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

TRACK 12. CONCRETE PAVEMENT SUSTAINABILITY

TRACK 12 OVERVIEW

At its core, sustainability is the capacity to maintain a process or state of being into perpetuity. In the context of human activity, it has been expressed as “Development that meets the needs of the present without compromising the ability of future generations to meet their own needs.”⁽¹⁵⁾ Although not universally accepted, sustainability is often characterized as a three-legged stool supported by economic, environmental, and social considerations or pillars.⁽¹⁶⁾ Although there is often synergistic cooperation between the three pillars, it is also true in practice that a balance must be struck between competing interests. The system is in danger of toppling if only one or two of the pillars are considered because it will be unbalanced.

FHWA has recently initiated a dedicated program to explore sustainability aspects of concrete pavements. Within this program, it is maintained that the key to successfully increasing sustainability of concrete pavements is to consider all three pillars of sustainability by having the tools and data needed to quantify each and understanding the relationship one to one another. Sustainability, in the context of this track, is the use of materials and practices in concrete pavement design, construction, operation, preservation, rehabilitation, and recycling (things we do now) that reduce life-cycle costs, improve the environmental footprint, and increase the benefits to society (things we need to learn to do).

Research into sustainable practices must not only consider new construction, but it must also include the concrete pavement network which already exists. For example, a significant portion of the Nation’s highway system is more than 40 years old, with some portions over 50 years old. The interstate and State primary road construction era of the 1950s, 1960s, and 1970s, much of which featured the use of concrete pavements, was followed by a period of rehabilitation featuring repeated asphalt resurfacings of these pavements. It must be recognized that through the appropriate application of sustainable preservation techniques, the service lives of concrete pavements can be extended for decades without the need for rehabilitation. It is also recognized that as traffic loadings increase, it might be necessary to add structural capacity to the existing pavement. This can be accomplished by selecting improvement techniques such as of concrete overlays. The approach of extending the service life of the original pavement, and therefore maintaining equity, is fundamental to increasing sustainability of an existing system. By choosing an appropriate preservation strategy, the low maintenance attribute of a concrete pavement can be preserved, as opposed to using strategies that can eventually lead to the complete reconstruction of the pavement.

This goal and objectives for this track and the gaps and challenges for its research program are summarized below. 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, then follow.

Track 12 Goal

The goal of this track is to identify and quantify characteristics of concrete pavement systems that contribute to enhanced sustainability of roadways in terms of economic, environmental, and societal considerations.

Track 12 Objectives

The objective of this track is to identify and conduct research and transfer technology that enhances concrete pavement sustainability through the pavement’s life cycle (design, materials selection, construction, operation, preservation, rehabilitation and recycling). Work will include the following:

1. Development of advanced materials and processes that optimize reuse and conservation and measurably reduce waste, energy consumption, water usage, and pollutants generated during all phases of the pavement’s life cycle.
   
   
2. Creation of innovative designs that make full use of the versatility of concrete as a paving material to improve pavement sustainability.
   
   
3. Adoption of construction practices that directly enhance the overall sustainability of concrete pavements through increased efficiency, reduced emissions and waste, and decreased social disruption.
   
   
4. Application of preservation, rehabilitation, and recycling strategies that enhance the sustainability of the existing network of concrete pavements.
   
   
5. Refinement of LCCA to fully account for the economic attributes of sustainable
   concrete pavements.
   
   
6. Acquisition, preservation, and distribution of data as part of an environmental life-cycle inventory (LCI) that accounts for all the individual environmental flows to and from a concrete pavement throughout its entire life cycle, and the adoption of an internationally recognized environmental life-cycle analysis (LCA) approach that examines environmental aspects of concrete pavements through their life cycles.
   
   
7. Further identification and quantification of social considerations that are affected by concrete pavement for inclusion in the integrated design process.
   
   
8. Development of strategy selection criteria to assist in the decision making process, allowing various alternatives to be compared based on economic, environmental, and social considerations.
   
   
9. Application of technology transfer for existing concrete pavement technologies that support the “triple bottom line.”
   
   
10. Coordination and collaboration with work being performed under other CP Road Map tracks.

Track 12 Research Gaps

The track 12 research gaps are as follows:

• Insufficient knowledge in the development and implementation of materials that can have a marked effect on concrete pavement sustainability.
  
  
• Insufficient understanding of sustainability impacts in the design phase with regard to optimization of materials, jointing systems, support, geometry, performance modeling, and construction expediency.
  
  
• Insufficient understanding of construction process impacts on sustainability, including concrete materials and production, transport, placement and consolidation, finishing, curing, and joint sawing, all of which can be made more sustainable through increased efficiency, reduced waste, and quality improvements.
  
  
• Insufficient understanding of the impact on sustainability of construction sequencing and traffic flow through construction zones.
  
  
• Lack of modeling techniques to anticipate optimal timing of various preservation treatments and increased efficiency and longevity of the treatments applied.
  
  
• Lack of design methods for overlays that include sustainability parameters. Research is also needed to investigate interactions with the original pavement, bond longevity, slab geometry effects, and continued fatigue damage to the original pavements.
  
  
• Lack of knowledge on in situ recycling and making full use of recycled concrete aggregate in all layers of the newly constructed pavement, including new concrete.
  
  
• Insufficient methods for LCCA for estimating initial cost, timing, cost of preservation and rehabilitation, and the value at the end of life.
  
  
• Lack of a robust and unbiased environmental LCA quantification process to identify the most desirable solution.
  
  
• Lack of consensus on considering and quantifying other environmental and social considerations for LCA, including vehicular fuel efficiency, surface reflectivity (for visibility and heat island effect), friction/wet weather safety, noise, storm water runoff, and treatment of smog.

