Time and traffic flow are often two of the most critical factors highway engineers face when paving is in question. The typical reaction to using concrete paving where there is limited time to close lanes has been "And what are we to do about the traffic?" For the last several years, FHWA has worked closely with the paving industry to evaluate a family of techniques that will allow for the effective use of concrete in these situations.

This project evaluates techniques that will allow concrete paving to be used in situations where there is limited time to close traffic lanes. Coordinated efforts include technical assistance to State DOTs, evaluation of test sections, co-sponsorship of workshops and national conferences, the integrated use of concrete mobile laboratories, and a task force to develop detailed practices and procedures. Two major technical issues that were studied by a joint task force included the strength values at which the pavement can be opened to traffic and temperature management of concrete slabs.

The task force analyzed recent research and development findings that used different modeling techniques to allow for earlier opening values than those currently considered acceptable. Many State specification values for either compressive or flexural strengths used as criteria for opening to traffic have been established independent of pavement thickness, traffic type, or curing techniques.

A second issue involves determining the proper use of curing blankets to accelerate strength gain and to maintain a uniform temperature gradient within the slab. Current literature had no any in-depth discussion of these issues and no known models capable of analyzing the system, so a concise report was published in 1995, which included the technical papers developed by the task force, FHWA-SA-94-080.

As part of this project, more than 40 workshops were given. In a future NHI course, the scope of the workshop portion of this project will be expanded to include retrofit edgedrains and drainage of flexible pavement. (See DP-87 Phase II, under Asphalt Pavement Design and Construction.) There are currently no planned activities for this project. All future activities involving accelerated rigid paving techniques will be included as part of TE-30, High Performance Concrete Pavements (HPCP).

Technical assistance and site visits, equipment loan through Demonstration Project 75, "Mobile Concrete Laboratory," and speakers are still available.

FHWA reports on six accelerated rigid paving projects are available through the Office of Technology Applications. A report entitled, "Accelerated Rigid Paving Techniques, State of the Art" is available from the Portland Cement Association.

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U.S. Department of Transportation
Federal Highway Administration