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Lignes directrices pour l’utilisation des panneaux d’affichage de la vitesse

lun, 11/05/2018 - 18:56
Lignes directrices pour l’utilisation des panneaux d’affichage de la vitesse
by Ermatinger,V; Guglielmino,M; Kellner,S; Kozak,DA; Lovicsek,M; Otten-Andrew,M.
2017.
CA6 ARH_65 2017A63Z - MAIN


Les panneaux d’affichage dynamique de la vitesse sont utilisés dans plusieurs provinces et territoires du Canada. Ils permettent aux conducteurs de voir leur vitesse, habituellement affichée à côté du panneau indiquant la limite de vitesse permise. Ces dispositifs sont destinés à faire prendre conscience aux conducteurs des limites de vitesse en affichant en temps réel la vitesse à laquelle ils conduisent leur véhicule. On a pu constater qu’ils sont efficaces peu de temps après leur installation. Les Lignes directrices pour l’utilisation des panneaux d’affichage de la vitesse ont été mises au point afin de définir les meilleures pratiques et de fournir des recommandations pour la conception et l’utilisation de panneaux d’affichage de la vitesse dans le contexte canadien pour diverses situations. Ces Lignes directrices permettent et favorisent l’uniformité dans l’utilisation des dispositifs dans tout le Canada; elles ont été rédigées dans le but de servir de document de référence détaillé complémentaire à utiliser conjointement avec le Manuel canadien de la signalisation routière (MCSR).

Guide de conception, de construction, d’entretien et d’inspection des murs de soutènement de sol stabilisé mécaniquement

lun, 11/05/2018 - 18:41
Guide de conception, de construction, d’entretien et d’inspection des murs de soutènement de sol stabilisé mécaniquement
by Van Dyk,A; Bathurst,RJ; Maher,M; Boone,S.
2017.
CA6 ARH_63 2017D21Z - MAIN


Les murs de soutènement de sol stabilisé mécaniquement (MSSM) sont depuis longtemps utilisés comme murs de soutènement, mais il n’est pas toujours évident de déterminer qui est l’ultime responsable de la conception, de l’assurance de la qualité, de la gestion des actifs et de la réparation des murs, ainsi que de la surveillance en service des murs déjà construits, en particulier en cas de problèmes importants relativement à la construction ou la tenue en service. Le présent guide offre aux maîtres d’ouvrages, ingénieurs, fournisseurs et entrepreneurs des MSSM des lignes directrices pratiques en matière de sélection, de conception, de construction et d’inspection de ces ouvrages, surtout dans le cadre de projets de travaux publics. Le guide a été élaboré sur la base de l’examen de la littérature existante, complétée par de l’information transmise par divers intervenants dans ce domaine. Il ne cherche pas à reproduire les très nombreuses lignes directrices de conception déjà publiées, ni l’information connexe. Il vise plutôt à mettre en évidence les diverses facettes de l’état actuel de la pratique au Canada et à proposer des modifications à la pratique actuelle afin de corriger certaines lacunes.

Manual for Bridge Evaluation

dim, 11/04/2018 - 20:40
Manual for Bridge Evaluation
Highway Committee on Bridges and Structures.
3rd Edition.
2018.
US6 ABK___ 2018B62 - MAIN


This manual has been developed to assist bridge owners by establishing inspection procedures and evaluation practices that meet the National Bridge Inspection Standards (NBIS). The manual has been divided into eight sections, with each section representing a distinct phase of an overall bridge inspection and evaluation program. This edition updates Sections 3: Bridge Management Systems; 4: Inspection; 6: Load Rating; and 7: Fatigue Evaluation of Steel Bridges.