Track 12 Research Challenges

The track 12 research challenges are as follows:

• Developing standards and recommendations for the use of sustainable materials.
  
  
• Developing standard procedures and recommendations for LCCA and LCA.

Research Track 12 Estimated Costs

Table 64 shows the estimated costs for this research track.

Track 12 Organization: Subtracks and Problem Statements

Track 12 problem statements are grouped into the following nine subtracks:

• Subtrack 12-1. Materials and Mixture Proportioning Procedures for Sustainable Concrete Pavements.
  
  
• Subtrack 12-2. Design Procedures for Sustainable Concrete Pavements.
  
  
• Subtrack 12-3. Construction Practices for Sustainable Concrete Pavements.
  
  
• Subtrack 12-4. Preservation, Rehabilitation, and Recycling Strategies for Sustainable Concrete Pavements.
  
  
• Subtrack 12-5. Improved Economic Life-Cycle Cost Analysis for Sustainable Concrete Pavements.
  
  
• Subtrack 12-6. Adoption and Implementation of Environmental Life-Cycle Assessment for Sustainable Concrete Pavements.
  
  
• Subtrack 12-7. Design Procedures for Sustainable Concrete Pavements.
  
  
• Subtrack 12-8. Concrete Pavement Decisions with Environmental Impact.

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 12-1. MATERIALS AND MIXTURE PROPORTIONING PROCEDURES FOR SUSTAINABLE CONCRETE PAVEMENTS

Table 65 provides an overview of this subtrack.

Problem Statement 12-1-1. New Generation Concrete Mixtures for Sustainable Pavements

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-1. Materials and Mixture Proportioning Procedures for Sustainable Concrete Pavements.
  
  
• Approximate duration: 2 years.
  
  
• Estimated cost: $500,000.

Current proportioning methods for concrete mixtures are empirically based and do not consider the impact of decisions made on economic, environmental, and societal impacts. Guidelines need to be developed that allow practitioners to access new and existing systems to make wise decisions that go beyond simply making the cheapest mix.

The tasks include the following:

1. Review tools available.
   
   
2. Review mix proportioning approaches.
   
   
3. Develop guidelines.
   
   
4. Publish guidelines.

Benefits: Reduced impact due to use of cementitious materials in concrete pavements.

Products: Guidelines for mix proportioning.

Implementation: Implementation of the guidelines developed.

Problem Statement 12-1-2. Use of Supplementary Cementitious Materials for Sustainable Concrete Pavements

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-1. Materials and Mixture Proportioning Procedures for Sustainable Concrete Pavements.
  
  
• Approximate duration: 2 years.
  
  
• Estimated cost: $400,000.

SCMs have been used extensively in concrete pavements for several decades, primarily for their technical and economic benefits. Work needs to be conducted that will review the environmental effects of their use and to recommend dosages that maximize sustainable benefits without compromising engineering performance.

The tasks include the following:

1. Review environmental effects of SCMs.
   
   
2. Review SCM effects on mixture performance.
   
   
3. Develop guidelines for dosage envelopes.
   
   
4. Publish guidelines.

Benefits: Reduced impact due to use of SCMs in concrete pavements.

Products: Guidelines for SCM usage.

Implementation: Implementation of the guidelines developed.

Problem Statement 12-1-3. Use of Low-Impact Local and Recycled Materials in Sustainable Concrete Pavements

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-1. Materials and Mixture Proportioning Procedures for Sustainable Concrete Pavements.
  
  
• Approximate duration: 2 years.
  
  
• Estimated cost: $600,000.

Usage of recycled materials is growing in usage in concrete pavements. Work needs to be conducted that will review the environmental effects of its use, assembles current knowledge, and recommends protocols for its use without compromising engineering quality.

The tasks include the following:

1. Review environmental effects of recycled materials.
   
   
2. Review recycled materials effects on mixture performance.
   
   
3. Develop guidelines for selection, dosage, and QA.
   
   
4. Publish guidelines.

Benefits: Reduced impact due to use of recycled materials in concrete pavements.

Products: Guidelines for recycled materials usage.

Implementation: Implementation of the guidelines developed.

Problem Statement 12-1-4. Carbon Neutral and Carbon Sequestering Cements for Sustainable Concrete Pavements

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-1. Materials and Mixture Proportioning Procedures for Sustainable Concrete Pavements.
  
  
• Approximate duration: 3 years.
  
  
• Estimated cost: $1 million.

Cements that produce lower carbon dioxide during their manufacture are being developed. Work is needed to investigate their cost, environmental impact, constructability, and durability in concrete pavements. Guidelines need to be developed to help specifiers make decisions regarding their acceptability and use.

The tasks include the following:

1. Review economic and environmental effects of carbon dioxide neutral cements.
   
   
2. Review materials effects on mixture performance in fresh and hardened states.
   
   
3. Develop guidelines for selection, dosage, and QA.
   
   
4. Publish guidelines.

Benefits: Reduced impact due to use of innovative cementitious materials in concrete pavements.

Products: Guidelines for innovative cementitious materials usage.

Implementation: Implementation of the guidelines developed.

Problem Statement 12-1-5. Durability-Enhancing Admixtures for Sustainable Concrete Pavements

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-1. Materials and Mixture Proportioning Procedures for Sustainable Concrete Pavements.
  
  
• Approximate duration: 1–3 years.
  
  
• Estimated cost: $300,000–$500,000.

The admixture industry is working to develop and implement innovative materials that enhance the performance of concrete mixtures for pavements. Work is needed to investigate their cost, environmental impact, constructability, and durability in concrete pavements. Guidelines need to be developed to help specifiers make decisions regarding their acceptability and use.

