Accueil

TAC Library French

S'abonner à flux TAC Library French
New TAC Library Materials.
Mis à jour : il y a 53 min 27 sec

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.

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.

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.

12-Year Performance Review of Bloomington Road (York Region Road 40) Rehabilitation Rehabilitation using Cold In-Place Recycling and a 6.7 mm Fine Stone Mastic Asphalt

mer, 04/04/2018 - 20:46
12-Year Performance Review of Bloomington Road (York Region Road 40) Rehabilitation Rehabilitation using Cold In-Place Recycling and a 6.7 mm Fine Stone Mastic Asphalt
by Moore,T; Farashah,MK; Esenwa,M; Varamini,S; Kucharek,AS.
2017.
Proceedings of the Sixth-Second Annual Conference of the Canadian Technical Asphalt Association (CTAA): Halifax, Nova Scotia.
CA6 AIH___ 2017P13 - MAIN


Bloomington Road, Regional Highway 40 in the Regional Municipality of York, serves as a major artery for vehicles accessing Highway 404. The section under review between Kennedy Road and Highway 48 was built in 1969 and rehabilitated with an innovative pavement design in 2005. Prior to rehabilitation, the asphalt surface was severely oxidized with extensive thermal cracking, however, the longitudinal and transverse profiles of the roadway were in relatively good condition and there was no sign of major structural failures. Rehabilitation of the roadway consisted of Cold In-Place Recycling (CIR), a Heavy-Duty Asphalt Binder Course (HDBC) Hot Mix Asphalt (HMA), and a 6.7 mm rut-resistant fine-graded Stone Mastic Asphalt (SMA). This paper provides a review of the design and construction details for the pavement lifts, as well as material and process selection details. Special consideration is given to the curing of the CIR and the rut resistance of the SMA lift. This paper also presents a long-term field performance evaluation of the rehabilitated pavement section with quantified in-situ performance by means of field observations, laboratory evaluations of retrieved pavement specimens, and semi-automated pavement performance data survey collected by York Region over twelve years of in-service pavement life.

Using Complex Modulus (E*) Test to Evaluate Moisture Damage of Hot Mix with Glass Aggregates

mer, 04/04/2018 - 19:38
Using Complex Modulus (E*) Test to Evaluate Moisture Damage of Hot Mix with Glass Aggregates
by Lachance-Tremblay,E; Vaillancourt,M; Perraton,D; Di Benedetto,H.
2017.
Proceedings of the Sixth-Second Annual Conference of the Canadian Technical Asphalt Association (CTAA): Halifax, Nova Scotia.
CA6 AIH___ 2017P12 - MAIN


Evaluation of the moisture damage of HMA is normally conducted on loose aggregate coated with binder or on HMA compacted samples; both methods having their respective disadvantages. Those tests are empirical and are susceptible to give misinterpretation of moisture damage. The complex modulus test for asphalt mixtures, also known as the dynamic modulus, characterizes the mixtures Linear Visco-Elastic (LVE) properties. This paper presents a method used at LCMB to evaluate the moisture damage of HMA samples based on LVE measurements. Two reference mixtures and three mixtures with glass aggregates were tested. One set of samples contained hydrated lime as an anti-stripping additive. First, the LVE properties of the samples were evaluated in a dry condition. Then, the samples were saturated with water and cured into a water bath at 60 deg C for 14 days and evaluated again. Overall, complex modulus test is very effective at evaluating the moisture damage of asphalt samples. This method has multiple advantages and many analysis options, which make it very interesting to evaluate moisture damage. Moreover, it was found that hydrated lime is a very effective anti-stripping additive. For some of the mixtures with anti-stripping agent, water soaking had little effect on the LVE properties.

Comparison of New Test Methods and New Specifications for Rutting Resistance and Elasticity of Modified Binders

ven, 03/30/2018 - 09:35
Comparison of New Test Methods and New Specifications for Rutting Resistance and Elasticity of Modified Binders
by Moraes,R; Swiertz,D; Bahia,H.
2017.
Proceedings of the Sixth-Second Annual Conference of the Canadian Technical Asphalt Association (CTAA): Halifax, Nova Scotia.
CA6 AIH___ 2017P11 - MAIN


There is no consensus among state highway agencies as to the appropriate binder specifications required for adequate quality control and acceptance of modified binders. Supplemental tests have been adopted in addition to standard Performance Grade (PG) tests and are often referred to as “PG+” procedures. The Multiple Stress Creep and Recovery (AASHTO M332) test has been proposed to replace the AASHTO M320 for PG grading of binders. However, some agencies are concerned that asphalt binder formulation will change after adopting the new system, while others are unsure how to relate the current M320 grades to the new S, H, and V grades. In this study, testing of a large number of binders was completed and correlations between results of “PG+” test and MSCR tests were performed. Regarding the MSCR test, results show that the %R parameter is a good candidate to detect the presence, and potentially the quantity, of elastomeric modification. However, using universal limits for the MSCR %R parameter that are dependent on Jnr values in not practical nor useful since current binder formulations are controlled differently by agencies. Furthermore, no logical equivalency of M320 PG grades to M332 traffic grades was identified, so changes to binder formulations are anticipated.

