JPH04270155A - Composition for lightweight concrete - Google Patents

Abstract

PURPOSE:To reduce the weight while maintaining the strength of a concrete product obtained by adding water to a blend of a cement with an ultralightweight coarse aggregate, a fine aggregate and a viscosity improver by blending the aforementioned components. CONSTITUTION:The aforementioned composition for lightweight concrete is formed from a blend composed of a cement (e.g. portland cement, alumina cement or blast furnace cement), an ultralightweight coarse aggregate (e.g. trade name; Neolite(R)), an ultralightweight fine aggregate (e.g. white fine aggregate, composed of quartz and having 5-0.3mm grain diameter) and a viscosity improver (e.g. trade name; Silica fume(R)). The blending ratios thereof are, e.g. 100 pts.wt. cement, about 75-80 pts.wt. ultralightweight coarse aggregate, about 95-105 pts.wt. ultralightweight fine aggregate and about 7-10 pts.wt. viscosity improver. Water is then added thereto so as to provide about 55-60 ratio of the water : cement. Thereby, the objective lightweight concrete having, e.g. about <=0.9 specific gravity of a hardened body is obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for lightweight concrete that can be suitably used as a material for partition walls in buildings, as well as various building materials and civil engineering materials.

0002

BACKGROUND OF THE INVENTION Conventionally, various concrete products have been provided including building materials, civil engineering materials, and the like. In these concrete products, various cements are used, such as Portland cement and alumina cement, and various additives such as water reducers, activators, thickeners, aggregates, and reinforcing materials are mixed into these cements. has been done. In addition, as aggregates mixed in such concrete products, gravel (river gravel, quarried gravel), sand (mountain sand, river sand), natural lightweight aggregate, artificial lightweight aggregate, etc. are used. By appropriately blending such aggregates and the various additives mentioned above to form a concrete composition, concrete products having various properties depending on the purpose can be obtained.

0003

[Problems to be Solved by the Invention] In recent years, there has been a desire to shorten the construction period, regardless of whether it is related to architecture or civil engineering. One way to shorten this construction period is to prepare concrete materials in advance at a factory, transport them to the site, and simply place them in the designated locations at the site, instead of pouring various types of concrete materials on site. There are many concrete products that can be considered, such as just placing them in certain locations. However, such concrete products are generally heavy and difficult to load and unload during transportation, and positioning at the construction site is extremely difficult, especially at narrow sites where cranes cannot be used. There were some complaints. This invention was made in view of the above circumstances, and its purpose is to provide a concrete composition for obtaining a product that is lighter than conventional concrete products and easier to transport and handle. .

0004

[Means for Solving the Problems] The concrete composition of the present invention contains cement, ultra-light coarse aggregate, ultra-light fine aggregate, and a thickener. And so.

[0005] The composition for lightweight concrete of the present invention will be explained in detail below. As the cement in the composition of the present invention, various known cements such as Portland cement, white cement, alumina cement, and blast furnace cement can be used depending on the desired properties of the product.

[0006] As the ultra-light coarse aggregate, one having a specific gravity of 0.9 or less, such as Neolite (trade name; manufactured by Niijima Bussan Co., Ltd.), is preferably used. Note that it is preferable that the ultra-light coarse aggregate has a particle size of about 15 mm or less in order to ensure sufficient strength of the resulting concrete product. In addition, as the ultra-light fine aggregate, similar to the above-mentioned ultra-light coarse aggregate, those with a specific gravity of 0.9 or less, such as Neolite (trade name; manufactured by Niijima Bussan Co., Ltd.) and white fine aggregate made of quartz, are used. Suitably used. Here, this ultra-lightweight fine aggregate is not particularly limited, but from the viewpoint of the strength and specific gravity of the concrete product obtained, the particle size is 5 to 0.3.
It is preferable to use a material of about mm. In addition, as a thickener, for example (trade name [silica sum]; EIKE
(manufactured by M Japan Co., Ltd.) is preferably used, but other commonly used materials can also be used.

[0007] The blending ratio of these materials is not particularly limited and may be changed as appropriate depending on the type of cement used, but in order to make the specific gravity of the resulting hardened product 0.9 or less, , for 100 parts by weight of cement, ultra-light coarse aggregate is about 75 to 80 parts by weight, ultra-light fine aggregate is about 95 to 105 parts by weight, and thickener is about 7 to 1 part by weight.
Water is added and kneaded so that the water-cement ratio is about 55 to 60.

