are prefabricated panels that are compact and easily transportable. They have been mainly used for expedient construction of temporary airfields, rapid airfield repair or to provide maneuvering support for military aircraft, and it has rarely been used in civil aviation, due to lack of design and construction specifications. Because of the limited use, matting systems had very few studies to explain its behavior under different circumstances, and previous evaluations have commonly been restricted by full-scale testing, with only a few numerical models found in the academic environment. However, knowing the practicality of the material, matting systems are being considered to be used under the long term and extreme weather conditions, such as in remote northern communities in Canada. For this purpose, a finite element model of aluminum panels laid on a soft soil has been built in the ABAQUS FEA Software adopting a solid element to represent the soil, shell elements for the panels, and hinge-type connections along the panels. The model was used to predict stress and strain along the panel set under static loads. After validated with full scale results, different soil stiffness was tested in order to assess the panel's behavior under certain conditions.
One of the many sectors that has been highly affected by COVID-19 is retail industry. Fearful of contracting the virus, people are seen to avoid traditional bricks and mortar trades, which led to rapid diffusion of various online businesses. People are found to be more comfortable in online shopping than going to shopping malls physically during the pandemic. These sudden changes in shopping behavior have had crucial implications on business operations. It is important to understand how retail industry is transforming due to the pandemic for suggesting sustainable planning interventions for reconfiguration of urban core. This research conducts an exploratory analysis using public discourse data in Twitter to understand how retail is changing in the time of COVID-19 and e-commerce. First, using Twitter API, tweets related to COVID-19 crisis, in-store shopping, e-shopping and retails are extracted. Then, text mining and topic modelling is applied on the tweets to analyze general people’s real-time concerns, opinions and sentiments related to shopping in the time of pandemic. Multiple analytical frameworks are used, such as, wordclouds, sentiment analysis to identify frequently occurring words and topics in those discussions. This research also identifies challenges as well as solutions for safe reopening of conventional retails through analyzing general public opinions. Results of this study will assist policy makers to reshape retail structure with an aim to help revive economy in the post-COVID time. Outcomes will also offer insights on how to utilize the shopping behavior change during the pandemic to reshape downtown areas of cities with a focus on promoting sustainable travel behavior.
Dielectric profiling systems developed under the US Federal Highways Administration Strategic Highway Research Program 2 (SHRP2) Solutions program provide a means to estimate the in-place compaction of asphalt concrete by correlation to the relative dielectric constant of the near-surface materials. The Pavescan™ system, a ground penetrating radar-based surface dielectric profiling system produced by Geophysical Survey Systems Inc., was used to continuously scan segments of an asphalt concrete pavement placed during two paving projects in 2019 that were constructed in Nova Scotia. The first project involved a paving trial of a C-HF asphalt mixture placed on 25 mm thick steel plates to simulate an orthotropic steel bridge deck. Pavescan™ data was recorded over various sections which received different levels of compaction effort to create a wide range of in-place density. Excellent correlation was observed between the surface dielectric measured from the pavement surface reflection and the bulk density of core samples, yielding a coefficient of determination equal to 92.2%. The trial also indicated that the minimum mat thickness that could be tested without interference from the underlying steel plate was approximately 45 mm. The correlation developed for test data obtained on the steel plates did not accurately predict the bulk density of the same asphalt mixture compacted on granular base, indicating an interaction between compaction and the underlying base stiffness. Pavescan™ surveys were also completed on five segments of asphalt mixture placed on a rural roadway. The most accurate predictions of bulk density resulted when using daily calibrations of bulk density from cores and the measured surface dielectric constant with a 94.7% rate of correctly predicting air void contents above and below 7.5%. A comparison of the Pavescan™ results and quality assurance sampling within the same locations of the mat provided consistent measures of quality. However, contour plots of the surface dielectric or interpreted compaction were effective in mapping lower levels of compaction associated with transverse and longitudinal cold joints in the mat.
