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Active Projects II

SPR 769

Safe and Effective Speed Reductions for Freeway Work Zones Phase 2 

 
Project Coordinator:
Jon Lazarus
Research Agency:
Oregon State University
Principal Investigator:
John Gambatese
Start Date for ODOT:
June 1, 2013
Completion Date for ODOT:
February 28, 2015
 
OVERVIEW:
In response to requests from the Associated General Contractors (AGC) Oregon-Columbia
Chapter, ODOT began a research study in FY2013 (SPR-751) to look for ways to safely reduce
speeds through work zones on preservation projects taking place on high-speed freeways.
Freeway preservation projects typically require traffic lane reductions to allow workers to
rehabilitate worn pavements. During lane closures, work activities take place immediately
adjacent to live traffic – traffic that is often travelling at high speeds. ODOT is interested in
strategies to safely reduce these speeds and subsequently improve the overall safety of the work
zone for drivers and for workers.
Phase 1 of this study (SPR 751) included two paving projects, one on I-84 near The Dalles and
one on I-5 just north of the McKenzie River Bridge. On each project, different traffic control
measures (TCMs) were implemented and speed data was collected both prior to and within the
work zone.
 
OBJECTIVE:
The proposed research comprises augmenting the SPR-751 study to address the issues and needs
identified by the TAC. This proposal includes conducting two additional case study projects at a
reduced cost. The additional case studies will be on paving projects similar to SPR-751, and
include a reduced total number of treatments focused on the following specific traffic control
measures: “SPEED 50” signs, PCMS signs on a roller(s) or a stationary trailer(s), and radar
speed reader trailers. As with SPR-751, the overall goal of the proposed research is to assist
ODOT with enhancing the safety of work zones on high-speed roadways.
 
Safe and Effective Speed Reductions for Freeway Work Zones Phase 2 Work Plan

QUARTERLY REPORTS
FY 14
FY 15
 
 
 
 qtr. 3
 
 
 
 
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SPR 770

Impact of Cascadia Earthquake on Seismic Evaluation

 

Project Coordinator:
Steve Soltesz
Research Agency:
Portland State University
Principal Investigator:
Peter Dusicka
Start Date for ODOT:
December 16, 2013
Completion Date for ODOT:
March 31, 2016
 
OVERVIEW:
The seismic risk used for bridge design and retrofit is defined by hazard maps of ground
acceleration values. To generate the maps, an algorithm called a Probabilistic Seismic Hazard
Analysis (PSHA) is used to combine multiple regional sources of ground shaking. Each source
has a different intensity, probability of occurrence, and distance to a specific location. For
Oregon, one key source of ground shaking in the PSHA is from the Cascadia Subduction Zone
(CSZ); however, a CSZ earthquake can have significantly different ground motion as a
standalone event than what is captured in the values derived from the PSHA.
 
OBJECTIVE:
The objective of this project is to provide ODOT with the best rational estimate of ground
acceleration values for designing and retrofitting bridges.
 
Impact of Cascadia Earthquake on Seismic Evaluation Criteria of Bridges Work Plan
 

QUARTERLY REPORTS
 
FY 14
FY 15
 
 
 ​qtr. 3
 ​qtr. 4
 
 
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SPR 771

Risk Factors Associated with High Potential for Serious Crashes

 

Project Coordinator:
Mark Joerger
Research Agency:
Montana State University
Principal Investigator:
Ahmed Al-Kaisy/David Veneziano
Start Date for ODOT:
November 21, 2013
Completion Date for ODOT:
May 26, 2015
 
OVERVIEW:
Crashes are random events and consequently, can occur at any location along the roadway. On
roadways with higher traffic volumes, the more frequent occurrence of crashes allows for the
direct identification of high crash locations using historical data. However, on local roads, crash
occurrence, particularly fatal and serious injury crashes, is less frequent. This makes it difficult
to identify trends and treat hazardous sites based on historical data. Geometric, traffic and other
features may lend themselves toward crashes potentially happening in spot locations. Therefore,
an approach to identifying these types of risk factors on low volume roads is necessary.
 
OBJECTIVE:
The proposed research will identify risk factors and features that contribute to crashes along low
volume roads and the cost effectiveness of countermeasures to address them. Research objectives
include:
Identify risk factors and features that contribute to crash occurrence and which can be corrected
by selected low cost countermeasures, with a specific focus on low and moderate volume roads
with sporadic crash occurrence.
Develop a risk index of different factors and features that practitioners should look for and that
can be addressed using selected low cost countermeasures along low and moderate volume
roads.
Establish the cost effectiveness/thresholds for the low cost countermeasures that are selected for
use in addressing risk factors on low to moderate volume roads.
Conduct limited case studies to demonstrate the use of the identified risk factors and application
of the cost effectiveness thresholds that are developed.
 