Investigation of the Tensile Strength of Hot Mix Asphalt Incorporating Pulp Aramid Fiber

ven, 03/30/2018 - 09:35
Investigation of the Tensile Strength of Hot Mix Asphalt Incorporating Pulp Aramid Fiber
by Saliani,SS; Carter,A; Baaj,H; Badeli,S.
2017.
Proceedings of the Sixth-Second Annual Conference of the Canadian Technical Asphalt Association (CTAA): Halifax, Nova Scotia.
CA6 AIH___ 2017P10 - MAIN


Premature cracking of flexible pavements is a very common problem in Canada. Nowadays, it is common to use several types of additives and modifiers to asphalt binders and asphalt mixes to improve their performance and increase the service life of flexible pavements. In order to mitigate pavement cracking, the asphalt mixes used in the pavement structure need to have a high resistance to fatigue or thermal cracking according to their position in the pavement structure. Several studies reporting on the use of fibers in asphalt concrete have been found in the literature. The objective of this project is to study the impact of the addition of Pulp Aramid Fiber (PAF) to Hot Mix Asphalt (HMA) in terms of mix design and indirect tensile strength. The optimum asphalt content of the fiber mixes is first determined and then the impact of fiber on their volumetric properties is investigated. Finally, the behavior of PAF in HMA is characterized by indirect tensile testing at different conditions. PAF mixes showed better ductility, even at lower temperatures, than the control mix. Therefore, PAF would lead to an improvement of the resistance to low temperature cracking and would delay crack propagation in the mix.

A Review of Distress and Roughness Performance Models in Nova Scotia's Pavement Management System

ven, 03/30/2018 - 09:35
A Review of Distress and Roughness Performance Models in Nova Scotia's Pavement Management System
by Hegazi,M; Marlin,A; Whieley-Lagace,L.
2017.
Proceedings of the Sixth-Second Annual Conference of the Canadian Technical Asphalt Association (CTAA): Halifax, Nova Scotia.
CA6 AIH___ 2017P09 - MAIN


Nova Scotia Transportation and Infrastructure Renewal (NSTIR) implemented its pavement management system (Highway Pavement Management Application or HPMA) in 2008. NSTIR conducts annual pavement condition surveys on their highway network. Data collected includes International Roughness Index (IRI), which is used to calculate a Roughness Index (RI). Surface distress data is also collected to calculate a Distress Index (DI). The RI and DI are combined into an overall Pavement Quality Index (PQI). In 2016, NSTIR initiated a project to review their pavement prediction models. Differences in historical data trends were noted during the initial model review. These differences were thought to be a result of technological advancements in data collection equipment. The study examined the existing roughness and distress indices to determine if and/or how changes in data collection technology have impacted the measured pavement condition. The investigation included a review of the historical roughness and distress data. Based on this data review, changes were made to the roughness and distress models to better reflect current NSTIR data and conditions. A feedback analysis was then conducted on the prediction models to conduct performance modeling on the HPMA. This paper details the data investigation and updated models.

Detailed Evaluation of Select CIR Projects in Alberta

ven, 03/30/2018 - 09:35
Detailed Evaluation of Select CIR Projects in Alberta
by Sharma,V; Johnston,A; McMillan,C; Khan,A; Grell,D.
2017.
Proceedings of the Sixth-Second Annual Conference of the Canadian Technical Asphalt Association (CTAA): Halifax, Nova Scotia.
CA6 AIH___ 2017P08 - MAIN


Alberta Transportation has completed rehabilitation of a number of highway sections using Cold In-place Recycling (CIR) and Full Depth Reclamation (FDR) over the years. In order to better understand the mechanism responsible for the formation of transverse cracks (specifically to see if transverse cracks are reflecting from the underlying pavement) and the susceptibility of the recycled material to moisture induced damage, Alberta Transportation retained Tetra Tech to undertake pavement inspections and analysis of selected projects rehabilitated using CIR and FDR. A total of five highway segments rehabilitated with CIR and one highway segment rehabilitated with FDR were included in the study. The study included a review of background information, visual crack mapping, pavement inspection using Ground Penetrating Radar, asphalt pavement coring, determination of moisture content in the CIR portion of the cores, and visual assessment of the cores to identify the progression and type of cracks. The key objectives were to investigate the performance of the pavements rehabilitated with CIR in terms of transverse crack formation and moisture susceptibility. This paper discusses the completed evaluation and findings from the study and further expands on Alberta Transportation’s experience with CIR, as presented at the 2016 CTAA Conference.

