AGGREGATE GRADATION CONTROL FOR PCC PAVEMENTS: Improving Constructability of Concrete Pavements by Assuring Consistency of Mixes

摘要

Money which is supposed to be used to repair older pavements is being diverted to fix many new rigid pavements owned by the U.S. Ah-Force (USAF). Additionally, latent surface defects in new pavements are sources of debris which are ingestion hazards to high performance jet aircraft. An evaluation of the construction records and pavement cores from projects constructed since 1987 suggest that poor mixture proportioning practices and a high variability in aggregate gradation directly effects the Constructability of pavements. Deficiencies in mixture proportions result in mixtures which require the employment of poor concrete construction practices to achieve a visually acceptable placement and finish. Aggregate grading controls are an effective method of minimizing the potential for Constructability problems and variability. Gradation controls are an effective method of improving the placement characteristics and finish quality of new concrete pavements. Process controls can be incorporated into construction specifications for the purpose of assuring that the concrete is consistent and that the potential for early distress syndrome is minimized.