Risk Factors Associated with High Potential for Serious Crashes Work Plan

QUARTERLY REPORTS
 
FY 14
FY 15
 
 
 qtr. 3
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SPR 772

Investigation of Bicycle and Pedestrian Count Technologies

Project Coordinator:
Lyn Cornell
Research Agency:
Portland State University
Principal Investigator:
Miguel Figliozzi 
Start Date for ODOT:
October 1, 2014
Completion Date for ODOT:
June 30, 2016 
 

OVERVIEW:

The Oregon Department of Transportation (ODOT) maintains a statewide license to traffic signal controller software (Northwest Signal Voyage) which has a red clearance (all-red) extension feature to dynamically extend the red clearance if a vehicle is detected that has or will likely run the red signal indication. This smart, adaptive red clearance treatment provides additional safety protection when risks of a RLR event is high, but is passive in other cases, thus having almost no impact on intersection capacity & delay. The cost is very low to implement this smart intelligent transportation system (ITS) treatment and over 500 intersections currently have controllers with this software feature available to them (and that number is growing). While widely available in Oregon, little is known about the impacts of this feature on intersection safety or best practice for detector placement and settings to maximize the safety/crash reduction benefits of the red clearance extension feature. Preliminary research suggests that detector placement is critical to achieving optimal benefits. This research would develop quantitative information about the safety effects of red clearance extensions from simulated data and available empirical data. The there is a clear opportunity to leverage the controller and software investments to larger safety gains and provide ODOT the opportunity to provide leadership on an issue of national importance. The value of this research is potentially high. 

OBJECTIVE:

 The overall goal of the proposed research is to quantify the safety performance of alternative red clearance extension detection and controller settings to mitigate RLR crashes at intersections in Oregon. More specifically, the objective is to determine where detection zones should be placed so as to maximize RLR crash avoidance potential (detection further away from the stop bar), while minimizing the likelihood of false red light extensions (extension is triggered for a stopping vehicle), and to establish optimal timing parameters for various objectives. 

Investigation of Bicycle and Pedestrian Count Technologies Work Plan

 

QUARTERLY REPORT

FY 15
FY 16
 
 
 
 
 
 
 

 

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SPR 773

Optimal Timing and Detection Practices for Red Clearance Extensions
 
Project Coordinator:
Mark Joerger
Research Agency:
Oregon State University
Principal Investigator:
David Hurwitz
Start Date for ODOT:
July 1, 2014
Completion Date for ODOT:
March 1, 2016
 
OVERVIEW:
The Oregon Department of Transportation (ODOT) maintains a statewide license to traffic signal controller software (Northwest Signal Voyage) which has a red clearance (all-red) extension feature to dynamically extend the red clearance if a vehicle is detected that has or will likely run the red signal indication. This smart, adaptive red clearance treatment provides additional safety protection when risks of a RLR event is high, but is passive in other cases, thus having almost no impact on intersection capacity & delay. The cost is very low to implement this smart intelligent transportation system (ITS) treatment and over 500 intersections currently have controllers with this software feature available to them (and that number is growing). While widely available in Oregon, little is known about the impacts of this feature on intersection safety or best practice for detector placement and settings to maximize the safety/crash reduction benefits of the red clearance extension feature. Preliminary research suggests that detector placement is critical to achieving optimal benefits. This research would develop quantitative information about the safety effects of red clearance extensions from simulated data and available empirical data. The there is a clear opportunity to leverage the controller and software investments to larger safety gains and provide ODOT the opportunity to provide leadership on an issue of national importance. The value of this research is potentially high.
 
OBJECTIVE:
The overall goal of the proposed research is to quantify the safety performance of alternative red clearance extension detection and controller settings to mitigate RLR crashes at intersections in Oregon. More specifically, the objective is to determine where detection zones should be placed so as to maximize RLR crash avoidance potential (detection further away from the stop bar), while minimizing the likelihood of false red light extensions (extension is triggered for a stopping vehicle), and to establish optimal timing parameters for various objectives.  
 
