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

TRACK 7. CONCRETE PAVEMENT MAINTENANCE AND PRESERVATION

TRACK 7 OVERVIEW

In the current economic climate, the need to maintain and preserve existing highway infrastructure assets has taken on a much greater importance. This is reflected by highway agency budgets shifting funding from new construction and/or reconstruction to maintenance. This shift in priorities is not likely to change over the next decade, emphasizing the importance of establishing reliable procedures and developing new and innovative methods for concrete pavement maintenance and preservation.

Studies have shown that proper maintenance and preservation treatments can significantly extend the life of concrete pavement, even well beyond their intended design life. There is a need to identify and implement proven maintenance and preservation practices and techniques and to ensure proper application of those treatments.

Furthermore, many enhancements to existing maintenance and preservation treatments are envisioned. Automation of distress and maintenance need identification, and automation application of maintenance and preservation treatments can greatly reduce the cost and expedite the application of treatments, as well as enhance safety for maintenance workers.

Research in this track will include the following:

• Optimization of concrete pavement preservation.
  
  
• Optimization and automation of concrete pavement maintenance treatments.
  
  
• Distress identification and preservation treatments.
  
  
• Development of feedback loops for concrete pavement preservation effectiveness.

There is significant crossover with the problem statements presented in this track and other tracks. Notably, problem statements from track 2 related to effect of improvements in maintenance and preservation treatments on pavement design, problem statements from track 5  related to advancements in equipment automation for maintenance and preservation, and problem statements from track 9 related to the effect of maintenance and preservation on pavement life.

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 7 Goal

This track will focus on optimization and deployment of maintenance and preservation treatments for PCC pavements in order to preserve the asset and maximize its lifespan.

Track 7 Objectives

The track 7 objectives are as follows:

1. Establish proven concrete pavement preservation methods and optimized preservation strategies for maximizing pavement life.
   
   
2. Establish essential concrete pavement maintenance needs and automated methods for identifying these needs.
   
   
3. Identify proven, new, and innovative methods for automated pavement maintenance treatments and provide guidance for use of these methods.
   
   
4. Establish methods for automated distress identification and assessment of necessary preservation treatments.
   
   
5. Establish a system for continuous feedback on the effectiveness of pavement preservation methods such that adjustments can be made in a timely manner.

Track 7 Research Gaps

The track 7 research gaps are as follows:

• Insufficient data on effectiveness of maintenance and preservation treatments in preserving or extending pavement life.
  
  
• Lack of understanding on the importance of tracking maintenance and preservation treatments for monitoring effectiveness.
  
  
• Insufficient data on the costs of maintenance and preservation treatments.
  
  
• Lack of understanding of when to apply preservation treatments in preemptive manner to mitigate potential distresses.
  
  
• Lack of understanding of the importance of various maintenance and preservation treatments under different traffic and climatic conditions.

Research Challenges

The track 7 research challenges are as follows:

• Quantifying the benefits of maintenance and preservation treatments on pavement life.
  
  
• Quantifying the costs of maintenance and preservations treatments in the context
  of a life-cycle cost analysis (LCCA).
  
  
• Fostering a culture which emphasizes the importance of maintenance and preservation treatments as a means for preserving and extending pavement life and not just as a reactive treatment for distresses.

Research Track 7 Estimated Costs

Table 38 shows the estimated costs for this research track.

Track 7 Organization: Subtracks and Problem Statements

Track 7 problem statements are grouped into the following four subtracks:

• Subtrack 7-1. Optimization and Automation of Pavement Maintenance.
  
  
• Subtrack 7-2. Optimized Concrete Pavement Preservation.
  
  
• Subtrack 7-3. Distress Identification and Preservation Treatment.
  
  
• Subtrack 7-4. Feedback Loop for Concrete Pavement Preservation Effectiveness.

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 7-1. OPTIMIZATION AND AUTOMATION OF PAVEMENT MAINTENANCE

This subtrack addresses pavement maintenance including optimization and automation of maintenance treatments. Table 39 provides an overview of this subtrack.

Problem Statement 7-1-1. Advancements in Forensic Analysis of Concrete Pavements

• Track: 7. Concrete Pavement Maintenance and Preservation.
  
  
• Subtrack: 7-1. Optimization and Automation of Pavement Maintenance.
  
