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Innovative Funding Mechanism for Roadway Construction in Strathcona County’s Industrial Heartland Area

Mon, 04/10/2017 - 18:51
Innovative Funding Mechanism for Roadway Construction in Strathcona County’s Industrial Heartland Area
by Sillers,S; Tong,B.
2017.
TAC 2017: Investing in Transportation: Building Canada's Economy - - 2017 Conference and Exhibition of the Transportation Association of Canada.
CA6 ARH_10 2017A5105 - INTERNET


Investing in an efficient transportation system is crucial to a country's economy. While federal and provincial governments in Canada have access to income and consumption taxes, municipal governments typically rely upon property taxes, fees, and transfers from senior levels of government to fund transportation infrastructure. With modern fuel-efficient cars, alternative energy sources, and advanced technologies used in vehicles, fuel tax, as currently administered, may become a less reliable source of funding. Municipalities face a desperate need to find stable, long-term funding for vital roadway projects in an environment of increasing demands from users, downloading of responsibilities, dwindling or unreliable transfers, and reluctance from senior government to grant additional taxation powers. Municipalities have begun examining alternative funding mechanisms including local improvement taxes, development charges, user fees, tax increment financing, public-private-partnerships, and Contribution in Aid of Construction (CIAC). Strathcona County has expanded on the CIAC concept for funding infrastructure to support industrial growth in an equitable manner that manages risk and adheres to Alberta`s Municipal Government Act. Contribution in aid of construction is a condition placed on the approval of subdivision or issuance of a development permit that requires developers to enter into a development agreement with the municipality to construct or pay for the construction of particular roadways that give access to the development. Strathcona County is a specialized municipality located immediately adjacent to Edmonton, Alberta. The adoption and usage of a CIAC policy within Strathcona County's oil and gas-based economic expansion zone, the Industrial Heartland Area (IHA), has proven to be an effective, flexible, equitable and simple means of upgrading and constructing the system of local roads that satisfies the needs of industrial developers without putting undue financial burdens on industry or County taxpayers. This paper discusses the advantages and disadvantages of many different alternative funding methods available to municipal government in Alberta; describes the experience Strathcona County has gained in implementing CIAC as a funding mechanism; and demonstrates how the CIAC system functions. Although it is recognized that no single method will work in all situations, in all communities, it is hoped that important lessons are conveyed through the example given.

Stated Preference Survey for Passenger Sensitivities to Travel Costs in the Greater Toronto Hamilton Area

Mon, 04/10/2017 - 18:21
Stated Preference Survey for Passenger Sensitivities to Travel Costs in the Greater Toronto Hamilton Area
by Kravis,R; Routley,M; Iacobacci,M; Huang,C; Charette,G; Noroozi,R; McGaughey,O.
2017.
TAC 2017: Investing in Transportation: Building Canada's Economy - - 2017 Conference and Exhibition of the Transportation Association of Canada.
CA6 ARH_10 2017A5104 - INTERNET


Metrolinx conducted a stated preference survey on passenger sensitivity to transit fare, cost, and other service factors in the Greater Toronto Hamilton Area (GTHA). This project is the largest fare sensitivity survey conducted within the GTHA (3,500+ responses collected from September to October, 2016), and the first fare sensitivity study completed in the region in decades. The results include elasticities for various travel segments broken down by time of day, origin/destination, and mode of travel, enabling better forecasts of how specific groups of passengers (e.g., off-peak GO Rail users, automobile users, local transit users) might respond to changes in price and service. This work can help evaluate existing and future pricing strategies, service changes, and other projects that may affect revenue and ridership across the entire GTHA.