The tasks include the following:

1. Review economic and environmental effects of chemical admixtures.
   
   
2. Review the effects of chemical admixtures on mixture performance in fresh and hardened states.
   
   
3. Develop guidelines for evaluation, selection, dosage, and QA.
   
   
4. Publish guidelines.

Benefits: Reduced impact due to use of chemical admixtures in concrete pavements.

Products: Guidelines for chemical admixtures usage.

Implementation: Implementation of the guidelines developed.

SUBTRACK 12-2. DESIGN PROCEDURES FOR SUSTAINABLE CONCRETE PAVEMENTS

Table 66 provides an overview of this subtrack.

Problem Statement 12-2-1. Planning Tools to Enhance Concrete Pavement Sustainability from Project Inception

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-2. Design Procedures for Sustainable Concrete Pavements.
  
  
• Approximate duration: 3 years.
  
  
• Estimated cost: $800,000–$1 million.

Current pavement design approaches do not consider the impact of decisions made on economic, environmental, and societal impacts. Guidelines need to be developed that allow practitioners to access new and existing systems to make wise decisions that go beyond simply making the cheapest pavement.

The tasks include the following:

1. Review economic and environmental effects of pavement design.
   
   
2. Develop guidelines for reducing impacts while maintaining engineering quality.
   
   
3. Publish guidelines.

Benefits: Reduced impact due to use of improved design approaches.

Products: Guidelines for pavement design based on sustainable practices.

Implementation: Implementation of the guidelines developed

Problem Statement 12-2-2. Long-Life Design for Sustainable Concrete Pavements

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-2. Design Procedures for Sustainable Concrete Pavements.
  
  
• Approximate duration: 2 years.
  
  
• Estimated cost: $700,000–$900,000.

An integral part of improving sustainability of any construction element is to extend the lifetime, thereby reducing the frequency of repairs or rehabilitation and their associated impacts on materials consumption and traffic delays. There is a need to develop a coherent approach to ensuring that pavements built or repaired in the future will last for their intended lifetime, or beyond, with a reasonable degree of reliability.

The tasks include the following:

1. Review approaches for pavement design and construction that extend the longevity of the systems.
   
   
2. Develop guidelines to implement promising approaches.
   
   
3. Publish guidelines.

Benefits: Reduced impact due to reduced repair and rehabilitation.

Products: Guidelines for pavement design and construction leading to extended lifetimes.

Implementation: Implementation of the guidelines developed.

Problem Statement 12-2-3. Use of Recycled and Industrial Byproducts in Underlying Pavement Layers

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-2. Design Procedures for Sustainable Concrete Pavements.
  
  
• Approximate duration: 2 years.
  
  
• Estimated cost: $400,000.

Associated with the use of recycled materials in concrete mixtures is the potential to use significant quantities of such materials in the pavement support system. There is a need to develop guidelines on the selection and use of such materials without compromising
engineering quality.

The tasks include the following:

1. Review approaches for pavement design and construction that extend the longevity of the systems.
   
   
2. Develop guidelines to implement promising approaches.
   
   
3. Publish guidelines.

Benefits: Reduced impact due to reduced landfill and use of virgin materials.

Products: Guidelines for pavement design and construction using recycled materials.

Implementation: Implementation of the guidelines developed.

Problem Statement 12-2-4. Two-Lift Sustainable Concrete Pavement Construction

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-2. Design Procedures for Sustainable Concrete Pavements.
  
  
• Approximate duration: 2 years.
  
  
• Estimated cost: $1 million.

Construction of concrete pavements using the two-lift technique potentially allows the use of materials that are not ideal for the surface layer or the use of premium materials in the top layer that would be prohibitive in the full section. There is a need to develop guidelines on the selection and use of such a system without compromising engineering quality. There is also a need to be able to quantify the benefits of such an approach in terms of economics, environmental, and societal metrics.

The tasks include the following:

1. Review alternatives for pavement design and construction using two-lift construction systems.
   
   
2. Develop guidelines to quantify and implement promising approaches.
   
   
3. Publish guidelines.

Benefits: Reduced impact due to reduced optimized use of materials.

Products: Guidelines for pavement design and construction using two-lift construction systems.

Implementation: Implementation of the guidelines developed.

Problem Statement 12-2-5. Integration of Optimized Surfaces in Sustainable Concrete Pavement Design

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-2. Design Procedures for Sustainable Concrete Pavements.
  
  
• Approximate duration: 2 years.
  
  
• Estimated cost: $250,000–$350,000.

The surface of a concrete pavement is the interface with traffic and the environment. As such, the quality of the surface has a strong influence on the durability, fuel consumption of traffic, and noise associated with the pavement. There is a need to develop guidelines on the selection and construction of pavement surfaces to minimize negative impacts while providing extended lifetimes.

The tasks include the following:

1. Review alternatives for pavement surface design and construction.
   
   
2. Develop guidelines to implement promising approaches.
   
   
3. Publish guidelines.

Benefits: Reduced impact due to surface effects.

Products: Guidelines for pavement surface design and construction.

Implementation: Implementation of the guidelines developed.

Problem Statement 12-2-6. Precast Sustainable Concrete Pavement Design Systems for the Urban Environment

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-2. Design Procedures for Sustainable Concrete Pavements.
  
  
• Approximate duration: 2 years.
  
  
• Estimated cost: $500,000–$600,000.

The use of precast systems is gaining momentum as a practical means of completing durable pavement rehabilitation without extended construction time, thus significantly reducing disruptions to traffic. There is a need to develop guidelines on the selection, design, and construction of such systems.

The tasks include the following:

1. Review alternatives for precast pavement design and construction.
   
   
2. Develop guidelines to implement promising approaches.
   
   
3. Publish guidelines.

Benefits: Reduced impact due to traffic delays during pavement rehabilitation.

Products: Guidelines for precast pavement construction.

Implementation: Implementation of the guidelines developed.