Asphalt Re-recycling

jeu, 10/04/2018 - 19:29
Asphalt Re-recycling
by Kriz,P; Tardiff,BJ; Sta. Maria,SR; Shirts,RD.
2017.
Proceedings of the Sixth-Second Annual Conference of the Canadian Technical Asphalt Association (CTAA): Halifax, Nova Scotia.
CA6 AIH___ 2017P19 - MAIN


Use of Reclaimed Asphalt Pavement (RAP) is beneficial to both road owners and builders as it allows for significant raw material cost reduction, while potentially maintaining expected pavement service life. In upcoming decades, the recycling of previously recycled pavements (i.e. re-recycling) will become widespread. There is currently little technical knowledge on how or how many times asphalt pavement can be recycled while sustaining its expected durability. A novel asphalt binder aging method involving thin layers, heat, water spray, and UV radiation was developed to simulate approximately 20 years of in-service aging. The aged binder was recovered and blended with a softer, virgin binder. The blend was subjected to the next aging cycle. The process was repeated four times to simulate four recycling cycles (80 years) at 25 percent RAP addition. Three virgin binders were tested: standard Performance Grade (PG), one grade softer PG, and standard PG softened with paraffinic oil to one PG softer binder. Very detailed chemical and rheological analyses were performed to understand the impact of multiple recycling on irreversible chemical changes and evolution of rheological properties over the time. Results indicated that at moderate recycling levels, re-recycling is a viable option if an appropriate virgin binder is used.

Prince Edward Island’s Experience with Hot In-place Asphalt Recycling

jeu, 10/04/2018 - 18:40
Prince Edward Island’s Experience with Hot In-place Asphalt Recycling
by Yeo,S; Sherren,M; Pigott,S.
2017.
Proceedings of the Sixth-Second Annual Conference of the Canadian Technical Asphalt Association (CTAA): Halifax, Nova Scotia.
CA6 AIH___ 2017P18 - MAIN


The local geology of Prince Edward Island (PEI) primarily consists of material soft in nature that does not meet traditional aggregate specifications for the production of Hot Mix Asphalt (HMA) or other surface treatments. Therefore, roughly 95 percent of PEI’s HMA aggregates must be obtained and imported from off-Island sources. The associated work, expense, and environmental impact involved has raised the Department’s interest in the viability of asphalt recycling as a potential surface treatment option. As a trial basis, the Department committed to recycling ten, one-kilometer sections of road ranging in classification from Local to Collector roads in 2016. Acceptance or rejection of the work was largely based on the ability of the Contractor to achieve the specified penetration values of the modified binder and visual inspection for defects, as well as requirements for cross slope, grade and joint construction of the completed HIR. The HIR process was constantly monitored in the field by Department staff and although not forming part of the specifications, properties such as compaction, smoothness, and asphalt cement content were monitored. This paper is an account of our experiences and lessons learned from the recent application of HIR undertaken within the Province of PEI.

Performance-based Asphalt Mixture Development Process to Optimize Material Durability and Pavement Design

mar, 09/04/2018 - 20:37
Performance-based Asphalt Mixture Development Process to Optimize Material Durability and Pavement Design
by Croteau,JM; Pianarosa,S; Harrison,T; Slawinsky,C; Brissaud,L.
2017.
Proceedings of the Sixth-Second Annual Conference of the Canadian Technical Asphalt Association (CTAA): Halifax, Nova Scotia.
CA6 AIH___ 2017P17 - MAIN


In the summer of 2015, Standard General Inc. – Calgary (SGIC), a subsidiary of Colas Canada Inc., introduced a new paving material called Betoflex® with the goal of resolving a recurring permanent deformation issue of two taxiways leading to Runway 17/35 at the Calgary Airport. The 2015 mixture was developed using the French Level 2 methodology to ensure that rutting resistance performance was achieved while maintaining good mixture workability to facilitate placement and compaction. In the spring/summer of 2016, Level 4 testing was performed on various Betoflex® mixtures that could potentially be used in the Calgary area. Level 4 testing was also performed on typical mixtures used in Calgary to benchmark Betoflex® with local mixtures. The Level 4 mix-design provides information for pavement design (stiffness modulus and fatigue resistance) using the French ALIZÉ-LCPC software. This paper provides an overall perspective of the engineering of asphalt mixtures to achieve “in-service” performance not only for durability (moisture resistance and rutting), but also for pavement design performance (stiffness modulus and fatigue resistance). It also discusses how the ALIZÉ-LCPC pavement design software uses Level 4 mix-design information to optimize pavement thicknesses and/or pavement performance reliability with respect to fatigue and large radius rutting.