  
• Approximate duration: Not available.
  
  
• Estimated cost: $500,000–$750,000.

Many highway departments must evaluate in-service pavements and determine the reasons for good, marginal, or poor pavement performance. Often, a clear understanding of the all the elements of design, materials, construction, and in-service data is necessary to determine precisely what occurred or caused some action. In the past several years, the concrete paving industry has examined many pavements to determine the specific causes of a distress and has spent much time and money pulling together data. This problem statement will create a structure to examining pavements and develop a better way to determine remaining pavement life.

The tasks include the following:

1. Conduct a literature review of projects that have undergone significant in-service evaluations to identify the key methods used to obtain and test samples of the pavements.
   
   
2. Identify the key forensic tests that could help identify various problems, focusing on durability, loss of smoothness, surface texture changes, and joint deterioration.
   
   
3. Develop a statistically based method to conduct a forensic study that will determine the probability that a distress was caused by a specific series of actions.
   
   
4. Develop a forensic study manual that includes visual distress survey techniques, suggested tests, sampling and testing of such samples, and the most likely cause of certain visual distresses based on these tests.
   
   
5. Conduct a literature search for the current methods to determine remaining structural and surface characteristic life for concrete pavements, including concrete overlay sections.
   
   
6. Identify ways to calculate remaining life based on current design methodologies including the new MEPDG. Include the field tests, sample size, and reliability.
   
   
7. Develop a forensic study manual that includes methods to determine the structural and surface characteristic life for concrete pavements and ways to calculate remaining life based on current design methodologies.
   
   
8. Develop an integrated forensic study manual that considers both manuals (from tasks 4 and 7) and that can be used to produce an overall pavement condition status report with remaining life.

Benefits: Forensic analysis that could be tied with the determination of remaining life to develop criteria for selecting appropriate rehabilitation and pavement strengthening actions to extend the existing pavement performance life.

Products: A state-of-the-art forensic study manual.

Implementation: This research may be divided into separate contracts for tasks 1–4, 5–7, and 8. The research results will be implemented through technology transfer of the forensic study manual.

SUBTRACK 7-2. OPTIMIZED CONCRETE PAVEMENT PRESERVATION

This subtrack focuses on optimizing concrete pavement preservation in order to mitigate distresses and maximize the life of the pavement. Table 40 provides an overview of this subtrack.

Problem Statement 7-2-1. Improvements to Concrete Pavement Restoration/Preservation Procedures

• Track: 7. Concrete Pavement Maintenance and Preservation.
  
  
• Subtrack: 7-2. Optimized Concrete Pavement Preservation.
  
  
• Approximate duration: 4 years.
  
  
• Estimated cost: $2–$3 million.

Many State highway agencies currently apply preservation techniques to all types of pavements, including concrete. As the Nation’s interstate highways age, more effective CPR and preservation techniques have become daily activities for many State highway agencies. Techniques include joint repair, dowel retrofitting, shoulder replacement (includes retrofitting with tied PCC), slab replacement, full-depth patching with PCC, grouting and fill of voids, and diamond grinding.

Though several guidelines explain these tasks, very few mechanistic-based procedures evaluate the effectiveness of such repairs in preventing or delaying future distress and its progression. One design procedure that uses mechanistic-based procedures to evaluate and determine the feasibility of CPR is found in the MEPDG.⁽¹⁾

The tasks include the following:

1. Evaluate the MEPDG mechanistic-based procedures for assessing the effectiveness of JPCP subjected to CPR.⁽¹⁾
   
   
2. Enhance the MEPDG JPCP procedures and develop new procedures for evaluating CPR performed on other concrete pavement types, such as CRCP and JRCP.(1) At minimum, the procedure should consider existing pavement design features, climatic conditions, traffic loading, existing distress conditions that include materials durability, future loadings data, and advanced M-E modeling to determine future CPR pavement performance based on key performance indicators.
   
   
3. Develop improved guidelines and procedures for designing CPR/preservation projects. These should include improved procedures that assess the window of opportunity for applying preservation techniques to existing concrete pavements.
   
   
4. Develop improved procedures for estimating the remaining life (both structural and functional) of existing concrete pavements so that improved restoration or concrete overlay decisions can be made.
   