Review and Recommendations for Canadian LCCA Guidelines

Mon, 04/10/2017 - 18:10
Review and Recommendations for Canadian LCCA Guidelines
by Moges,M; Ayed,A; Viecili,G; Abd El Halim,A.
2017.
TAC 2017: Investing in Transportation: Building Canada's Economy - - 2017 Conference and Exhibition of the Transportation Association of Canada.
CA6 ARH_10 2017A5103 - INTERNET


Life Cycle Cost Analysis (LCCA) is an engineering tool that is used to facilitate sound investment decision-making in the management of infrastructure. Transportation agencies can use LCCA in the selection of cost-effective pavement designs, and evaluation of future maintenance, rehabilitation, and/or reconstruction strategies. Using LCCA can also increase transparency in the project selection process, ensuring agencies make strategic decisions that maximize the expected value of their investments. This paper reviews the current LCCA practices in place across transportation agencies in Canada and in select international agencies. The review focuses on the LCCA policies of the provinces of Alberta, British Columbia, Manitoba, Nova Scotia, Ontario, Quebec, and Saskatchewan. The practice guidelines of the Federal Highway Administration (FHWA), American Concrete Pavement Association (ACPA), Asphalt Pavement Alliance (APA), and the World Bank (WB) are also reviewed. The objective of the study is to develop a Canadian LCCA Standard Practice Guideline based on best practices. The guideline provides guidance on LCCA for alternate pavement-type bidding. The guideline is also instrumental in the development of user-friendly excel based tool to aid in the analysis of life cycle costs of alternate pavement designs. The study reviewed best practices relating to length of analysis period, discount rate, (agency, user, and environmental) costs, economic criteria method, and computational approach for life cycle cost analysis. Based on the review, recommended practices for conducting LCCA in pavement design were identified and are proposed as input for a Standard Practice Guideline.

Comprehensive Business Case Framework for Evaluating Transit Projects

Mon, 04/10/2017 - 17:59
Comprehensive Business Case Framework for Evaluating Transit Projects
by Johri,A; Routley,M.
2017.
TAC 2017: Investing in Transportation: Building Canada's Economy - - 2017 Conference and Exhibition of the Transportation Association of Canada.
CA6 ARH_10 2017A5102 - INTERNET


Metrolinx is developing an evidence-based evaluation framework for business cases to inform investment decisions for transit projects. The Business Case Framework ensures that effective evaluation of options is conducted as a project advances through planning, design, delivery, and operation. The business case supports a systematic process of identifying, quantifying, and comparing expected benefits and costs of a project in a consistent and clear manner over its lifecycle. The work combines strategic and financial perspectives with the rigour of economic cost benefit analysis, while also incorporating operational issues and challenges.

20 Avenue Street Lab Party

Mon, 04/10/2017 - 17:44
20 Avenue Street Lab Party
by Malzer,J.
2017.
TAC 2017: Investing in Transportation: Building Canada's Economy - - 2017 Conference and Exhibition of the Transportation Association of Canada.
CA6 ARH_10 2017A5101 - INTERNET


The 20 Avenue N Street Lab Party was a first for Calgary – a public engagement trial using temporary materials to transform a street into a possible complete street configuration. This document describes the steps and tools that were developed to host the 20 Avenue N ‘Street Lab Party’. This project was initiated and completed in 2016. The City of Calgary hosted a Street Lab on August 20, 2016. The 20 Avenue N street lab party involved piloting street enhancements using tactical urbanism principles: inexpensive, quick, and temporary. The opportunity was intended to allow residents to participate in the planning and execution of the improvements to determine whether the benefits and drawbacks can be more fully assessed through experiences and observed data sets as compared with more traditional engagement approaches. This project was nominated for the TAC Sustainable Urban Transportation Award.

Bilan 2016 : accidents, parc automobile, permis de conduire

Mon, 04/10/2017 - 17:18
Bilan 2016 : accidents, parc automobile, permis de conduire
2016.
CA2PQ DT_700 2016B31 - MAIN


Ce dossier statistique porte sur les accidents de véhicules routiers, les victimes, les titulaires d'un permis de conduire et les véhicules en circulation. Il présente le même type de reseignements statistiques que que les publications antérieures et couvre rétrospectivement une période globale de six ans.

