Contractors use it, manufacturers make it and building codes require it: ready-mixed concrete produced according to ASTM C94/C94M, Specification for Ready-Mixed Concrete.
C94/C94M, first approved in 1935 and recently revised, continues to provide both producers and purchasers with requirements covering the quality of the material, defined as concrete manufactured and delivered to a purchaser in a fresh state. And now, a new, second edition of a book about C94/C94M presents a revised and detailed explanation, with examples, of the standard's use and application. The book is Manual 49, User's Guide to ASTM Specification C94/C94M on Ready-Mixed Concrete, co-published by ASTM International and the National Ready Mixed Concrete Association.
For owners, architects, design engineers, contractors, testing agencies and attorneys seeking an in-depth understanding of the specification, the manual offers just that. "This manual is unique in that it takes an existing material specification and discusses the intent and purpose of each clause in it," says Colin Lobo, Ph.D., P.E., senior vice president of the Engineering Division of the Ready Mixed Concrete Association, Silver Spring, Md., who wrote the manual with D. Gene Daniel, a ready-mixed concrete industry veteran and a 50-year ASTM International member. While the primary audience for the manual might be ready-mixed concrete producers, the book also can assist purchasers and specifiers in understanding what is involved when the specification is cited in contract documents.
"This book addresses responsibilities of stakeholders in a construction project, the production aspects of concrete, issues that need to be managed for conformance with this specification, and the delivery aspect and factors that are controlled by this specification," says Daniel. Information on general concrete technology is also included.
Manual 49 chapters correspond to the sections of the standard, featuring discussion of the section and accompanying images, photos and numerical examples. The book has been updated to reflect changes in C94/C94M and the standards cited in it since the first edition of the manual. In addition, the chapter addressing statistical concepts for proportioning concrete mixtures for strength and the associated strength acceptance criteria used in project specifications has been extended.
The specification is the direct responsibility of 100-member Subcommittee C09.40 on Ready-Mixed Concrete, a part of Committee C09 on Concrete and Concrete Aggregates. And the manual - like the specification - takes into account technological changes in the industry and its greater emphasis on sustainable construction, according to the authors.
Specification C94/C94M provides requirements for the component materials of ready-mixed concrete, noting that the purchaser's specification governs if requirements differ. The standard also describes needed ordering and technical information, as well as delivery, inspection and sampling.
Manual 49, User's Guide to ASTM Specification C94/C94M on Ready-Mixed Concrete, the authors say, is intended to be an essential reference for concrete construction industry stakeholders on the production and delivery of ready-mixed concrete.