Problem Statement 12-2-7. Identifying Long-Life Concrete Pavement Types, Design Features, Foundations, and Rehabilitation/Maintenance Strategies

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-2. Design Procedures for Sustainable Concrete Pavement.
  
  
• Approximate duration: 3 years.
  
  
• Estimated cost: $800,000–$1.2 million.

This research will identify both conventional and innovative pavement types likely to provide long life, including an evaluation of the advantages and limitations of different pavement designs for long-life applications and the possible preservation strategies for each pavement type. With certain pavement types, pavement service life may be extended significantly through preservation treatments, although in some design situations, any major pavement treatment within a certain period may be unacceptable. Examples of promising design features include continuous reinforcement, widened slabs, stabilized base, positive subdrainage, large-diameter dowel bars, and uniform and stable foundations. This research will investigate various means of satisfying the long-life pavement goals, considering the entire pavement life cycle and including rehabilitations where appropriate. Site conditions, such as traffic level, subgrade properties, climate, and local aggregate and material properties, significantly affect pavement performance, and feasible pavement strategies will be identified in light of such factors.

The tasks include the following:

1. Evaluate existing concrete pavements that claim to be long life (those currently in design by States, those in service, and those that have been previously rehabilitated including existing high-performance concrete sites).
   
   
2. Identify concrete pavement design features that lend themselves to good LTPP and lower the risk of poor performance (e.g., continuous reinforcement, widened slabs, stabilized base, and large-diameter dowel bars).
   
   
3. Evaluate the effects of the design features identified under task 1 on LTPP and develop a short list of design features that significantly affect LTPP. Use existing survival curves in these studies where available.
   
   
4. Identify both conventional and innovative pavement types likely to provide long life. Consider at least the following:
   
   
5. Full-depth concrete for new construction.
   
   
6. Concrete overlay rehabilitation.
   
   
7. No foundation rehabilitation.
   
   
8. No pavement intrusion over its lifespan.
   
   
9. Additional thin concrete surfacing on the top.
   
   
10. Staged concrete over concrete construction that does not change the foundation.
    
    
11. Identify the various means of satisfying the long-life pavement goals by considering the entire pavement life cycle, including restorations and rehabilitations where appropriate, maintenance done to the joint, and considering that site conditions, such as traffic level, subgrade properties, climate, and local aggregate, significantly affect pavement performance. Consider also environmental sustainability.
    
    
12. For each pavement type identified under task 1, evaluate advantages and limitations for the long life applications including the factors identified in task 2, such as evaluating possible rehabilitation strategies for each pavement type, life-cycle cost, etc.
    
    
13. Determine promising pavement types and strategies for providing long life based on the results of tasks 1 through 3.

Benefits: Feasible pavement strategies for providing long life that will provide input throughout track 9.

Products: Feasible pavement strategies and promising features for providing long life for each type of concrete pavement selected and case studies of past long-life concrete pavements.

This problem statement is linked to problem statement 9-2-1.

SUBTRACK 12-3. CONSTRUCTION PRACTICES FOR SUSTAINABLE CONCRETE PAVEMENTS

Table 67 provides an overview of this subtrack.

Problem Statement 12-3-1. Adoption of Automated and Wireless Control and Quality Monitoring Instrumentation to Improve Construction Quality

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-3. Construction Practices for Sustainable Concrete Pavements.
  
  
• Approximate duration: 3 years.
  
  
• Estimated cost: $750,000–$950,000.

For QA systems to be effective, data should be precise and collected in a timely manner. Rapidly obtained information will allow faster responses to changes and stoppages when a system gets out of control. There is a need to develop devices that report the critical performance characteristics of a mixture for the first few hours after placement and beyond. Systems to collect and interpret the data must accompany the devices.

The tasks include the following:

1. Review alternatives for real-time data collection using embedded devices.
   
   
2. Develop systems to collate and interpret data.
   
   
3. Develop guidelines to implement promising approaches.
   
   
4. Publish guidelines.

Benefits: Improved QA based on automated data collection systems.

Products: Guidelines for automated data collection systems.

Implementation: Implementation of the guidelines developed.

Problem Statement 12-3-2. Increase Energy Efficiency and Reduce Pollution at the Plant and Construction Site

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-3. Construction Practices for Sustainable Concrete Pavements.
  
  
• Approximate duration: 2 years.
  
  
• Estimated cost: $400,000–$600,000.

Environmental impact of pavement construction can be reduced by making the construction process more efficient and cleaner. There is a need to investigate and implement techniques that can be used to achieve this aim.

The tasks include the following:

1. Review and investigate techniques to make the construction process more efficient without compromising engineering quality.
   
   
2. Develop guidelines to implement promising approaches.
   
   
3. Publish guidelines.

Benefits: Reduced pollution and energy consumption on construction sites.

Products: Guidelines for more efficient construction systems.

Implementation: Implementation of the guidelines developed

Problem Statement 12-3-3. Guidelines to Reduce and Eliminate Construction Waste

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-3. Construction Practices for Sustainable Concrete Pavements.
  
  
• Approximate duration: 2 years.
  
  
• Estimated cost: $300,000–$500,000.

Environmental impact of pavement construction can be reduced by cutting back construction waste. There is a need to investigate and implement techniques that can be used to achieve
this aim.

The tasks include the following:

1. Review and investigate techniques to make the construction process more efficient without compromising engineering quality.
   
   
2. Develop guidelines to implement promising approaches.
   
   
3. Publish guidelines.

Benefits: Reduced waste at construction sites.

Products: Guidelines for more efficient construction systems.

Implementation: Implementation of the guidelines developed.

Problem Statement 12-3-4. Guidelines to Minimize the Use of Water During Construction

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-3. Construction Practices for Sustainable Concrete Pavements.
  
  
• Approximate duration: 1 year.
  
