Long-Term Plan for Concrete Pavement Research and Technology - The Concrete Pavement Road Map: Volume II, Tracks

1. Examine the problem statements in subtrack ND 1 (Field Control), modify as appropriate, and divide them into specific, manageable contracts.
2. Arrange the contracts in a carefully sequenced plan that reflects a logical progress of research and available funding.
3. Expand each of the broad research problem statements included in the subtrack into a detailed research plan with specific objectives, tasks, and funding recommendations.
4. Review and provide direction for the various research contracts underway to ensure that they fulfill their objectives and allow future contracts to use their results. Guide the additional work required if a contract fails to achieve its objectives and additional work is necessary.

1. Identify performance-based concrete mix design properties.
2. Determine suitable limits for performance-based mix design properties.
3. Identify techniques/devices that can determine the desired mix design properties.
4. Modify existing devices/techniques or develop new devices for measuring the mix design parameters accurately in the field, producing the same results as laboratory tests.
5. Develop recommendations for deploying field tests on projects using performance-based mix designs.

1. Identify all tests required for field validation.
2. Work with owner-agencies to identify test validation locations that represent different climatic conditions, materials, pavement types, construction procedures, and mix designs.
3. Work with contractors and owner-agencies to perform validation testing at various field sites.
4. Evaluate repeatability, reliability, and variability for each test.
5. Recommend improvements to test equipment and procedures.
6. Document the best practices for performing field validation tests.

1. Identify the concrete properties shown to affect concrete pavement performance, including parameters indirectly affecting performance (i.e., properties that may affect constructability and thereby affect pavement performance).
2. Determine limits for performance-based properties.
3. Identify practical field tests for measuring mix properties.
4. Develop recommendations concerning PRS for mix properties.

1. Examine the problem statements in subtrack ND 2 (Nondestructive Methods), modify as appropriate, and divide them into specific, manageable contracts.
2. Arrange the contracts in a carefully sequenced plan that reflects a logical progress of research and available funding.
3. Expand each of the broad research problem statements included in the subtrack into a detailed research plan with specific objectives, tasks, and funding recommendations.
4. Review and provide direction for the various research contracts underway to ensure that they fulfill their objectives and allow future contracts to use their results. Guide the additional work required if a contract does not achieve its objectives and additional work is necessary.

1. Identify NDT methods and devices for temperature and moisture sensing.
2. Determine the reliability and variability of the test methods and devices under field conditions.
3. Modify existing devices or develop practical new devices that accurately monitor temperature and moisture during pavement construction.
4. Develop recommendations for deploying NDT techniques/devices for temperature and moisture monitoring.

1. Identify existing NDT techniques that determine pavement thickness.
2. Determine the variability of existing methods and assess whether this variability is acceptable for QC testing.
3. Modify existing nondestructive techniques or develop new techniques that measure slab thickness at intervals as short at 30.5 cm (1 ft) quickly, accurately, and cost effectively.
4. Develop recommendations for deploying nondestructive thickness sensing devices.

Many transportation agencies use dowel and tie bars to ensure adequate load transfer across joints in concrete pavements. If constructed properly, dowel bars should be exactly parallel to both the surface and centerline of the hardened slab. Unfortunately, this is not always the case, as misalignment can occur from either misplacement (incorrect initial positioning of the dowels), displacement (movement during the paving operation), or both. Tie bars should be centered over a longitudinal joint to secure adjacent slabs effectively. Misaligned dowel bars can cause joints to lock-up or even fault, and thus significantly affect pavement performance. There is no clear consensus among agencies on the level of practical limits on dowel placement tolerances. Normally, a maximum allowable alignment error of 0.64 cm (0.25 inch) per 45.7 cm (18 inches) length of dowel bar is specified, although the Georgia DOT specifies an allowable tolerance of 7.2 cm (3 inches) per 2.4 m (8 ft) both horizontally and vertically, and several other agencies specify an allowable tolerance of 2.5 cm (1 inch) per 1.2 m (4 ft) both horizontally and vertically. Unfortunately, these specifications are difficult to enforce because there is no efficient and reliable technique for determining in situ dowel misalignment. However, recent development of the MITSCAN-2 and MIT-SCAN-2F devices has provided an opportunity to obtain accurate dowel position information efficiently and cost effectively.

Research is needed that either modifies existing dowel bar alignment sensing equipment or develops new equipment for use during the paving process. Real-time measurements of dowel bar alignment immediately behind the paving operation will alert the contractor and inspectors to alignment problems, allowing for paver adjustments and possible corrections to misaligned dowel bars.

1. Identify existing nondestructive dowel and tie bar alignment sensing devices.
2. Modify existing devices or develop new devices that permit testing during the paving operation.
3. Evaluate the accuracy of the devices on actual pavement sections and make recommendations for deploying the devices for concrete paving construction projects.

1. Identify existing moisture sensors or other devices that measure curing effectiveness.
2. Modify existing devices or develop new devices to monitor curing effectiveness.
3. Validate curing effectiveness detection devices on paving projects.
4. Develop recommendations for deploying curing effectiveness detection devices.

1. Identify existing nondestructive support-sensing devices.
2. Modify existing devices or develop new devices that continuously monitor pavement support layers.
3. Integrate support-sensing devices into the paving operation to make adjustments automatically.
4. Validate support-sensing equipment on actual paving projects.
5. Develop recommendations for deploying support-sensing equipment on paving projects.

