Denki Kagaku Kogyo Kabushiki Kaisha

Japanese National Railways

Toa Doro Kogyo Co., Ltd.

Nippon Kayaku K.k.

Koji Nakagawa

Yoshiharu Watanabe

Kenkiti Hirano

Ikuji Kishi

Makoto Fukuda

Yutaka Harada

Yoshiro Higuchi

Tateki Ohtsuki

Toshio Sato

Iwazo Kawaguchi

Renichi Kondo

Yasushi Kasahara

Minoru Sirasawa

Hirosi Yamagisi

Shozo Sakamaki

A concrete composition for making concrete moldings of high strength is provided which comprises 400-600 kg. of Portland cement per unit m.sup.3 of concrete, 3-30% by weight of insoluble (Type II) anhydrous calcium sulfate and 0.1-3% by weight of cement dispersing agent. A method for making concrete moldings of high strength having the above components are also provided which comprises subjecting to pre-steaming and then steam curing under atmospheric pressure. According to the present invention, concrete moldings having both high compressive strength and pre-stress with reduced relaxation can be obtained only in a day without subjecting to autoclave curing.

Concrete composition for making concrete moldings and method for making

A cement retarder is provided which comprises 5 to 20% by weight, based on the weight of said retarder, of gluconic acid and/or tartaric acid and/or a water soluble salt thereof, 30 to 10% by weight, based on the weight of said retarder, of citric acid and/or an alkali salt thereof, and 50 to 85% by weight, based on the weight of said retarder, of an alkali carbonate. A rapid hardening cement is also provided which contains the above cement retarder.

Cement retarder and rapid hardening cement containing the same

A quick hardening cement-asphalt composition used as a grout for a ballast-filled track structure comprising

Quick hardening cement-asphalt composition

A method for working quick hardening cements comprising preparing (A) a composition comprising a cement paste, mortar or concrete and (B) a composition comprising a powder or suspension composition of calcium aluminate and inorganic sulfate, mixing the composition (A) and the composition (B) and quickly executing the mixture immediately after the admixture.

Method for execution of quick hardening cement

A fire retardant thermosetting resin composition containing tricalcium aluminate hexahydrate as a filler.

Fire retardant thermosetting resin composition

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Niigata, Japan

Koji Nakagawa