   
5. Develop enhanced pavement management data to support cost-effective
   pavement preservation.

Benefits: Improved guidelines and design procedures for the activities involved with restoring and preserving existing concrete pavements, resulting in improved decisionmaking for potential CPR projects in terms of selecting needed treatments (i.e., DBR), predicting remaining life, and further validating CPR as a reliable alternative.

Products: Improved guidelines and design procedures for several types of concrete overlays that improve their reliability, viability, and cost effectiveness.

Implementation: This research will provide practical technological improvements to CPR that will be implemented immediately into design procedures. This problem statement is linked to problem statement 2-3-4.

Problem Statement 7-2-2. Optimizing Procedure for New Design and Future Maintenance and Rehabilitation Capable of Minimizing Total Life-Cycle Costs, Lane Closure Time, and Other Design Goals Over the Range of Design Life

• Track: 7. Concrete Pavement Maintenance and Preservation.
  
  
• Subtrack: 7-2. Optimized Concrete Pavement Preservation.
  
  
• Approximate duration: 6 years.
  
  
• Estimated cost: $1–$2 million.

The MEPDG evaluates a trial design provided by the designer.⁽¹⁾ The proposed design must make several trial runs before an acceptable design is established, and this is only for the first performance period. The design procedure does not consider future rehabilitations, nor does it provide optimization procedures to minimize life-cycle costs or even first costs. An optimization procedure to be incorporated into the current and future versions of the pavement design guide is needed.

The tasks include the following:

1. Develop design procedure concepts that consider multiple initial trial designs and multiple optional rehabilitation alternatives and then select designs from among the initial ones that optimize (i.e., minimize or maximize) a desired factor. This factor could be life-cycle costs, initial construction costs, future rehabilitation costs, and user delay costs, among others. Design procedure concepts should be developed for shoulders, tied shoulders, and alternative shoulder materials.
   
   
2. Develop software to accomplish the optimization described above in the first task.
   
   
3. Validate the software using several actual projects provided by State highway agencies.

Benefits: New and innovative design options that will improve options to consider for the design and provide more cost-effective and reliable concrete pavement designs.

Products: A comprehensive system that, for a given design project, analyzes a number of alternative initial designs, future preservation treatments, and rehabilitation options and determines the optimum combination to minimize life-cycle costs, initial construction costs, the cost of shoulders and widened slabs, or lane closure time. The system also addresses other needs of the designer. Such a system could handle varying design lives from 8 to over 60 years.

Implementation: Current mechanistic-based procedures in the MEPDG do not optimize.⁽¹⁾ This capability is needed and will be implemented into design procedures immediately. This problem statement is linked to problem statement 3-2-5.

Problem Statement 7-2-3. Fully Automated Concrete Pavement Restoration Equipment

• Track: 7. Concrete Pavement Maintenance and Preservation.
  
  
• Subtrack: 7-2. Optimized Concrete Pavement Preservation.
  
  
• Approximate duration: 4 years.
  
  
• Estimated cost: $1–$2 million.

DBR has become a well-established and proven technique for restoring load transfer across concrete pavement cracks and joints. Full- and partial-depth patching techniques commonly repair failed slab segments and spalling, respectively. However, these techniques are still labor intensive and time consuming. This research will conceptualize and develop fully automated equipment for both DBR and slab patching. The equipment should complete these CPR techniques in a one-pass process. For DBR, this will include cutting and cleaning slots across a crack or joint, inserting the dowel bars, and patching the slots. If possible, the process will also incorporate diamond grinding. Patching will include sawing and removing the existing concrete, inserting tie/dowel bars as necessary, and placing, consolidating, and curing patching material. In all cases, the equipment should adequately retrofit an entire lane width in a single pass.

The tasks include the following:

1. Determine the equipment feasibility for one-pass DBR and/or patching operations. Examine alternative patching materials and the feasibility of incorporating diamond grinding into the operation.
   
   
2. Determine the production requirements (speed of operation) for these CPR operations.
   
   
3. Conceptualize and develop one-pass CPR equipment.

Benefits: Fully automated DBR and patching equipment that will expedite these CPR processes, requiring less labor and lowering costs.

Products: Fully automated one-pass DBR and patching equipment.

Implementation: This work will result in fully automated DBR and concrete slab patching equipment. This problem statement is linked to problem statement 5-6-3.

