Long-Term Plan for Concrete Pavement Research and Technology— The Concrete Pavement Road Map (Second Generation): Volume II, Tracks

TRACK 6. INNOVATIVE CONCRETE PAVEMENT JOINT DESIGN, MATERIALS, AND CONSTRUCTION

TRACK 6 OVERVIEW

Concrete has a propensity to crack. Because controlling cracks is essential for pavement performance, joints are an important feature of concrete paving. As the FHWA Technical Advisory Concrete Pavement Joints explains, “The performance of concrete pavements depends to a large extent upon the satisfactory performance of the joints. Most JCP failures can be attributed to failures at the joint, as opposed to inadequate structural capacity.”⁽⁹⁾

Ideal joints must be relatively easy to install and repair. They should also consolidate around the steel, provide adequate load transfer, seal the joint or provide for water migration, resist corrosion, open and close freely in temperature changes, enhance smoothness and low noise, and be aesthetically pleasing. Joint failure can result in faulting, pumping, spalling, and breaking of corners, as well as blowups and transverse cracking (if lockup occurs).

Joints can also fail prematurely. Deterioration of concrete pavement joints has been reported nationwide, particularly in the northern States. Pavements affected include State highways, city and county streets, and parking lots. While it should be emphasized that only a small number of concrete pavements is affected, the distress is common enough to warrant research to identify preventative measures.

The problem statements in this track address new and innovative joint design, materials, construction, and maintenance activities. There is much room in this research for innovative concrete pavement joint design, such as in research to address the coefficient of thermal expansion and shrinkage issues. Additional incremental improvements to joint design, such as tie-bar design for longitudinal joints, are addressed under track 2. Much of the proposed research in this track will develop important improvements, though the track also specifies research that will help develop breakthrough technologies. The problem statements also recognize that future joint repair will proceed quickly, and they propose research for accomplishing faster joint repair.

The following concepts will be investigated:

• Private and public sector knowledge and experience will be used to identify ways to enhance jointed pavements.
  
  
• Many JCPs that have lasted many years without dowels will require retrofitting with dowels to control faulting. Techniques will be explored.
  
  
• Doweled joints will be designed to last 60 years in relatively heavy traffic.
  
  
• CRCP will solve the problem of joint lifespan by eliminating the joints entirely.
  
  
• Joints for concrete overlays (performance life 20 years and less) have not been studied sufficiently. The cost of a doweled joint in thin pavement can be exceptionally high for the life expectancy. Research in this track will develop a scaled-down but fully functional joint for this product, with owners specifying a less robust but fully functional joint for the shorter design period.

The following introductory material summarizes the goal and objectives for this track and the gaps and challenges for its research program. A table of estimated costs provides the projected cost range for each problem statement, depending on the research priorities and scope determined in implementation. The problem statements, grouped into subtracks, follow.

Track 6 Goal

This track will identify, develop, and test new and innovative joint concepts for concrete pavements that are more cost effective, reliable, and durable than current alternatives.

Track 6 Objectives

The track 6 objectives are as follows:

1. Identify the mechanisms leading to premature deterioration, along with remedies for both existing pavements and new construction.
   
   
2. Identify new and innovative alternatives to handling the forming, opening/closing, load transferring, and sealing for transverse and longitudinal concrete pavement joints.
   
   
3. Identify criteria for the design, materials, and construction of exceptionally long-lasting joints (e.g., more than 50 years) (also see track 9).
   
   
4. Determine optimum joint design for concrete overlays.
   
   
5. Determine optimum joint design for low-volume, long-life pavements.
   
   
6. Develop an advanced high-speed computational model for joint condition analysis that can improve joint design, materials, and construction.
   
   
7. Develop and field test new and innovative joint designs to determine their cost effectiveness, reliability, and durability.
   
   
8. Develop and validate rapid methodology for evaluating existing joint conditions so that joints can be preserved and repaired.

Track 6 Research Gaps

The track 6 research gaps are as follows:

• Lack of cost-effective joint designs for all pavement types.
  
  
• A need for joint fillers and sealants.
  
  
• Lack of adequate joint materials.
  
  
• Lack of adequate joint construction.
  
