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Evaluation of Laboratory Coating and Compaction Procedures for Cold Mix Asphalt

Mon, 05/09/2022 - 18:25
Evaluation of Laboratory Coating and Compaction Procedures for Cold Mix Asphalt
by Swiertz,D; Johannes,P; Tashman,L; Bahia,H.
2012.
Asphalt Paving Technology 2012: Journal of the Association of Asphalt Paving Technologists - Austin, Texas, April 1-4, 2012.
US6 AFN___ 2012P04 - MAIN


Within the construction community, efforts to conserve energy and reduce emissions in asphalt paving applications have led to an increase in the usage and popularity of sustainable pavement design practices. Cold mix asphalt (CMA) is one such practice, as it consumes less energy in key components of the mix production process by allowing materials to be produced and mixed at ambient temperatures, thus allowing pavers to reduce total energy usage and emissions. CMA remains a limited niche material in most areas of the United States, despite its apparent energy and emissions benefits, because of lack of knowledge in CMA mix design, comparatively high emulsified asphalt costs, and, most importantly, unknown criteria for volumetric and performance characteristics of the constructed CMA pavement. A review of the current CMA mix design procedures and challenges associated with their usage is presented in this paper, and insight into the initial phases of developing a more comprehensive laboratory mix design method is offered. Aggregate coating and the determination of appropriate compaction conditions for dense graded CMA samples using a modified Superpave Gyratory Compactor (SGC) are the focus for the laboratory testing in this study. Using imaging analysis software, which provides a more objective and reliable method than visual observations, aggregate coating was evaluated. Aggregate coating is dependent on the selected emulsion content, laboratory mixing time and mixing condition, aggregate gradation, and to a lesser extent, pre-mix aggregate moisture, as indicated by the results. A high dependence on compaction pressure and sample curing time is suggested by volumetric analyses of compacted samples.

Rutting characterization of warm mix asphalt and high RAP mixtures

Mon, 05/09/2022 - 18:12
Rutting characterization of warm mix asphalt and high RAP mixtures
by Vargas-Nordcbeck,A; Timm,DH.
2012.
Asphalt Paving Technology 2012: Journal of the Association of Asphalt Paving Technologists - Austin, Texas, April 1-4, 2012.
US6 AFN___ 2012P03 - MAIN


The objectives of this study were to perform a rutting characterization of warm mix asphalt (WMA) mixtures and mixtures containing high reclaimed asphalt pavement (RAP) and to determine the effects of production temperature and material type on permanent deformation. This study was based on data from the National Center for Asphalt Technology (NCAT) Test Track Phase IV research cycle and included a control section, two WMA sections and two sections with 50% RAP. Field measurements indicated that high RAP mixes had higher moduli and experienced lower vertical pressures than virgin mixes. The use of WMA technologies tended to increase permanent deformation while the addition of high RAP contents resulted in less rutting. Laboratory tests on recovered binders showed increased binder stiffness for high RAP mixes and no significant effect for virgin WMA mixes. Mixture tests of laboratory compacted samples did not reflect the observed field performance accurately.

Renewable Fuel Co-Products - Potential Uses in Asphalt

Mon, 05/09/2022 - 18:03
Renewable Fuel Co-Products - Potential Uses in Asphalt
by Trewella,JC; Bonaquist,R; Sanchez,V.
2012.
Asphalt Paving Technology 2012: Journal of the Association of Asphalt Paving Technologists - Austin, Texas, April 1-4, 2012.
US6 AFN___ 2012P02 - MAIN


An area of rapid growth, particularly in the United States and Europe, is the production of renewable liquid transportation fuels. The potential for using co-products from this rapidly growing manufacturing base as blending components in asphalt is examined in this paper. Preparations of several blends of biofuel co-products in a paving grade asphalt binder were made, and measurements of performance grading properties were taken. In accordance with American Association of State Highway and Transportation Officials (AASHTO) T283 to evaluate resistance to moisture damage, asphalt concrete mixtures using the various blends and a somewhat moisture sensitive aggregate were tested. Some of these materials may be useful as binder extenders, having minimal impact on the performance grade while imparting added benefits, as indicated by initial laboratory findings.

