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).

Cement additive and cement composition

PROBLEM TO BE SOLVED: To provide a spray material capable of obtaining quick-setting spray concrete having high initial strength development of ≥3 N/mmfrom 10 minutes after spray, capable of achieving early stabilization of a natural ground just after excavation, and having pH of ≤11.0.SOLUTION: A spray material includes a cement material comprising blast furnace slag-containing cement and fly ash, a high-strength admixture, a quick setting agent, fine aggregate, coarse aggregate and water. The spray material has a constitution wherein the content of the fly ash is 30-400 pts.mass with respect to the 100 pts.mass blast furnace slag-containing cement, the high-strength admixture contains gypsum, 0.5-5 pts.mass alkali metal carbonate and 0.2-5 pts.mass oxycarboxylic acids with respect to the 100 pts.mass gypsum in terms of CaSO, the content of the high-strength admixture is 6-20 pts.mass with respect to the 100 pts.mass cement material, the quick setting agent contains calcium aluminate containing 1-4 pts.mass SiOin terms of oxides, and 1-50 pts.mass alkali metal aluminate and 1-20 pts.mass calcium hydroxide with respect to the 100 pts.mass calcium aluminate, the content of the quick setting agent is 6-20 pts.mass with respect to the 100 pts.mass cement material, and the content of water is 30-55 pts.mass with respect to the 100 pts.mass cement material.

Spray material and spraying method using the same

PROBLEM TO BE SOLVED: To provide a spray material which contains no polymer emulsion, is inexpensive, has excellent durability and can be applied thickly by one spray operation, and to provide a spray construction method. SOLUTION: The spray material contains cement, pozzolan fine powder, holmite based mineral and/or high molecular thickening agent, sand of aggregate and lightweight aggregate in the quantity of 100-260 pts.mass sand of the aggregate per 100 pts.mass cement, 2-15 pts.mass lightweight aggregate having ≤0.7g/cm 3 bulk density per 100 pts.mass sand. The high molecular thickening agent is hydroxy ethyl methyl cellulose. The spray material can further contains an expansive agent, a shrinkage reducing agent, a fluidizing agent, an air entraining agent, a fiber and a setting accelerating agent. In the spray construction method using the spray material, the spray thickness per one layer is controlled to ≥90 mm. COPYRIGHT: (C)2006,JPO&NCIPI

Spray material and spray construction method using the same

The present invention relates to an alkali-activated binder which can be used as a binder for replacing cement, and more particularly, to an alkali-activated binder, and to mortar, concrete, concrete products, and wet loess paving material comprising the binder, in which inorganic sodium-free alkaline materials are contained to reduce the total amount of Na 2 O and K 2 O in concrete, thus improving the workability and the strength stability and inhibiting the alkali-aggregate reaction.

Alkali-activated binder, alkali-activated mortar, concrete products and wet red clay paving material using binder

PROBLEM TO BE SOLVED: To provide a cement admixture and a cement composition capable of exhibiting excellent crack self-healing properties even in a small amount with no possibility of reducing fluiditySOLUTION: There is provided a cement admixture which contains blast furnace slug particles containing 05 mass% or more of iron and a stimulating material containing at least one selected from the group consisting of calcium hydroxide, calcium oxide, calcium sulfate, aluminum sulfate and lithium sulfate

Cement admixture and cement composition

PROBLEM TO BE SOLVED: To provide a continuous mixing and spraying system capable of continuously mixing and spraying dry cement mortar containing a high-viscosity polymer with attaining stable quality, and a spraying method. SOLUTION: The system comprises a storage hopper, inside which a horizontal screw shaft is housed, guides the dry cement mortar, containing re-emulsifiable polymer powder charged by rotating the screw shaft, to an outlet, and can manufacture wet cement mortar by continuously supplying pressurized water to the continuously sent dry cement mortar in such a manner that a water/dry cement mortar ratio is set to be in the range of 10-15 wt.%. In the spraying method for the cement mortar, the wet cement mortar, which is continuously mixed by the continuous mixing system, is pumped; and the pumped wet cement mortar and compressed air are combined, mixed and sprayed. COPYRIGHT: (C)2007,JPO&INPIT

