Moisture damage in asphalt mixtures has become a widely discussed topic due to its high influence on asphalt mixture behavior. Moisture damage is a phenomenon that relates to the loss of stiffness and strength of asphalt mixtures because of exposure to moisture under the influence of mechanical loading of traffic, which results in what is known as stripping. Moisture damage that leads to the deterioration in the integrity of asphalt pavement plays a key role in the occurrence of other distress types including fatigue cracking, rutting, etc. Therefore, this study aims to evaluate the influence of the addition of coarse recycled concrete aggregate (CRCA) on the tensile strength and moisture sensitivity of Ontario Superpave mixtures. Mix designs of asphalt mixtures were performed for two types of CRCA at various proportions (0%, 15%, 30%, and 60%). The impact of CRCA types on the tensile strength and moisture sensitivity of asphalt mixtures were evaluated. The obtained results also are statistically analyzed. The findings showed that the tensile strength of hot mix asphalt (HMA) mixtures that included different CRCA types with various proportions have higher values than the control mix. Additionally, the laboratory outcomes revealed that all TSR values for mixtures that included different CRCA types with various percentages are higher than the minimum required value of MTO specifications. This indicated a highly successful performance for these mixtures that included CRCA. The results of the ANOVA analysis showed that there is a statistically insignificant effect of CRCA type, and proportion on the TSR. However, the type of CRCA has a higher effect on the results of TSR compared to the CRCA percentage.
In northern climate, asphalt paving season is relatively short, and paving is often done late in the season when weather conditions are less than ideal. Warm Mix Asphalt (WMA) technology has the capability of lowering the temperature at which the asphalt is mixed and compacted by 30°C or more without compromising the performance of asphalt pavement. The reduced difference between asphalt mix and ambient temperature results to a lower cooling rate thus allowing long haul, sufficient compaction time and late season projects compared to the conventional Hot Mix Asphalt (HMA). This potential benefit means, among others, an extended paving season for the City of Winnipeg. Reduction in production temperature also generates other positive impacts both economically and environmentally. The objective of this study is to evaluate the installation of WMA to compile experiences with this technology and evaluate their effects on construction methods and performance. The study further attempts to evaluate the effectiveness of the WMA chemical additives and its dosage rate as liquid anti-strip agents on the properties of WMA mixtures through field and laboratory testing program. In addition to the overall effectiveness of WMA, the study aimed to evaluate its economic cost relative to Hot Mix Asphalt (HMA). Three WMA mixtures using three different chemical additive dosages (0.3, 0.5 and 0.7 percent by weight of asphalt cement) were tested. Among the different additive dosage used, the 0.5% had a better overall performance. The moisture sensitivity tests indicated the highest Tensile Strength Ratio (TSR) at this dosage, suggesting the lowest moisture damage susceptibility. The study also showed that WMA can be successfully placed using conventional HMA paving practices and procedures. The WMA price was between 2% to 11% higher than conventional HMA including the costs of additional testing as well as the WMA additives. It is expected that in future large paving contracts, the cost of WMA will decrease when the contracts do not include the additional testing and contractors realize the financial benefit of reduced energy consumption in the production of WMA.
Ce guide présente la modération de la circulation en tant que méthode de réduction de la vitesse et du débit de la circulation non locale qui s’infiltre dans les quartiers. Il présente les principes de modération de la circulation, il suggère un processus d’introduction et de mise en place de la modération de la circulation, et il décrit l’applicabilité, l’efficacité et le principe de conception pour une vaste gamme de dispositifs de modération de la circulation. Ces dispositifs sont classés dans les catégories suivantes : déviation verticale, déviation horizontale, rétrécissement de la route, traitement de surface, marques sur chaussée, restriction de l’accès, portes d’entrée, application de la loi, information, espace partagé, nouvelles technologies et mesures.
La marche est une activité vitale qui nécessite une infrastructure adéquate, élément central d’un réseau de transport durable, équitable et sécuritaire. Le contrôle des passages pour piétons représente un défi pour les ingénieurs en circulation, urbanistes, concepteurs de routes et autres, compte tenu de la nécessité de répondre, en toute sécurité, aux besoins des piétons d’une manière qui soit en interrelation avec les autres utilisateurs du réseau de transport. Le Guide de contrôle des passages pour piétons a été élaboré principalement pour compléter l’information sur les dispositifs de contrôle des passages pour piétons et leurs applications figurant dans le Manuel canadien de la signalisation routière (MCSR). Son principal objectif est de favoriser une approche uniforme dans tout le pays relativement au contrôle des passages pour piétons. Pour ce faire, un outil d’aide à la décision a été développé afin de faciliter le processus de prise de décisions au moment de déterminer la nécessité de réguler la circulation, afin de permettre aux piétons de traverser la route en toute sécurité, et de déterminer le type de dispositif de signalisation le plus adéquat pour la section de la route visée, l’exposition aux véhicules et la demande en matière de circulation piétonne.