Evaluation of Work Zone Throughput and User Delay Models

Sat, 03/11/2017 - 21:11
Evaluation of Work Zone Throughput and User Delay Models
by Nikolic,G; Tighe,S; McCabe,B; Bhim,R; Rouhieh,B; Hadayeghi,A.
2017.
TAC 2017: Investing in Transportation: Building Canada's Economy - - 2017 Conference and Exhibition of the Transportation Association of Canada.
CA6 ARH_10 2017A5130 - INTERNET


Lane closures on highways during construction results in reductions in capacity which ultimately leads to premature queuing and significant delay for road users. To minimize user delay costs, contractors are required to keep highway lanes open during the peak traffic hours and work during non-peak hours (typically nights). These limitations can reduce the quality of the work and extend project duration. To improve the efficiency of the work and reduce user delay costs, it is important to identify the factors that affect the capacity or throughput of a construction zone and attempt to design the construction zone to maximize the capacity. These factors can be categorized into a number of groups including design parameters of the workzone, traffic composition, time of day, geometry of the highway and presence of the police or construction related signs. In this study, several types of data was collected from various work zones on 400 Series Highway within Central Ontario under the jurisdiction of the Ministry of Transportation Ontario. The data include geometric data associated with a workzone, travel time/speed of vehicles approaching a workzone, volume of vehicles approaching a workzone and within the workzone, and the queue upstream of the lane closure locations. Utilizing the large data set collected, Multiple Regression Models (MRM) and Negative Binomial Models (NBR) were developed for the prediction of the throughput at work zones based on lane closure layout and geometric characteristics. In addition, a Simplified Work Zone User Delay Analysis (SZUDA) model was developed (building off the developed models), which calculates user delays by approximating queue lengths at work zones. The study also collected data and developed an Aimsun Microsimulation model to validate the regression model predictions. The results of this study can be used to develop a practical tool that provides a fast and efficient estimate of a workzone throughput during construction and calibrated to Canadian conditions.

Évaluation des sols d’infrastructure pour la conception des chaussées aéroportuaires en béton

Sat, 03/11/2017 - 19:34
Évaluation des sols d’infrastructure pour la conception des chaussées aéroportuaires en béton
by Benkouar,M; D'Amours,L; Chevalier,F.
2017.
TAC 2017: Investing in Transportation: Building Canada's Economy - - 2017 Conference and Exhibition of the Transportation Association of Canada.
CA6 ARH_10 2017A5129 - INTERNET


Les paramètres géotechniques nécessaires pour concevoir les chaussées sont l’épaisseur et les propriétés mécaniques, thermiques et hydrauliques des matériaux et des sols présents. La présente expertise, bien qu’ayant une portée limitée, semble indiquer que les indices CBR calculés lors des études préalables au moyen d’essais DCP dans les trous de forages devraient faire l’objet d’une correction pour considérer le confinement apporté par le remblai routier présent au-dessus de ces sols. Les indices CBR mesurés alors que le sol argileux est recouvert de remblai étaient surestimés de 25 à 30 % par rapport aux résultats, DCP et CBR in situ, mesurés sur le même dépôt exposé. 16 Le nombre d’essais effectués dans le cadre de ce projet ne permet toutefois pas de déterminer une relation ou un facteur de correction à appliquer systématiquement aux résultats mesurés lors de l’étude géotechnique. Un seul type de sol (argile silteuse) a été caractérisé et l’épaisseur du remblai routier était assez uniforme. La correction requise pourrait être différente de celle observée dans la présente étude si les conditions étaient différentes.

Establishment of Traffic Signal Policies and Procedures for Adoption on Saskatchewan’s Highway Network

Sat, 03/11/2017 - 18:54
Establishment of Traffic Signal Policies and Procedures for Adoption on Saskatchewan’s Highway Network
by Steel,PHA; Holland,J.
2017.
TAC 2017: Investing in Transportation: Building Canada's Economy - - 2017 Conference and Exhibition of the Transportation Association of Canada.
CA6 ARH_10 2017A5128 - INTERNET