  
• Estimated cost: $100,000–$200,000.

Environmental impact of pavement construction can be reduced by cutting back water usage during construction. There is a need to investigate and implement techniques that can be used to achieve this aim.

The tasks include the following:

1. Review and investigate techniques to make the construction process more efficient with respect to water usage without compromising engineering quality.
   
   
2. Develop guidelines to implement promising approaches.
   
   
3. Publish guidelines.

Benefits: Reduced waste at construction sites.

Products: Guidelines for more efficient construction systems.

Implementation: Implementation of the guidelines developed.

Problem Statement 12-3-5. Innovative Curing Methodologies for Sustainable Concrete Pavements

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-3. Construction Practices for Sustainable Concrete Pavements.
  
  
• Approximate duration: 12 years.
  
  
• Estimated cost: $200,000–$300,000.

Concrete longevity is directly affected by the quality of the concrete in the top surface, which, in turn, is governed by the effectiveness of the curing regime. There is a need to investigate techniques to ensure effective curing and to implement them.

The tasks include the following:

1. Review and investigate techniques to ensure effective curing.
   
   
2. Develop guidelines to implement promising approaches.
   
   
3. Publish guidelines.

Benefits: Improved concrete quality.

Products: Guidelines for more effective curing techniques.

Implementation: Implementation of the guidelines developed.

SUBTRACK 12-4. PRESERVATION, REHABILITATION, AND RECYCLING STRATEGIES FOR SUSTAINABLE CONCRETE PAVEMENTS

Table 68 provides an overview of this subtrack.

Problem Statement 12-4-1. Use of Advanced Sensors to Monitor the Quality and Health of Concrete Pavements

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-4. Preservation, Rehabilitation, and Recycling Strategies for Sustainable Concrete Pavements.
  
  
• Approximate duration: 3–4 years.
  
  
• Estimated cost: $800,000–$1.2 million.

Preventative maintenance and repairs to pavements can be more cost effective if data are available on the current condition of the system. Embedded sensors would be helpful in this data collection. There is a need to develop devices that report the critical performance characteristics of a pavement through its life. Systems to collect the data and interpret it must accompany the devices.

The tasks include the following:

1. Review alternatives for real-time data collection using embedded devices.
   
   
2. Develop systems to collate and interpret data.
   
   
3. Develop guidelines to implement promising approaches.
   
   
4. Publish guidelines.

Benefits: Improved concrete longevity at reduced cost.

Products: Guidelines for embedded devices.

Implementation: Implementation of the guidelines developed.

Problem Statement 12-4-2. Concrete Pavement Performance Modeling for Improved Timing of Preservation and Rehabilitation

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-4. Preservation, Rehabilitation, and Recycling Strategies for Sustainable Concrete Pavements.
  
  
• Approximate duration: 3 years.
  
  
• Estimated cost: $800,000–$1 million.

Preventative maintenance and repairs to pavements can be more cost effective if information is available on the rate of deterioration of the system. Models to analyze available data would be helpful in this data collection. There is a need to develop models to predict the critical performance characteristics of a pavement through its life.

The tasks include the following:

1. Review alternative models for data analysis on pavement condition.
   
   
2. Develop new systems.
   
   
3. Develop guidelines to implement promising approaches.
   
   
4. Publish guidelines.

Benefits: Improved concrete longevity at reduced cost.

Products: Guidelines for pavement condition modeling.

Implementation: Implementation of the guidelines developed.

Problem Statement 12-4-3. Innovative Preservation and Restoration Strategies

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-4. Preservation, Rehabilitation, and Recycling Strategies for Sustainable Concrete Pavements.
  
  
• Approximate duration: 3 years.
  
  
• Estimated cost: $750,000.

Preventative maintenance and repairs to pavements can be more cost effective using innovative approaches. There is a need to investigate, assess, and implement such approaches.

The tasks include the following:

1. Review alternative models for preservation and restoration.
   
   
2. Develop guidelines to implement promising approaches.
   
   
3. Publish guidelines.

Benefits: Improved concrete longevity at reduced cost.

Products: Guidelines for pavement restoration.

Implementation: Implementation of the developed guidelines.

Problem Statement 12-4-4. In Situ Concrete Pavement Recycling Techniques

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-4. Preservation, Rehabilitation, and Recycling Strategies for Sustainable Concrete Pavements.
  
  
• Approximate duration: 3 years.
  
  
• Estimated cost: $800,000–$1.2 million.

Usage of recycled materials is growing in usage in concrete pavements. An efficient use of such materials is to recycle the existing pavement either into new concrete or into the base layers. Work needs to be conducted to review the environmental effects of its use, assemble current knowledge, and recommend protocols for its use without compromising engineering quality.

The tasks include the following:

1. Review environmental effects of recycling in situ materials.
   
   
2. Develop guidelines for selection, dosage, and QA.
   
   
3. Publish guidelines.

Benefits: Reduced impact due to the use of recycled materials in concrete pavements.

Products: Guidelines for recycled materials usage.

Implementation: Implementation of the guidelines developed.

Problem Statement 12-4-5. Concrete Overlay Construction Through Innovative Techniques and Equipment

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-4. Preservation, Rehabilitation, and Recycling Strategies for Sustainable Concrete Pavements.
  
  
• Approximate duration: 2 years.
  
  
• Estimated cost: $400,000–$500,000.

An effective approach to making the best use of the equity in an existing, albeit deteriorated, pavement is to apply concrete overlays. Work needs to be conducted to review the environmental and engineering benefits of this approach and to develop innovative ways to apply them.

The tasks include the following:

• Review environmental and engineering effects of innovative overlay construction.
  
  
• Develop guidelines for selection, dosage, and QA.
  
  
• Publish guidelines.