[0008] The reason why the ultra-light coarse aggregate is set at about 75 to 80 parts by weight is because if it is added in excess of 80 parts by weight, the strength of the concrete will be impaired, whereas if it is less than 75 parts by weight, the specific gravity of the resulting product will be reduced. This is because the weight becomes high and sufficient weight reduction cannot be achieved. In addition, we use ultra-lightweight fine aggregate of 95 to 105
The reason why the amount is about 105 parts by weight is because the specific gravity becomes heavy if more than 105 parts by weight is added, while the strength decreases if less than 95 parts by weight. Furthermore, add a thickener to 7 to 1
The reason why the amount is about 0 parts by weight is because if it is less than 7 parts by weight, the viscosity of the resulting product will be impaired, while if it is added in excess of 10 parts by weight, no significant improvement in viscosity can be expected.

[0009] In addition to the cement and aggregate mentioned above, various additives, such as water reducing agents (
A high performance water reducing agent), a foaming agent, a fluidizing agent, an admixture, etc. are appropriately blended, and various fibers and pigments are also blended. Here, the fibers used include glass fiber, vinylon, aramid fiber, carbon fiber, and various ceramic fibers, and the addition of these fibers can increase the strength of the concrete product obtained. Also,
The amount of such fibers added is approximately 1 to 4% by volume of the entire concrete composition; if it is less than 1% by volume, the reinforcing effect will not be exhibited, and if it exceeds 4% by volume, the reinforcing effect will not be achieved. This is not preferable because the cost remains almost the same and the cost increases. Regarding pigments, especially when the concrete product to be formed is an external wall, white cement is used as the cement, and pigments are added to color the concrete itself, which is used to improve the appearance of the concrete product. .

[0010] A composition having such a composition is kneaded in the same manner as ordinary concrete, and then filled into, for example, a mold of a desired shape and appropriately cured to produce a concrete product. The concrete product obtained in this manner maintains sufficient strength as concrete, and has a specific gravity of, for example, 0.9 or less, which makes it lightweight enough to float on water.

[0011]

EXAMPLES The present invention will now be explained in more detail with reference to Examples. White cement (trade name [White Portland Cement]; manufactured by Dainippon Cement Co., Ltd.) was used as the cement, and ultra-light coarse aggregate (trade name [Neolite]; manufactured by Niijima Bussan Co., Ltd.) was added to 100 parts by weight of this white cement. ), 99 parts by weight of ultra-light fine aggregate (trade name [Neolite]; manufactured by Niijima Bussan Co., Ltd.), and 7 parts by weight of a thickener (trade name [Silicasum]; manufactured by EIKEM Japan Co., Ltd.).
Parts by weight of each were blended, and further, 1.5 parts by weight of S-FF (trade name) manufactured by Nippon Seeker Co., Ltd. and 0.08 parts by weight of Hymetrose (trade name) manufactured by Shin-Etsu Chemical Co., Ltd. were added as admixtures. Furthermore, the water-cement ratio was 57.
Water was added and kneaded so as to give a concentration of 1. At this time, air was mixed into the kneaded material in an amount of about 12% by volume based on the kneaded material by a well-known method.

The obtained mixture was placed in a mold and subjected to a conventional curing treatment to obtain a cylindrical concrete molded body having a length of 0.2 m and a diameter of 100 mm. When the strength of the obtained compact was examined, it was confirmed that the compressive strength was approximately 120 to 180 kg/cm2, which was sufficient to have the strength normally required for a concrete product. Furthermore, when the specific gravity of this molded article was measured, it was found to be 0.94, which confirmed that it had sufficient lightness.

[0013]

[Effects of the Invention] As explained above, the composition for lightweight concrete of the present invention is a mixture of cement, ultra-light coarse aggregate, ultra-light fine aggregate, and a thickener. The concrete product obtained by adding water, etc. to this has sufficient strength as concrete, and has a much lower specific gravity than conventional concrete. Therefore, if the composition of the present invention is formed into a material for construction and civil engineering, such as a partition wall of a building, in a factory or the like, the construction period can be shortened because it is easy to transport and handle. .

Claims (1)

[Claims] 1. A composition for lightweight concrete, comprising a blend of cement, ultra-light coarse aggregate, ultra-light fine aggregate, and a thickener.