Problem Statement 7-2-4. Accelerated Concrete Pavement Restoration Techniques

• Track: 7. Concrete Pavement Maintenance and Preservation.
  
  
• Subtrack: 7-2. Optimized Concrete Pavement Preservation.
  
  
• Approximate duration: 5 years.
  
  
• Estimated cost: $500,000–$1 million.

Rehabilitation of high-volume rigid pavements requires techniques that minimize disruption to traffic. Usually this restricts construction to nighttime. However, many techniques that have been developed and proven effective for CPR have not been evaluated fully as they pertain to accelerated construction. Research is needed to develop guidelines to help select strategies for rehabilitating high-volume rigid pavements that consider constraints such as lane closures and construction windows. Repair of UTW is one such technique that needs to be investigated, as there are no established guidelines for UTW repair under short time constraints for lane closures. Likewise, partial-depth repair of PCC pavement has shown promise, but guidelines have not been developed for this technique. Full-depth repair of CRCP is another CPR technique that requires guidelines for materials and construction practices. Additionally, environmental effects of CPR techniques must be addressed. For example, slurry from the diamond grinding process is considered by some State regulatory agencies to be an environmental hazard that could contaminate groundwater supply. While many States do not regard the slurry as hazardous, the concrete pavement industry needs to examine ways to contain and dispose of the slurry in response to certain State regulatory agencies’ decisions. In general, all aspects of accelerated CPR techniques need to be fully documented including materials, construction practices, and environmental effects.

The tasks include the following:

1. Identify common CPR techniques currently used by owner-agencies.
   
   
2. Conduct surveys and interviews of contractors and transportation agencies to determine the current state of the practice for different CPR techniques and successes and failures for different techniques.
   
   
3. Develop best practice guidelines for each of these techniques based on the surveys and interviews.
   
   
4. Develop a decision matrix for agencies to use in determining applicable CPR techniques, with consideration for accelerated construction.
   
   
5. Evaluate new CPR techniques as they are developed.

Benefits: Best practice guidelines for accelerated CPR techniques.

Products: Best practice guidelines for accelerated CPR techniques.

Implementation: This research will result in best practice guidelines for common CPR techniques This problem statement is linked to problem statement 8-4-7.

SUBTRACK 7-3. DISTRESS IDENTIFICATION AND PRESERVATION TREATMENT

This subtrack addresses automated methods for distress identification and appropriate preservation treatments. Table 41 provides an overview of this subtrack.

Problem Statement 7-3-1. Automated Concrete Pavement Crack Sensing and Sealing

• Track: 7. Concrete pavement maintenance and preservation.
  
  
• Subtrack: 7-3. Distress identification and preservation treatment.
  
  
• Approximate duration: 4 years.
  
  
• Estimated cost: $500,000–$1 million.

Crack sealing is necessary maintenance that prevents water and debris from intruding into PCC pavement cracks. Water and debris intrusion can result in corrosion of the reinforcement and spalling at the cracks. However, crack sealing is time consuming and labor intensive. Research is needed to investigate the viability of automated crack sensing and crack sealing equipment. Automated processes would not only eliminate much of the manual labor involved, but it would also create a safer working environment, possibly eliminating the need for traffic control during sealing operations. Automated crack sensing equipment could be vehicle-mounted and could use visual imaging, laser scanning, or other techniques to detect cracks. After crack detection, vehicle-mounted sealing equipment could then seal the crack with epoxy, asphalt, or other material. Although automated sealing would be impossible at high speeds, vehicle-mounted equipment would only require a moving traffic control setup.

The tasks include the following:

1. Identify existing equipment or develop new automated concrete pavement crack sensing equipment.
   
   
2. Identify existing equipment or develop new automated crack sealing equipment.
   
   
3. Develop equipment for integrating crack sensing and crack sealing into a single operation.

Benefits: Automated concrete pavement crack sensing and crack sealing equipment that requires less labor and minimal traffic control and provides a safer working environment for crack sealing.

Products: Automated crack sensing and crack sealing equipment/vehicle.

Implementation: This work will result in automated concrete pavement crack sensing and crack sealing equipment. This problem statement is linked to problem statement 5-6-2.

Problem Statement 7-3-2. Development of Innovative Ways for Detecting Joint Deterioration in New and Older Pavements

• Track: 7. Concrete Pavement Maintenance and Preservation.
  