Benefits: Reduced costs by using existing equity in pavements.

Products: Guidelines for overlay construction.

Implementation: Implementation of the developed guidelines.

Problem Statement 12-4-6. Recycled Concrete Processing/Improvement

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-4. Preservation, Rehabilitation, and Recycling Strategies for Sustainable Concrete Pavements.
  
  
• Approximate duration: 4 years.
  
  
• Estimated cost: $1–$2 million.

Reconstructing concrete pavements produces large stockpiles of old concrete material that can be reused in some form for new construction. Several studies have examined sophisticated methods to separate concrete into components that can be used as aggregates and cement precursors. One method heats concrete to between 1,202 and 1,292 °F in an electrical furnace. Another promising technology called Franka-Stein treats concrete in a powerful electric arc using electrodynamic fragmentation, which separates the electrically weak material boundaries prevalent in concrete. In addition to producing clean aggregate, the Franka-Stein process separates cementitious material that can replace natural raw material in cement production. Research is needed to further investigate these recycling methods to determine their cost effectiveness, considering the energy consumption of the separation process.

The tasks include the following:

1. Identify existing processes for separating recycled concrete including Franka-Stein and others.
   
   
2. Evaluate the effectiveness of the separation processes and the suitability of the resulting material for reuse in new concrete pavement.
   
   
3. Evaluate the cost versus benefit of different recycling processes, considering the energy consumption of the separation process.
   
   
4. Work with contractors and industry representatives to develop new equipment or modify and adapt existing equipment for rapid recycling of concrete pavement.

Benefits: Equipment that will separate crushed concrete properly into materials that can be used for new concrete, minimizing or eliminating waste from reconstructed concrete pavements.

Products: Equipment and recommendations for separating crushed concrete into usable materials.

Implementation: This work will result in equipment for recycling and processing concrete pavement and recommendations for using recycled materials in new concrete. This problem statement is linked to problem statement 5-5-2.

SUBTRACK 12-5. IMPROVED ECONOMIC LIFE-CYCLE COST ANALYSIS FOR SUSTAINABLE CONCRETE PAVEMENTS

Table 69 provides an overview of this subtrack.

Problem Statement 12-5-1. Establish Key Input Parameters to Conduct an Economic Life-Cycle Cost Analysis

• Track: 12. Concrete Pavement Sustainability.
• Subtrack: 12-5. Improved Economic Life-Cycle Cost Analysis for Sustainable Concrete Pavements.
• Approximate duration: 2–4 years.
• Estimated cost: $800,000–$1 million.

A valid cost analysis of alternative pavement systems must include the full life cycle. For the analysis to be sufficiently precise, the input parameters have to be the right ones, and the data used also have to be correct. Work needs to be conducted that will review the current economic models to ensure that the parameters in use are appropriate.

The tasks include the following:

1. Review input parameters used in LCCA.
2. Develop guidelines for selection of parameters and sources of data.
3. Publish guidelines.

Benefits: Improved LCCA models.

Products: Guidelines for LCCA.

Implementation: Implementation of the guidelines developed.

Problem Statement 12-5-2. Development of a User-Friendly Life-Cycle Cost Analysis Tool

• Track: 12. Concrete Pavement Sustainability.
• Subtrack: 12-5. Improved Economic Life-Cycle Cost Analysis for Sustainable Concrete Pavements.
• Approximate duration: 2 years.
• Estimated cost: $300,000.

A valid cost analysis of alternative pavement systems must include the full life cycle. Work needs to be conducted that will review the current economic models to ensure that they are sufficient.

The tasks include the following:

1. Review input models used in LCCA.
2. Develop guidelines for selection and use of models.
3. Publish guidelines.

Benefits: Improved LCCA models.

Products: Guidelines for LCCA.

Implementation: Implementation of the developed guidelines.

SUBTRACK 12-6. ADOPTION AND IMPLEMENTATION OF ENVIRONMENTAL LIFE-CYCLE ASSESSMENT FOR SUSTAINABLE CONCRETE PAVEMENTS

Table 70 provides an overview of this subtrack.

Problem Statement 12-6-1. Create and Maintain a Concrete Pavement Specific Environmental Life-Cycle Inventory

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-6. Adoption and Implementation of Environmental Life-Cycle Assessment for Sustainable Concrete Pavements.
  
  
• Approximate duration: 3–4 years.
  
  
• Estimated cost: $1–$1.5 million.

A valid environmental analysis of alternative pavement systems must include the full life cycle. For the analysis to be sufficiently precise, the input parameters have to be the right ones, and the data used also have to be correct. Work needs to be conducted that will review and collect valid and up to date LCI data needed for all materials and systems used in concrete pavements.

The tasks include the following:

1. Collect, review, and store LCI data.
   
   
2. Make data available to users.
   
   
3. Publish guidelines.

Benefits: Single source for LCI data.

Products: LCI database.

Implementation: Make database available to users.

Problem Statement 12-6-2. Identify and Rank Environmental Impact Categories that Affect Concrete Pavement Sustainability

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-6. Adoption and Implementation of Environmental Life-Cycle Assessment for Sustainable Concrete Pavements.
  
  
• Approximate duration: 2 years.
  
  
• Estimated cost: $500,000–$700,000.

A valid environmental analysis of alternative pavement systems must include the full life cycle. For the analysis to be sufficiently precise, the correct impact categories have to be analyzed. Work needs to be conducted that will review and recommend which categories should be included in an analysis.

The tasks include the following:

1. Collect, review, and store LCI data.
   
   
2. Make data available to users.
   
   
3. Publish guidelines.

Benefits: Appropriate LCA tools.

Products: List of LCA categories.

Implementation: Make data available to users.