Continuous mixing and spraying system for cement mortar, and spraying method using it

PROBLEM TO BE SOLVED: To obtain a spraying material, sprayable on the surface of a natural ground exposed in a tunnel such as a road, a railway and a conduit, etc., and capable of remarkably improving the initial and long-term strength developing properties and more reducing the spraying thickness than that of a conventional material and realizing the reducing in operating cost or shortening of operating time and provide a spray working method using the spraying material. SOLUTION: This spraying material comprises a cement mortar consisting essentially of a fine powdery cement and gypsum and a quick setting agent consisting essentially of calcium aluminate, as necessary, an alkali material aluminate and/or an alkaline carbonate and one or more admixtures selected from the group consisting of a water-reducing agent, a setting retarder, a setting promoter and an ultrafine powder. The spraying method comprises using the spraying material.

Spraying material and spray working using the same

PROBLEM TO BE SOLVED: To provide a spraying material excellent in initial strength, long term strength and long term preservable property and low in rebound rate and to provide a spray method. SOLUTION: This spraying material is prepared by mixing a cement mortal consisting essentially of cement and gypsum with an accelerating agent consisting essentially of calcium aluminate, and the cement mortal is a general term of paste, mortal and concrete. An alkali aluminate or an alkali carbonate can be further added to the accelerating agent and an admixture such as a high performance water reducing agent, a setting retarder, a setting accelerator and ultrafine powder can be added to the spraying material.

Spraying material and spray method using the same

PROBLEM TO BE SOLVED: To provide a rust-preventive which inhibits corrosion of a steel material such as a reinforcing bar, a steel frame and a PC steel wire, and prevents rust from occurring, and to provide a rust-preventing method using it. SOLUTION: The composition of the rust-preventive comprises: one or more rust-preventive selected from a nitrite, an amine, a molybdate and a tungstate; calcium aluminate having a CaO/Al 2 O 3 mole ratio of 0.5 to 3; gypsum; and a setting retarder. The composition of the rust-preventive is set in a short period of time, shows proper viscosity, develops adequate strength in a short period of time, accordingly does not drain away a rust-preventing component when applied, fixes an active component around a reinforcing bar in a short period of time, and does not decrease the concentration of the active component around the reinforcing bar due to a concentration gradient formed by diffusion. Furthermore, the composition has to be applied only to an exposed reinforcing bar, so that it reduces the consumption, consequently is advantageous from a viewpoint of a cost, and shows an adequate rust-preventing effect for a long period. Accordingly, the composition is suitable for a rust-preventive which is applied with a spatula, a brush or a trowel, for reinforced concrete used in engineering works and construction. COPYRIGHT: (C)2005,JPO&NCIPI

Composition of rust-preventive, and rust-preventing method

PROBLEM TO BE SOLVED: To obtain a quick setting material, a spraying material and a quick setting spraying cement concrete capable of providing a spraying material hardly causing the decrease of a strength after 28 days material age, and capable of forming the hardened material having a high strength. SOLUTION: This quick setting material comprises calcium aluminate, a sulfate or the total of the calcium aluminate and the sulfate, <10 pts.wt. of an aluminic acid salt of an alkali metal based on 100 pts.wt. of the calcium aluminate, the sulfate or the total of the calcium aluminate, and 0-5 pts.wt. of an alkali metal carbonate based on 100 pts.wt. of the calcium aluminate, the sulfate, the alkali metal aluminate and the alkali carbonate. The spraying material and the quick setting spraying cement concrete include the quick setting material.

Mizushima Kazuyuki

Papers

Continuous mixing and spraying system for cement mortar, and spraying method using it

Spraying material and spray working using the same

Spraying material and spray method using the same

Composition of rust-preventive, and rust-preventing method

Quick setting material, spraying material and quick setting spraying cement concrete