Laboratory and Field Evaluation of Sustainable Photocatalytic Asphalt Pavements

Mon, 05/09/2022 - 17:57
Laboratory and Field Evaluation of Sustainable Photocatalytic Asphalt Pavements
by Hassan,M; Mohammad,LN; Dylla,H; Asadi,S; Cooper III,S.
2012.
Asphalt Paving Technology 2012: Journal of the Association of Asphalt Paving Technologists - Austin, Texas, April 1-4, 2012.
US6 AFN___ 2012P01 - MAIN


With the ability to trap and decompose organic and inorganic air pollutants, titanium dioxide (TiO2) is a promising technology to mitigate the harmful effects of vehicle emissions as a pavement coating. By introducing a new class of mixtures with superior environmental performance, this technology may revolutionize construction and production practices of hot-mix asphalt. Assessing the benefits of incorporating TiO2 in asphalt pavements was the objective of this study. The photocatalytic effectiveness and durability of a water-based spray coating of TiO2 was evaluated in the laboratory, in order to achieve this objective. Also presented in this study is the field performance of the country's first air-purifying photocatalytic asphalt pavement, located on the campus of Louisiana State University (LSU). It was shown by laboratory evaluation that TiO2 was effective in removing nitrogen oxide (NOx) and sulfur dioxide (SO2) pollutants from the air stream with an efficiency ranging from 31 to 55% for NOx pollutants and 4 to 20% for SO2 pollutants. Removal efficiency was achieved at a maximum for NOx and SO2 removal at an application rate of 0.05 l/m². The efficiency of NOx reduction is additionally affected by the flow rate of the ultraviolet (UV) light intensity, pollutant, and relative humidity. It is shown by preliminary field measurements that the measured NO concentrations were significantly reduced right after the application of the TiO2 surface coating on the asphalt pavement. However, in order to determine the durability of the surface coating, further field evaluation is required.

Asphalt Paving Technology 2012: Journal of the Association of Asphalt Paving Technologists - Austin, Texas, April 1-4, 2012

Mon, 05/09/2022 - 17:48
Asphalt Paving Technology 2012: Journal of the Association of Asphalt Paving Technologists - Austin, Texas, April 1-4, 2012
2012.
Asphalt Paving Technology 2012: Journal of the Association of Asphalt Paving Technologists - Austin, Texas, April 1-4, 2012.
US6 AFN___ 2012P01-34 - MAIN


This publication comprises papers presented at the annual meeting of the Association of Asphalt Paving Technologists that focus on all phases of asphalt research and applications, including mixing, mixture elements, and testing.Two highlights of this series volume are solutions to production and scale-up problems in asphalt plants, and an entire section is devoted to asphalt research and applications in Latin America. Technical sessions include the following topics: sustainable photocatalytic asphalt pavements; renewable fuel co-products; rutting characteristics of warm mix asphalt (WMA) and high reclaimed asphalt pavement (RAP) mixtures; laboratory and coating compaction procedures for cold mix asphalt; internal structure characterization of asphalt mixtures; viscoelastic properties of asphalt mixtures; interface condition characteristics and open-graded friction course; fracture energy; fatigue damage modeling; cracking resistance; asphalt mixtures with dry added ground tire rubber; loose mix aging and warm mix asphalt; grave bitumen 5 (GB5) mix design; high polymer plant-produced mixtures; bond energy; physico-chemical interaction; aging procedures; and delayed mechanical response in modified asphalt binders. Papers from the Symposium include the following topics: recent advances in production facilities; production and construction of hot mix asphalt (HMA) and WMA; layer thickness and achieving density; best practices for HMA longitudinal joints; and milling and paving operations. Papers from the International Forum include the following topics: asphalt specifications in Latin America; asphalt technology in Chile; asphalt specifications in Colombia; and asphalt research and specifications in Central America-Costa Rica.