Laboratory Study on the Effect of Asphalt Binder Rejuvenators on the Cracking Resistance of Hot Mix Asphalt

mar, 09/04/2018 - 19:35
Laboratory Study on the Effect of Asphalt Binder Rejuvenators on the Cracking Resistance of Hot Mix Asphalt
by Wielinski,JC; Magill.L; Campbell,C; Huber,GA.
2017.
Proceedings of the Sixth-Second Annual Conference of the Canadian Technical Asphalt Association (CTAA): Halifax, Nova Scotia.
CA6 AIH___ 2017P16 - MAIN


Asphalt binder rejuvenator use in Hot Mix Asphalt (HMA) has been gaining momentum not only to delay aging of the asphalt binder, but also to permit higher levels of binder replacement from recycled materials. In this study, an HMA mixture was designed with approximately 35 percent binder replacement from Reclaimed Asphalt Pavement (RAP). Per specifications, a binder grade adjustment from PG 64-22 to PG 58-28 was required. The control mixture contained a neat PG 58-28 binder. Three experimental binders contained asphalt binder that were a blend of PG 64-22 plus rejuvenator materials to produce a PG 58—28 binder. HMA mixtures containing all four asphalt were tested for cracking and rutting resistance. The laboratory study indicated that the control and experimental mixes had no difference I rutting resistance. Under short-term aging, all three experimental mixtures with rejuvenators had improved cracking resistance as measured by the Illinois Flexibility Index Test (IFIT). Under long-term aging conditions, no significant difference was observed among the control and the three experimental mixtures according to the Disc-Shaped Compact Tension (DCT) test. However, IFIT testing of long-term aged specimens showed improved cracking resistance for two of the three experimental mixtures compared to the control.

Safety Evaluation of Signalized Restricted Crossing U-Turn Intersections

sam, 06/02/2018 - 20:33
Safety Evaluation of Signalized Restricted Crossing U-Turn Intersections
by Hummer,JE; Rao,S.
2017.
US1 DTH680 2017S36 - MAIN


This study evaluated restricted crossing U-turn (RCUT) intersection and was conducted by the DCMF program for the Evaluation of Low-Cost Safety Improvements Pooled Fund Study. RCUT is defined as a three-approach or four-approach intersection where minor street left-turn and through movements (if any) are rerouted to one-way downstream U-turn crossovers. RCUTs are also known as superstreets, J-turns, reduced conflict intersections, and synchronized streets. Previous research has shown that unsignalized RCUTs are generally safer than conventional options. However, there are no known studies specific to the safety of signalized RCUTs. The objective of this effort was to collect and analyze crash data to develop a crash modification factor (CMF) for signalized RCUTs. This study collected and analyzed crash data before and after conversion of 11 intersections from conventional to RCUT design. The intersections were in suburban areas on four- or six-lane arterials. For most individual sites and groups of sites examined, odds ratio tests showed that there were high-quality comparison sites available, and regression to the mean was not an issue. The project team recommends a CMF of 0.85 for overall crashes and 0.78 for injury crashes for the conversion of a conventional intersection to an RCUT intersection. Based on those CMFs, the project team produced an estimated benefit-to-cost ratio of 3.6 to 1.0 when considering safety and operations or 2.6 to 1.0 considering safety only.

Safety Evaluation of Edge-Line Rumble Stripes on Rural Two-Lane Horizontal Curves

sam, 06/02/2018 - 20:25
Safety Evaluation of Edge-Line Rumble Stripes on Rural Two-Lane Horizontal Curves
by Himes,S; Gross,F; Persaud,B; Eccles,K.
2017.
US1 DTH680 2017E26 - MAIN