Assessment of consolidation settlement under a highway embankment requires particular consideration regarding the variability in fill heights as well as the thickness and proprieties of underlying clayey soils. Settlement calculation based on one-dimensional consolidation theory often relies on the evaluation of the critical section and assumes the applied load to be infinite in the x and z directions. Advanced solutions based on the modified Cam-Clay theory that evoke 2D and 3D finite element modeling and account for the stress distribution and volume changes during yielding as well as the geometric configurations of the studied area could result in optimized conceptions when light weight fill is required. This paper examines as a case study the consolidation settlement under an existing embankment on highway 50, in Quebec, Canada using 2D and 3D FEM modified Cam-Clay theory. The models will be validated against historical data. Then, the models are applied to design the new embankment of the adjacent north bound lanes where light weight fill will be required. The results obtained from these models are compared with those provided by the 1D consolidation theory.
Paving-grade asphalt binders are specified based on their properties in an original state following a specification such as the Performance Graded (PG) Asphalt Binder Specification. However, there has always been an interest in determining the properties of asphalt binder of in-place asphalt mixtures for research or forensic investigation purposes. With the increased use of reclaimed asphalt pavement (RAP), many user agencies are also looking for ways to evaluate the properties of the blended asphalt binder (i.e., new binder and old binder from RAP) since this also has an impact on the asphalt pavement performance. One option is to conduct mixture performance testing. Another option is to conduct solvent extraction-recovery testing on the asphalt mixture and determine the physical properties of the recovered asphalt binder. This research compares the physical properties of original asphalt binder, that binder extracted and recovered from a plant produced asphalt mix, and the properties of the asphalt mix as determined through performance testing. The purpose to evaluate how the various asphalt binder and mix parameters predict the performance of the asphalt pavement layer. Seven asphalt mixes are included in the study using typical PG grades and surface asphalt mixes used in Canada. Two of the asphalt mixes incorporated 15% RAP for comparison with non-RAP mixes. Performance tests conducted on the asphalt mixtures include dynamic modulus, flow number, and Illinois Flexibility index (I-FIT), which is a performance index used predict the asphalt mixture’s resistance to cracking obtained from a semi-circular bending (SCB) fracture test.
Traffic characterization to develop appropriate traffic inputs for pavement design using Mechanistic Empirical Pavement Design procedure (PavementME) is a crucial and challenging task. The purpose of this study was to develop traffic inputs such as vehicle class distributions for different axle configurations, growth factor, monthly adjustment factors, number of axles per truck, monthly and hourly distribution factors, and axle groups per vehicle, which can be used as inputs for pavement design, using PavementME, in Alberta. Weigh-In-Motion (WIM) data from eight different stations in Alberta, collected from 2007 to 2019, was analyzed to characterize traffic loads as inputs for PavementME. Traffic inputs were developed at two levels: Level 1 (site-specific) and Level 2 (provincial averages). Simple statistical analyses like minimums, maximums, averages, and standard deviations both for individual stations and for all stations were completed to develop confidence in the Level 2 inputs. The effects of the developed Level 1, Level 2, and PavementME default Level 3 traffic inputs were studied on the predicted performance at many highway segments of asphalt pavements. Among all traffic parameters, vehicle class distribution (VCD) and monthly adjustment factor (MAF) varied the most between the hierarchical input levels. In addition, Axle Load Distribution (ALD) showed moderate differences between the three input levels. Alberta‘s diverse truck traffic, changing during different times of the year, lead to the differences in MAF and VCD. A sensitivity analysis was conducted of the impact of the developed Level 1, Level 2, and PavementME default Level 3 traffic inputs on the predicted performance of flexible pavements. In this context, the results indicate that flexible pavement performance is most sensitive to vehicle classification. The results also indicated more variance in total permanent deformation, AC top-down and total fatigue cracking for different input levels. This study recommends the Level 1 (site-specific) inputs be used for pavement analysis and design. For projects where site-specific data are not available, a Level 2 provincial average traffic inputs should be used, which will provide more representative inputs than the default traffic inputs.