  
• Lack of methodology for joint preservation and repairs.
  
  
• Lack of much needed technology to provide adequate load transfer on low-volume roads (slab on grade) that costs less than dowels but remains fairly reliable.
  
  
• Insufficient understanding of base, subbase, and subdrainage selection for concrete pavements.

Track 6 Research Challenges

The track 6 research challenges are as follows:

• Provide adequate and cost-effective joint designs for several concrete pavement applications that require differing joint designs, including designs for low-volume rural and urban roadways.
  
  
• Determine the best joint designs, materials, and construction procedures for these applications (i.e., concrete overlays, low-volume solutions, heavy traffic, stage construction with low initial costs, and tunnels).
  
  
• Provide new and conclusive models and data that address the need for filling/sealing transverse and longitudinal joints.
  
  
• Determine the best solution for all concrete pavement applications located in various site conditions, filling a major gap in the knowledge.
  
  
• Consider that concrete joint materials endure saturation and freeze thaw as well as high pressures from incompressibles and determine ways in which concrete design can reduce joint deterioration.
  
  
• Determine ways to overcome the joint problems that result from
  construction inadequacies.
  
  
• Develop methodology and equipment for determining a joint’s structural and functional condition and selecting preservation and repair actions that maintain its effectiveness.
  
  
• Determine the optimum type of base, subbase, or subdrainage for joint performance.
  
  
• Determine the optimum site conditions and base types for joint performance.

Research Track 6 Estimated Costs

Table 34 shows the estimated costs for this research track.

Track 6 Organization: Subtracks and Problem Statements

Track 6 problem statements are grouped into the following three subtracks:

• Subtrack 6-1. Joint Design Innovations.
  
  
• Subtrack 6-2. Joint Materials, Construction, Evaluation, and Rehabilitation Innovations.
  
  
• Subtrack 6-3. Innovative Joints Implementation.

Each subtrack is introduced by a brief summary of the subtrack’s focus and a table listing the titles, estimated costs, products, and benefits of each problem statement in the subtrack. The problem statements follow.

SUBTRACK 6-1. JOINT DESIGN INNOVATIONS

This research in this subtrack will develop and implement detailed joint design and construction concepts. Table 35 provides an overview of this subtrack.

Problem Statement 6-1-1. Identify, Develop, and Evaluate Innovative Concepts for Concrete Pavement Joint Design, Materials, and Construction

• Track: 6. Innovative Concrete Pavement Joint Design, Materials, and Construction.
  
  
• Subtrack: 6-1. Joint Design Innovations.
  
  
• Approximate duration: 4 years.
  
  
• Estimated cost: $700,000–$1 million.

Joints have consistently been problematic in concrete pavements. Their designs have been very empirical, causing many failures over the years. The concrete material around the joint often deteriorates more rapidly than the rest of the slab due to greater moisture and freeze-thaw exposure as well as highly concentrated stress points caused by incompressibles. Many construction problems have also occurred in placing load transfer devices and tie-bars and in joint-forming activities, such as late sawing or inadequate sawing depth. Innovative joint design, materials, and construction methods are needed to address these problems, along with innovative crack filling or sealing methods. This research should also consider the joints in CRCP, in which crack forming is critical, and examine previous research on this topic. Finally, this research should consider the joint design in precast concrete pavements.

The tasks include the following:

1. Identify innovative joint design, materials, and construction concepts. Consider major concrete pavement applications including low-volume roads and streets, concrete overlays of varying thicknesses, high-traffic concrete pavements, and other special concrete pavement uses. For example, examine the bobsled procedure for longitudinal joints developed in Iowa.
   
   
2. Develop each promising concept so that it can be evaluated.
   
   
3. Evaluate each concept, providing its expected reliability, durability, and cost effectiveness. Include crack forming in CRCP.
   
   
4. Recommend concepts for further development and testing.

Benefits: Jointing alternatives that are significantly more reliable, cost effective, and durable than those currently in use.

Products: Recommended new and innovative joint design, materials, and construction alternatives.

Implementation: The innovative joint concepts developed in this research will be used in many research activities throughout track 6.