The Development of Crash Modification Factors (DCMF) program conducted safety evaluations of edge-line rumble stripes (ELRSs) on rural two-lane horizontal curves for the Evaluation of Low-Cost Safety Improvements Pooled Fund Study. This study evaluated the application of ELRSs on rural two-lane horizontal curves. ELRSs are a variation of common shoulder rumble strips used to alert drowsy or distracted drivers when they are leaving the travel lane to the right. ELRSs are installed with the edge-line pavement marking placed directly over the rumble strip. Geometric, traffic, and crash data were obtained at treated rural two-lane horizontal curves in Kentucky and Ohio. To account for potential selection bias and regression-to-the-mean, an empirical Bayes before–after analysis was conducted using reference groups of untreated rural horizontal curves with similar characteristics to the treated sites. The analysis also controlled for changes in traffic volumes over time and time trends in crash counts unrelated to the treatment. Owing to a small sample for the reference group in Kentucky and a simultaneous statewide curve warning sign upgrade program in Ohio, alternative reference sites were used to account for annual trends. The results for Kentucky indicated statistically significant reductions for total, injury, run-off-road (ROR), and nighttime crashes, with crash modification factors (CMFs) of 0.75, 0.64, 0.74, and 0.63, respectively. The results for Ohio indicated statistically significant reductions for all crash types, with total, injury, ROR, nighttime, and nighttime ROR CMFs of 0.79, 0.79, 0.78, 0.75, and 0.71, respectively. The two States’ results could not be combined because of the statewide curve signing program in Ohio. It is important to note that all crash types considered in this research excluded intersection-related and animal crashes. Benefit–cost (B/C) ratios were estimated to be 331:1 for Kentucky and 477:1 for Ohio. If ELRSs were used as a curve-specific treatment, the B/C ratio would likely be much smaller because of the higher installation cost; however, these results suggest that the treatment can be highly cost effective.

Ontario Must Prepare for Vehicle Automation Part 2: How Skilled Governance Can Influence its Outcome

sam, 05/26/2018 - 05:35
Ontario Must Prepare for Vehicle Automation Part 2: How Skilled Governance Can Influence its Outcome
by Grush,B; Niles,J; Schlecter,B.
2017.
CA6 ARG750 2017O55 Part.2 - MAIN|INTERNET


This report recommends that our regional and municipal bus transit authorities move from an acquire-and-operate mode to one of specify-and-regulate. There are two key and menacing drawbacks to an acquire-and-operate approach. First, we are entering an era in which technology is changing faster than any government agency can respond, meaning that the risk associated with choosing, acquiring and deploying rapidly innovated automated transportation systems becomes untenable. A March 2017 staff report from the Toronto Transit Commission illustrates this, as detailed in this report. Second, the cost of new systems, new infrastructure and attrition of existing systems is out of taxpayer reach without commercial involvement if we are to move dramatically away from household car ownership. Finally, this report recommends a way to specify and regulate growing fleets that is focused entirely on optimization and inclusion. This involves licensing regulated operators to manage fleets under government social-performance criteria. These fleet operators would be free to innovate vehicles, services and prices — subject to safety, privacy and security certification. Beyond performance criteria and certifications, this approach represents an all-digital market system managed via fees and subsidies based entirely on social performance metrics. It is critical that all segments of urban society be served by this “new mobility.”

Ontario Must Prepare for Vehicle Automation: Automated vehicles can influence urban form, congestion and infrastructure delivery

sam, 05/26/2018 - 05:35
Ontario Must Prepare for Vehicle Automation: Automated vehicles can influence urban form, congestion and infrastructure delivery
by Grush,B; Niles,J; Baum,E.
2016.
CA6 ARG750 2016O55 Part.1 - INTERNET


The purpose of this report is to look at why and how government agencies and public interest groups can and should influence the preferred types and deployment of automated vehicles and the implication of related factors for planning.