Climate change concerns and continuously increasing costs of bituminous pavement materials are an ongoing challenge for the pavement industry and road owners. Reduced demand for paper is an ongoing challenge for the forest industry. To help overcome these challenges, FPInnovations, with partners and collaborators involved with in the production and use of asphaltic concrete pavements, have initiated research into a lignin-modified bitumen for Canadian pavements. This greener modified bitumen, first developed in 1980 by the Federal Highway Administration (FHWA), shows great promise but mainly in European trials with climatic conditions and geological contexts that are different from North America. Although the Canadian study aims at analyzing the technical, economic, and environmental feasibility of lignin-modified bitumen, this paper will emphasize research on the thermo-mechanical properties of lignin-modified bitumen to optimize the bitumen mixture for the Canadian context. Lab testing, conducted at École de Technologie Supérieure (ETS) laboratories, consisted, first, in evaluating the optimum lignin-bitumen ratio, mixing time and temperature, and mixing apparatus. First phases of testing were conducted on one source of lignin and a PG58-28 bitumen using a conventional and a high shear mixer. Up to 30% of the bitumen was replaced by lignin. To evaluate short-term and long-term impacts of the mixtures, testing included storage stability, viscosity, measurement of rheological properties at high and low temperatures (dynamic shear, creep stiffness, creep recovery), aging, specific gravity, etc. Preliminary results show very good homogeneity of the lignin-bitumen mix using a conventional mixer at 150°C mixing temperature and promising thermal and mechanical properties of the optimal mix. Upon conclusive results on the first phases of this work, a hot mix asphalt will be formulated using the optimum lignin-modified bitumen and tested. Testing on HMA will be focused on rutting, thermal cracking, complex modulus, compaction, resistance to moisture induced damage, etc. The new product has the potential to reduce the environmental impact of asphaltic concrete while offering enhanced performance and reduced cost.
The Hamburg Wheel Tracking Test (HWTT) per AASHTO T324 has been widely used to evaluate rutting resistance and moisture susceptibility of asphalt mixtures and is tested at various temperatures by different agencies. Research has shown that there is a Critical Stripping Temperature (CST) above which visco-plastic rutting and moisture damage occur during HWTT, while tests below the CST only exhibit visco-plastic rutting. The objective of the current study was to determine the CST needed for representative asphalt concrete mixtures used in Nova Scotia which use PG 58S-28 and PG 58H-28 binders. Optimized asphalt concrete mix designs were completed for three local aggregate sources which have historically exhibited low, medium, and high levels of moisture susceptibility without using anti-stripping additives. HWTT testing was completed at four different water bath temperatures for each aggregate source and PGAB combination to determine the CST. The creep and stripping slopes were analyzed for each test based on AASHTO T324 to determine the Stripping Inflection Point (SIP) of the mixture. The SIP indicates how quickly the material begins to experience significant moisture-induced damage. While this approach has been adopted by several transportation agencies, AASHTO T324 does not provide a specific method of analysis, so the results tend to be subjective and variable with poor repeatability. A novel method which separates visco-plastic and moisture damage effects in HWTT results was also used to analyze the HWT test results, yielding the Visco-plastic Ratio (VR) which characterizes the mixtures rutting resistance under dry conditions and the Moisture Ratio (MR) defined as the percentage of total rutting that results from moisture-induced deformation at a total rut depth of 12.5 mm. A strong correlation was observed between MR and the existence of significant moisture damage as defined via the AASHTO T324 method as exceedance of a maximum rutting depth of 12.5 mm and a minimum SIP of 15,000 passes as used by Maine DOT. It was found that an MR of 30% appears to provide a reliable threshold for verifying moisture susceptibility of asphalt mixtures. This systematic approach could replace the more complex and subjective AASHTO method to objectively and reliably detect and quantify moisture-induced damage in susceptible asphalt concrete mixtures. The CST for local asphalt mixtures using PG 58S-28 and PG 58H-28 binders were found to be 46°C and 50°C, respectively.