RAP Paving - British Columbia Perspective

ven, 03/30/2018 - 09:35
RAP Paving - British Columbia Perspective
by Sharma,V; Johnston,L; Hogg,B; Schmidt,A; Van Reekum,A.
2017.
Proceedings of the Sixth-Second Annual Conference of the Canadian Technical Asphalt Association (CTAA): Halifax, Nova Scotia.
CA6 AIH___ 2017P07 - MAIN


The British Columbia Ministry of Transportation and Infrastructure (MoTI) has been using 100 percent Reclaimed Asphalt Pavement (RAP) to pave numerous side roads in its network for more than 15 years with mixed results. The RAP is typically transported off site and recycled by adding a rejuvenator and processing the material through a pugmill. The cold recycled mix is then transported to site and placed using conventional paving equipment as a wearing surface – a surfacing layer of Hot Mix Asphalt (HMA) is not placed. Although the BC MoTI has been using this procedure for over a decade, no study to evaluate the addition rate of the rejuvenator, mix design, recycling process, or testing to determine the quality of the recycled mix was ever completed. The crushed granular equivalency or structural layer coefficient of the recycled mix was also never developed. This paper will document the findings of a laboratory program undertaken to evaluate the optimum addition rate of the rejuvenator, curing period prior to the placement of the recycled mix, and compaction criteria, as well as the structural layer coefficient and crushed granular equivalency of the recycled RAP. A case history of several previously completed projects using cold recycled RAP pavement are also presented.

Creating Economical and Well-Performing Binders via Modification by Epoxidized Plant-derived Oil Materials

ven, 03/30/2018 - 09:35
Creating Economical and Well-Performing Binders via Modification by Epoxidized Plant-derived Oil Materials
by Podolsky,JH; Hernandez,N; Williams,RC; Cochran,EW.
2017.
Proceedings of the Sixth-Second Annual Conference of the Canadian Technical Asphalt Association (CTAA): Halifax, Nova Scotia.
CA6 AIH___ 2017P06 - MAIN


Asphalt binders produced at refineries are becoming stiffer due to an ever-increasing demand for more expensive lighter and heavier fraction products such as gasoline, jet fuel, and lube oils. To increase output of lighter fractions and heavy gas oils, refineries have gone through upgrades producing higher amounts of stiffer asphalt binders such as Vacuum Distillation (VD) tower, Solvent De-Asphalting (SDA), and Residuum Oil Super critical Extraction (ROSE) unit bottoms. Materials used to soften/repair stiff asphalt binders are known as fluxes. Through recent work at Iowa State University, great potential was seen for epoxidized plant oil materials as fluxes/rejuvenators. Within this work two epoxidized plant oil products derived from soybeans, EBS and EMS were manufactured and used for modifying three stiff asphalt binders produced from VD tower, SDA and ROSE units. A full Superpave binder investigation found that improvement in low temperature performance was greater than improvement in high temperature performance for the SD and ROSE unit bottoms when using either EBS or EMS. It was also found that substantial decreases in costs, fuel usage, and emissions could be gained through the use of EBS and EMS in the production of asphalt mix.

Mixture Design and Field Experience: Coloured Hot Mix Asphalt on Bus Rapid Transit (BRT) Lanes in Ontario

ven, 03/30/2018 - 09:35
Mixture Design and Field Experience: Coloured Hot Mix Asphalt on Bus Rapid Transit (BRT) Lanes in Ontario
by Varamini,S; Esenwa,M; Tighe,SL; Farashah.MK; Moore,T.
2017.
Proceedings of the Sixth-Second Annual Conference of the Canadian Technical Asphalt Association (CTAA): Halifax, Nova Scotia.
CA6 AIH___ 2017P05 - MAIN


The Regional Municipality of York, in collaboration with Metrolinx (an agency of the Government of Ontario), has implemented Bus Rapid Transit (BRT) lanes along the three most heavily travelled roads in York Region. To enhance visibility and assist motorists when navigating this new transit system, a special red-coloured asphalt mixture was employed as a surface layer. The colour was achieved by using a selected aggregate bland, colouring pigment, and specially formulated asphalt mixture. This paper provides information on steps employed in the design of coloured asphalt mixture such as: 1) selection of performance graded asphalt cement suitable for the Region’s climatic conditions and traffic loadings, 2) designing an aggregate blend to match the desired colour, ) performing a volumetric analysis for the special Hot Mix Asphalt to meet physical requirements of Superpave 12.5 FC2, and 4) performance testing to capture the impact of pigment on the mixture’s strength and durability at different in-service temperatures. Performance testing was performed at the Centre for Pavement and Transportation Technology located at the University of Waterloo. Production and paving experience with the coloured asphalt mix are also included in this paper, as well as field performance in terms of manual and automated distress survey.

Pages