Denki Kagaku Kogyo Kabushiki Kaisha

Haneda Humepipe Co., Ltd.

Yoshiharu Watanabe

Koji Nakagawa

Mineo Ito

Hisayuki Shimizu

Takashi Shimamura

Hirotoshi Hagiwara

Noriaki Matsubara

Masanobu Ashida

Hitoshi Moriyama

Hiroyoshi Serizawa

Masaru Murase

Tetsuo Shibata

Gorou Sakai

Toshimichi Ichinomiya

Toshio Ohno

Yoshihiro Hishiki

Kazunori Takada

Kazuhiro Aizawa

An ultra high strength fiber-reinforced cement composition includes cement, silica fume, coal gasification fly ash, insoluble anhydrous gypsum, and metal fiber having a length between 5 and 30 mm and a diameter of between 0.1 and 1 mm. The coal gasification fly ash is spherical fine particles having a maximum particle size between 5 and 10 &#x3bc;m. Mass ratio of the silica fume: the coal gasification fly ash is 95 through 50 portions: 5 through 50 portions.

Ultra high strength fiber-reinforced cement composition, ultra high strength fiber-reinforced mortar or concrete and ultra high strength cement additives

A process for producing a concrete product, which includes a step of preparing a primary concrete by mixing a super dry consistency concrete having a unit amount of water of at most 100 kg/cm.sup.3, a step of preparing a secondary concrete by weighing a suitable amount of the primary concrete and adding at least water, a water reducing agent and a setting accelerator thereto, followed by remixing, and a step of molding the secondary concrete in a formwork.

Process for producing a concrete product

A concrete composition for use in a roller compacted placing method includes a cement, an aggregate, an organic acid and/or a salt thereof and a set accelerating inorganic salt.

Concrete composition for roller compacted placing method

A cement additive contains a superplasticizer, an inorganic strength increasing agent such as calcium sulfate or silica fume and bentonite.

Cement additive containing superplasticizer and bentonite

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

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Itoigawa, Japan

Yoshiharu Watanabe