The Neptune Bulk Terminals in North Vancouver plays an integral role in connecting the Canadian economy with oversea markets by transporting 30 million tonnes of products annually. As part of the approx. $24 million Neptune Cargill Overpass Extension Project to improve access to a growing port terminal in the North Shore Trade Area, Stantec provided engineering design and construction support for the new overpass extension which was completed in 2019. This grade separation offers a direct route into the terminal coal storage yard from Low Level Road and the existing Neptune/Cargill Overpass, improving terminal operations and efficiency in goods movement. The new bridge spans approximately 56m on a curved alignment over a maintenance road entrance to an existing settlement pond, terminal access road, and multiple freight rail tracks. This paper discusses the challenges our team faced to accommodate rail operations, maintenance, rehabilitation, seismic hazards, girder erection, and traffic management. From the early stages in our design process, integration of operations played an important role. This overpass extension project was actually envisaged at the time of the Low Level Road Project and Neptune/Cargill Overpass original construction in 2013-2014 as part of the next phase in development. Our multi-discipline design team was intimately aware of the community impacts, port operations and site constraints given our previous involvement having worked in the area, and this was valuable to developing an innovative design solution that met the project objectives. Minimizing and avoiding rail operation disruption was a key consideration for the new grade separation, in addition to the adverse soil conditions that included areas of lateral spreading and liquefaction hazards. While developing designs of the steel bridge girders, we had to consider fabrication and shipment of the superstructure to site which required careful consideration of rail logistics and structure element sizing. The resulting solution of the bridge (steel tub girders acting in composite action with concrete deck) allowed to streamline the construction sequence. The steel components of the superstructure were fabricated out of Province and assembled on site, and then rapidly installed via self-propelled modular transporter (SPMT) units. With close coordination of the designer, terminal operator, railways, and contractor, Accelerated Bridge Construction (ABC) techniques were used to save project costs and enhance safety with minimal overhead works above the live rail envelope.
Permeable interlocking concrete pavements (PICP) allow stormwater to infiltrate directly through aggregate-filled joints. Best practices for the winter operation of PICP is poorly understood. Unlike conventional impervious pavements, melted snow and ice infiltrates directly through the PICP joints to underlying aggregate layers, underdrains or native soils. The University of Toronto conducted this study at a PICP test pad, constructed in 2017, located at the Toronto and Region Conservation Authority’s (TRCA) Kortright Centre for Conservation in Vaughan, Ontario. The test pad included four 2 m by 2 m (6.6 ft by 6.6 ft) PICP cells constructed with a generic grey paver arranged in a herringbone pattern and one 2 m by 2 m (6.6 ft by 6.6 ft) asphalt control cell. A perforated pipe drained the PICP cells. The asphalt cell was drained via a catch basin. Concrete curbs between cells prevent the inter-mixing of flows. De-icing practices were tested over two winter seasons in 2018 and 2019. Two PICP cells received road salt at medium 0.049 kg/m2 (10 lb/1000 ft2) and low 0.024 kg/m2 (5 lb/1000 ft2) application rates and two cells received road salt pre-wetted with beet juice also at medium and low application rates. The asphalt control cell received road salt at a medium application rate. Surface friction, surface temperature and water quality were measured. The results of this study indicate that the PICP provides equivalent or higher levels of safety compared with asphalt when treated with de-icing products at medium or low application rates. Re-freezing of melted snow and ice after sunset was observed on the asphalt surface creating black ice but not on the PICP cells. Consequently, compared to asphalt pavements, PICP surfaces will require use of less deicers and will have lower risk of slips and falls for pedestrians and lower risk of skidding for vehicles throughout the winter.
The City of Lloydminster (City) is centered along the Trans-Canada Highway (Highway 16) and straddles the Alberta/Saskatchewan interprovincial border along Highway 17. As an economic centre along major highways, the City attracts, and is impacted by, the movement and transport of goods and dangerous goods. The City has expressed concern over the movement of dangerous goods through the heart of the City along the major highways and has explored options to alter the truck routes and dangerous goods routes. A June 2017 report presented to the Governance and Priorities committee offered options for the alteration and amendment of the truck routes and dangerous goods routes. The report proposed adding truck routes within the City along with some deletions, as well as rerouting dangerous goods traffic around the periphery of the City. At that time City Council recognized that changes to the truck routes and dangerous goods routes would require a lot of discussion between the City and stakeholders. The purpose of the project was to further review and refine options for alternate truck routes and dangerous goods routes within the City of Lloydminster and to consult with industry, emergency services, carriers, local business owners, other community stakeholders, and the general public. In addition to route option development the project provided a comprehensive signage plan and cost estimate associated with the signage plan. This paper will discuss the process undertaken to review and revise the truck routes and dangerous goods routes within the City.