Every year, through the winter/spring seasons, potholes appear with detrimental effects to roadway structure, vehicles and driver comfort. Potholes are the result of small area defects or deterioration in the pavement which may require reactive, “emergency” repair, followed by more substantial permanent repairs when weather conditions improve. This Guide identifies current Canadian agency practices with respect to pothole repair and outlines best practices from both Canadian and international agencies. Recommendations are provided for appropriate temporary and long-term patching strategies for spring, summer and winter and for evaluating and selecting appropriate patching products that will lead to the improved performance of chip seal, asphalt and concrete surfaced roadways for Canadian climate conditions. This Guide also provides recommended guidelines for the evaluation of new patching products and their compatibility with native road surfaces.
This article presents the results of the LE2AP Life+ project. LE2AP is acronym for Low Emission2 Asphalt Pavement, where the 2 indicates that emission of pollutants and noise are considered. LE2AP concentrates on a novel way of circular-asphalt recycling. Key issues in LE2AP are that reclaimed asphalt is first decomposed into its components. Reclaimed aggregates hardly containing bitumen and bitumen rich mortar sand, which is a mixture of bitumen, filler and sand, are obtained. The mortar sand is used as the main ingredient for quality LE2AP mortar. During production LE2AP mortar is heated without meeting a flame or superheated air and is homogenized and treated with rejuvenator and soft bitumen. LE2AP mortar is then foamed and fed into the mixer where it is mixed with reclaimed stone at 100-110 deg C to obtain an asphalt mixture of high quality, containing a high percentage of reclaimed material and produced at low temperature. The LE2AP project is partially funded by a LIFE+ grant and it is believed that LE2AP may contribute to much needed circular asphalt recycling at lowered temperature and low emissions. LE2AP came to provisory conclusions in October/November 2016 with the installation of two two-layer PA, porous asphalt, test sections with a combined length of 2.3 km. Key properties of these test sections are: production temperature: ll0-125 deg C, noise reduction: 5.3-8.4 dB(A), re-use: 82%-93%, CO2 reduction: 51%. The performance of the test sections is being monitored and until now (September 2017) the sections perform well.
This study evaluated the cracking characteristics of asphalt materials containing RAP/RAS and prepared with WMA technology. Tests were performed in the laboratory and at A full-scale testing facility. Ten test lanes were built at FHWA's Accelerated Loading Facility (ALF). The experimental design included three RAP percentages up to 44% by weight (40% recycled binder ratio, RBR), two WMA technologies (water foaming and chemical additive), one RAS percentage with 20% RBR, and two different virgin binders (PG 58-28 and PG 64-22). Specimens prepared from loose mixes sampled from the construction and field cores sampled at different times were evaluated using the direct tension monotonic test. Performance grade and cracking resistance of asphalt binders recovered from tested loose mix and field cores were determined. The laboratory monotonic testing results were compared to and statistically correlated to the ALF field cracking performance. Experimental results from both laboratory mix and binder tests capture the oxidative aging that occurs with time in the top lift. Aging observed in the bottom lift of the asphalt pavement was considerably less. One of the mechanical parameters developed from the mix monotonic test closely correlated with the binder tolerance strain obtained from the binder DENT test. Long-term oven aging aged the mix significantly more severely than was observed in three-year old ALF sections. Testing of ALF materials shows that the mixtures with 40% MP RBR or 20% MS RBR and stiff binder exhibited the worst cracking performance. A softer PG grade was found to be effective at improving the performance for 40% RAP RBR mixes but ineffective at improving the performance of 20% RAS RBR mix. No difference in field performance was observed between the HMA and WMA mixtures having the same mix design. Statistical analysis indicated a strong correlation between the direct tension monotonic mix test and ALF field testing in terms of evaluating the cracking resistance of the asphalt mixtures containing RAP/RAS and produced as HMA or WMA.