 
QUARTERLY REPORT
FY 15
FY 16
 
 
 
 
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SPR 774

Road User Charge Economic Analysis
Project Coordinator:
Tony Knudson
Research Agency:
Oregon State University
Principal Investigator:
B. Starr McMullen/Haizhong Wang
Start Date for ODOT:
July 29, 2014
Completion Date for ODOT:
December 31, 2016
 
Overview:
 
Decreasing fuels tax revenues combined with increasing infrastructure costs has led to the exploration of alternative strategies for financing the transportation system. As Oregon continues to lead the nation in exploring a VMT based Road User Change (RUC), it is important that ODOT do its best to understand and address questions that arise as a variety of fee structures and implementation strategies are suggested. While such an approach has the potential to provide a more stable revenue source, while possibly addressing other goals (such as the state’s 2050 vision for greenhouse gas (GHG) emission reduction targets), it is important to know how various rate structures and implementation strategies may impact different socio-economic groups and regions of the state. This study would help ODOT address concerns raised by stakeholders, and also help inform any future decisions made by the Oregon Legislature regarding a road user charge structure and implementation plan.
 
Objective:
 
The research will produce a technical analysis, as well as an associated report that outlines the results of the analysis. This project will be utilized by the Office of Innovative Partnerships, which spearheads the road user charge, ODOT’s Transportation Planning Unit which developed the Statewide Transportation Strategy that is part of an integrated statewide effort to reduce greenhouse gas emissions from Oregon’s transportation sector.
 
 
 
Quarterly Reports:
 
 FY 15
 
 
 
 
 
 
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SPR 775

Titanium for Strengthening Existing Reinforced Concrete Bridges
 Project Coordinator:
 Tengfei Fu
 Research Agency:
 Oregon State University
 Principal Investigator:
 Chris Higgins
 Start Date at ODOT:
 July 1, 2014
 Completion Date for ODOT:
 September 30, 2016
 
 
Overview:
Oregon has many reinforced concrete bridges that were built in the 1950’s. The bridges from this era commonly have poor reinforcing details such as longitudinal reinforcing bars terminating in areas under stress, inadequate bar splices, and insufficient vertical reinforcement. Consequently, these older ODOT bridges often are evaluated as deficient and require remediation.  It is anticipated that on-going load rating and evolving loading requirements will uncover many deficient bridges for years to come.
Current practice and previous ODOT research provide design options for strengthening.  A common option is to bond carbon fiber reinforced polymer (CFRP) strips either on the surface or just below the surface.  The method relies solely on the adhesive bond to transfer stresses to the CFRP; consequently, the full strength of the CFRP is never utilized because the concrete near the bond fails first.  To compensate for the relatively weak bond, more strips are installed to distribute stresses across more bond surfaces.  If space is not available for more strips, a more elaborate strengthening scheme may be deployed.
In a current ODOT-funded research project, a titanium alloy bar has been developed that is lightweight and has high-strength and high ductility and is impervious to environmental degradation.  The bar can be produced over a wide range of sizes.  Unlike CFRP, a key feature of this material is that it can be bent.  Consequently, the ends of the titanium bar can be bent to ninety degrees and embedded deep into a beam that needs strengthening.  This mechanical anchorage overcomes the problem of the weak bond and allows the titanium reinforcing material to utilize its high strength. These characteristics make it both a structurally and economically effective choice over CFRP and other alternatives.
Based on the current research, a titanium retrofit was deployed on a bridge over I-84.  In the strengthening design, the number of supplemental reinforcement elements per girder line was reduced from twelve for CFRP to four for titanium.  The retrofit was approximately 30% less costly and is expected to have better structural performance than CFRP.
The characteristics of titanium reinforcement, particularly its ability to be bent, open up possible cost savings for a wide range of strengthening situations.  Three areas listed in the Research Objectives have been identified for further research to exploit the advantages of titanium reinforcement for strengthening.
 
Objective:
The research has three objectives to expand the use of titanium reinforcement:
• Develop a splicing method that allows supplemental reinforcing bars to be deployed along the full length of girders including through the intermediate diaphragms that protrude from most beams.
• Develop an unbonded strengthening detail that eliminates the need to cut grooves into the concrete surface, thereby reducing labor costs, epoxy material costs, and construction time.
• Develop methods to apply exterior titanium bars to strengthen girders with inadequate transverse reinforcement.
 
