Abstract: A masking material for use in a heating process includes: a base material comprising a resin as a main resin component and containing a magnetic substance, the resin having a higher melting point than a temperature of the heating process, the magnetic substance having a higher Curie temperature than the temperature of the heating process; and a releasable protective layer formed on one surface of the base material, the releasable protective layer comprising a releasable protective material. The masking material has excellent heat resistance property and can be repeatedly used.

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.

Abstract: A concrete pit containing radioactive waste is surrounded by a low diffusion layer of cement-based material, which in turn, is surrounded by a low water permeability layer of sodium-type bentonite and the leaching out of calcium ions from the low water permeability layer is inhibited by mixing sodium bicarbonate or sodium carbonate with the sodium-type bentonite/sand mixture of the low water-permeability layer so that leached calcium ions form a barrier layer having calcium carbonate as the main component in the vicinity of the interface between the layers.

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.

Abstract: A masking material for use in a heating process includes: a base material comprising a resin as a main resin component and containing a magnetic substance, the resin having a higher melting point than a temperature of the heating process, the magnetic substance having a higher Curie temperature than the temperature of the heating process; and a releasable protective layer formed on one surface of the base material, the releasable protective layer comprising a releasable protective material. The masking material has excellent heat resistance property and can be repeatedly used.

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).

Abstract: A concrete pit containing radioactive waste is surrounded by a low diffusion layer of cement-based material, which in turn, is surrounded by a low water permeability layer of sodium-type bentonite and the leaching out of calcium ions from the low water permeability layer is inhibited by mixing sodium bicarbonate or sodium carbonate with the sodium-type bentonite/sand mixture of the low water-permeability layer so that leached calcium ions form a barrier layer having calcium carbonate as the main component in the vicinity of the interface between the layers.

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).

Abstract: A method is provided for making a fiber-reinforced slag gypsum cement lightweight hardened product. The method consists essentially of mixing (1) from 5 to 140 parts by weight of aggregates having a maximum size of not larger than 2000 .mu.m to (2) 100 parts by weight of a mixture which comprises 100 parts by weight of Portland cement, (3) from 20 to 350 parts by weight of slag fine powder which has a fineness ranging from 6,000 to 12,000 cm.sup.2 /g as Blaine's specific surface area, (4) from 0 to 20 parts by weight of lime, (5) from 20 to 100 parts by weight of calcium aluminate and gypsum fine powder, (6) 0.01 to 1.5 parts of a setting retardant; mixing water, prefoamed foams and reinforcing fibers with the mixture to obtain a slurry; subjecting the slurry to molding to obtain a molded product; removing the molded product to obtain a hardened product; and curing the hardened product with steam.

Abstract: The invention provides a method of manufacturing a hydraulic hardening material having the steps of milling vitreous blast furnace slag and classifying the milled slag to provide slag powder having a blaine specific surface area of 6,000 to 12,000 cm.sup.2 /g. The hydraulic hardening material manufactured by the method is used as a Portland blast furance cement raw material.