The Saskatchewan Ministry of Highways and Infrastructure (the Ministry) completed a study in 2015 to expand their compliment of safety countermeasures along medium to high volume corridors and intersections. The report recommended to only consider the implementation of traffic signals where certain operational and safety conditions were met. The Ministry has not traditionally used signals at isolated, high speed rural intersection as a safety countermeasure because of the risk that collision severity will increase, in addition to compromising the intended mobility of these free-flowing major highway systems. Within this context, the Ministry retained Tetra Tech to assist in the development of policies and procedures for signal adoption. The policies will guide the Ministry to determine whether traffic conditions are/are not favourable to support signal implementation at locations under review. Policy statements were developed from current industry practices and from other jurisdictions’ guidelines and policy documents. A total of 13 statements were recommended to address: conditions where traffic signals could be considered, conditions where they may not be appropriate and other policy decision items. The current procedures adopted by the Ministry date back to 1989, and followed closely to the Transportation Association of Canada (TAC) guidelines of that time. As part of this latest initiative, Tetra Tech reviewed the current TAC procedures as well as other industry practices to confirm the approach that should be adopted that represents the Saskatchewan context. The recommendation for the Ministry was to adopt a hybrid of approaches used in North America jurisdictions that address the following: Achieving a minimum traffic volume for various time periods (eight-hour, four-hour and peak-hour volumes); Meeting a specific collision experience threshold that demonstrates under certain conditions, installing signals can benefit an intersection by reducing collisions of a high severity and type sufficiently to offset the increase in similar/lower severity collisions; Coordinated signal system to address adequate progression of vehicles along the main corridor; and Demonstrated improvement in the level of service and delay. This paper will present a summary of current industry practices, to discuss the establishment of policies and preferred warrants for adoption by the Ministry, as well as to provide the findings of a calibration check that applied the recommended policy statements and warrant procedures on four candidate intersections.

Effectiveness and Benefits of Calcium Chloride Stabilized Road Base: A Township of Woolwich Study

Sat, 03/11/2017 - 16:07
Effectiveness and Benefits of Calcium Chloride Stabilized Road Base: A Township of Woolwich Study
by Duclos,A; Ambaiowei,D; Wheildon,L.
2017.
TAC 2017: Investing in Transportation: Building Canada's Economy - - 2017 Conference and Exhibition of the Transportation Association of Canada.
CA6 ARH_10 2017A5127 - INTERNET


Different additives (cementitious, bituminous, chemical, mechanical, biological, and proprietary blends) are routinely used to improve material properties of poor soils and aggregates ranging from highly expansive clays to more granular materials. Whereas the benefits of some of these additives are accounted for in pavement design and lifecycle processes; the benefits of Calcium Chloride (CaCl2) – a common chemical soil stabilizer is not considered. The hygroscopic properties of CaCl2 effectively stabilizes soils through the attraction of moisture and subsequent evaporation resistance, improving compaction during construction which in turn ensures a strong and durable base material. An additional benefit of CaCl2 particularly in cold regions, is its ability to decrease the freezing point of water consequently providing enhanced resistance to frost heaving. Leaning on the successes and challenges of calcium chloride stabilized road base in Canada, this on-going Township of Woolwich study investigates the effectiveness of a 35% CaCl2 road base application for improving the short and long-term performance of an asphalt surfaced roadway and reducing the overall life-cycle costs. This study employs a monitoring program of Falling Weight Deflectometer (FWD) testing - prior to and after base stabilization, after paving and after one winter cycle - to characterize the short and long-term benefits by comparing the performance of the CaCl2 stabilized and non-stabilized (control) road base sections exhibiting good and poor drainage conditions. This paper presents the short-term findings of using CaCl2 for base stabilization. The economic benefits of incorporating CaCl2 in road base applications is evaluated, and a case for considering the benefits of a CaCl2 stabilized road base during design is further assessed.

