Since 1999, the goal of the Federal Highway Administration’s (FHWA) Concrete Pavement Technology Program (CPTP) has been to achieve new and improved methods of using concrete pavement in the construction, repair and reconstruction of highways. More than 30 research projects have been initiated under the CPTP focusing on advanced pavement design, improved concrete materials, improved construction processes, repair and rehabilitation, work-force training and enhanced user satisfaction. The CPTP’s goal is now becoming a reality, with a host of products resulting from this research now available or soon to be released.
The new repair and rehabilitation guidelines address rapid pavement repair and rehabilitation techniques. For example, a set of techniques has been developed for using precast concrete pavement to perform full-depth repairs of existing concrete pavements and to rehabilitate or reconstruct aging pavements. A precast pavement system that incorporates prestressed panels also has been developed for use in pavement rehabilitation or reconstruction. Demonstrations have been completed in Texas and California, and additional trials are in the planning stage in both Indiana and Missouri.
Another new product that can have an immediate impact for highway agencies is the Total Environmental Management for Paving (TEMP) system, which can be used to monitor fresh and hardened concrete temperatures in new pavements or repaired sections to determine the right time to open the pavement to traffic. Accessible on a hand-held or laptop computer, the TEMP system provides instant feedback on pavement temperature and concrete strength development. The software, which is expected to be available in 2005, utilizes the maturity concept, based on time and temperature relationships, to predict concrete strength.
One of the construction management tools evaluated under the CPTP is the MIT Scan-2 device. Based on principles of magnetic pulse induction, this device can be used to evaluate dowel bar alignment in concrete pavements. The device rides on lightweight tracks as it is pulled across either fresh or hardened concrete. It can be used to determine the three-dimensional position of all dowels in a joint in a single pass, with an LCD display, as well as graphical and numeric position data for each dowel, available immediately. Field trials for the device, in parallel research sponsored by the American Concrete Pavement Association (ACPA) as well as the CPTP, have been conducted in California, Georgia, Indiana, Kansas, Missouri, Nevada, North Carolina, South Carolina and Washington state.
Preliminary results have shown the MIT Scan-2 device to be reliable, efficient and accurate, as well as quick and easy to use. Reports from both the ACPA study and FHWA’s CPTP project will be available during the first quarter of 2005. The device is available commercially and is already being used in Europe.
State highway agencies and others can tap into the knowledge gained by the CPTP research projects through new two-day workshops that have evolved from the CPTP work. Workshops are available on the following topics:
- Long-life portland cement concrete pavement design and construction features and cost-benefit analysis of these features;
- Concrete paving materials and optimization of concrete mix design;
- Best practices for concrete pavement design, materials, construction and rehabilitation; and
- Concrete pavement construction best practices—recent advances.
The CPTP technology transfer effort for products developed to date is programmed to run through 2007. Ongoing CPTP research projects include ones looking at smoothness criteria for concrete pavements and at developing a protocol for identifying incompatibility in concrete materials. For more information about the CPTP research initiatives and products, visit www.fhwa.dot.gov/pavement/conhome.htm.