L’utilisation de lignes d’alerte audiotactiles, ou bandes d’alerte sonores, afin de prévenir les sorties involontaires de voie

Tue, 03/29/2022 - 19:09
L’utilisation de lignes d’alerte audiotactiles, ou bandes d’alerte sonores, afin de prévenir les sorties involontaires de voie
by Cocu,X; Goubert,L.
Dossier C.R.R. ; 20.
BE6 ACE__6 2019D20 - MAIN


Bien que les lignes d’alerte audiotactiles aient fait leurs preuves en termes de réduction des accidents par sortie de voie, l’utilisation de ce dispositif de sécurité reste limitée, probablement à cause de l’absence de lignes directrices pratiques et de l’idée qu’elles s’accompagnent de problèmes tels que la pollution sonore, la gêne pour les deux-roues et une difficulté d’entretien. Ce dossier a comme objectif de décrire les différents dispositifs qu’il est possible d’installer, leurs caractéristiques géométriques et leur efficacité afin de synthétiser les paramètres pratiques principaux entrant en ligne de compte, et ainsi d’aider le gestionnaire dans sa décision de conception et de placement afin de maîtriser les inconvénients cités ci-avant, aux fins de réduire le nombre d’accidents par sortie de route. Ce document repose principalement sur une analyse approfondie de la littérature américaine (les bandes d’alerte sonores y étant abondamment utilisées) et des résultats du projet français Roadsense (chapitres 2 à 4). Le chapitre 5 propose, sous la forme d’une liste de questions, une aide à la décision pour guider les concepteurs et les gestionnaires dans le choix de recourir à l’usage des lignes d’alerte audiotactiles. Enfin, le chapitre 6 présente les conclusions de toute cette démarche, ainsi que les perspectives en termes d’études complémentaires, veille technologique et développement futur.

Exigences performantielles des matériaux de jointoiement pour revêtements modulaires

Tue, 03/29/2022 - 18:02
Exigences performantielles des matériaux de jointoiement pour revêtements modulaires
by Boonen,E; Lybaert,M; Beeldens,A.
2018.
Compte rendu de recherche C.R.R. ; 45.
BE6 ACE__4 2018R45 - MAIN


Pour les revêtements modulaires, le jointoiement constitue un élément essentiel de la structure de voirie. Pour pouvoir effectivement remplir le rôle de revêtement, les joints doivent toujours être remplis du matériau approprié. Le type de matériau de jointoiement et la durabilité du joint dans son ensemble sont donc aussi de grande importance pour la stabilité du revêtement à long terme. Cette publication CRR fait le compte rendu du projet biennal de recherche prénormative PREVOSTRAT (en entier “Prestatie-eisen voor innovatieve voegvullingsmaterialen in bestratingen met kleinschalige elementen”), réalisé par le CRR avec le soutien du SPF Economie et le Bureau de Normalisation (NBN) et en collaboration avec l’Universiteit Gent (unité d’enseignement Plantaardige Productie). L’étude avait pour but d’établir des méthodes d’essai et les exigences performantielles correspondantes pour des matériaux de jointoiement innovants, liés ou non, appliqués dans les revêtements routiers modulaires (en béton, terre cuite ou pierre naturelle). Parallèlement aux conclusions principales et résultats de l’étude, ce compte rendu de recherche propose également des directives et des recommandations pour des exigences relatives aux matériaux de jointoiement dans les normes européennes et/ou cahiers des charges types belges.