Problem Statement 6-1-2. Select Promising Innovative Joint Design, Materials, and Construction Concepts and Further Develop to Trial Test Stage

• Track: 6. Innovative  Concrete Pavement Joint Design, Materials, and Construction.
  
  
• Subtrack: 6-1. Joint Design Innovations.
  
  
• Approximate duration: 5 years.
  
  
• Estimated cost: $700,000–$900,000.

Many new and innovative concepts are expected to be found for joint design, materials, and construction concepts. These concepts will be evaluated further for such key aspects as reliability, cost effectiveness, durability, ease of construction, maintainability, and others. A national group of experts will then select the most promising concepts to be developed into more detailed designs, plans, experimental designs, and specifications for construction and testing in future tasks. This research should consider crack forming in CRCP.

The tasks include the following:

1. Evaluate new and innovative joint design, materials, and construction concepts based on a wide range of criteria.
   
   
2. Consider major concrete pavement applications including low-volume roads and streets, concrete overlays of varying thicknesses, high-traffic concrete pavements, and other special concrete pavement uses.
   
   
3. Select the most promising concepts after further testing and development.
   
   
4. Fully develop each of the selected concepts so that they can be tested appropriately using ALFs, laboratory testing, and full-scale field construction and testing on actual highways.
   
   
5. Summarize results and document reports that include everything needed for construction
   and testing.

Benefits: Laboratory, accelerated field, and longer-term field testing of one or more concrete pavement joint concepts.

Products: Complete design, materials, and construction details on joint concepts.

Implementation: The innovative joint designs, materials, and construction concepts resulting from this research will be tested and evaluated under problem statement 6-2-1. States may implement some of the concepts immediately.

Problem Statement 6-1-3. Optimization of Mechanical Load Transfer Devices for Load Transfer Efficiency and Deterioration Models

• Track: 6. Innovative Concrete Pavement Joint Design, Materials, and Construction.
  
  
• Subtrack: 6-1. Joint Design Innovations.
  
  
• Approximate duration: 4 years.
  
  
• Estimated cost: $600,000–$800,000.

The MEPDG and other mechanistic design procedures directly model the effects of dowel bar diameter on faulting performance.⁽¹⁾ However, other aspects of doweled joint design, such as dowel length and spacing, are not considered directly. While most States currently use 18-inch-long dowel bars with uniform 12-inch spacing, the dowel bars located outside the wheel paths have little to no effect on critical pavement response and could be left out without adversely affecting pavement performance. Moreover, recent European research suggests that shorter dowel bars may be as effective as long dowel bars. European practice also suggests that smaller diameter dowels spaced more closely together (e.g., 10 inches) may produce good pavement performance. In addition, joint cost must be considered in implementation.

Innovative dowel bar designs, such as elliptical dowel bars recently tested and constructed in the United States, may also provide significant performance and/or cost advantages. In addition, dowels made of fiberglass, stainless steel, and a variety of other corrosion-resistant coverings are available. These alternative load transfer designs may substantially reduce initial pavement cost without reducing LTPP, at least in some cases. This research will optimize load transfer design by conducting comprehensive analytical modeling, laboratory testing, and field performance studies. The research findings will result in practical guidelines for load transfer design.

The tasks include the following:

1. Conduct a worldwide literature search, interviews with experienced engineers, and field surveys of existing high-performance concrete pavement sites to determine the state-of-the-art mechanical load transfer.
   
   
2. Identify ways to optimize mechanical load transfer devices at transverse joints for various highway and street classes and evaluate each for feasibility (cost effectiveness, reliability, constructability (e.g., bottom-up crack initiators), and maintainability).
   
   
3. Investigate the conditions that require mechanical devices to control differential deflections, erosion, faulting, and cracking of JCPs for all functional classifications of highways and streets, as well as special applications.
   
   
4. Analyze and evaluate each proposed concept.
   
   
5. Recommend concepts that should be developed and tested further, and develop a plan for
   this work.
   
   
6. Consider major concrete pavement applications including low-volume roads and streets, concrete overlays of varying thicknesses, high-traffic concrete pavements, and other special concrete pavement uses.
   