TAC 2017: Investing in Transportation: Building Canada's Economy - - 2017 Conference and Exhibition of the Transportation Association of Canada

Fri, 03/10/2017 - 20:01
TAC 2017: Investing in Transportation: Building Canada's Economy - - 2017 Conference and Exhibition of the Transportation Association of Canada
2017.
TAC 2017: Investing in Transportation: Building Canada's Economy - - 2017 Conference and Exhibition of the Transportation Association of Canada.
CA6 ARH_10 2017A5101-5179 - INTERNET

Performance Evaluation of REOB Modified Asphalt Binders and Mixtures

Wed, 03/08/2017 - 21:29
Performance Evaluation of REOB Modified Asphalt Binders and Mixtures
by Li,X; Gibson,N; Andriescu,A; Arnold,TS.
2016.
Asphalt Paving Technology 2016: Journal of the Association of Asphalt Paving Technologists - Indianapolis, Indiana, March 13-16, 2016.
US6 AFN___ 2016P07 - MAIN


This study evaluated a limited number, but well-controlled group of asphalt binders of the same PG grade made with a wide range of REOB contents; 0%, 2.5%, 6% and 15%. The most practical indicator of the possible presence of a considerable quantity of REOB with measureable changes to the rheological and performance characteristics was the difference between the BBR m-value temperature grade and the BBR S stiffness temperature grade, DTcritical. When a binder exhibited a large DTcritical it was associated with larger differences in performance losses depending on the binder tests and to a lesser extent the mixture test. The DTcritical performance disruption was made worse by oxidative aging by means of double PAV conditioning as well as holding the binder at extended low temperatures before testing. The impact of REOB on moisture damage resistance showed higher moisture sensitivity with increasing REOB content, but it did not interfere with liquid anti-strip additives. Mixture cracking tests results were mixed. Low temperature relaxation, strength and fracture measured with TSRST showed the fracture strength had slight increases or decreases with 2.5% and 6% REOB and could be interpreted as unaffected. Aging also improved the average strength of these mixes. However, the strength of the highest 15% REOB mix was measurably decreased and made worse by aging. The impact of REOB on intermediate temperature fatigue cracking performance depended on the aging condition and whether stress-control or strain-control performance was considered. To minimize risks a best practice needs to be developed which includes a maximum use level, taking into account both the variability of REOB and the effects on asphalt binders from different sources. Asphalt binder specifications might be refined by placing lower limits to BBR stiffness or a maximum allowable DTcritical. More focus should be placed on intermediate REOB levels such as near 10% to the 6% used in this study to better identify performance pitfalls and performance benefits from REOB and the corresponding DTcritical.

Laboratory Performance of Re-Refined Engine Oil Bottoms (REOB) Modified Asphalt

Wed, 03/08/2017 - 18:40
Laboratory Performance of Re-Refined Engine Oil Bottoms (REOB) Modified Asphalt
by Bennert,T; Ericson,C; Pezeshki,D; Haas,E; Shamborovskyy,R; Corun,R.
2016.
Asphalt Paving Technology 2016: Journal of the Association of Asphalt Paving Technologists - Indianapolis, Indiana, March 13-16, 2016.
US6 AFN___ 2016P06 - MAIN


Re-refined engine oil bottoms (REOB) are one of several products obtained in the refining of recovered engine oil and have been used in the asphalt industry since the 1980’s. Generally, REOB is used to help soften the base asphalt binder and is commonly used from 3 to 10% by weight in order to achieve desired low temperature asphalt binder properties. Recently, poor cracking performance in a number of Canadian and northern United States pavement sections have been blamed on the use of REOB to modify the asphalt binder. This has prompted state agencies in the northeast United States to ban its use, without necessarily understanding how REOB affects asphalt binder and mixture performance. A research effort was conducted to evaluate the laboratory performance of asphalt binders and mixtures modified with REOB. Two different sources of REOB were blended with different base asphalt grades at varying dosage rates in the study to achieve “softer” asphalt binders—similar to the current practice of REOB modification in the asphalt industry. Performance grading, master stiffness curves, double edged notch tension test, and Black Space analysis were conducted on the asphalt binders at different levels of laboratory aging. Additionally, the asphalt binders were used to produce asphalt mixtures for stiffness, permanent deformation, fatigue cracking and low temperature cracking performance. The research study showed that while being able to achieve softer asphalt binder grades in accordance with AASHTO R 29, the addition of REOB accelerates the age hardening effects in the asphalt binder, with higher levels of age hardening occurring at higher REOB dosage rates. The study also indicated that while the stiffness properties at low temperatures are not impacted by the REOB, the relaxation properties, as measured using m-slope of the Bending Beam Rheometer (BBR), are highly affected. Both the Black Space analysis, using the Glover-Rowe approach, and the DENT test show promise at identifying the age hardening effects and correlated well to mixture fatigue cracking in the Overlay Tester. Differences were found between the various asphalt mixture fatigue cracking tests in their respective ranking of fatigue cracking performance. Asphalt mixture permanent deformation and dynamic modulus of REOB modified asphalt mixtures showed similar performance to the neat asphalt binders when compared to the REOB modified asphalt binders of the same PG grade.