Selection of Appropriate Binder Grade for Changing Climate and Its Influence on Pavement Performance

Mon, 03/21/2022 - 20:38
Selection of Appropriate Binder Grade for Changing Climate and Its Influence on Pavement Performance
by Swarna,ST; Hossain,K; Bernier,A.
2021.
Proceedings of the Sixty-Sixth Annual Conference of the Canadian Technical Asphalt Association (CTAA): Cyberspace.
CA6 AIH___ 2021P20 - MAIN


ln the coming years, it is anticipated that the current Canadian climate will no longer be the norm, and temperatures will steadily increase as a result of anthropogenic climate change. Increased greenhouse gas concentrations in the atmosphere are the root cause of changing climate, which is only expected to worsen over time. Pavement performance models show that changing climate will result in accelerated pavement deterioration. To mitigate pavement deterioration, various adaptation strategies have been suggested in the recent literature. One of these adaptation strategies is upgrading the Superpave™ asphalt binder grade. It is well known that asphalt binder is highly sensitive to climate factors such as temperature and percent sunshine. Hence, reviewing asphalt binder grade is a vital step, and that can help decelerate pavement deterioration. This study aims to understand the impact of climate change on existing flexible pavements and identify the appropriate binder grades necessary to accommodate these effects across Canada. To achieve this goal, the analysis was carried out in six phases. Comparing pavement performance between current binder grades and proposed future binder grades confirms the necessity of considering proposed asphalt binder grades for future climate.

Surface Renewal of an Urban Motorway in the Montreal Area using an Ultra-thin Asphalt Concrete Pavement

Mon, 03/21/2022 - 20:05
Surface Renewal of an Urban Motorway in the Montreal Area using an Ultra-thin Asphalt Concrete Pavement
by Croteau,JM; Richard,P; Veillette,D; Bolduc,K.
2021.
Proceedings of the Sixty-Sixth Annual Conference of the Canadian Technical Asphalt Association (CTAA): Cyberspace.
CA6 AIH___ 2021P19 - MAIN


In 2020, paving work was performed to renew the surface of the Autoroute 25 urban motorway in the Montreal area. The paving solution needed to satisfy an operational requirement as execution of the work needed to be performed at night, and functional requirements as the technique needed to provide performance regarding smoothness, friction, rutting and surface defects. An Ultra-Thin Asphalt Concrete Pavement (UTACP) technique was selected. There is a long history of successful applications of this UT ACP technique in France and in the USA. The uniqueness of the Autoroute 25 work relates to the placement technique, which allowed the usage of conventional equipment, and the tack coat, which was designed to avoid bleeding in the wheel path and snowplows surface scuffing outside the wheel path. This paper provides information on the engineering that lead to the selection of the ultra-thin asphalt concrete pavement. It provides the reasons as to why it was critical to select a paving technique with an aggressive surface texture to satisfy the contract friction requirements. Information is provided as to how the specifications were developed to facilitate the administration and the execution of the work. Finally, performance results regarding friction and smoothness are presented.

Asphalt Mix Design and Acceptance Specifications: Ensuring Adequate Asphalt Binder Content

Mon, 03/21/2022 - 19:32
Asphalt Mix Design and Acceptance Specifications: Ensuring Adequate Asphalt Binder Content
by Huber,GA; Beeson,M; Pine,W; Campbell,C.
2021.
Proceedings of the Sixty-Sixth Annual Conference of the Canadian Technical Asphalt Association (CTAA): Cyberspace.
CA6 AIH___ 2021P18 - MAIN


Since early days of asphalt mix design the objective has been to determine an appropriate amount of asphalt binder for resistance to rutting and cracking. Mixture volumetric properties were developed in the 1920s, but calculations were not developed until the 1960s to quantify asphalt binder on the outside of aggregate particles and establish the minimum effective volume of asphalt binder. Current AASHTO specifications are based on the volume of effective asphalt binder calculated using Voids in the Mineral Aggregate (VMA) plus absorbed asphalt binder. The process is clearly defined in the specifications, but some agencies have chosen other approaches believing them to be more correct, more accurate, or easier to implement. Such alternate approaches can bring unintended consequences that may not be recognized. This paper investigates the use of alternate approaches to control asphalt content and the role of specifications in achieving the desired content. The paper presents a method of accepting mixtures based on the direct use of effective asphalt volume and the measurement of bulk specific gravity of extracted aggregate. The paper presents 14 years of experience with different acceptance specifications and the resultant asphalt contents.