   
7. Further develop and test concepts (lab, accelerated loading, and full-scale field testing).
   
   
8. Prepare a final research report and implementation guide for optimizing mechanical load transfer devices.

Benefits: Cost-effective, reliable, and durable load transfer devices for concrete pavement joints.

Products: Recommendations and guidelines for improved load transfer devices for LTE of joints and validated and implementable procedures and guidelines that optimize joint load transfer systems for use with transverse concrete pavement joints.

Implementation: This research will be implemented directly into concrete pavement design procedures. Some agencies will implement experimental sections immediately.

Problem Statement 6-1-4. Development of an Advanced High-Speed Joint Analysis Tool

• Track: 6. Innovative Concrete Pavement Joint Design, Materials, and Construction.
  
  
• Subtrack: 6-1. Joint Design Innovations.
  
  
• Approximate duration: 4 years.
  
  
• Estimated cost: $1–$2 million.

Adequate joint design is essential to the long-term performance of JCPs. Consequently, evaluating the adequacy of joint designs depends on the ability to predict joint performance by considering the effects that combinations of pavement design, site, climate, and construction factors have on performance. Although the MEPDG contains innovative methods for assessing joint design based on mechanistic principles (e.g., load transfer deterioration models and effect of dowels), no automated modeling tools exist that comprehensively evaluate joint design effectiveness and its impact on future pavement performance.(1) This study will develop such a tool. The model developed with this research could be implemented as a stand-alone procedure or incorporated into an overall design procedure, such as the MEPDG. Results from this type of evaluation can then be included in mechanistic-based models to predict joint deteriorating, pumping, and faulting.

The tasks include the following:

1. Evaluate all available FEM and other joint models and determine whether any might be used after further development or would fit the needs of this work.
   
   
2. Identify the specific goals, objectives, and scope of this joint analysis tool.
   
   
3. Include data on crack deterioration in CRCP.
   
   
4. Develop an advanced high-speed computerized joint analysis tool.
   
   
5. Validate the tool using available experimental data.
   
   
6. Prepare a user’s guide and technical documentation for the joint analysis tool, along with examples and limitations.

Benefits: Ability to analyze a wide variety of joint systems in 3D to help evaluate and develop new and innovative joint systems.

Products: FEM model that provides advanced and high-speed analysis of complex joint systems under traffic and climatic loadings that researchers and designers could use to determine joint design adequacy.

Implementation: This research will analyze joint designs for trial construction under problem statement 6-2-1. The model developed could also further research and development work and be used by States in special joint design for critical projects.

Problem Statement 6-1-5. Development of Advanced Joint Sealing Procedures

• Track: 6. Innovative Concrete Pavement Joint Design, Materials, and Construction.
  
  
• Subtrack: 6-1. Joint Design Innovations.
  
  
• Approximate duration: 4 years.
  
  
• Estimated cost: $1.5–$2.5 million (cost share of $1 million by industry).

Joint sealing has become a major issue in concrete pavement design. Sealing JCP joints (both immediately after construction and during routine maintenance and rehabilitation) is costly and can significantly influence the overall life-cycle cost of JCPs. Joint sealing is thought to minimize the extent to which precipitation penetrates the pavement structure, thus preventing the base course or subgrade erosion that eventually causes joint faulting, loss of support, and related cracking. By minimizing moisture infiltration, joint sealing may also reduce durability-related distresses such as concrete D-cracking. Joint sealing is also thought to prevent solid particles (including aggregates) from filling up joint openings, reducing the likelihood of joint spalling and blowups. However, whether joint sealing extends pavement life is questionable. At least one State has stopped sealing joints, replacing the seal with a single narrow sawcut, leaving nothing in the joints. Several others have constructed test sections with both thin-cut nonsealed joints and alternative joint seals to evaluate performance. A major FHWA study currently underway will evaluate existing data on sealed and nonsealed joint performance. Meanwhile, studies show that the incompressibles that infiltrate joints can push bridge back walls and abutments and seriously damage them. Also, blowups caused by incompressibles have occurred on many longer jointed reinforced pavements (no longer built) and a few short jointed pavements. Clearly, more advanced joint modeling and testing with and without seals will shed more light on this issue and allow for more informed decisions. This study will develop a mechanistic model demonstrating joint infiltration by water and incompressibles that can analyze the impacts of both. The model should also be able to test nonsealed joints of optimum configurations.

