Project specifications that are prescriptive in nature often limit the types and quantities of ingredients and material proportions for concrete, which can stifle innovation, increase costs, and limit effective communication and cooperation with local producers.
As the cement and concrete industry endeavour to reduce the carbon emissions associated with their products, innovations are being introduced to market at a rapid pace, but are encountering challenges to adoption because of specifications that do not allow their use for a variety of reasons. They either do not recognize new materials or processes, are too slow to evaluate and approve proposed changes, or set criteria that is in direct opposition to carbon reductions as the inadvertent consequence of conservative engineering practices. These challenges contrasted against the need for urgent climate action have created an impetus to transition towards more performance-based specifications.
Performance-based specifications, which represent an alternative to current prescriptive specifications, provide details of required results such as strength and other mechanical properties along with requirements for durability and serviceability. The results are verifiable through measurement or testing to assure the product meets the desired requirements. These specifications are free of process limitations such as restrictions on materials, mixture proportions, and construction methods. Performance-based specifications encourage innovative and optimized products and construction methods along with rigorous quality management systems that lead to superior products and satisfied customers. There is a strong synergy between performance specifications and goals for sustainable construction.
The National Ready-Mixed Concrete Association has a P2P Initiative in the United States that provides a series of useful resources that outline the benefits of transitioning toward performance-based specifications as an industry. A sampling of those resources is provided below: