President/chief technologist, Kiln Technology Inc., Allentown, PA
There is currently a significant trend toward performance-oriented specifications for hydraulic cements. A performance specification is one which primarily or exclusively defines what its object does rather than what it is, how it is made, or what it looks like. Performance specifications for cement are not new phenomena; they have been with us from the earliest stages of standards development. The goal has always been what the cement does, but the “trend” to performance “accelerated” in the mid-1970s, driven partly by antitrust considerations.
A performance-oriented specification for blended cements has almost completed the ASTM process and should appear soon in the Annual Book of ASTM Standards. It is a “pure” performance specification, intended to exist in parallel with the current hybrid specification, Specification for Blended Hydraulic Cements (C 595). ASTM C 595 prescribes that a blended cement may contain only a limited suite of materials and then applies property (performance) requirements to the resulting product. Many existing blended cements with long histories of commercial acceptance, such as product cements (block, pipe, precast, etc.), are not now included in ASTM specifications. The new specification eliminates the restriction on constituents and composition, but requires that any blended cement be demonstrated to meet specified criteria for the primary performance attributes that can reasonably be measured. A similar performance specification for portland cement is nearing the point of Committee ballot. Can masonry cement be far behind?
Paper ID: CCA10597J