1. Identify techniques/equipment for measuring concrete workability.
2. Modify existing equipment or develop new equipment that continuously monitors mix workability.
3. Validate workability sensing equipment on actual paving projects.
4. Integrate workability sensing equipment with automated batching and paving equipment.
5. Develop recommendations for deploying workability sensing equipment.

Placement activities, such as slipform paving, reduce the quantity of entrained air in concrete by as much as 2 percent. Air tests are not currently taken after slipform paving, but rather are taken from samples either at the plant or in front of the paving machine. However, this testing procedure systematically ignores the impact of the pavement placement operation on air content. Durability studies have revealed problems with freeze-thaw damage due to an inadequate quantity of entrained air. Studies also show that both the amount of entrained air and the spacing between the air bubbles is important. Air tests are not taken behind the paving machine primarily because these tests are destructive. The current testing standard, ASTM C 231, would require removing concrete from the finished slab.

This research will develop a test method or procedure to determine the air content (amount and spacing of bubbles) of plastic concrete after paving. Although the air void analyzer has been shown to indicate air content (amount and spacing of bubbles) accurately, it still usually requires that concrete be removed from the finished surface, and the testing apparatus is not necessarily suited for field applications. This research will identify appropriate technology to create accurate and durable test equipment that can determine air content properties quickly, permitting automatic adjustments to mix proportions.

1. Identify existing equipment for classifying air content (quantity and bubble spacing) accurately.
2. Modify existing equipment or develop new durable and economical automated equipment/sensors that can assess air content behind the paver quickly.
3. Validate air sensing equipment on actual paving projects.
4. Integrate automated air sensing equipment/sensors with batching and paving equipment.
5. Develop recommendations for deploying air sensing equipment for paving operations.

1. Develop sensing equipment that can determine the density of the mixture and volumetric proportions of concrete constituents quickly.
2. Validate density and volumetric sensing equipment on an actual paving project.
3. Develop recommendations for deploying automated sensing equipment.

The California Profilograph is the equipment most commonly used to measure pavement smoothness, providing information to the contractor in as little as 4 to 6 hours after placing conventional concrete pavement. While this is the fastest available method for providing smoothness information, it is not fast enough to indicate bumps or dips to the paving crew during finishing operations. Wet smoothnessmeasuring devices that can be mounted to slipform machines or a trailing construction bridge are needed. These devices will provide direct feedback to the paving finishing crew and to automated paving equipment. The crew can then eliminate surface deviations while the concrete remains plastic, and the paving machine could adjust to correct smoothness irregularities caused by the paver. This method will provide a uniform surface and eliminate areas that must be ground after construction.

This research will develop a wet smoothness-measuring device that produces information translatable to the California Profile Index or IRI. Evaluating the accuracy of the smoothness-measuring device will be necessary to demonstrate its accuracy relative to the California Profilograph. In addition, a manual describing the testing equipment and indexing procedure should be developed to implement this equipment and procedure.

1. Identify wet smoothness-measuring devices.
2. Adapt the smoothness-measuring devices to slipform paving operations.
3. Develop a system that combines the new smoothness measurements with software that automatically calculates the simulated California Profile Index and IRI.
4. Validate the wet smoothness measurements on an actual paving project.
5. Develop recommendations for deploying the smoothness-sensing equipment during the paving operation.

1. Identify surface texture measurement equipment/techniques that can be used on fresh (plastic) concrete to determine skid resistance and splash/spray potential.
2. Identify correlations between surface texture measurements, skid resistance, and splash/spray potential.
3. Modify existing equipment or develop new sensing equipment that measures surface texture properties on fresh concrete.
4. Develop necessary correlations between surface texture properties, skid resistance, and splash/spray potential.
5. Validate surface texture measurement equipment on actual paving projects.
6. Develop recommendations for deploying surface texture sensing equipment.

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.

1. Identify models that have been shown to predict concrete pavement performance based on construction variables.
2. Identify sensing equipment that could be incorporated into the intelligent paving system.
3. Integrate sensors/equipment and models into the intelligent paving system.
4. Validate the intelligent paving system on actual paving projects.
5. Develop recommendations for deploying the intelligent paving system.

1. Examine the problem statements in subtrack ND 3 (Nondestructive Testing and Intelligent Control System Evaluation and Implementation), modify as appropriate, and divide them into specific, manageable contracts.
2. Arrange the contracts in a carefully sequenced plan that reflects a logical progress of research and available funding.
3. Expand each of the broad research problem statements included in the subtrack into a detailed research plan with specific objectives, tasks, and funding recommendations.
4. Review and provide direction for the various research contracts underway to ensure that they fulfill their objectives and allow future contracts to use their results. Guide the additional work required if a contract does not achieve its objectives and additional work is necessary.

1. Compile information on QC field tests and equipment, particularly for monitoring performance-based properties.
2. Develop workshops and present material on QC field testing.

1. Compile information on NDTs and equipment for PCC pavement construction.
2. Develop workshops to introduce NDT equipment and evaluation procedures to contractors and owner-agencies.

1. Compile information on NDT and ICS products and technologies ready for implementation, including thorough descriptions, photos, and video.
2. Develop Web-based training modules for each new product or technology.
3. Create a Web site for accessing the training modules and maintain the Web site with updates or refinements for new and existing products.

1. Structure a unified concrete PMS that considers user needs.
2. Identify the databases for concrete pavements currently in use and the potential links between these databases.
3. Develop a prototype system and populate it with a limited set of data. Evaluate this system and update it as necessary.
4. Develop and deploy the final unified concrete PMS.