High-Strain Asphalt Interlayer for Reflective Cracking: A 20+ Year Review

Mon, 03/21/2022 - 18:56
High-Strain Asphalt Interlayer for Reflective Cracking: A 20+ Year Review
by Blankenship,P; McKay,ZD; Bausano,J.
2021.
Proceedings of the Sixty-Sixth Annual Conference of the Canadian Technical Asphalt Association (CTAA): Cyberspace.
CA6 AIH___ 2021P17 - MAIN


Since the early l 990's, asphalt interlayers of about 25-mm thick have been used in the United States (U.S.) to greatly delay the onset of reflective cracking over Portland cement concrete and asphalt pavements. Koch Materials Company introduced technology to the U.S., which had been previously used in France. The asphalt interlayer mixture is comprised of fine aggregate with high dust and high asphalt content. This is not just a "recipe" mixture, but a performance-based specification that consists of a high-strain, 4-point flexural beam fatigue test to ensure extreme flexibility and a mixture stability test (Hveem Stability, Asphalt Pavement Analyzer, etc.) for adequate rut resistance. Interlayer test sections were placed strategically thought the U.S. in various climatic zones to further adjust the performance specification and testing temperatures. Today, the asphalt Reflective Crack Relief Interlayer (RCRI) is used in some form in Texas, Kentucky, Kansas, Wisconsin, Iowa, New Jersey, along with other states. With the need to control cracking, RCRI is a valid option for contractors to use local materials to build asphalt interlayers to control/delay cracking. Today, the interlayer can be designed with newer tests like the indirect tensile asphalt cracking test (IDEAL-CT) or flexural beam fatigue coupled with a rutting test such as the Hamburg Wheel Tracker, all with climate-adjusted test temperatures.

High-Float Emulsion Residue: Suitable Methods and Metrics for Testing Viscoplastic Materials

Mon, 03/21/2022 - 18:37
High-Float Emulsion Residue: Suitable Methods and Metrics for Testing Viscoplastic Materials
by Suda,J; Varamini,S; Bickle,E; Kucharek,AS.
2021.
Proceedings of the Sixty-Sixth Annual Conference of the Canadian Technical Asphalt Association (CTAA): Cyberspace.
CA6 AIH___ 2021P16 - MAIN


Despite the advantages of utilizing High-Float (HF) emulsions in asphalt surfacing applications, formulation and development of such emulsions is a challenging task. This is mainly due to current testing practices used by agencies in specifying the so called "consistency or flow behaviour" of HF residue. These testing practices are informally known as the penetration test, the viscosity test, and the float test. These test methods are empirical in nature and have limitations when properly characterizing non-Newtonian materials, such as HF residues. This technical paper is a sequel to a 2016 CTAA paper "High-float Emulsion Residue: Its Unique Rheology and Microstructure," where a detailed review of current HF residue testing used in Canada was reported. The current paper provides further insight on how current empirical methods of testing could be potentially replaced by one-single, more practical test procedure using the Dynamic Shear Rheometer (DSR). In addition to rheological studies, employment of various residue recovery techniques are also included to demonstrate significant effects of distillation techniques on behaviour of an HF residue. Based on the findings, the stress-ramp procedure can be used to set appropriate shear rates for specific HF residues, measure apparent viscosity, and indicate whether the residue is effectively viscoplastic.

Performance de sécurité des infrastructures cyclables au Canada

Mon, 03/21/2022 - 15:18
Performance de sécurité des infrastructures cyclables au Canada
by Montufar,J; Chapman,S; Poapst,R; Bahar,G.
2020.
CA6 ARH_60 2020S12Z - INTERNET