 
 
Quarterly Reports:
 
 FY 15
 
 
 
 
 
 
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SPR 776

 Quantifying Noise Impacts from ODOT Aggregate Source Operations
 Project Coordinator:
 
 Research Agency:
 
 Principal Investigator:
 
 Start Date at ODOT:
 
 Completion Date for ODOT:
 
 
Overview:
 
 
Objective:
 
 
Quantifying Noise Impacts from ODOT Aggregate Source OPerations Work Plan
 
Quarterly Reports:
 
 
 
 
 
 
 
 
 
 
 
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SPR 777

Chip Seal Design and Specifications
 Project Coordinator:
 Jon Lazarus
 Research Agency:
 Iowa State University
 Principal Investigator:
 Douglas Gransberg/Chris Williams
 Start Date at ODOT:
 July 18, 2014
 Completion Date for ODOT:
 July 31, 2016
 
 
Overview:
 
The RFP defines the problem as a need to “revisit” ODOT’s chip seal design methodology and specifications using common chip seal design methodologies found elsewhere in the US and internationally as a benchmark to identify potential approaches to improve the ODOT chip seal program. The crux of the issue revolves around the upcoming loss of experienced maintenance personnel and the fact that the current ODOT “The technique used to apply chip seals is currently referred to as more of an ‘art’ than ‘science’ and is based on “an experienced person conducting a visual inspection during the application and making adjustments in binder and/or aggregate (chip) rate.” Therefore, ODOT requires a rational chip seal design methodology based on quantitative measurements that can be successfully replicated by contractors in the field and which does not demand the current amount of professional judgment to be successful.
Objective:
 
Per the RFP, “the objective of this research is to document methods and report the performance of chip seals designed using different methodologies. Once quantified, the research will identify best practices that can be implemented.”
 
Quarterly Reports:
 FY 15
 
 
 
 
 
 
 
 
 
 
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SPR 778

 Safety Effectiveness of Pedestrian Crossing Enhancements
 Project Coordinator:
Lyn Cornell
 Research Agency:
Portland State University
 Principal Investigator:
 Chris Monsere/Miguel Figliozzi
 Start Date at ODOT:
 September 18, 2014
 Completion Date for ODOT:
 September 30, 2016
 
 
Overview:
ODOT’s Tech Services Branch is implementing a pedestrian safety countermeasure program which will direct HSIP funding toward pedestrian safety counter measures (approximately $4 million has been set aside for both pedestrian and bicycle safety improvements). Data-driven safety decision-making–including implementation of the Highway Safety Manual–requires the development of crash modification factors (CMFs) for various roadway improvements. Over the last decade, the Oregon DOT has systematically implemented many pedestrian crossing enhancements (PCEs) across the state. The most commonly deployed treatments include continental crosswalk markings, pedestrian median islands, curb bulb outs, pedestrian activated flashing beacons and advanced stop bars. The existing literature on driver yielding clearly indicates that medians are a significant pedestrian safety feature and pedestrian-hybrid beacons improve driver stopping compliance (both of these are included in the FHWA countermeasures clearinghouse and have CMFs). Rectangular Rapid Flash Beacons (RRFB) also improve driver stopping compliance but the safety effects (CMFs) have not yet been quantified.
 
Still, many questions remain regarding the quantification of the positive impact of PCEs on overall crashes (i.e. medians may also reduce vehicle crashes) and the transferability of national results. As driver behavior and culture vary, estimates of safety effects (CMFs) are more accurate and relevant when developed from or calibrated by a robust, local data set. In Oregon, installations of crosswalks on state highways at mid-block or uncontrolled intersections require the approval of the State Traffic-Roadway Engineer (STRE). Because of this approval procedure, there is already a comprehensive list of pedestrian crossing enhancements for the state highway system.  A careful integration of the well-documented installations of PCEs across the state with relevant traffic, roadway features, and land use data provides a unique opportunity to conduct  research to estimate safety effectiveness of PCE designs in Oregon for improved data-driven decisions.
  
Objectives:
The objective of this research is to estimate the effectiveness of PCEs on multimodal safety in Oregon design contexts to derive CMFs calibrated to Oregon (i.e. not only pedestrian crashes but also motorized vehicles and bicycle crashes in the vicinity). This research will carefully consider the type of enhancement, the geometry, the surrounding land uses, and pedestrian/vehicle exposures. The results of this research will provide decision-makers with a valuable tool to guide future PCE deployments. The results of this research can also set the foundation for future cost/benefit analysis of PCEs.
 