Safety Evaluation of Multiple Strategies at Stop-Controlled Intersections

ven, 05/25/2018 - 05:33
Safety Evaluation of Multiple Strategies at Stop-Controlled Intersections
by Le,T; Gross,F; Persaud,B; Eccles,K; Soika,J.
2018.
US1 DTH680 2018S12 - MAIN


The Development of Crash Modification Factors program studied the safety performance of various stop-controlled intersections for the Evaluation of Low-Cost Safety Improvements Pooled Fund Study. This study evaluated the safety effectiveness of multiple low-cost treatments at stop-controlled intersections. Improvements included basic signing and pavement markings. This strategy is intended to reduce the frequency and severity of crashes at stop-controlled intersections by alerting drivers to the presence and type of approaching intersection. Geometric, traffic, and crash data were obtained at three- and four-legged, two- and four-lane major road, and urban and rural stop-controlled intersections in South Carolina. To account for potential selection bias and regression to the mean, an empirical Bayesian before–after analysis was conducted, using reference groups of untreated intersections with similar characteristics to the treated sites. The analysis also controlled for changes in traffic volumes throughout time and time trends in crash counts unrelated to the treatments. The aggregate results indicate reductions for all crash types analyzed (i.e., total, fatal and injury, rear-end, right-angle, and nighttime). The reductions are statistically significant at the 95-percent confidence level for all crash types. For all crash types combined, the crash modification factors (CMFs) are 0.917 for all severities and 0.899 for fatal and injury crashes. The CMFs for rear-end, right-angle, and nighttime crashes are 0.933, 0.941, and 0.853, respectively. The benefit–cost ratio estimated with conservative cost and service life assumptions is 12.4 to 1 for total crashes at unsignalized intersections. The results suggest that the multiple low-cost treatments, even with conservative assumptions on cost, service life, and the value of a statistical life, can be cost effective

The Road to Vision Zero: Zero Traffoc Fatalities and Serious Injuries

jeu, 05/24/2018 - 04:36
The Road to Vision Zero: Zero Traffoc Fatalities and Serious Injuries
by Calibaba,J.
2017.
CA7 FAT150 2017R58 - MAIN


Vision Zero is a priority road safety framework for Canada, as outlined by the Canadian Council of Motor Transport Administrators (CCMTA) in the release of their Road Safety Strategy 2025 (RSS 2025). The strategy, released in 2016, focuses on the long term of ensuring Canada’s roads are the safest in the world, while adding a greater focus on the vision of “towards zero” serious injuries and fatalities on the roadways. The Vision Zero Advocate Institute, supported by ATS Traffic, is the market leader in Vision Zero. Current studies point to a clear disparity in municipal comprehension and implementation of Vision Zero initiatives. The Vision Zero Advocate Institute closes that gap. (from the introduction)

Development and Evaluation of a Non-Tracking Asphalt Emulsion for Tack Coats and Fog Seals

ven, 05/04/2018 - 20:42
Development and Evaluation of a Non-Tracking Asphalt Emulsion for Tack Coats and Fog Seals
by Kucharek,AS; Esenwa,M; Varamini,S; Bickle,E; Cormier,A.
2017.
Proceedings of the Sixth-Second Annual Conference of the Canadian Technical Asphalt Association (CTAA): Halifax, Nova Scotia.
CA6 AIH___ 2017P15 - MAIN


Tack coats are thin applications of asphalt emulsion between the layers of a pavement structure with the role of enhancing adhesion. Fog seals are thin emulsion applications to pavement surface for protecting the surface from oxidation and water ingress, as well as reducing the risk of raveling and stone loss. One of the downsides of using asphalt emulsions for these applications is the required breaking and curing time. Even after curing, traditional emulsion grades will track onto nearby surfaces. Slow curing fog seals require longer road closures and/or a light sand application before trafficking. This paper presents the development stages of a non-tracking emulsion developed for bond coats and fog seals. The emulsion was formulated and engineered to be fast curing and provide a hard, non-tracking surface, suitable to support traffic without the use of sand application. Its tracking properties were assessed using novel tracking and curing tests, and its performance as a bond coat was measured using the tack coat shear test developed by McAsphalt. Trial projects of tack coating and fog seals were conducted from 2013 to 2016 throughout several Canadian provinces. Performance to date in the field, as well as some observed challenges, are presented.