La popularité croissante que connaît le cyclisme comme mode de transport au Canada a entraîné le développement, par de nombreuses juridictions, de nouvelles infrastructures cyclables qui répondent mieux aux besoins de sécurité et de mobilité des cyclistes. Toutefois, il existe une incompréhension globale de la performance de sécurité des différents types d’infrastructures cyclables dans le contexte canadien. La présente étude caractérise la performance de sécurité de diverses infrastructures cyclables dans le but d’aider les spécialistes canadiens à évaluer la performance de sécurité potentielle de nouvelles infrastructures cyclables. Ce rapport, dont le but est de servir de document d’information, repose sur une analyse documentaire exhaustive, une enquête auprès des juridictions, une série d’études de cas locales et internationales et un sondage auprès des utilisateurs finaux. En outre, ce document comporte un organigramme de sélection des installations qui peut aider les spécialistes à mieux choisir des installations cyclables appropriées en mettant en évidence des points dont il faudra tenir compte dans le choix d’installations cyclables et d’aménagements aux carrefours. L’une des principales conclusions de cette étude est qu’il existe de vastes lacunes en matière de données et de connaissances quant à la performance de sécurité des infrastructures cyclables au Canada. Ces lacunes portent sur les collisions et autres données de substitution sur la sécurité, les données portant sur les débits de vélos et de piétons (données sur l’exposition), les débits de circulation par type de véhicule, l’information sur la performance des installations cyclables en hiver et autres sujets. De plus, il existe d’importantes lacunes en matière de connaissances sur les seuils associés à une meilleure performance de sécurité quant à différents facteurs qui influent sur la sécurité des infrastructures cyclables au Canada (par ex., le débit de circulation, le débit de vélos, la proportion de camions et d’autobus et la fréquence des points d’accès). On note également un manque de connaissances à l’étranger.

Impact of Mixer Type and Mixing Time for Hot Mix Asphalt with High Reclaimed Asphalt Pavement Content on Mix Performance

Fri, 03/18/2022 - 19:02
Impact of Mixer Type and Mixing Time for Hot Mix Asphalt with High Reclaimed Asphalt Pavement Content on Mix Performance
by Bérubé,MA; Bilodeau,K; Carter,A.
2021.
Proceedings of the Sixty-Sixth Annual Conference of the Canadian Technical Asphalt Association (CTAA): Cyberspace.
CA6 AIH___ 2021P15 - MAIN


The mixing process in the laboratory is directed by standards. Those standards make recommendations and present some limits. The influence of the laboratory technique to produce asphalt mixes affects the properties and performance of the mixes. Different mixers that produce different mixing energy that are used for different mixing time are considered acceptable, and those variations affect the materials. It could have major impact on aggregates and asphalt mix properties, on the bitumen oxidation, and on the compaction. This paper presents the effect of the mixing process in laboratory for Hot-Mix Asphalt (HMA) with high content of Reclaimed Asphalt Pavement (RAP). Three types of mixers have been used for this research project. For each mixer type, four mixing times were selected based on the mixer properties. The stiffness of bituminous mixture was also evaluated with dynamic tests (waves propagation) and indirect tensile modulus tests (ITSM). According to the results, voids during the SCG compaction have changed with the mixing time for all mixer types and all gyrations. A translation based on the mixing time between the different curves has been observed. For stiffness, results changed through the mixing time and an optimum was obtained for each mixer type.

Effect of Biochar as a Filler in Asphalt Mixtures

Fri, 03/18/2022 - 17:43
Effect of Biochar as a Filler in Asphalt Mixtures
by Owolabi,OO; Sanchez,X.
2021.
Proceedings of the Sixty-Sixth Annual Conference of the Canadian Technical Asphalt Association (CTAA): Cyberspace.
CA6 AIH___ 2021P14 - MAIN


Every year, the government spends a huge sum of money on repairing roads. The damage incurred on the roadways is attributed to several factors, one of which is the asphalt mixture used to pave the roadways. Sometimes, raw asphalt binder does not have adequate properties to make the roadways durable. Therefore, additives or modifiers are sometimes incorporated to improve the asphalt mixtures, which in turn enhances the performance of asphalt pavements. This study aims to examine the effect of incorporating biochar in asphalt mix. While previous studies have been conducted on the effect of biochar on the asphalt binder, not much has been done to study the effect of biochar on the asphalt mix. This study will help bridge the gap of a lack of substantial research on this aspect. From the tests completed, it was deduced that biochar could have the potential to improve the cracking resistance of the mixes; however, the susceptibility to permanent deformation would increase. From the investigation, the use of fast pyrolysis biochar is preferred. Further research is required to study the performance of asphalt mixes using biochar as an asphalt modifier instead of using it as a filler.

