Abstract

Provided are a water-blocking filler, the swelling properties of which do not decrease easily even when in contact with water containing calcium ions, and a filler for engineered multi-barriers with said water-blocking filler as the engineered multi-barrier filler. A water-blocking filler mainly comprising sodium bentonite obtained by mixing 30 weight % or less, in terms of inner percentage, of a pozzolan substance such as fly ash or silica fume with said bentonite, and a filler using said water-blocking filler that is used for engineered multi-barriers in radioactive waste disposal facilities.

IPC Classes  ?

• B01J 20/12 - Naturally occurring clays or bleaching earth
• G21F 9/34 - Disposal of solid waste
• G21F 9/36 - Disposal of solid waste by packagingDisposal of solid waste by baling
• B09B 3/00 - Destroying solid waste or transforming solid waste into something useful or harmless
• G21F 9/16 - Processing by fixation in stable solid media

Abstract

Provided is a neutralization-preventive high-early-strength cement composition characterized by comprising 60 to 97 wt% of a highly reactive cement and 3 to 40 wt% of an inorganic admixture, wherein the highly reactive cement is produced by adding 1.5 to 4.0 wt% of gypsum in terms of SO3 content to a highly reactive cement clinker that has a mineral composition comprising more than 70% of C3S and less than 5% of C2S as calculated in accordance with a Bouge's equation, an L. S. D. value of more than 1 and a free lime content of 0.5 to 7.5 wt%, and the inorganic admixture comprises at least one material selected from a blast furnace slag, an anhydrite, a limestone micropowder and a pozzolan substance. The neutralization-preventive high-early-strength cement composition enables the efficient use of a previously developed highly reactive cement having a high C3S content and an extremely low C2S content, and is suitable as a cement for a concrete or a mortar which is used under a low-temperature environment such as a cold region or an environment in which neutralization is likely to progress.

IPC Classes  ?

• C04B 7/345 - Hydraulic cements not provided for in one of the groups
• C04B 14/28 - Carbonates of calcium
• C04B 18/08 - Flue dust
• C04B 18/14 - Waste materialsRefuse from metallurgical processes
• C04B 22/06 - OxidesHydroxides
• C04B 22/14 - Acids or salts thereof containing sulfur in the anion, e.g. sulfides
• C04B 28/02 - Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
• C04B 111/22 - Carbonation resistance

Abstract

Provided are a water-blocking filler, the swelling properties of which do not decrease easily even when in contact with water containing calcium ions, and a filler for manmade multi-barriers with said water-blocking filler as the manmade multi-barrier filler. A water-blocking filler mainly comprising sodium bentonite obtained by mixing 30 weight% or less, in terms of inner percentage, of a pozzolan substance such as fly ash or silica fume with said bentonite, and a filler using said water-blocking filler that is used for manmade multi-barriers in radioactive waste disposal facilities.

IPC Classes  ?

• C09K 3/10 - Materials not provided for elsewhere for sealing or packing joints or covers
• C09K 17/02 - Soil-conditioning materials or soil-stabilising materials containing inorganic compounds only
• C09K 17/08 - Aluminium compounds, e.g. aluminium hydroxide
• G21F 9/34 - Disposal of solid waste
• G21F 9/36 - Disposal of solid waste by packagingDisposal of solid waste by baling

Abstract

Disclosed is a hydraulic cement composition which is applicable to a structure that does not always require alkalinity, is mainly composed of a blast-furnace slug, and discharges CO2 in a drastically reduced amount. The hydraulic cement composition comprises: 100 parts by mass of a mixture comprising 60 to 90% by mass of a blast-furnace slug micropowder having a powder fineness of 3000 to 13000 cm2/g, 5 to 20% by mass of plaster and 5 to 35% by mass of Portland cement; and 10 to 30 parts by mass of a recycled concrete micropowder that is isolated from a demolished concrete and contains 3 to 15% by mass of hydroxide calcium.

IPC Classes  ?

• C04B 7/153 - Mixtures thereof with other inorganic cementitious materials or other activators

Abstract

The problem of the decline in quality of a low-diffusion layer (4) due to the leaching out of calcium ions from said layer (4) and the problem of reduced performance and change in quality of a low water-permeability layer (5) due to conversion of sodium type bentonite to the calcium type are resolved in an artificial multi-barrier for a radioactive waste treatment facility wherein a low-diffusion layer (4) comprising cement-based material and a low water-permeability layer (5) having sodium type bentonite as the main component are in contact.  A concrete pit (3) housing radioactive waste (2) is established in a tunnel (1), the low-diffusion layer (4) comprising cement-based material is arranged on the outside, and the low water-permeability layer (5) is arranged on the outside of said low-diffusion layer.  Sodium bicarbonate at a concentration supersaturating the mixing water or sodium carbonate exceeding the saturation concentration in the mixing water is mixed with the sodium-type bentonite/sand mixture of the low water-permeability layer (5) and when calcium ions leach out from the low diffusion layer (4), a barrier layer having calcium carbonate as the main component is formed in the vicinity of the interface between the low-diffusion layer (4) and the low water-permeability layer (5).

IPC Classes  ?

• G21F 9/36 - Disposal of solid waste by packagingDisposal of solid waste by baling

Abstract

A cement additive contains industrial waste and has the effect of inhibiting formation of monosulfate in a hardened cementitious material. The cement additive contains specifically calcium carbonate, gypsum and coal ash and/or blast-furnace slag powder. This enables efficient use of industrial waste, allows inhibiting monosulfate formation in the hardened cementitious material, and allows producing a hardened cementitious material having good durability (sulfate resistance).

IPC Classes  ?

• C04B 14/28 - Carbonates of calcium
• C04B 18/06 - Combustion residues, e.g. purification products of smoke, fumes or exhaust gases

Abstract

A cement additive which functions to inhibit an industrial waste and a hardened cementitious material from generating a monosulfate. It comprises calcium carbonate, plaster, and coal ash and/or blast furnace slag particles. This additive enables an industrial waste to be effectively utilized and can give a hardened cementitious material inhibited from generating a monosulfate therein. Thus, a hardened cementitious material having satisfactory durability (resistance to sulfates) can be produced.

IPC Classes  ?

• C04B 22/10 - Acids or salts thereof containing carbon in the anion, e.g. carbonates
• C04B 18/14 - Waste materialsRefuse from metallurgical processes
• C04B 22/06 - OxidesHydroxides
• C04B 22/14 - Acids or salts thereof containing sulfur in the anion, e.g. sulfides