Sources: National Ready Mixed Concrete Association, Silver Spring, Md.; CP staff
Following June committee week in Anaheim, Calif., ASTM International Subcommittee C09-40 on Ready Mixed Concrete has issued a new C94, Standard Specification for Ready-Mixed Concrete. In contrast to the predecessor version, NRMCA Engineering staff notes, ASTM C94-15 places the onus on the customer to communicate all requirements for concrete from a project specification; sets mix air content at levels for moderate and severe exposure; directs the purchaser, when ordering ready mixed, to either state the required air content or indicate finished concrete exposure type; requires purchaser to indicate density when ordering heavy weight mixes, and clarifies terms for ordering lightweight aggregate by stating equilibrium density; and, contains appendix revisions advising on strength overdesign concepts.
A proposal to permit use of electronic tickets was balloted, but remains subject to resolution. In near-term balloting and meetings, Subcommittee C09-40 will revisit such issues as eliminating time limits to delivery; a performance-based option and scheduling when ordering concrete; and, defining batch water with consideration for water held back for addition at the jobsite. Development of a new specification for returned-concrete reuse is progressing.