Comprehensive Evaluation of Illinois Flexibility Index and Disc-Shaped Compact Tension Tests as Asphalt Mixture Durability Indices and Performance Acceptance Criteria: Ontario Experience

Fri, 03/18/2022 - 17:22
Comprehensive Evaluation of Illinois Flexibility Index and Disc-Shaped Compact Tension Tests as Asphalt Mixture Durability Indices and Performance Acceptance Criteria: Ontario Experience
by Salehi-Ashani,S; Tighe,SL.
2021.
Proceedings of the Sixty-Sixth Annual Conference of the Canadian Technical Asphalt Association (CTAA): Cyberspace.
CA6 AIH___ 2021P13 - MAIN


Illinois Flexibility Index Test (I-FIT) and Disc-Shaped Compact Tension (DC(T)) test have shown promise to characterize the intermediate and low temperature cracking resistance of asphalt mixtures, respectively. In this research five plant-produced mixtures were subjected to two laboratory long-term aging protocols and tested with DC(T) and I-FIT. The statistical analysis of the results showed that both aging methods have comparable Flexibility Index values DC(T) test results showed that asphalt mixtures containing hard PGAC were more sensitive to long-term aging. The I-FIT test was also conducted at three temperatures to investigate the sensitivity of I-FIT parameters to testing temperature variations. The statistical analysis of the results showed that asphalt mixtures containing hard PGAC were more sensitive to the drop of testing temperature. In addition, I-FIT test was conducted at various intermediate temperatures to investigate the effect of intermediate temperatures on I-FIT parameters. Finally, the DC(T) test was conducted at three testing temperatures to investigate the effect of temperature sensitivity on DC(T) results, which showed that a reduction in testing temperature caused the fracture energy values to decrease.

Development and Field Experience with Performance-Based Asphalt Mixture Used in Thin Asphalt Pavement

Wed, 03/16/2022 - 20:41
Development and Field Experience with Performance-Based Asphalt Mixture Used in Thin Asphalt Pavement
by Varamini,S; Esenwa,M; Kennedy,M.
2021.
Proceedings of the Sixty-Sixth Annual Conference of the Canadian Technical Asphalt Association (CTAA): Cyberspace.
CA6 AIH___ 2021P12 - MAIN


This paper presents an asphalt mixture solution that can be placed as a thin layer (less than 40 mm) over granular base to provide a hard-top driving surface. This paper further provides steps in understanding the response of the mix and steps required to translate such responses into developing a performance-based requirement for the asphalt mix. The performance-based design steps are explained in this paper to provide an insight into how low-temperature flexibility and long-term fatigue behaviour of a mix is assessed and related to repetitive stresses expected from low to medium level of traffic coupled with environmental conditions expected in Southern Ontario. Production and paving experience with this asphalt mix solution are also included in this paper, as well as more than two-year field performance of a trial section in Southern Ontario.

Using Bio-Modifiers for Recycling RAP and Improving the Performance of RAP-Incorporated Mixtures Designed for Different Pavement Demonstration Projects

Wed, 03/16/2022 - 18:17
Using Bio-Modifiers for Recycling RAP and Improving the Performance of RAP-Incorporated Mixtures Designed for Different Pavement Demonstration Projects
by Arabzadeh,A; Staver,MD; Podolsky,JH; Williams,RC; Cochran,EW.
2021.
Proceedings of the Sixty-Sixth Annual Conference of the Canadian Technical Asphalt Association (CTAA): Cyberspace.
CA6 AIH___ 2021P11 - MAIN