The tasks include the following:

1. Collect and summarize all research studying sealed and nonsealed joint performance and the current techniques for modeling water and incompressible intrusion and migration into concrete pavements and synthesize the results.
   
   
2. Develop an advanced analytical approach to joint movement, sealing, and infiltration for use in this and future studies.
   
   
3. Predict hourly movements over several years using EICMs and FEMs.
   
   
4. Model the potential damage caused when incompressibles infiltrate joints and result in stress buildup.
   
   
5. Ensure that the model handles all types of conventional concrete base courses, joint spacing, and thermal coefficients of expansion.
   
   
6. Validate the model using laboratory and in-service pavements.
   
   
7. Identify new and innovative seals and nonsealed configurations that can be tested with the water and incompressible infiltration models and field tested to address long-term pavement needs.
   
   
8. Construct a series of test sections to evaluate the new sealing and nonsealing concepts.
   
   
9. Document the results and recommend the most promising approach to sealing or not sealing joints, both longitudinal and transverse, in all geographic areas in the United States.

Benefits: Resolution to the sealing or nonsealing joint issue that improves long-term concrete pavement cost effectiveness, performance, and reliability.

Products: A lab- and field-validated comprehensive model for joint movement over annual climate cycles, joint infiltration models for water and incompressibles, and an FEM model of the joint and pavement structure that analyzes the impacts of water and incompressibles on pressure buildup, spalling, and base and subgrade erosion. Research linked to the model developed under problem statement 2-1-3.

Implementation: The results of this research will be implemented immediately into the MEPDG and by States.

Problem Statement 6-1-6. Guidelines for Implementing New and Innovative Joint Design, Materials, and Construction Concepts

• Track: 6. Innovative Concrete Pavement Joint Design, Materials, and Construction.
  
  
• Subtrack: 6-1. Joint Design Innovations.
  
  
• Approximate duration: 4 years.
  
  
• Estimated cost: $300,000–$500,000.

The extensive research and development conducted under track 6 must be documented in detailed joint design guidelines. The research findings from this research track must also be documented. This will include detailing the design, materials, and construction of each of the concepts as well as assessing the overall performance of their promise to improve conventional joint technology and procedures.

The tasks include the following:

1. Summarize the potential for the pavement joint design, materials, and construction procedures developed in track 6 to provide a significant improvement over conventional joint designs, materials, and construction procedures if fully implemented.
   
   
2. Develop practical manuals and guidelines for designing and constructing the innovative pavement joint concepts developed in this track.
   
   
3. Provide assistance for implementing the new innovative pavement joint designs, materials, and construction procedures.

Benefits: Direct assistance for immediately implementing the entire work of this innovative
joint track.

Products: Practical manuals and guidelines that can be used by those involved in designing and constructing innovative concrete pavement joint concepts, major applications of concrete pavements, including low-volume roads and streets, concrete overlays of varying thicknesses, high-traffic concrete pavements, and other special concrete pavement uses, as well as crack forming in CRCP and joint design for precast pavements.

Implementation: This research will result in a joint manual to be used by designers
and engineers.

SUBTRACK 6-2. JOINT MATERIALS, CONSTRUCTION, EVALUATION, AND REHABILITATION INNOVATIONS

This research in this subtrack will construct and rehabilitate joints in the field. Table 36 provides an overview of this subtrack.

Problem Statement 6-2-1. Constructing, Testing, and Evaluating Promising Concrete Pavement Joint Design Concepts

• Track: 6. Innovative Concrete Pavement Joint Design, Materials, and Construction.
  
  
• Subtrack: 6-2. Joint Materials, Construction, Evaluation, and Rehabilitation Innovations.
  
  
• Approximate duration: 7 years.
  
  
• Estimated cost: $2.5–$4 million (excluding construction costs, only includes engineering and testing and reporting; cost sharing of $1 million by industry).