Predicting HMA Fatigue Using the Double Edge Notched Tension Test and Multiple Stress Creep Recovery Test

ven, 05/04/2018 - 20:11
Predicting HMA Fatigue Using the Double Edge Notched Tension Test and Multiple Stress Creep Recovery Test
by Aurilio,M; Mikhailenko,P; Baaj,H.
2017.
Proceedings of the Sixth-Second Annual Conference of the Canadian Technical Asphalt Association (CTAA): Halifax, Nova Scotia.
CA6 AIH___ 2017P14 - MAIN


Fatigue resistance is an important factor for high quality Hot Mix Asphalt (HMA). Asphalt cements containing higher concentrations of polymer are known to be more strain tolerant, which can provide improved fatigue resistance in HMA. Use of polymer modified asphalt cement is a proven way to improve fatigue performance. Many municipalities and the Ontario Ministry of Transportation have implemented the Double Edge Notched Tension (DENT) test to improve the fatigue performance of the asphalt cement and the corresponding HMA. The DENT test is performed at an intermediate temperature that should correspond with fatigue performance. The Multiple Stress Creep Recovery (MSCR) test is an environmental test that measures the compliance and elastic response of an asphalt binder. The MSCR test is conducted at the high-performance grade temperature based on the local 7-day maximum temperature. The results from this research have shown that there is no clear relationship between increasing concentration of polymer modification and DENT performance. On the other hand, the percent recovery showed a very good correlation with polymer modification and performance. Based on the information presented in this paper, the MSCR is ultimately expected to be validated by HMA fatigue testing while the DENT is not.

Safety Evaluation of Red-Light Indicator Lights at Intersections

mar, 05/01/2018 - 19:27
Safety Evaluation of Red-Light Indicator Lights at Intersections
by Himes,S; Gross,F; Persaud,B; Eccles,K.
2017.
US1 DTH680 2017S16 - MAIN|INTERNET


The Development of Crash Modification Factors program conducted the safety evaluation of red-light indicator lights (RLILs) at intersections for the Evaluation of Low-Cost Safety Improvements Pooled Fund Study. This study evaluated safety effectiveness of RLILs. RLILs are auxiliary lights mounted on signal heads, mast arms, or poles that are directly connected to a traffic-control signal. The RLIL activates at the onset of the red phase and allows an enforcement officer to observe red-light running from downstream of the intersection. This strategy is intended to reduce the frequency of crashes resulting from drivers disobeying traffic signals by providing a safer and more efficient means for police to enforce the red interval. Geometric, traffic, and crash data were obtained at treated four-legged signalized intersections in Florida. To account for potential selection bias and regression-to-the-mean, an empirical Bayes before–after analysis was conducted using reference groups of untreated four-legged signalized intersections with characteristics similar to those of the treated sites. The analysis also controlled for changes in traffic volumes over time and time trends in crash counts unrelated to the treatment. Results indicate statistically significant crash reductions for most crash types. Disobeyed signal crashes had an estimated crash modification factor (CMF) of 0.71. Total crashes, fatal and injury crashes, right-angle, and left-turn crashes had estimated CMFs of 0.94, 0.86, 0.91, and 0.60, respectively. The benefit-cost ratio estimated with conservative cost and service life assumptions was 92:1 for four-legged signalized intersections. The results suggest that the treatment, even with conservative assumptions on cost, service life, and the value of a statistical life, can be cost effective. In addition to the crash-related benefits, RLILs can improve the efficiency and safety of red-light running enforcement efforts. While this study did not evaluate the efficiency and safety impacts with respect to enforcement, it should be noted that RLILs do allow police to observe violators from a downstream position, eliminating the need for a second observer (upstream) and the need to pursue a violator through the red light.

Author's Closure: Comments on "Cold Winter and Early Pavements Cracking Observed in Ontario"

sam, 04/28/2018 - 09:33
Author's Closure: Comments on "Cold Winter and Early Pavements Cracking Observed in Ontario"
by Uzarowski,L.
2017.
Proceedings of the Sixth-Second Annual Conference of the Canadian Technical Asphalt Association (CTAA): Halifax, Nova Scotia.
CA6 AIH___ 2017P22 - MAIN


The authors of the original 2015 paper entitled “Cold Winter and Early Asphalt Pavement Cracking Observed in Ontario” would like to acknowledge the detailed response provided by Dr. Keith MacInnis, Senior Technical Advisor, Canadian Asphalt Industries, Hamilton, Ontario. We also appreciate that the above noted paper generated interest and discussion around this critical topic. The subject described in the paper was of great importance to the road owners, and the Canadian Technical Asphalt Association (CTAA) is the best forum for this kind of discussion. This paper provides comments from the lead author of the paper in response to the comments that were provided by Dr. Keith MacInnis on the original 2015 paper.

