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CONCRETE LIBRARY OF JSCE NO. 22, DECEMBER l993
RECOMMENDED PRACTICE FOR CONCRETE CONTAINING AIR-ENTRAINING AND HIGH-RANGE WATER-REDUCING AGENTS -DRAFT-
(Translation from the CONCRETE LIBRARY No. 74 published by JSCE, July l993)
JSCE Research Subcommittee on High Quality Concrete Working Group on Flowable Concrete
Subcommittee Chairman Shigeyoshi NAGATAKI	WG Chairman Yasuhiko YAMAMOTO			WG Secretary Hidetaka UMEHARA
WG Members
Masao FUJIOKA Nobuyuki OHTSUKI		Kenichi MOTOHASHI Toru KAWAI	Yasuaki HIRABAYASHI Makoto TAKEYAMA
WG Members from Sponsoring Organization
Tetsuya ANDO Hideo YAGI	Mitsugu SUGIMOTO Yutaka OHKAWA			Tadaaki HAGA Choji YAMAKAWA
PREFACE An air-entraining and high-range Water-reducing agent is a new type of chemical admixture developed and commercialized in Japan. The distinctive feature of the agent is that, along With adequate inbuilt air-entraining properties, it has a water-reducing capability higher than that of ordinary air.-entraining and water-reducing agents, as well as an excellent slump-retaining capability. The agent can thus be used at the time of mixing concrete in the same manner as ordinary air-entraining and water-reducing agents. When concrete containing this agent is to be produced to have the same slump as conventional concrete, it requires a lover amount of water. When the unit water content is the same as that of conventional concrete, the concrete containing the agent provides the quality that matches that of superplasticized concrete, while being manufacturable at a ready-mixed concrete plant. In recent years, the unit water content of concrete has inevitably tended to increase due to the worsening availability of quality aggregate, the remarkable spread of concrete pumping for rational construction practice, the diversified construction methods and structures, and so forth. Since the use of an air-entraining and high-range Water-reducing agent is a quite effective means of producing concrete of high-quality and/or high-performance while overcoming such present conditions, applications of the agent to concrete for public structures are gradually increasing for the purposes of reducing the unit water content and/or improving workability of concrete. However, these purposes can be surely attained without impairing other properties of concrete only when the agent of good quality is used in an appropriate manner. It is therefore essential to formulate guidelines to be followed when using the agent. Under such circumstances as mentioned above, the Concrete Committee of the Japan Society of Civil Engineers (JSCE) conducted research work for about 3 years to formulate the drafts of both the quality standard and Recommended Practice for the agent at the request of the Japan Concrete Admixture Association The Working Group on Flowable Concrete of- the JSCE Research Subcommittee on High Quality Concrete organized in December 1989 assumed a leading role in the activity. JSCE CONCRETE LIBRARY No.74 issued in July l993 summarizes all the achievements of the research activities by the Working Group on Flowable Concrete, and contains "Recommended Practice for Concrete Containing an Air-Entraining and High-Range Water-Reducing Agent (Draft) ", JSCE Standard "Air-Entraining and High-Range Water-Reducing Agents for Concrete", other references pertaining to concrete containing the agent, and "Recommended Practice for. Superplasticized Concrete (Revised Version)". The present paper is the translation of the essential parts of the "Recommended Practice for Concrete Containing an Air-Entraining and High-Range Water-Reducing Agent (Draft) " All of its articles and some of their important commentaries were translated into English. It is hoped that this Recommended Practice will contribute to the sound spread of concrete made using the agent and help to produce concrete of high quality and high placeability.