Problem Statement 12-6-3. User-Friendly Internationally Acceptable Environmental Life-Cycle Assessment Toolkit for Sustainable Concrete Pavements

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-6. Adoption and Implementation of Environmental Life-Cycle Assessment for Sustainable Concrete Pavements.
  
  
• Approximate duration: 2 years.
  
  
• Estimated cost: $200,000–$300,000.

A valid environmental analysis of alternative pavement systems must include the full life cycle. For the analysis to be usable, a toolkit is required that assists operators through the process of conducting a complex LCA. Work needs to be conducted to develop such a toolkit.

The tasks include the following:

1. Develop toolkit for LCA for pavements.
   
   
2. Make toolkit available to users.

Benefits: Appropriate LCA tools.

Products: LCA toolkit.

Implementation: Make toolkit available to users.

Problem Statement 12-6-4. Guidelines and Implementation Package for Conducting an Environmental Life-Cycle Assessment of Pavement Alternatives

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-6. Adoption and Implementation of Environmental Life-Cycle Assessment for Sustainable Concrete Pavements.
  
  
• Approximate duration: 1–3 years.
  
  
• Estimated cost: $350,000–$450,000.

A valid environmental analysis of alternative pavement systems must include the full life cycle. For the analysis to be usable, users need training in how to conduct a complex analysis appropriately.

The tasks include the following:

1. Develop training materials for LCA for pavements.
   
   
2. Train users in use of the toolkit.

Benefits: Appropriate LCA tools.

Products: LCA training.

Implementation: Provide training to users.

SUBTRACK 12-7. DESIGN PROCEDURES FOR SUSTAINABLE CONCRETE PAVEMENTS

Table 71 provides an overview of this subtrack.

Problem Statement 12-7-1. Innovative Approaches to Remove Pollutants from Air and Water Using Concrete Pavements

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-7. Design Procedures for Sustainable Concrete Pavements.
  
  
• Approximate duration: 3 years.
  
  
• Estimated cost: $1–$1.5 million.

Concrete pavements have a relatively large surface area and have a strong influence on surface flow of rainwater. Work is needed to investigate the potential to include innovative catalysts in the mixture that will initiate or assist with reducing pollution concentrations in water and air in contact with the surface. Such compounds may include but are not limited to titanium dioxide-based materials.

The tasks include the following:

1. Investigate potential catalysts.
   
   
2. Perform laboratory tests of catalyst effectiveness.
   
   
3. Perform field tests of catalyst effectiveness.
   
   
4. Implement.

Benefits: Reduced pollution.

Products: Recommendations on use of pollution-reducing systems.

Implementation: Publish recommendations and provide training to users.

Problem Statement 12-7-2. Quantify and Document the Impact of Pavement Reflectivity on the Urban Heat Island

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-7. Design Procedures for Sustainable Concrete Pavements.
  
  
• Approximate duration: 2 years.
  
  
• Estimated cost: $1 million.

Concrete pavements have a relatively large surface area and may have a strong influence on air temperatures. Work is needed to quantify the magnitude of this effect and the factors that affect it.

The tasks include the following:

1. Investigate effects of pavement color on local air temperatures.
   
   
2. Develop relationships between temperature and pavement characteristics.
   
   
3. Develop recommendations.
   
   
4. Conduct technology transfer activities.

Benefits: Reduced heat island effects.

Products: Recommendations on preferred pavement colors.

Implementation: Publish recommendations and provide training to users.

Problem Statement 12-7-3. Quantify and Document Artificial Lighting Needs for Various Pavement Surface Reflectivities and Optimize for Energy Savings

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-7. Design Procedures for Sustainable Concrete Pavements.
  
  
• Approximate duration: 2 years.
  
  
• Estimated cost: $1 million.

Concrete pavements have a relatively large surface area and have a strong influence on lighting needs for traffic. Work is needed to quantify the change in energy required for traffic based on pavement color.

The tasks include the following:

1. Investigate effects of pavement color on lighting needs for safety.
   
   
2. Develop relationships between lighting and pavement characteristics.
   
   
3. Develop recommendations.
   
   
4. Conduct technology transfer activities.

Benefits: Reduced energy required for lighting.

Products: Recommendations on preferred pavement colors.

Implementation: Publish recommendations and provide training to users.

Problem Statement 12-7-4. Determine, Quantify, and Optimize Pavement Factors that Contribute to Public Health and Safety

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-7. Design Procedures for Sustainable Concrete Pavements.
  
  
• Approximate duration: 5–7 years.
  
  
• Estimated cost: $2–$3 million.

Many factors related to pavement construction and use impact public health and safety. There is a lack of cohesive information about these affects. Work is needed to develop a central resource where information on these factors can be accessed.

The tasks include the following:

1. Investigate and quantify effects of pavements on public health and safety.
   
   
2. Develop relationships between pavement characteristics and public health and safety.
   
   
3. Develop recommendations.
   
   
4. Conduct technology transfer activities.

Benefits: Improved public health and safety.

Products: Recommendations for pavement construction and use as they impact public health and safety.

Implementation: Publish recommendations.

Problem Statement 12-7-5. Tire-Pavement Noise Sensing

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-7. Design Procedures for Sustainable Concrete Pavements.
  
  
• Approximate duration: 2 years.
  
  
• Estimated cost: $500,000–$1 million.

Tire-pavement noise is important to consider in concrete pavement construction, and many States have implemented noise-level restrictions on new pavement construction. Tire-pavement noise can increase the cost of a paving project significantly if noise mitigation measures are required. Therefore, determining potential tire-pavement noise during construction is important if measures are to be taken to reduce noise levels. Research to develop techniques and equipment for measuring pavement noise potential during construction is needed. Sensing equipment mounted to the paving train immediately behind the finishing and texturing operations could sense and predict noise potential in real time. This information would allow the contractor to adjust the paving equipment to reduce noise potential and perhaps correct in-place concrete that is still plastic. Noise-sensing equipment will provide instant results for a large enough section of pavement to indicate the noise potential for whole surfaces adequately.

