Performance Specifications

Over the years, the ready mixed concrete industry has evolved with technological advances and improved production practices of concrete producers.  Unfortunately, the typical project specifications are still prescriptive in nature (specifying how to produce the concrete mix).  Prescriptive specifications do not give the producer the flexibility to produce the most effective and efficient concrete, stifling innovation by limiting the types and quantities of ingredients and material proportions.  Prescriptive specifications may be overly conservative which can lead to higher costs, inappropriate applications with unintended negative results, and ultimately unsatisfied customers.

A shift to performance-based specifications may be the next step in the evolution of the concrete industry.  Performance-based specifications define required results such as strength and other mechanical properties, requirements for durability and serviceability, and requirements for placement.  The results are verifiable through field measurement and testing to assure the product will meet the specified performance requirements.  Performance-based specifications encourage innovative products and construction methods along with rigorous quality management systems that can lead to superior products and satisfied customers.

There are many challenges to implementing performance-based specifications.  Currently, there are no accepted model performance specifications in the United States that can be used as a guide for developing performance-based project specifications.  Most building code requirements and standards for concrete, including ACI 318 and ACI 301, are predominantly prescriptive in nature.  Although they allow the use of performance specifications, they don’t provide guidance on how they should be used or which criteria or test methods should be implemented.  Consequently, performance specifications are rarely used.

Many advocates within the industry are encouraging a transition from specifications that are prescriptive in nature to more performance-based specifications.  NRMCA (National Ready Mixed Concrete Association) established a P2P (Prescription to Performance) Initiative that promotes performance specifications to allow concrete producers more opportunity for innovation.

Currently, SDC is working to facilitate the development of standards and specifications that would not only permit, but encourage, the use of performance specifications.  In addition to developing a strategic plan to compliment the P2P Initiative, SDC is championing an ACI Innovative Task Group to accelerate the widespread use of performance-based specifications.  The ultimate goal is the incorporation of such information into documents such as ACI 318 and ACI 301.