Light Colour Asphalt Pavement

sam, 04/28/2018 - 09:33
Light Colour Asphalt Pavement
by Uzarowski,L; Rizvi,R; Manolis,S.
2017.
Proceedings of the Sixth-Second Annual Conference of the Canadian Technical Asphalt Association (CTAA): Halifax, Nova Scotia.
CA6 AIH___ 2017P21 - MAIN


Light Colour Asphalt Pavement (LCAP) is a process of designing and constructing asphalt pavements that meets the Leadership in Energy and Environmental Design (LEED) Solar Reflective Index (SRI) requirement that at a minimum 50 percent of the hardscape can be constructed using materials having an SRI value of 29 or higher. The purpose of the development of LCAP is to provide developers looking to achieve LEED certification with a paving alternative that provides performance that is equivalent to conventional asphalt pavement, but that will also meet the requirement of LEED. The LCAP process includes aggregate selection, asphalt mix modification, placement of asphalt mic, stripping of surface asphalt film from new pavement, and evaluation of reflectivity of aggregates, mixes, and in-place pavements. The very light colour aggregate from Coco’s Badgley Island Quarry was identified as a suitable material for LCAP. Conventional new asphalt pavements have an SRI of about 0, and weathered asphalt pavements have an SRI of about 6. This paper describes the importance of LCAP technology in reducing the heat island effect, the benefits of using it, required testing, and practical development of a LCAP mix.

Investigation into Temperature Effect on AASHTO Back Calculated Subgrade Resilient Modulus

sam, 04/28/2018 - 09:33
Investigation into Temperature Effect on AASHTO Back Calculated Subgrade Resilient Modulus
by Reggin,A; Palsat,B; Riessner,M; Juhasz,M.
2017.
Proceedings of the Sixth-Second Annual Conference of the Canadian Technical Asphalt Association (CTAA): Halifax, Nova Scotia.
CA6 AIH___ 2017P20 - MAIN


Over the past 25 years, Alberta Transportation (AT) has collected successive datasets of Falling Weight Deflectometer (FWD) deflection data over their 21,000 km (almost entirely flexible) highway network. A study was conducted to investigate the variation in back calculated subgrade modulus between two or more test dates in different collection years using AT’s FWD inventory data. Presently, AT uses the AASHTO 1993 method for the design of flexible pavement rehabilitation. The AASHTO 1993 design method only applies a temperature correction to the FWD central deflection, which is not directly used for estimated subgrade support strength, and therefore does not account for subgrade strength variation as a function of temperature at the time of testing. This paper presents a subgrade modulus temperature correction model developed from the FWD inventory data. The model was able to reduce the variation of subgrade modulus by a statistically and practically significant amount. If implemented, the model can be incorporated into the pavement rehabilitation design method to either minimize the risk of an under-designed pavement from using a higher than typical back calculated subgrade modulus, or minimize the risk (added costs) of over-design from using lower than typical back calculated subgrade modulus.

Automated Vehicles Symposium 2017: Summary of a Symposium

mer, 04/18/2018 - 01:36
Automated Vehicles Symposium 2017: Summary of a Symposium
2018.
Transportation Research Circular ; 232.
US6 AMF_75 C - MAIN


TRB's E-Circular 232: Automated Vehicle Symposium 2017: Summary of a Symposium highlights the themes from an event that took place on July 11–13, 2017 in San Francisco, California. The report follows the general symposium agenda. The presentations by speakers in the general sessions are summarized, including the highlights from the 25 breakout sessions. A list of the posters presented in two sessions is provided. The appendices provide a description of the key topics covered in the breakout sessions.

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