Denki Kagaku Kogyo Kabushiki Kaisha

Yasuhiro Nakashima

Takayuki Higuchi

Minoru Morioka

Shunichi Mishima

Isao Terashima

Mitsuo Takahashi

Masaki Daimon

Masahiro Iwasaki

Hiroyuki Ohashi

Takamitsu Murokawa

Kenji Yamamoto

Youhei Yamagishi

Atsumu Ishida

Tomohito Kobayashi

Etuo Sakai

A slurry quick-setting admixture comprising an alkaline earth metal carbonate, a water-soluble acidic substance, calcium aluminate, an alkali metal sulfate, and water; and a quick-setting cement concrete comprising such a slurry quick-setting admixture and cement concrete. The slurry quick-setting admixture may further contain calcium sulfate, calcium hydroxide and/or aluminum hydroxide, a retarder, etc. The spraying method comprises mixing water and a powder quick-setting admixture comprising an alkaline earth metal carbonate, a water-soluble acidic substance, calcium aluminate and an alkali metal sulfate, to form a slurry quick-setting admixture, mixing this slurry quick-setting admixture with cement concrete to form a quick-setting cement concrete, and spraying this quick-setting cement concrete.

Quick-setting admixture and spraying method using it

To provide a spraying material having an excellent quick-setting property and excellent adherability, a small alkali amount and excellent initial strength development, and a spraying method using it. The spraying material comprises a liquid quick-setting admixture containing an aluminum source, a sulfur source and a fluorine source, one or more quick-setting aids selected from the group consisting of calcium aluminate, calcium sulfoaluminate, calcium aluminosilicate, an alkali metal-containing substance, calcium hydroxide and aluminum hydroxide, and a cement concrete, and the method is to spray this spraying material.

Spraying material and spray technique employing the same

A cement admixture and a cement composition having a carbonation suppressing effect and a heat-of-hydration suppressing effect are provided. A cement admixture containing one or more non-hydraulic compounds selected from the group consisting of &#x3b3;-2CaO.SiO, &#x3b1;-CaO.SiOand calcium magnesium silicate, a cement composition containing said admixture, and a carbonation suppressing method by use of said cement admixture or cement composition. According to the present invention, a remarkable carbonation suppressing effect can be obtained particularly when used in portland blast-furnace slag cement. This leads to an effective use of steelmaking slag and the like, and the load of clinker can be reduced, so that a cement composition of a low environmental load type can be attained. Further, this is suitable for cements in conformity with the EN standards, which are used in civil engineering and building industries.

Cement admixture, cement composition, and method for suppressing carbonation using the same

A cement admixture of a low environmental load type, capable of reducing hexavalent chromium, having a small slump loss or heat of hydration, hardly neutralized and capable of suppressing autogenous shrinkage to a low level; a cement composition; and cement concrete employing it, are presented. The cement admixture comprises a slowly cooled slag powder which contains melilite as the main component and which has a carbon dioxide absorption of at least 2%, has a COabsorption of at least 2%, has a loss on ignition of at most 5%, contains at least 0.5% of sulfur present as non-sulfuric acid form sulfur and/or has a concentration of non-sulfuric acid form sulfur to elute, of at least 100 mg/l, and further, preferably, has a degree of vitrification of at most 30%, a melilite lattice constant a of from 7.73 to 7.82 and/or a Blaine specific surface area of at least 4,000 cm/g.

Cement admixture, cement composition, and cement concrete made therefrom

A cement composition of an environmental impact reducing type, used in the field of civil engineering and construction, which provides initial strength-development equal to that of ordinary Portland cement and which can reduce the clinker calcination amount, is provided. A cement composition containing Portland cement having a 3CaO.SiOcontent of at least 60% and a slowly cooled blast furnace slag powder, wherein the content of the slowly cooled blast furnace slag powder is from 10 to 50 parts per 100 parts of the cement composition.

Cement composition

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Niigata, Japan

Yasuhiro Nakashima