Highway Quality Compendium
Concrete Pavement Technology Program Introduces New and Improved Tools for Pavements
Since 1999, the Federal Highway Administration's (FHWA) Concrete Pavement Technology Program (CPTP) has conducted research on improved methods of using concrete pavement in the construction, reconstruction, and repair of Federal-aid highways. More than 30 research projects centering around the following six focus areas have been initiated under CPTP: advanced pavement design, improved concrete materials, improved construction processes, repair and rehabilitation, workforce training, and enhanced user satisfaction. Products resulting from this research that are now available or soon to be released include software, concrete materials guidelines, and construction management tools.
The Total Environmental Management for Paving (TEMP) software system, for example, can be used to monitor temperatures in newly placed pavements to determine the appropriate times to open the pavement to traffic. TEMP combines temperature, maturity, and strength predictions into a single measurement system that can be accessed on a project site or remotely with a handheld or laptop computer, providing instant feedback on pavement temperature and concrete strength development. "The strength prediction system is mature and implementable now for pavement applications," says Shiraz Tayabji of Construction Technology Laboratories, Inc. (CTL), which has been overseeing CPTP product implementation for FHWA. The software is expected to be released in 2005.
The new concrete materials guidelines resulting from the CPTP cover rapid repair and rehabilitation techniques. One example is a set of techniques for using precast concrete pavement to perform full-depth repairs of existing concrete pavements and to rehabilitate or reconstruct existing pavements. The goal is to minimize user delays by reducing the time needed for project repairs or rehabilitation, while ensuring a quality product. The full-depth precast repair technique has been demonstrated in several States to date, including Colorado, Michigan, and Virginia. The precast pavement system developed for use in rehabilitation or reconstruction incorporates prestressed panels and has been demonstrated in Texas and California. Several other States, including Indiana and Missouri, are looking at holding demonstration projects for precast paving.
Construction management tools researched under CPTP include a variety of products, from procedures to actual hardware. One promising piece of technology recently reviewed is known as MIT Scan-2. This new device is based on principles of magnetic pulse induction. The CPTP research project tested its usefulness in evaluating dowel bar placement in concrete pavements and found it to be reliable, efficient, and accurate. The device rides on tracks as it is pulled across fresh or hardened concrete and can be used to determine the position and orientation (vertical and horizontal alignment) of all dowels in a joint in a single pass. Preliminary results are available almost immediately. Developed in Germany, the scanner's algorithms and user interface have been adapted for U.S. conditions. The device is available commercially and is already in use in Europe.
The MIT Scan-2 can be used to evaluate dowel bar placement in concrete pavements. The device rides on tracks as it is pulled across fresh or hardened concrete.
CPTP has also developed 2-day workshops on high-performance, long-life concrete pavements. Workshops available are:
- 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.
Each workshop incorporates innovative concrete pavement technologies and research findings that have resulted from CPTP projects. To schedule a workshop in your State or region, or to have a condensed version of the workshop presented in conjunction with a conference or meeting, contact Sam Tyson at FHWA, 202-366-1326 (email: firstname.lastname@example.org).
CPTP's current technology transfer effort is scheduled to run through 2005. FHWA is developing a long-term plan to continue existing research and expand the program, with funding potentially coming from a consortium of Federal, State, and industry sources.
Reprinted from Focus, December 2004.