  
• Subtrack: 7-3. Distress Identification and Preservation Treatment.
  
  
• Approximate duration: 4 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:

1. Looseness.
   
   
2. Problematic positioning.
   
   
3. Aggregate interlock wearout.
   
   
4. Consolidation.
   
   
5. PCC deterioration around dowel bars.
   
   
6. PCC 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:

• 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.
  
  
• Identify procedures, equipment, methodologies, and concepts that have been or could be used for joint evaluation and summarize them 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.
  
  
• Conduct a field survey and analysis of tie-bar and X-stitching performance and installation for longitudinal joints and random cracks.
  
  
• Analyze and evaluate each technology.
  
  
• Recommend technologies to be advanced for further development and testing. Develop a plan for this needed work.
  
  
• Perform the additional development and testing work (lab, accelerated loading, and full-scale field testing).
  
  
• 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. This problem statement is linked to problem statement 6-2-2.

SUBTRACK 7–4. FEEDBACK LOOP FOR CONCRETE PAVEMENT PRESERVATION EFFECTIVENESS

This subtrack addresses the need for a continuous feedback look on the effectiveness of concrete pavement preservation treatments in preserving and extending pavement life. Table 42 provides an overview of this subtrack.

Problem Statement 7-4-1. Strategic Application of Preservation Treatments to Preserve Long-Life Concrete Pavement

• Track: 7. Concrete Pavement Maintenance and Preservation.
  
  
• Subtrack: 7-4. Feedback Loop for Concrete Pavement Preservation Effectiveness.
  
  
• Approximate duration: 2 years.
  
  
• Estimated cost: $500,000–$700,000.

Through strategic use of restoration and rehabilitation techniques, extending the service life of concrete pavements may be possible. This research will investigate the feasibility of applying restoration or rehabilitation treatments to preserve and further extend the service life of long-life pavements. All possible alternatives should be considered, including CPR treatments and concrete overlays. The optimum application timing, based on pavement condition and rehabilitation objectives, should also be determined. Finally, the feasibility of indefinitely preserving the original pavement structure should be investigated.

The tasks include the following:

1. Identify all available and other potential restoration or rehabilitation treatments for the pavement types identified under problem statement 9-2-1.
   
   
2. Conduct field surveys of promising treatments and document case studies.
   
   
3. Investigate the feasibility of preserving and further extending the service life of the identified pavement types by applying restoration or rehabilitation treatments.
   
   
4. Investigate the feasibility of indefinitely preserving the original pavement structure.
   
   
5. Recommend the optimum application timing of restoration or rehabilitation treatments, based on pavement condition, that will extend pavement service life or indefinitely preserve the original pavement structure.
   
   
6. Prepare detailed guidelines for designers.

Benefits: Recommendations on the optimum application timing of restoration or rehabilitation treatments that will extend pavement service life or indefinitely preserve the original pavement structure, as well as a tool for practicing engineers to use in designing long-life cost-effective concrete pavements with minimal restoration.

Products: Recommendations on the type, design, construction, and optimum application timing of restoration or rehabilitation treatments for extending pavements service life or indefinitely preserving the original pavement structure.

Implementation: This research will be coordinated closely with work in track 2 and will provide a product needed to ensure that long-term preservation treatments are considered fully and available. This problem statement is linked to problem statement 9-2-3.

Problem Statement 7-4-2. Guidelines for a Supplemental Pavement Management System and Feedback Loop for Continuous Concrete Pavement Improvements

• Track: 7. Concrete Pavement Maintenance and Preservation.
  
  
• Subtrack: 7-4. Feedback Loop for Concrete Pavement Preservation Effectiveness.
  
  
• Approximate duration: Not available.
  
  
• Estimated cost: $500,000–$750,000.

Current highway agency PMSs are used primarily for programming highway rehabilitation activities. However, with few exceptions, they cannot provide sufficient information for improving the engineering aspects of design, construction, materials, and rehabilitation. The key reason is that many of these systems cannot link various types of information (e.g., design, construction, rehabilitation, maintenance, and traffic) on specific segments of the current highway network to each other. Another reason is that insufficient data are being collected. These deficiencies make it difficult to use the system to assess problems, enhance designs, improve material and construction specifications, and optimize rehabilitation and
life-cycle costing.

