AASHTO PP 84-20 (2021)

Specifications for concrete pavement mixtures have traditionally been prescriptive, with State Highway Agencies (SHA) specifying means and methods for both constituent materials and specific requirements for proportioning. This places the majority of the performance risk on the SHA and limits innovation. Recent trends of blending cementitious materials, reducing paste content, using modern additives and admixtures, and other innovations in the industry provide the opportunity to move towards specifying the performance characteristics of concrete mixtures and allowing industry to design mixtures that meet specific performance requirements. New methods to evaluate concrete performance have been developed, and others are being formulated, that can result in improved performance and economics. Further, shifting the responsibility for performance to the contractor provides an opportunity for innovation.

This practice covers elements of a concrete pavement mixture that considers, and includes, alternative performance characteristics for acceptance.

In Section 6 of this practice, SHA traditions of using prescriptive methods are respected while also offering options to use one or more performance measures instead.

This practice is intended to provide SHAs flexibility in their approach to the use of alternative performance measures and includes a range of choices that can be selected to best fit the needs of the agency.

Life cycle cost of concrete pavements will be considerably reduced, as a result of extended service life, by reducing material and construction variability. This is achieved by a robust quality control (QC) program.

Performance values included are for an average concrete pavement life in the range of 30 yr. Due to normal materials and testing variability and available local contractor expertise, some risk exists in predicting actual service life. As service life prediction models and test methods mature, that risk is expected to be reduced.

Substantial research has shown that a key to reduce the life cycle cost of concrete is by reducing construction variability.

When performance-based measures are selected, the importance of quality control increases; compliance with the acceptance criteria are predicated on a well-designed and executed QC program that includes process, production, and construction control.