Taiheiyo Cement Corporation

The University of Tokyo

Komatsu Corporation

Yasuhide Higo

Takafumi Noguchi

Eichi Manabe

Minoru Yoshimoto

Dianchao Wang

Takeshi Hamada

Kazuya Kuriyama

Wataru Kataoka

Takahito Nozaki

Provided is a simple and low-cost method for efficiently fixing a sufficient amount of carbon dioxide contained in a carbon dioxide-containing gas (e.g. a plant exhaust gas). The method of fixing carbon dioxide comprises a contact step of bringing a carbon dioxide-containing gas having a temperature of 350° C. or more into contact with a cementitious hardened body to fix carbon dioxide in the carbon dioxide-containing gas to the cementitious hardened body. The carbon dioxide-containing gas may be a gas that is free from being supplied with moisture before the contact step and during the contact step. One of examples of the carbon dioxide-containing gas is a plant exhaust gas.

Carbon dioxide fixation method

Provided is a method of fixing a sufficient amount of carbon dioxide contained in a carbon dioxide-containing gas (e.g., a plant exhaust gas) simply, at low cost, and efficiently. The method of fixing carbon dioxide includes a contact step of bringing a carbon dioxide-containing gas into contact with powdery or grainy particles, which are each formed of a cementitious hardened body and each have a particle size of 40 mm or less, at a temperature of from 75° C. to 110° C. to fix carbon dioxide contained in the carbon dioxide-containing gas to the powdery or grainy particles, wherein the relative humidity of the carbon dioxide-containing gas is adjusted in accordance with the particle size of the powdery or grainy particles and the state of adjustment of moisture content of the powdery or grainy particles before the contact step.

Disclosed is a counterweight which is filled with a heavy-weight concrete containing, instead of currently used iron ores, a heavy-weight aggregate that scarcely causes the material segregation from cement paste and which can be produced at a low cost and is effectively enhanced in the filling factor of heavy-weight concrete into a case. A counterweightcomprises a caseand heavy-weight concrete filled therein, wherein the heavy-weight concrete contains a heavy-weight fine aggregate containing 20 mass % or more of aggregate particles having particle diameters of less than 0.15 mm and 20 mass % or more of aggregate particles having particle diameters of 2.5 mm to less than 5 mm.

Counterweight

It is aimed at providing a heavy concrete, which does not require addition of a thickener such as methyl cellulose, which is less in segregation between a heavy aggregate and a cement paste, and which is high in flowability and excellent in construction ability. The present invention provides a heavy concrete comprising, at least, a cement, a heavy aggregate, and water, mixed with one another, characterized in that the heavy fine aggregate includes hot scarves brought about in a scarfing process of a steel slab surface. The present invention further provides the above-described heavy concrete characterized in that the heavy fine aggregate includes fine aggregate particles passing through a sieve having a nominal size of 0.15 mm, in an amount of 10% to 20% in mass percentage, and the heavy fine aggregate includes spherical particles each having a distortion irregularity of 3.3 or less as defined below, in an amount of 20% or more in the whole of particles having diameters between 50 &#x3bc;m inclusive and 5 mm inclusive in the heavy fine aggregate:[Distortion irregularity]=[Length of circumferential outline of particle]/[Diameter of true circle having the same area as the area of the particle providing the outline].

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Sakura, Japan

Yasuhide Higo