This paper examines the implications of climate change on cross slope with respect to geometric design and road safety. The importance of risk to the highway infrastructure due to climate change has been recognized nationally by the Public Infrastructure Engineering Vulnerability Committee (PIEVC) Engineering Protocol and internationally by the ISO 31000 Risk Management standard. Uncertainty in infrastructure design is outlined in the ASCE Manual of Practice No. 140-Climate -Resilient Infrastructure Adaptive Design and Risk Management (2018). In Canada BCMoTI is developing climate change-resilient designs for highway infrastructure in British Columbia. Examples of climate change parameters typically used in highway design include rainfall, temperature, snow, wind, sea level and water flow. This paper focuses on rainfall and whether current design standards for cross slope will provide sufficient drainage from a road safety perspective. The TAC 2017 Geometric Design Guide for Canadian Roads notes that “the normal cross slope of 0.02m/m on paved tangent roadways provides positive drainage to the curbs.” As well the TAC Guide acknowledges that “some Canadian road agencies use a cross slope of 0.03m/m on paved tangent sections to reduce the risk of Hydroplaning.” One of these agencies is the New Brunswick Department of Transportation and Infrastructure (NBDTI) and this paper discusses their experience with a cross slope of 0.03m/m in terms of operations and safety. The paper includes a global review of cross slope design practice and cross slope research with respect to hydroplaning. For example, the Austroads Guide to Road Design Part 3 Geometric Design (2013) states “crossfalls flatter than 2% do not drain adequately, and even 2% should only be prescribed for concrete pavements where levels and surface finish are tightly controlled. Unless compaction and surface shape are well controlled during construction, pavements with less than 2.5% crossfall will hold small ponds on the surface, which cause potholes to develop and hasten pavement failure. Rutting of the pavements is also more likely to hold water, increasing the risk of pavement deterioration and vehicle aquaplaning when the pavement crossfall is less than 3%”. In a report by John C. Glennon (2006), Roadway Hydroplaning-The Trouble with Highway Cross Slope, states that “based on research findings and in consideration of pavement irregularities (settlements, wheel ruts, etc) that seem all too common, AASHTO should consider recommending 2-2.5% minimum cross slopes to minimize the propensity for hydroplaning particularly for high-speed highways. This paper concludes with a recommendation that TAC should undertake a research project to determine the most appropriate cross slope that mitigates the impact of climate change on drainage related safety concerns.
With provincial and municipal infrastructure budgets as stretched as ever, and greater accountability demanded with respect to sustainability in rehabilitation programs, the salvage value of existing infrastructure is of critical importance. From a sustainable development perspective, there is an imperative to utilize as much as possible of existing infrastructure, and to minimize waste generation when undertaking renewals. A key factor in this process, especially with respect to transportation structures, is to decide how much of the existing concrete can be salvaged. This is not just a question of establishing existing condition but predicting future life for a complex construction material that may already be 50, or more, years old. Unfortunately, the practical evaluation of old concrete is not as simple as reviewing the results of a series of standard laboratory tests such as compressive, tensile or flexural strength, chloride profiling, and air voids content. Improving our ability to reliably determine the in-situ health of old concrete can support cost-saving engineering decisions to retain bridge piers and abutments while only replacing the deck; reline an existing tunnel rather than replace it; or to leave old concrete pavement in place beneath a multilane freeway. The techniques are varied and project-specific. They rely on an understanding of the components of structural concrete: steel, aggregates and cement paste, and how they interact and deteriorate. The evaluation techniques comprise destructive and non-destructive testing but with the essential component of concrete petrography. This latter technique can detect the early stages of destructive chemical reactions and may be used to determine to what stage such reactions have progressed and might continue to progress; the signs of freeze-thaw damage; the impact on concrete integrity from the corrosion of reinforcing steel; and other aspects. With this detailed knowledge, the appropriate remedial solutions can be identified, taking advantage of the vast array of effective modern specialty concrete repair products and techniques that are available. This paper will discuss the approaches to the condition evaluation of old concrete structures with a focus on concrete petrography and present some case studies to illustrate the benefits of an effective concrete health check before deciding on full reconstruction.
