A large double box girder cast-in-place segmental bridge constructed using a balanced cantilever method, this project provided many opportunities to explore the benefits of concrete maturity testing on a wide range of applications. The Con-Cure system was used to determine early-age in-place strength. Once sufficient strength had been reached, the contractor was allowed to begin stressing operations, moving formwork and was able to cease external heating operations. This project is being highlighted as a foremost use of concrete maturity testing in a segmental cast-in-place bridge and is featured in a paper by Bruce Kates, lead engineer on the project.
In Mr. Kates’ words: “[The Maturity] method lends itself to those conditions which require high early strength to allow the partial removal of forms for cycling of the equipment to the next placement location, or the application of post-tensioning forces into the structure. Besides providing reliable strength assessment, the procedure includes a record of the concrete temperature during the entire curing period, which helps to assess cold weather procedures when minimum temperatures are specified. The advantage is in cost savings due to reduced construction time and/or avoidance of costly repairs resulting from low-strength concrete which may be loaded too early as the result of a mishandled cylinder test.