Modifying the asphalt mixture design appears to be a viable method for obtaining improvements in pavement durability. This paper reports a demonstration project focused on achieving an optimal 95 percent in-place density through a modified mixture design. The project tasks included-milling and overlaying an existing pavement in Indiana. Control and test mixtures were used to evaluate the effect of mixture design modifications on the asphalt pavement construction performance. The control mixture was designed in the laboratory at '4 percent air voids using the conventional Superpave volumetric mixture design method ln contrast, the test mixture was prepared at 5% air voids using a modified laboratory mixture design. Quality control and quality assurance data analysis reported a 93.3 and 95.3 percent in-place density average for the control mixture and test mixture, respectively. Additionally, new 'probabilistic and analytical metrics are proposed to compare the construction performance of both mixtures. The findings of this field study validate the potential benefits of using a modified mixture design to construct asphalt pavements with increased densities. Implementation of this methodology can be easily accomplished using conventional laboratory and construction equipment.
This paper examines the taxi industry in Canada. The analysis considers the economic model of regulation, the Competition Bureau‘s advocacy of competition in the taxi industry, and the competitive struggle between the regulated taxi industry and the Transportation Network Companies (TNCs).
The remarkable increase in vehicle ownership over the past six decades has placed great emphasis on studying travel demand in urban areas. The transportation literature has traditionally focused on the decisions made by households to own private vehicles. However, there is a clear absence of any study which looked into the temporary rental of vehicles to meet personal travel needs. The majority of the existing studies on rental fleets have been focused on the optimization of fleet logistics to maximize revenue, which is highly dependent on proper logistics management for car rental companies(e.g. Fink and Reiners, 2006).Understanding consumers’ motivations behind renting a vehicle is as important as fleet optimization. The rationale behind this is that rental vehicle companies would normally invest in acquiring vehicles that are in great demand by their clients. This is particularly the case since rental vehicle companies, like all other businesses, are primarily driven by profit maximization which is dependent on consumers’ demand for particular goods. In this paper, the analysis strives to fill the existing gap in the literature by determining the characteristics of vehicle renters and evaluating the factors influencing the purpose for renting vehicles for temporary use in the Canadian market.
Organized volunteer driver programs are emerging as solutions to fill the transportation service gap for those unable to meet their personal transportation needs independently with the private automobile and where taxi, transit or active transportation are unrealistic or unavailable options. Volunteer driver programs (VDP) are typically able to serve areas of low population density at a lower overall cost than paratransit services by using volunteer labour and vehicles (Beverly Foundation, 2008). They replicate the on-demand travel and social aspects associated with relying on friends and family for transportation, which is attractive to those who do not have access to a personal network. VDPs can be stand-alone programs, extensions of non-profit or charitable activities, or in some instances in the United States, are integrated as part of rural transit (Schlachman, 2009). This paper summarizes recent efforts to quantify the types and levels of best practices employed by successful VDPs in New Brunswick through the development and application of a Maturity Model that quantified how groups define, manage, measure, and control key processes. These were explored in terms of organizational attributes (e.g. budget, number of users) of seven VDPs participating in the research. Quantifying the effects of organisational factors will provide existing VDP the tools to self -evaluate and provide a resource for future VDP to consult.
Transportation can be considered as one of the main and essential human activities, that involves nearly everyone on a daily basis. To date, numerous travel demand models have been developed, using both aggregated and disaggregated approaches, for modeling short-term and long-term choices of travelers, such as activity participation, timing, transport mode, activity location, route choice, work/residential location, and vehicle ownership (Oppenheim, 1995; Ortuzar & Willumsen, 2011). Complexities in individual travel behavior have increased with continued urban development and rapid technological progress. Trip chaining and multimode transport, flexible working hours, self-employment, and online shopping have become far more common in recent years (Goran, 2001). As travel behavior becomes more complex, travel demand forecasting requires more detailed information. From a disaggregated modeling point of view, there are significant associations between trips and the activity participation of travelers (Kitamura, Chen, & Pendyala, 1997). Furthermore, travelers with varying socio-demographic and socio-economic characteristics in the region have divergent time-use activity patterns. This paper presents a new disaggregated travel demand microsimulation model framework that is sensitive to the mix of variables connected to travelers’ decisions. New pattern recognition and inference models are developed to identify population clusters with homogeneous time-use daily activity patterns, and to predict activity selection and scheduling behavior of these population cohorts. The representative behavior within each cluster is then used as an information guide for modeling the 24-hour activity schedule and the travel linked to it. The proposed model is applied to data from the large Halifax STAR household travel diary survey. The proposed modeling framework has much higher reproducibility and shorter computational time compared to alternative modeling frameworks.
