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Kitatsuji M.,Miyagi University | Aoyama H.,Mirukon Co. | Saito K.,Takemoto Oil and Fat Co. | Endo T.,Tohoku Gakuin University
Concrete under Severe Conditions: Environment and Loading - Proceedings of the 6th International Conference on Concrete under Severe Conditions, CONSEC'10 | Year: 2010

Increased use of fly ash is expected from the standpoint of the effective use of natural resources and measures against alkali-silica reaction. However, it is difficult to adequately control the air content of fly ash concrete, as unburnt carbon contained in fly ash adsorbs the air-entraining admixture, posing a risk of reducing the resistance of concrete to frost damage. In this study, a prefoam-type air-entraining admixture of a whipped cream consistency, which is less prone to the effect of unburnt carbon, was used to entrain fine air bubbles into concrete, in an attempt to enhance its resistance to frost damage. The prefoamtype air-entraining admixture was found to be capable of reducing the spacing factor of fly ash concrete and thus effective against freezing and thawing action. © 2010 Taylor & Francis Group, London.

Yonezawa T.,Takenaka Corporation | Sakai E.,Tokyo Institute of Technology | Koibuchi K.,Inc. DC | Kinoshita M.,Takemoto Oil and Fat Co.
fib Symposium 2012: Concrete Structures for Sustainable Community - Proceedings | Year: 2012

A technology for substantial reduction of CO2 foot print of concrete structures was studied. The study resulted in a proposal of a technology named Energy CO2 Minimum (ECM) Cement Concrete System. The system consists of a newly developed high-slag cement (ECM cement) and structures for which the cement with weakness of rapid carbonation can be used. In this paper outline of the study and the performances of the concrete and improved soil for the structures using the cement is presented.

Mitsui K.,Takenaka Corporation | Yonezawa T.,Takenaka Corporation | Kojima M.,Takenaka Corporation | Kinoshita M.,Takemoto Oil and Fat Co. | Mihashi H.,Tohoku Institute of Technology
Zairyo/Journal of the Society of Materials Science, Japan | Year: 2011

Super high strength concrete with compressive strength of 150 to 200N/mm2 using hybrid fiber reinforcement of organic and steel fiber was developed. Properties of fluidity of fresh concrete and effect of curing condition on strength development were studied. Viscosity of fresh concrete was significantly reduced by newly developed Maleate polycarboxylate-based superplasticizer. Strength development of high strength concrete was enhanced by high temperature steam curing. Hybrid fiber reinforcement was effective to improve toughness and fire resistance of super high strength concrete. The higher the aspect ratio and tensile strength of steel fiber, the higher the toughness of concrete became. Hybrid fiber reinforcement enables to reduce spalling and to maintain fire resistance for 3 hours in super high strength concrete columns. © 2011 The Society of Materials Science, Japan.

Hachiya I.,Mie University | Matsumoto T.,Mie University | Inagaki T.,Mie University | Takahashi A.,Mie University | And 2 more authors.
Heterocycles | Year: 2010

3,4-Ethylenedioxythiophene (EDOT) was synthesized from commercially available (Z)-but-2-ene-1,4-diol or but-2-yne-1,4-diol using epoxidation, etherification, and thiophene formation. © The Japan Institute of Heterocyclic Chemistry.

Tanano H.,Japan National Institute for Land and Infrastructure Management | Tanimura M.,Taiheiyo Cement Corporation | Kinoshita M.,Takemoto Oil and Fat Co. | Nawa T.,Hokkaido University
AIJ Journal of Technology and Design | Year: 2012

This report investigates basic properties, such as compressive strength, drying shrinkage and freeze-thaw resistance, of normal strength concrete containing shrinkage reducing agent (SRA) of three brands, by same cement and aggregates as well as water-to-cement ratio (=0.5). SRA-added concretes show that compressive strength tend to lower with the increase in dosage, drying shrinkage strain is obviously reduced (more than approximately 15 %), while freeze-thaw resistance is significantly deteriorated.

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