Takenaka Komuten Co., Ltd.

Fujisawa Pharmaceutical Company, Ltd.

Sanyo Chemical Industries, Ltd.

Nippon Nyukazai Co., Ltd.

Takenaka Doboku Co., Ltd.

Takenaka Corporation

Masaharu Sakuta

Koichi Ito

Toshio Saito

Yasuhiko Yoshioka

Tsunetoshi Shioya

Tadahiro Kaya

Yoshifumi Shimoyama

Kunio Yanagibashi

Iwao Uchizaki

Hiroyuki Yamakawa

Soichi Kiya

Masashi Sugiyama

Kyoichi Tanaka

Keisuke Fujioka

Shyuzo Endoh

Toshiharu Urano

The present invention provides a method for improving the durability of cement-hydraulic substances, the method decreasing the dry shrinkage of cement-hydraulic-set substances such as concrete, mortar or related substances, and increasing resistance to a repetition of the freezing and thawing of the cement-hydraulic-set substances, by the use of terminal alkyletherified compounds or terminal alkylesterified compounds of polymers having --C.sub.2 H.sub.5 O-- and/or --C.sub.3 H.sub.6 O-- as a repetitive unit.

Durability improving agent for cement-hydraulic-set substances, method

The invention relates to a hydraulic cement composition comprising, as a carbonation inhibitor of the cement composition, at least one compound of the formula (I):

Cement composition and a process for preparation thereof

Concrete composition for underwater use

A cement composition is provided which has the property of being inseparable in water, having improved strength and no effect in delaying setting time or reducing strength. It is produced at a cheaper cost by reducing the amount of a polyacrylamide compound to a considerable great extent. The polyacrylamide compound is present in an amount of 0.1 to 3% by weight based on the weight of cement, when a dialdehyde is added thereto.

Cement composition for laying underwater

A concrete composition is provided which has the property of being inseparable in water and no effect in delaying setting time or reducing strength. A polyacrylamide partial hydrolysate having a molecular weight of one million or higher and a hydrolysis degree of from 0.5 to 20% moles is present in an amount of 0.5 to 4% by weight based on the cement constituent proportion.

Water-inseparable concrete composition

Growing community of inventors

Tokyo, Japan

Masaharu Sakuta