 
 
Quarterly Reports:
 
 FY 15
 
 
 
 
 
 
 
 
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SPR 779

 Risk Factors for Pedestrian and Bicycle Crashes
 Project Coordinator:
 Mark Joerger
 Research Agency:
 Portland State University/Oregon State University
 Principal Investigator:
 Chris Monsere/Haizhong Wang
 Start Date at ODOT:
 November 10, 2014
 Completion Date for ODOT:
 August 31, 2016
 
Overview:
In Oregon, pedestrian and bicyclist fatalities comprise more than 15% of all traffic deaths and are of primary concern for many communities in Oregon (there were 56 bicycle and 247 pedestrian fatalities in the last five years). Oregon has identified pedestrian and bicycle crashes as a primary focus area for investing infrastructure funding and has marked approximately $4 million in the All Roads Safety Program to help address this key need. However, developing a plan for targeted investments is challenging because pedestrian and bicycle crashes are uncommon enough to make it difficult to predict where they will occur next. This random nature also makes it difficult to identify high crash locations and corridors.  As preliminary work towards this problem, ODOT TRS hired a consultant in Spring 2013 to prepare a plan to reduce bicycle and pedestrian crashes by focusing limited resources on locations that have the greatest potential for crash reductions.  The objectives of the plan were to match key effective safety systemic infrastructure countermeasures with potential locations for improvements by identifying a few key patterns of behavior and roadway conditions that cause the high risk locations. The results of the plan were presented and discussed with stakeholders from around Oregon.  The identification of risk factors and the magnitude of their influence on the likelihood of future crashes were significantly constrained by limited roadway information used in the analysis such as bicyclist and pedestrian volumes, the presence of a crossing treatment, presence of a turn lane, driveway activity, and sight distances.  To improve ODOT’s ability to target limited resources more certainty is needed about the most important risk factors.
 
Objectives:
The objective of this work is to develop a tool for ODOT to improve methods to identify and prioritize locations with increased risk, rather than a simple crash history, so they can be proactively treated. Using the consultant’s work as a starting point, this research would continue to investigate the factors related to the common causes of pedestrian and bicycle crashes.  This research will seek to identify key risk factors that contribute to higher than average numbers of serious or fatal pedestrian and bicycle crashes to generate best practices in pedestrian and bicycle problem identification and prioritization, and identify data elements that support decision making and prioritization.
 
 
 
Quarterly Reports:
 
 FY 15
 
 
 
 
 
 
 
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SPR 780

Strategies to Increase the Service Life of Existing Bridge Decks
 Project Coordinator:
 Norris Shippen
 Research Agency:
 Oregon State University
 Principal Investigator:
 Burkan Isgar
 Start Date at ODOT:
 July 1, 2014
 Completion Date for ODOT:
 September 30, 2016
 
 
 
Overview:
The ultimate goal of the research is to provide ODOT with a protocol to assess bridge decks during its ongoing bridge deck treatment operations using practical and fast SR measurements and additional quantitative tools that are easy-to-use, intuitive and user-friendly. Using these tools ODOT inspection engineers will be able to (1) decide if chloride profiling is necessary, and if so, on which locations on the deck these measurements should be performed, (2) predict chloride profiles using SR measurements, environmental data, moisture content predictions, and salt exposure history, and (3) make time-to-damage predictions. To achieve this core objective a two-part research plan is developed. The plan involves concurrent experimental and modeling studies.
 
The core objective of experimental program is to correlate SR data from bridge decks with critical performance indicators such as chloride profiles, transport properties of concrete, as well as time-to-corrosion and time-to-damage predictions. The experimental study will focus on the impact of concrete type, reinforcement detailing, salt exposure, temperature and moisture variations, and freeze-thaw cycles on SR measurements over a period of ~18 months. A number of factors that are known to affect SR measurements, such as cracking and corrosion, are not part of the experimental program because these are currently studied under another project led by one of the PIs of the current work. The results of that ongoing study on the effect of cracking and corrosion on SR will be used in the current project.
 
The parallel modeling study will address the following challenges: (1) correction of SR measurements for environmental conditions and slab properties; (2) predicting chloride profiles in concrete using SR measurements, slab data, environmental data, and salt exposure history, and; (3) making corrosion risk and time-to damage predictions to guide the selection of bridge decks for pre-emptive corrosion mitigation procedures.
 
 
Objective:
 
The objective of the research is to provide ODOT with a protocol to select bridges for its ongoing bridge deck treatment operations using quantitative tools that are practical and quick. These quantitative tools will be in the form of concrete SR measurements, time-to damage predictions, and when necessary, strategically-selected chloride depth profiles. Specific objectives include the addressing of the five gaps and challenges that are identified in Section 2.1.
 