Correlating Field Performance to Laboratory Dynamic Modulus from Indirect Tension and Torsion Bar

Wed, 03/08/2017 - 18:30
Correlating Field Performance to Laboratory Dynamic Modulus from Indirect Tension and Torsion Bar
by Yang,S; Braham,A; Underwood,S; Hanz,A; Reinke,G.
2016.
Asphalt Paving Technology 2016: Journal of the Association of Asphalt Paving Technologists - Indianapolis, Indiana, March 13-16, 2016.
US6 AFN___ 2016P05 - MAIN


Dynamic modulus has several useful functions in flexible pavements, including stress/strain characterization, rutting and cracking characterization, an input into several analytical and numerical models, and a primary input into PavementME Design. While the traditional dynamic modulus test is run in the uniaxial configuration, this is not possible for field cores. Therefore, the Indirect Tension dynamic modulus (IDT E* ) and torsion bar shear modulus (torsion bar G* ) have been developed. However, there has been limited research looking at analyzing the data from field cores for these two geometries, comparing modulus data from the two geometries, examining in-service aging of dynamic modulus, and quantifying pavement conditions using dynamic modulus. This research examines ten field sections in Arkansas, comprised of four “good” performing sections, two “medium” performing sections, and four “poor” performing sections in an attempt to address these four questions. First, this research found that using AASHTO T 342 and AASHTO R 62 can lead to irrational coefficients but provide rational results. Second, while the IDT E* and torsion bar G* values were similar at high modulus values, the IDT E* values began to increase as the modulus decreased compared to the torsion bar G* values, increasing to over a decade of difference. Third, a noticeable difference was observed between the modulus values of the bottom surface layer and top surface layer, with the bottom surface layer showing higher modulus values in all cases. While the upper surface layer showed higher oxidation, other weathering effects such as moisture and traffic appear to have overwhelmed the oxidation effect and pavement deterioration has reduced the integrity of the mix. Finally, both the IDT E* and torsion bar G* were not able to quantify a noticeable difference between poor and medium performing sections, and medium and good performing sections, but were able to quantify a difference between the poor and good behaving sections. Overall, the IDT E* and torsion bar G* tests were able to produce consistent master curves, correlate to each other, identify differences between surface course lifts, and quantify differences in field performance.

Uniaxial Shear Tester—Test Method to Determine Shear Properties of Asphalt Mixtures

Wed, 02/08/2017 - 21:03
Uniaxial Shear Tester—Test Method to Determine Shear Properties of Asphalt Mixtures
by Zak,J; Monismith,CL; Coleri,E; Harvey,JT.
2016.
Asphalt Paving Technology 2016: Journal of the Association of Asphalt Paving Technologists - Indianapolis, Indiana, March 13-16, 2016.
US6 AFN___ 2016P04 - MAIN


The main focus of the paper is to present the concept of a newly developed Uniaxial Shear Tester (UST) and to investigate the correlation between results from the UST and the Superpave Shear Tester (SST), a tool broadly recognized for asphalt mix design and rutting susceptibility evaluation. In this study, the UST testing principles, finite element analysis of stresses, and comparison of measured data are presented. The correlation was assessed on the basis of two tests, the repeated shear test and the small amplitude oscillation test also referred as the shear frequency sweep test. It was shown that the material characteristics determined from UST and SST are highly correlated. The dependencies are discussed in the sense of linear correlation and correlation coefficients. Test variability is discussed in the paper.