Superpave mix design method developed by the Strategic Highway Research Program (SHRP) was implemented to create a mix design system, performance-based asphalt binder specifications, and performance-based asphalt mix specifications. SHRP was successful with the implementation of the first and the second of the objectives. However, the third objective, i.e. performance-based asphalt mix specifications, was not implemented successfully due to some complexities. Since highway agencies have been only practicing the mix design and asphalt binder specifications to capture rutting susceptibility of asphalt pavements, there is a lack of practicing appropriate performance test to investigate rutting performance of asphalt mixtures. Due to the continuous increase in the number of heavy truck traffic, municipalities such as Regional Municipality of York in Ontario are experiencing excessive rutting in most of their intersections. Implementing an appropriate performance method and threshold on rutting that could help the agencies specifying high rut resistance mixtures during tendering process Therefore, the purpose of this paper is to provide the state of the art in testing asphalt mixtures suitability to rutting and shoving. This paper would further evaluate the practicality of these test methods to the asphalt mixtures primarily used in Ontario.
Although Ontario has among the most generous and flexible commercial truck weight and dimension regulations, its truck-based industries must compete with those in other Canadian provinces that have instituted designated route or corridor -type transportation programs. Notably, British Columbia, Alberta, and Saskatchewan permit B -train trucks with 70.5-88.0 tonnes combined gross vehicle weight (GCVW) under these programs. FPInnovations, on behalf of Resolute Forest Products, is pursuing a similar opportunity in Ontario. Specifically, two 9-axle B-train configurations have been proposed for use in a log hauling corridor near Thunder Bay. If successful, the initiative will not only benefit the (northwest) Ontario forest industry through log hauling savings and improved competitiveness but also will reduce truck traffic, pavement maintenance, and GHG emissions. In this study, the loading and dimensions of the proposed configurations were optimized to maximize payloads while ensuring safe vehicle dynamic performance, adequate bridge and culvert capacities, and acceptable pavement impacts. This paper emphasizes the development of a novel and flexible methodology for assessing the pavement impacts of the proposed 9-axle B-train configurations. Given that the tridem-drive 9-axle log B-train is still under consideration by the Ministry of Transportation of Ontario (MTO), discussion in this paper was limited to the tandem-drive 9-axle log B-train.
Properly designed and constructed concrete pavements should provide a serviceable life of 50 years or more, without the need for major rehabilitation and with only minimal maintenance interventions required. The main challenge to achieving this outcome is design and construction quality. We frequently see recently constructed concrete pavements develop cracking that can eliminate the economic benefit of having constructed with concrete in the first place. In the case of airfield pavements, the early onset of distress can be much more serious than in the case of highway pavements but in all cases it has significant economic impact on maintenance expenditures and operational safety. While it is not unexpected to have early age plastic shrinkage cracking in concrete pavements and it is recognized as not representing a severe distress, this type of cracking can be eliminated with appropriate concrete mix design and strictly adhering to best practices for concrete placement, finishing and curing. However, it is the development of premature structural cracking that once it occurs is very difficult to repair and thus needs to be avoided, where possible. Based on case studies, this paper explores the range and types of early age distresses that all too frequently occur in even properly designed concrete pavements. By identifying the causes of these distresses, the means for avoiding them becomes clear. The lessons learned point to the imperative of achieving uniform pavement support, of managing and coping with adverse construction conditions, and having in place the appropriate level of independent quality assurance inspection and testing during all critical stages of construction.
This report addresses current and potential countermeasures that may reduce conflicts and the resulting fatalities and injuries among vulnerable road users (VRUs) (i.e., pedestrians and bicyclists) struck by heavy vehicles, including buses in urban areas. Urban rather than rural areas are the focus because statistically, the majority of VRU collisions with heavy vehicles take place within cities. It is important to note that this report does not make any recommendations or favour one approach over another, as any such recommendation of one or more potential countermeasure(s) is outside the scope of this project.
The location, design and operation of roads can be highly influential to the character, function and livability of adjacent communities and land uses. Both urban and rural roadways have strong linkages with the natural environment. Fish, wildlife, birds, waterbodies, vegetation communities and local air and water quality are affected by roads and vehicular traffic. Roads can alter habitats, increase wildlife mortality and facilitate the spread of invasive weeds. The concept of “road ecology” is relatively new, and its primary focus is on the potential effects of roadways on natural landscapes and processes as an element of sustainable transportation systems. This document provides decision-making criteria to assist in various aspects of roadway design and operation for management of sustainable road systems.