This research will develop guidelines for a supplement to a PMS that includes concrete pavement design, construction, materials, and rehabilitation data in a format conducive to engineering decisionmaking. NCHRP 1-19 developed a system for concrete pavements in the 1980s that could serve as a starting point for this work.⁽¹⁰⁾ In addition, recent FHWA research into the use of PMS data for engineering decisions should be reviewed fully, including an existing National Highway Institute (NHI) course on the engineering uses of PMS data.

The tasks include the following:

1. Review State highway agency PMSs to determine which might improve engineering decisionmaking capabilities. For example, the Illinois PMS for pavements and materials was developed specifically for this purpose.
   
   
2. Review previous research studies (e.g., NCHRP 1-19, FHWA, Illinois and Arizona PMS development, and NHI courses) that address the use of PMS data for engineering decisionmaking.⁽¹⁰⁾
   
   
3. Develop guidelines that State highway agencies can use to improve their PMS so that they can be used to make key engineering decisions.
   
   
4. Prepare implementation documents that highway agencies can use to assess their PMS and to extend them to help engineering decisions improve design, construction, materials, and rehabilitation.

Benefits: PMSs that provide sufficient information for improving design, construction, materials, and rehabilitation and guidelines that produce information sufficient for key engineering decisions.

Products: Guidelines for developing a supplemental PMS that includes design, construction, materials, and rehabilitation data in a format conducive to engineering decisionmaking.

Implementation: This research will produce implementation documents that highway agencies can use to assess their PMS and make better design, construction, materials, and rehabilitation engineering decisions.

Problem Statement 7-4-3. The Economic and Systemic Impacts of Concrete Pavement Mix-of-Fixes Strategies

• Track: 7. Concrete Pavement Maintenance and Preservation.
  
  
• Subtrack: 7-4. Feedback Loop for Concrete Pavement Preservation Effectiveness.
  
  
• Approximate duration: Not available.
  
  
• Estimated cost: $250,000–$500,000.

The mix-of-fixes concept, developed by the Michigan Department of Transportation (MDOT), identifies a family of renewal solutions for pavements and bridges that can be incorporated into capital improvement projects. These solutions vary in cost and expected service life. Relative costs could vary greatly per square unit of work, while service life could vary from 3–5 years for surface treatments and thin overlays to 50 years or more for total reconstruction. Generally, a longer desired service life (one that minimizes downstream project traffic disruptions) requires a higher initial cost. However, while MDOT recognizes the need for the mix of fixes, it also recognizes the limited effectiveness of certain preservation strategies. The need for accelerated renewal and minimal disruption does not necessarily mark all infrastructure elements within a corridor for total reconstruction, replacement, and longest life solutions. How, then, can mix-of-fixes options be applied cost effectively while minimizing both current and downstream disruption?

The tasks include the following:

1. Identify the concrete pavement mix-of-fixes strategies currently available to State highway agencies including representative costs, service life, and the downstream impact of future renewal efforts. Strategies should describe the design lives of various key work elements for 15 to 60 years in various pavement scenarios. The strategies should also consider fixes known to be heavy maintenance items such as CPR, whitetopping, and bonded and unbonded concrete overlays.
   
   
2. Evaluate how these mix-of-fixes strategies can be integrated into renewal strategies to optimize the funds available, minimize impact on traffic, and maintain desired service levels.
   
   
3. Determine the overall reliability of assumptions about the life of each renewal strategy and the impact that shortened life may have on downstream traffic disruptions.
   
   
4. Determine the number of back-to-back short-life strategies that could be applied to bridges and pavements.
   
   
5. Determine the optimal time for selecting the proper fix including advanced methodologies for determining current structure or pavement condition and remaining life.
   
   
6. Prepare case studies that demonstrate the impact of integrating mix-of-fixes strategies into the corridor and broader network funding demands.

Benefits: Quantifications of a reasonable percentage of concrete pavement work with service life needs anywhere from 10 to 60 years.

Products: Advanced mix-of-fixes strategies that address a variety of performance and budget requirements; demonstration of the need to develop additional concrete pavement products that meet price and performance criteria.

Implementation: The analysis of economic and systemic impacts of mix-of-fixes strategies resulting from this research will be made available and useful through technology transfer activities. This problem statement is linked to problem statement 11-2-2.