Selection and Preliminary Evaluation of Laboratory Cracking Tests for Routine Asphalt Mix Designs

Wed, 02/08/2017 - 20:48
Selection and Preliminary Evaluation of Laboratory Cracking Tests for Routine Asphalt Mix Designs
by Zhou,F; Im,S; Hu,S; Newcomb,D; Scullion,T.
2016.
Asphalt Paving Technology 2016: Journal of the Association of Asphalt Paving Technologists - Indianapolis, Indiana, March 13-16, 2016.
US6 AFN___ 2016P03 - MAIN


Cracking has become a primary mode of distress in recent years that frequently drives the need for rehabilitation of asphalt pavements. Meanwhile, asphalt mix designs are becoming more and more complex with the increasing uses of recycled materials, recycling agents, binder additives/modifiers, and multiple warm mix asphalt technologies. Thus, there is an urgent need to identify reliable cracking tests that can be used for routine mix design to eliminate brittle mixes. This paper includes a critical review of cracking mechanisms and laboratory tests. A total of twelve cracking tests were discussed at a cracking test workshop held as part of the National Cooperative Highway Research Program (NCHRP) Project 9-57. Seven cracking tests were selected for further laboratory evaluation and field validation. Four of the simpler cracking tests from the seven were evaluated in this paper, these being Texas Overlay Test (OT), Disk-shaped Compact Tension (DCT) test, Semi-Circular Bend test from the Louisiana Transportation Research Center (SCB-LTRC), and SCB test at room temperature from Illinois (SCB-IL). A laboratory sensitivity study was performed, and the results showed that all four cracking tests were generally sensitive to asphalt mix components. However, there were some concerns with the DCT, SCB-LTRC, and SCB-IL. Both the DCT and SCB-IL were found to be not sensitive to asphalt binder content; and both the DCT and SCB-LTRC showed an unexpected increase in cracking resistance when adding RAS to the mix. Additionally, two sets of field test sections were used for preliminary validation of these four cracking tests. It was found that the OT, DCT, and SCB-IL provided rankings which matched the measured field performance for the two sections on US62, Texas; and the OT and SCB-LTRC were valid for six APT test sections. Further validation with different mixes, traffic and climate is needed.

Evaluation of Asphalt Mixture Laboratory Long-Term Aging Methods for Performance Testing and Prediction

Wed, 02/08/2017 - 20:26
Evaluation of Asphalt Mixture Laboratory Long-Term Aging Methods for Performance Testing and Prediction
by Elwardany,MD; Rad,FY; Castorena,C; Kim,YR.
2016.
Asphalt Paving Technology 2016: Journal of the Association of Asphalt Paving Technologists - Indianapolis, Indiana, March 13-16, 2016.
US6 AFN___ 2016P02 - MAIN


Aging has long been recognized as a major distress mechanism for asphalt concrete and, by extension, asphalt pavements. Aging causes the material to stiffen and embrittle, which leads to a high potential for cracking. Although a significant amount of effort has been placed on understanding the aging process of asphalt binder, less effort has been put forth to develop laboratory aging procedures for producing aged mixture specimens for performance testing. An optimal laboratory conditioning procedure to simulate long-term aging for performance testing and prediction is required in order to integrate the effects of long-term aging in pavement prediction models and other mechanistic design and analysis methods. In this study, oven aging and pressure aging vessel aging are applied to both loose mix and compacted specimens in order to evaluate and select an aging method to simulate long-term aging for performance testing and prediction. The selected method must be able to maintain specimen integrity in order to be used for performance testing and prediction. Efficiency, practicality, and versatility also are considered in evaluating the aging methods. The results demonstrate that loose mix aging in an oven is the most promising aging method to produce mixture specimens for performance testing in terms of efficiency, specimen integrity, versatility, and cost.