 
Quarterly Reports:
 FY 15
 
 
 
 
 
 
 
 
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SPR 781

Improving Adaptive/Responsive Signal Control Performance: Implications of Non-Invasive Detection and Legacy Timing Practices
 
 Project Coordinator:
 Jon Lazarus
 Research Agency:
 Northern Arizona University
 Principal Investigator:
 Edward Smaglik
 Start Date at ODOT:
 September 10, 2014
 Completion Date for ODOT:
 June 10, 2016
 
 
Overview:
ODOT is turning towards adaptive/responsive signal control strategies to improve the operational performance of coordinated corridors and networks. However, these newer control strategies require more information from the detection systems than more traditional control strategies. This requirement for higher resolution detection data could be addressed through the selection of in pavement detection; however, due to the capital costs associated with in-pavement detection systems ODOT is increasingly selecting non-invasive or passive detection systems such as video cameras, micro-wave, radar, or micro detection pucks, which are also easier to install and maintain. 
 
These non-invasive systems are currently performing below those standards established by the use of in-pavement detection. As such, ODOT is currently operating adaptive and responsive signal control by applying legacy timing and installation practices, and in doing so is not maximizing the benefits of its investment in advanced control strategies. The use of passive detection can degrade optimal intersection performance up to 20%, resulting in longer delays to the public, inefficient use of cycle time, increased traffic queuing, increased fuel consumption, increases risk of traffic crashes due to congestion and results in sub-optimal signal operations. 
 
Current ODOT standards of practice for purchase, installation, layout and timing of non-invasive systems requires updating.  More realistic costs, installation practices, detection zone layouts and timing parameters are needed in order to capture the full measure of the more powerful data driven traffic signal controller systems currently being deployed throughout the State of Oregon.
 
 
Objective:
 
This research will develop a realistic installation guideline that supports the requirements of advance traffic signal controller operations, hybrid detection installations, and non-invasive detection optimization.  This guideline shall provide prototypical detection configurations and new timing standards with the goal of reducing or eliminating performance degradation. These guidelines will include a cost analysis that appropriately considers equipment and installation costs as well as the cost of increase delay to the motoring public due to the degradation of signal performance. The costs of this delay can be as much as ($18 per delay hour per/day per passenger vehicle) and as much as ($70 per delay hour per/day per interstate transit vehicle).
 
 
 
Quarterly Report:
 
 
 FY 15
 
 
 
 
 
 
 
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SPR 782

HMAC Layer Adhesion Through Tack Coat

 Project Coordinator:
 Norris Shippen
 Research Agency:
 Oregon State University
 Principal Investigator:
 Erdem Coleri
 Start Date at ODOT:
 December 9, 2014
 Completion Date for ODOT:
 August 31, 2016

 

Overview:

Tack coats are the asphaltic emulsions applied between pavement lifts to provide adequate bond between the two surfaces. The adhesive bond between the two layers helps the pavement system to behave as a monolithic structure and improves the structural integrity. The absence, inadequacy or failure of this bond result in a significant reduction in the shear strength resistance of the pavement structure and makes the system more vulnerable to many distress types, such as cracking, rutting, and potholes (Tashman et al. 2006).  

 

Tracking, the pick-up of bituminous material by construction vehicle tires, reduces the amount of tack coat in certain areas and creates a non-uniform tack coat distribution between the two construction lifts. This non-uniform tack coat distribution creates localized failures around the low tack coat locations and reduces the overall structural integrity of the pavement structure. In addition, tack coat type, residual application rate, temperature, and existing surface condition (cracked, milled, new, old, or grooved) are the other factors that affect the tack coat performance. By considering all these factors, a quality-control and quality-assurance process need to be developed to maximize tack coat performance during the design life. Although Louisiana Tack Coat Quality Tester (LTCQT) (Mohammed et al. 2006) can be used to predict in-situ tack coat performance, high cost of LTCQT ($40,000) may restrict its widespread use in overlay construction projects in Oregon.

 

Objective:

The major objective of this study is to develop a low cost test method to predict the after-construction bond performance from the tests conducted on the tack coat. In addition, the factors that influence the bond strength, such as existing surface condition, residual application rates, tack coat type, moisture, and temperature, will also be investigated to recommend revisions to current methods and practices. Using lab measurements, regression equations will be developed for different tack coat types to predict tack coat set times that can be used during construction to minimize tracking.  

 

HMAC Layer Adhesion Through Tack Coat Work Plan

 

Quarterly Reports

 FY 15
 
 
 
 
 
 
 

 

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