The tasks include the following:

1. Identify surface texture measurement techniques/equipment that can predict tire-pavement noise.
   
   
2. Modify existing equipment or develop new techniques/equipment that predict tire-pavement noise from surface texture measurements on fresh concrete.
   
   
3. Develop necessary correlations between surface texture measurement and pavement noise.
   
   
4. Validate noise-sensing equipment on actual paving projects.
   
   
5. Develop recommendations for deploying noise-sensing equipment.

Benefits: Prediction of tire-pavement noise potential during construction, allowing surface textures to be corrected while the concrete is still plastic and automatic adjustments to the surface texturing process to meet the tire-pavement noise restrictions and as-constructed pavements that meet stringent tire-pavement noise restrictions without the need for additional noise mitigation.

Products: Equipment for predicting pavement noise characteristics during construction.

Implementation: This work will result in noise-sensing equipment that can be used for new PCC pavement construction. This problem statement is linked to problem statement 3-2-11.

Problem Statement 12-7-6. Precast Quiet Pavement Surfaces

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-7. Design Procedures for Sustainable Concrete Pavements.
  
  
• Approximate duration: 5 years.
  
  
• Estimated cost: $500,000–$1 million.

Pavement noise, or the noise generated by tires on a pavement surface, is an important consideration in PCC pavement construction, particularly in urban areas. Different surface textures are being examined constantly for their effectiveness in reducing pavement noise. Unfortunately, many of the most promising surface textures are difficult to construct properly in the field. Precast concrete pavement panels, however, are cast in a controlled environment, affording a great deal of flexibility with surface texture. New surface texture technologies, such as extruded channels, are currently being evaluated abroad. While such textures may be difficult to construct in the field, they can be easy to incorporate into precast pavement panels. This research will identify new surface textures that show promise for reducing pavement noise, and it will evaluate the feasibility of incorporating them into precast pavement panels.

The tasks include the following:

1. Identify surface texture techniques that have been shown to reduce pavement noise.
   
   
2. Evaluate the feasibility of incorporating these surface textures into precast pavement panels versus conventional (slipform or fixed-form) PCC construction.
   
   
3. Evaluate the benefits versus costs of using precast panels with noise-reducing surface texture for PCC pavement construction.
   
   
4. Develop case studies or pilot projects that incorporate noise-reducing surface textures into precast pavement and evaluate their effectiveness.

Benefits: Exploration of noise-reducing techniques that may not be viable for conventional concrete pavements but that can be incorporated into precast concrete pavements.

Products: Recommendations for noise-reducing techniques for precast concrete
pavement surfaces.

Implementation: This research will be used to evaluate the viability of precast pavement with specialized, noise-reducing surface textures versus conventional pavement construction with conventional surface textures. This problem statement is linked to problem statement 8-2-5.

SUBTRACK 12-8. CONCRETE PAVEMENT DECISIONS WITH ENVIRONMENTAL IMPACT

Table 72 provides an overview of this subtrack.

Problem Statement 12-8-1. Strategic and Technical Issues Related to the Design and Construction of Truck-Only Concrete Pavements

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-8. Concrete Pavement Decisions with Environmental Impact.
  
  
• Approximate duration: Not available.
  
  
• Estimated cost: $250,000–$500,000.

The United States has seen dramatic increases in truck traffic over the past several decades, with truck traffic on some roadways approaching 50 percent. Private vehicle drivers often resent this level of truck traffic. Under the Public-Private Transportation Act, the Virginia Department of Transportation is examining proposals that would use exclusive truck lanes along the I–81 corridor. This research will consider the unique options involved in designing concrete pavement for truck-only lanes.

The tasks include the following:

1. Examine the geometrics associated with truck-only lanes including shoulders, lane widths, curvatures, speed limits, and breaking distances.
   
   
2. Examine size and weight issues for various concrete pavement designs, examining JCP and CRCP options.
   
   
3. Develop several pavement life-cycle options, including a maintenance tree and user costs for various rehabilitation options.

Benefits: Research that will help the highway community address the issue of truck-only lanes, specifically examining how concrete pavements might handle the loads associated with truck-only lanes.

Products: A thorough examination of the strategic policy and technical issues involved in designing concrete pavements for truck-only roadways or lanes.

Implementation: The results of this research will be implemented through technology sharing and application.

Problem Statement 12-8-2. Concrete Pavement Restoration Guidelines Specifically for City Streets and Arterials

• Track: 12. Concrete Pavement Sustainability.
  
  
• Subtrack: 12-8. Concrete Pavement Decisions with Environmental Impact.
  
  
• Approximate duration: Not available.
  
  
• Estimated cost: $250,000–$500,000.

While many State highway agencies have specifications for CPR, cities could benefit from specifications that directly address the unique problems associated with city streets and arterials. These problems include design methodologies, construction specification language, materials specifications, and installation guidelines.

The tasks include the following:

1. Develop a simplified pavement evaluation technique that includes criteria for specific techniques.
   
   
2. Develop a simplified CPR design procedure that addresses problems unique to city streets. Examine lateral injection thoroughly in the study.
   
   
3. Develop guide specification language that includes warranties and an area management approach.
   
   
4. Update existing installation guidelines to assure that they relate to city and county officials.
   
   
5. Develop final construction evaluation techniques that cities can use to determine compliance.

Benefits: Simplified guidelines that cities and counties can use to determine when and how to use CPR techniques; guide specifications that will let cities and counties more rationally decide how to use CPR techniques on their streets.

Products: CPR guidelines for city engineers and inspectors.

Implementation: The results of this research will be implemented through technology transfer activities.