The bio-modifiers used were Sub-Epoxidized Soybean Oil (SESO), Epoxidized Methyl Soyate (EMS), and Poly(Acrylated Epoxidized High Oleic Soybean Oil), PAEHOSO. The EMS and SESO, being bio-renewable reactive recycling agents, were used for recycling Reclaimed Asphalt Pavement (RAP) and increasing the mixtures' resistance to low-temperature cracking. The PAEHOSO, being a bio-renewable polymer, was used for increasing the mixtures' resistance to rutting. The rheological tests proved that the EMS and SESO can improve the low-temperature properties and the PAEHOSO can improve the high temperature properties of asphalt binders. Disk-shaped Compact Tension (DCT) and Hamburg Wheel Tracking (HWT) were the mechanical performance tests used for evaluating the mixtures' resistance to low-temperature cracking and rutting, respectively. According to the results obtained from the DCT test the SESO and EMS, when used for modifying the asphalt binders and mixtures, can successfully increase the low temperature cracking resistance. Based on the HWT and DCT test results, the PAEHOSO has a significant influence on increasing the resistance to rutting and low temperature cracking that is all due to increasing the elasticity of asphalt mixtures.

Field and Laboratory Methods of Evaluating Rutting and Shoving

Tue, 03/15/2022 - 17:47
Field and Laboratory Methods of Evaluating Rutting and Shoving
by Farashah,MK; Salehi-Ashani,S; Varamini,S; Baghaee Moghaddam,T; Tighe,SL.
2021.
Proceedings of the Sixty-Sixth Annual Conference of the Canadian Technical Asphalt Association (CTAA): Cyberspace.
CA6 AIH___ 2021P10 - MAIN


Due to the continuous increase in truck traffic loading to accommodate population growth needs, and also due to the impact of climate change, York Region is experiencing premature pavement failure in many of its heavy truck traffic intersections mostly in the form of pavement deformation or rutting and in some cases shoving. This suggests that pavement materials historically used in the Region may not satisfy the expected life cycle. Six approach intersections were selected by the Region to investigate the in-service performance and identify any need for material improvement. Field work included rut depth measurement and geotechnical investigation such as extracting core specimens, boreholes, and transverse Ground Penetration Radar (GPR) survey. Laboratory testing to test the resistance to rutting and shoving for the three asphalt mixtures placed at the intersections included 1) the Hamburg Wheel Tracking Device (HWTD) to evaluate the rutting resistance of mixtures as well as moisture susceptibility of compacted specimens while submerged in water, (2 the repeated load permanent deformation test or Flow Number (FN) test for predicting the rutting behaviour of the specimens, (3 a newly developed Uniaxial Shear Tester (UST), and (4) IDEAL Rutting Test to measure the shear properties of the asphalt mixes.

Use of OGFC to Address Drainage Issues for George Massey Tunnel

Tue, 03/15/2022 - 17:19
Use of OGFC to Address Drainage Issues for George Massey Tunnel
by Sharma,V; Babuin,C; Johnston,A; Bahamdun,S.
2021.
Proceedings of the Sixty-Sixth Annual Conference of the Canadian Technical Asphalt Association (CTAA): Cyberspace.
CA6 AIH___ 2021P09 - MAIN


The George Massey Tunnel is a major Fraser River Crossing on Highway 99 in Lower Mainland Vancouver. It is a 4- lane tunnel with an average daily traffic of about 100,000 vehicles. The tunnel was constructed in 1950's and is close to the end of its service life. The Province is considering replacing the existing tunnel with a new tunnel or a bridge in the near future. Therefore, the Ministry was looking at potential solutions to fix the water seepage issues for the 5-10- year term. The tunnel approaches have been exhibiting water seepage issues for the past several years. The river water seeps through the joints of the approach slabs, and the pavement surface stays wet at most times. Water seepage poses potential safety concerns during the winter season. Continuous water seepage results in poor pavement performance. Different options were considered as possible rehabilitation solutions. Considering potential of clogging of the voids in the OGFC surface layer, a solution involving the placement of a drainage layer on top of the approach slab followed by placement of two lifts of conventional HMA were constructed. This allowed for the seeping water to flow through the drainage layer without reaching the pavement surface.

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