Long-Term Aging of Asphalt Mixtures

Wed, 02/08/2017 - 20:17
Long-Term Aging of Asphalt Mixtures
by Yin,F; Arámbula-Mercado,E; Epps Martin,A; Newcomb,D; Tran,N.
2016.
Asphalt Paving Technology 2016: Journal of the Association of Asphalt Paving Technologists - Indianapolis, Indiana, March 13-16, 2016.
US6 AFN___ 2016P01 - MAIN


Aging of asphalt mixtures occurs during production and construction and continues throughout the service life of the pavement. Although this topic has been studied extensively, recent changes in asphalt mixture components, production parameters, and plant design have raised a need for a comprehensive evaluation that considers the impacts of climate, aggregate type, recycled materials, WMA technology, plant type, and production temperature. In this study, field cores were acquired from seven field projects at construction and several months afterwards, and raw materials were also collected for fabricating laboratory specimens that were long-term oven aged (LTOA) in accordance with selected protocols. The resilient modulus and Hamburg wheel tracking tests were conducted on both specimen types to evaluate the evolution of mixture stiffness and rutting resistance with aging. The concepts of cumulative degree-days and mixture property ratio were proposed to quantify field aging and its effect on mixture properties. Test results indicated that the LTOA protocols of two weeks at 140°F (60°C) and five days at 185°F (85°C) produced mixtures with equivalent in-service field aging of 7–12 months and 12–23 months, respectively, depending on climate. Finally, among the factors investigated in the study, WMA technology, recycled materials, and aggregate absorption exhibited a significant effect on the long-term aging characteristics of asphalt mixtures, while production temperature and plant type had no effect.

Asphalt Paving Technology 2016: Journal of the Association of Asphalt Paving Technologists - Indianapolis, Indiana, March 13-16, 2016

Wed, 02/08/2017 - 20:04
Asphalt Paving Technology 2016: Journal of the Association of Asphalt Paving Technologists - Indianapolis, Indiana, March 13-16, 2016
2016.
Asphalt Paving Technology 2016: Journal of the Association of Asphalt Paving Technologists - Indianapolis, Indiana, March 13-16, 2016.
US6 AFN___ 2016P01-30 - MAIN

Identification of BRT-Advantaged Age-group and Income Level Group by Examining Various BRT Cities

Mon, 01/09/2017 - 21:21
Identification of BRT-Advantaged Age-group and Income Level Group by Examining Various BRT Cities
by Dutta,U; Dutta,S.
2016.
Canadian Transportation Research Forum 51st Annual Conference - North American Transport Challenges in an Era of Change//Les défis des transports en Amérique du Nord à une aire de changement Toronto, Ontario, May 1-4, 2016.
CA6 AIP_10 2016P26 - INTERNET


Bus Rapid Transit (BRT) has generated great interest among small and large cities across the United States (e.g., Detroit, MI, Grand Rapids, MI, and Aspen, CO) as a means of improving mobility and accessibility, and optimizing the use of street space, at a relatively modest cost per mile ($10-$27 million). The main advantage of BRT is its ability to operate on all types of road infrastructures: mixed-flow arterials, mixed-flow freeways, dedicated arterial lanes, at-grade or fully grade-separated transitways, managed lanes, and tunnels. The purpose of this study is to identify BRT-advantaged age-groups and income level groups by examining various BRT cities. A group or sector is said to be “BRT-advantaged” when its population grows at a higher rate within a BRT shed than within the larger metropolitan region during the same time period. Shift-share analysis was conducted to identify various BRT-advantaged attributes. Shiftshare analysis is used to decompose changes in an attributes (such as age-group and income level) in local areas. For example, the analysis identifies age groups that have comparative advantage in local areas. The technique provides a picture of how well a region’s income level group and age groups are growing at a given moment in time. As a part of this effort, age-group and income level data of five BRT cities were collected before and after the implementation of BRT at region and BRT-shed level. BRT-advantaged attributes by each city, as well as combined were identified. With the precedent of specific populations thriving in a BRT shed, communities and their planners can target the appropriate age and income level groups in their marketing efforts. The author discussed the causes behind the influence of BRT on the various population groups.

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