Development Of A Concrete Maturity Protocol PDF Download

An extensive field and laboratory project was undertaken to evaluate the applicability of the concrete maturity method to predict opening to traffic criteria for portland cement concrete paving operations in Minnesota. The field study included visits to18 paving projects in the state over a three-year period. At these projects, different sensor types were evaluated. In the laboratory study, two-inch mortar cubes were tested to develop sensitivity analyses related to the proportions of cementitious materials, water-cementitious materials ratio, and other mix components. The study also evaluated different mathematical models and their ability to predict concrete strength relative to the computed maturity. In addition, a database of concrete mixes and their associated maturity curves were developed, as well as a spreadsheet for viewing maturity curves and entering new information into the database. A draft laboratory manual and a construction specification for creating and using maturity curves were developed. The results of this project include recommendations for maturity equipment, the method and ages for testing flexural beams when developing and validating maturity curves, the use of the exponential model for maturity curves, and suggestions for a construction specification and a laboratory manual. Further data collection and evaluation should be conducted by MnDOT as the method is implemented into standard practice. Appropriate modifications should then be made to ensure the method's ability to predict traffic opening and to enhance the effectiveness of paving operations.