Each new and innovative concept must be proven in the lab and field. With the results from problem statements 6-1-1 and 6-1-2, this research will construct experimental joints using both accelerated loading equipment and in-service highways. The concepts recommended for ALFs will be the ones that primarily depend on repeated axle loads, as this is the primary tool for evaluating these concepts. The in-service joint concepts evaluated over the long term would be constructed on regular highways subjected to normal traffic loadings. These studies will consider major concrete pavement applications including low-volume roads and streets, concrete overlays of varying thicknesses, high-traffic concrete pavements, and other special concrete pavement uses. This research will also consider crack forming in CRCP and precast pavement joints.

The tasks include the following:

1. Construct the accelerated loading joint concepts, begin testing, and document findings.
   
   
2. Construct the in-service highway joint concepts, begin testing, and document findings, working with States that have shown an interest in the work.
   
   
3. Document all research and testing results and modify the work plans as results become available.
   
   
4. Determine the cost of the various concepts for use in cost effectiveness studies.
   
   
5. Prepare detailed and comprehensive or brief summaries of the key findings obtained from the previous work.

Benefits: Laboratory and field validation of joint design, materials, and construction concepts.

Products: Laboratory tests, accelerated loading tests, and field tests of several new and innovative joint design, materials, and construction concepts that have been developed and validated or proven inadequate. Successful and cost-effective concepts will be well documented.

Implementation: This research will provide field validation for several innovative concrete pavement joint concepts.

Problem Statement 6-2-2. Development of Innovative Ways for Detecting Joint Deterioration in New and Older Pavements

• Track: 6. Innovative Concrete Pavement Joint Design, Materials, and Construction.
  
  
• Subtrack: 6-2. Joint Materials, Construction, Evaluation, and Rehabilitation Innovations.
  
  
• Approximate duration: 5 years.
  
  
• Estimated cost: $1–$1.5 million.

The condition of longitudinal and transverse joints is critical for identifying the appropriate preservation or rehabilitation strategy. Detailed joint condition information is also important for evaluating joint design effectiveness. Thus, the ability to detect and monitor the following potential problems is important for characterizing joint performance:

• Looseness.
  
  
• Problematic positioning.
  
  
• Aggregate interlock wearout.
  
  
• Consolidation.
  
  
• Concrete deterioration around dowel bars.
  
  
• Concrete fracture in the joint area.

Various devices capable of providing tomographic images of concrete may be used in this application, including the impact-echo device and the MIT-SCAN-2 for locating the dowels and tie-bars. This research will develop a mostly nondestructive method for evaluating and quantifying functional (e.g., faulting and spalling) and structural joint condition (e.g., LTE, opening, and closing). Adequate concrete consolidation around the dowel bars is important for good joint performance, both immediately after construction and over time, and must be measured.

The tasks include the following:

1. Conduct a worldwide literature survey and interview experts to identify the technologies available for determining a joint’s functional and structural condition to carry heavy traffic loadings over time. This joint could be a new or an older pavement.
   
   
2. Identify procedures, equipment, methodologies, and concepts that have been or could be used for joint evaluation. Summarize these in a concise document for an expert review panel. Based on the panel results, select the most promising technologies to produce a nearly or completely NDT procedure to evaluate concrete pavement joints.
   
   
3. Conduct a field survey and analysis of tie-bar and X-stitching performance and installation for longitudinal joints and random cracks.
   
   
4. Analyze and evaluate each technology.
   
   
5. Recommend technologies to be advanced for further development and testing.
   
   
6. Develop a plan for this needed work.
   
   
7. Perform the additional development and testing work (lab, accelerated loading, and full-scale field testing).
   
   
8. Prepare a final research report and implementation guide for ways to evaluate concrete pavement joints to determine their functional and structural conditions.

Benefits: Procedures to evaluate and recommend preservation and repair actions for
existing joints.

Products: Validated and implementable procedures and guidelines for rapidly and reliably evaluating existing concrete pavement joints to determine preservation and repair treatments as well as structural and functional condition.

Implementation: The joint deterioration detection methods developed in this research will be implemented immediately.

Problem Statement 6-2-3. Determining the Need and Identifying the Feasibility of Alternative Ways to Provide Pressure Relief and Load Transfer Efficiency for Concrete Pavements

• Track: 6. Innovative Concrete Pavement Joint Design, Materials, and Construction.
  