Le présent code de bonne pratique pour les revêtements en dalles, en dalles de grand format et en dalles préfabriquées en béton est un fil conducteur pour le choix du champ d’application, du dimensionnement de la structure, de la pose et de l’entretien de tels revêtements routiers. Les différents produits et finitions de surface correspondantes sont discutés, ainsi que la certification de qualité et le contrôle des éléments de pavage. Plusieurs applications spéciales, comme les revêtements perméables et les revêtements sur toitures, sont également présentées. Enfin, plusieurs exemples pratiques sont fournis qui démontrent comment la théorie peut être appliquée et comment éviter les dommages causés par une mauvaise utilisation de ces éléments en béton. Ce code de bonne pratique repose sur une analyse critique de la littérature existante, sur des modélisations et des méthodes empiriques, associées à la pratique et à l’expérience belge. Il s’adresse aux concepteurs, architectes, entrepreneurs, fabricants, gestionnaires routiers privés ou publics. Il vise à fournir un document technique de base afin d’encourager à l’avenir de nouvelles applications de qualité de ce type de revêtement en béton.
Existing transportation systems have been traditionally designed primarily for motorized vehicles and goods movement. This exerts a significant influence on the way Canadians travel in their daily lives to the point where it increases their risk of numerous negative health outcomes. The paradigm has begun to shift towards health-promoting transportation systems and environments. There is an opportunity to further build health considerations into transportation policies, planning, investment and design decisions. This report identifies the state of the practice, gaps, recommendations, and resources for strengthening the integration between health and transportation.
With increasing frequency, roadway corridor development and improvement projects are being procured through Design-Build-Finance-operate (DBFO) Public Private Partnerships (P3s). In these procurement environments the nature of the pavement design and engineering requirements change in several significant ways compared with the traditional Design-Bid-Build (DBB) in that the consequence of poor pavement performance (risk) in most aspects is transferred from the owner to the DFFO partners: designer, constructor and operator/concessionaire. A performance-based design approach is required which is founded on the principle that the design and construction of an asset is completed to achieve a set of prescribed performance results. This paper discusses the design and pavement management process for DBFO P3 flexible pavements and presents a case study of a project highlighting a particularly complex distribution-based roadway condition performance specification.
Le géoradar est une technique géophysique non destructive basée sur la propagation et la réflexion d’ondes électromagnétiques hautes fréquences. Cette technique, éventuellement en combinaison avec d’autres méthodes, permet d’améliorer la connaissance de la structure routière (épaisseurs, zones homogènes, défauts, armatures et impétrants). Cette étude avait pour objectif d’établir des méthodologies pour l’acquisition, le traitement et l’interprétation des mesures radar et de les évaluer sur un chantier de recyclage. Les différents cas pratiques qui ont permis d’établir et de valider ces méthodologies sont présentés dans le présent rapport.
Over time, new pavements deteriorate due to the effect of traffic loads and the environment. If appropriate treatments are applied during the early stages of deterioration, it is possible to improve pavement conditions and extend pavement life without increasing expenditures. The National Center for Asphalt Technology (NCAT) has partnered with the Minnesota DOT’s Road Research Facility (MnROAD) to conduct a pavement preservation study that evaluates the life-extending benefit of a variety of preservation treatments, ranging from crack sealing to thin overlays. The objective of this research partnership is to develop performance curves for the treated pavements under different conditions (climate, traffic and initial condition of the pavement). In this study, full-scale test sections were treated first in a southern location (Alabama) on roadways subjected to both low and high traffic levels, starting in the summer of 2012. The experiment was extended in 2016 to include test sections in a northern location (Minnesota) to evaluate the effect of cold climate, also for low and high traffic levels. Throughout this time, cracking, roughness, rutting and macrotexture data were collected biweekly to evaluate pavement performance. The observed trends in the first years of the experiment indicate that there is not a significant variation in roughness or rutting over time, and that performance is mainly affected by the amount of cracking. Furthermore, the condition of the pavement at the time of treatment significantly affects the performance of the treated pavements, as pavements that are treated while still in good condition tend to remain in that category for a longer time. The results also demonstrate the effectiveness of applying pavement preservation treatments versus the “do nothing” scenario. After 4.8 years, the amount of cracking observed is less than the amount expected if the sections were left untreated, even for sections treated with applications that are not designed to address cracking. The results shown in this paper should be considered preliminary and used with caution. Data collection efforts continue in both southern and northern locations with the objective of determining the life-extending benefits of pavement preservation treatments as a function of initial condition, climate and traffic.