JPS5948781B2 - Hydraulic object made by simultaneously bonding portland cement paste and alumina cement paste - Google Patents

Description

[Detailed Description of the Invention] Conventionally, concrete products made by mixing and molding Boltland cement and sand are molded with a rough surface, and it is necessary to paste another tile or the like to decorate the concrete surface. However, there were drawbacks that required time and effort.

In order to solve the above-mentioned drawbacks, the present invention has made it possible to simultaneously bond alumina cement paste to a part of the surface of Boltland cement paste during molding, thereby making it smooth and smooth. It is characterized in that it can be simultaneously molded into a molded product with a glossy surface to enhance the cosmetic effect.

Hereinafter, the structure of the present invention will be explained with reference to Examples.

Boltland cement paste is made by mixing Boltland cement with sand, gravel, etc. in appropriate proportions and kneading it with water.
Shirasu (volcanic ejecta) and alumina cement in an appropriate ratio (weight ratio of alumina cement to shirasu 10 to 5)
0%) and an alumina cement paste mixed with water and then filled into a mold in a bonded form and cured in air. Next, the effects of the present invention will be explained with reference to practical drawings.

The mineral composition of shirasu is 50-78% volcanic glass.
, feldspar and quartz 20-50% others, chemical analysis values 5i0260-75%, A120313-16%
, other trace components include approximately 2.6% Fe2O3, CaO
Approximately 2.8%, MgO approximately 0.5%, Na2O approximately 4.2%,
Of these, about 20% are other.

The silica and alumina contained in this volcanic glass, that is, the amorphous part, are mixed with cement and become hardening factors when water is added. Of these, alumina is contained in the cement when general-purpose cement such as Bortland cement is added. A large amount of ettringite Ca12Al4(OH)24(SO
4) 6.50H2O precipitates in the hardened cement as needle-like crystals, and its internal stress causes the cement phase to collapse from within, significantly reducing the strength of the hydraulic object and making it completely unusable. Alumina cement is an example of a component
Al203caosio2Fe2o3 other% 56.
As shown in the analysis example of 033.43.32.60.7, calcium aluminate is produced by mixing alumina and calcium oxide as main components with the above-mentioned shirasu containing silica and alumina as main components and adding water. However, when this and Portland cement-based paste come into contact, CaO. siO2, CasO4 and alumina cement paste can be combined with portland cement paste and alumina cement paste without the risk of reacting with the alumina cement contained in the alumina cement paste, silica in shirasu, and alumina to produce a large amount of the above-mentioned ettringite and weakening the bonding layer. It has been discovered that it is possible to obtain a hydraulic object that is simultaneously bonded and molded. Furthermore, in the alumina cement layer, a stable gel of calcium aluminate 3Ca0-Al2O3 6H20 is formed due to the hydraulic reaction between Al2O3 and CaO in the alumina cement and Al2O3 in the shirasu, which forms a gel between the voids between the crystalline particles and unreacted particles. Since it hardens by filling the voids in between, it becomes a strong hardened product, and the strength of alumina cement does not decrease over a long period of time, which is characteristic of alumina cement, but rather tends to increase. A glossy cured film of calcium aluminum silicate CaAl [Al(SiO4)2] is then formed on the surface of the cured product. Generally, when a paste of Portland cement and alumina cement is bonded, as mentioned above, calcium silicate, calcium sulfate, and alumina react violently, causing an abnormal reaction such as a rapid setting reaction, and the bonding surface becomes brittle. However, since Shirasu is mixed in the alumina cement-based paste used in the present invention, the alumina in the alumina cement becomes calcium aluminum silicate and is stabilized. Even when Portland cement paste mixed with sand and other aggregates is filled into the same mold, no abnormal reactions such as rapid setting reactions occur at the interface of both paste phases, and both paste phases remain in the same state. It hardens.

Therefore, for concrete blocks and panels, by using an inexpensive Portland cement-based paste for the main body and placing a Shirasu-Alumina cement-based paste on the surface and simultaneously molding and curing, it is easy to create molded products with smooth and glossy surfaces. It can be obtained easily and inexpensively, and the mixture of shirasu and alumina cement and its water-cured molded product exhibit a very light gray color close to white, so it is recommended to add a relatively small amount of zinc leather, titanium white, etc. It can be made pure white by using ferrite, and can be colored in various tones using Bengara, triiron tetroxide, and other arbitrary pigments, and has the effect of enhancing the cosmetic effect of block structures. .

Claims (1)

[Claims] 1. Joining a portland cement paste made by mixing Portland cement, sand, gravel, etc. in appropriate proportions and kneading with water, and an alumina cement paste made by mixing whitebait and alumina cement in appropriate proportions and kneading with water. A hydraulic object made by simultaneously bonding and molding portland cement paste and alumina cement paste, which is characterized by being hardened and molded into a shape.