  
• Subtrack: 6-2. Joint Materials, Construction, Evaluation, and Rehabilitation Innovations.
  
  
• Approximate duration: 4 years.
  
  
• Estimated cost: $500,000–$700,000.

Providing PRJs, both with and without mechanical load transfer, has created problems because these joints often do not function properly and require premature maintenance. Controversy has risen over where PRJs are needed and whether they are useful since some studies show that they may not have any positive value. This research will examine whether PRJs might be needed, locations where PRJs might help avoid pressure buildup problems, and ways that PRJs can be designed with mechanical load transfer.

The tasks include the following:

1. Conduct a worldwide literature search for PRJs and their design, use, and effectiveness and summarize the findings, including case studies wherever available (e.g., the use of regular expansion joints on the Illinois State Toll Highway Authority and the experience several States have had placing and maintaining PRJs). Include a summary of the technical information available for calculating the pressures and mechanisms involved. Also summarize the designs of joint load transfer efficiencies where possible.
   
   
2. Based on field surveys and expert interviews (along with the literature survey), prepare a case-by-case study in which PRJs were incorporated into various projects, including the projects’ performance and needs. Document these studies.
   
   
3. Based on these results, prepare guidelines for using PRJs that practicing engineers can use.

Benefits: Fewer problems associated with pressure buildup and PRJs in all aspects of
concrete pavements.

Products: Guidelines for using PRJs that will be made available to practicing engineers and highway agencies, resulting in better understanding of the needed locations and design of PRJs in concrete pavements.

Implementation: The PRJ methods resulting from this research will be implemented immediately.

Problem Statement 6-2-4. Evaluation and Materials Considerations to Prevent Joint Deterioration

• Track: 6. Innovative Concrete Pavement Joint Design, Materials, and Construction.
  
  
• Subtrack: 6-2. Joint Materials, Construction, Evaluation, and Rehabilitation Innovations.
  
  
• Approximate duration: 4 years.
  
  
• Estimated cost: $1–$2 million.

Premature joint deterioration is a significant problem for owners of concrete pavements. Further work is needed to assess the causes behind such deterioration and to develop materials systems that are less prone to this problem.

The tasks include the following:

1. Investigate causes of deterioration.
   
   
2. Investigate materials and mixtures that can resist deterioration mechanisms.
   
   
3. Develop guidelines.
   
   
4. Publish guidelines.

Benefits: Reduced failures in joints.

Products: Guidelines for mixtures.

Implementation: Implement recommendations developed.

SUBTRACK 6-3. INNOVATIVE JOINTS IMPLEMENTATION

This research in this subtrack implements the results from the previous two subtracks. Table 37 provides an overview of this subtrack.

Problem Statement 6-3-1. Implementation of Innovative Joint Design, Materials, and Construction

• Track: 6. Innovative Concrete Pavement Joint Design, Materials, and Construction.
  
  
• Subtrack: 6-3. Innovative Joints Implementation.
  
  
• Approximate duration: 9 years.
  
  
• Estimated cost: $800,000–$1 million.

Implementing innovative concrete pavement joint design, materials, and construction requires significant efforts, both in training the workforce and assuring management that the new concepts are feasible and reliable. This research will address both of these efforts. The results from many other tracks will help develop innovative joint concepts and will be coordinated closely with this research without duplicating efforts. For example, track 2 will provide new knowledge and procedures for base course erosion (see problem statement 2-1-3).

The tasks include the following:

1. Develop and present workshops dealing with many aspects of the mechanistic design process that focus on joint design, materials, and construction.
   
   
2. Organize national conferences and workshops about the joint design, materials, and construction process where States and other highway agencies can share their findings.
   
   
3. Develop Web-based online training tools.

Benefits: A workforce with the basic knowledge and understanding to design, specify materials, and construct new and innovative concrete pavement joints.

Products: Strong technology transfer of innovative concrete pavement joint design, materials, and construction to the workforce using workshops, conferences, and Web-based personnel training, as well as a workforce and management that know the new procedures, guidelines, and models to better design, construct, and specify materials related to concrete pavement joints.

Implementation: This work will provide the technology transfer critical to the success of the innovative joints track.