JPS59466B2 - Water resistant high strength gypsum composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-strength plaster composition with particularly excellent water resistance, which is mainly composed of limestone wax powder and is blended with specific calcium aluminate powder and cement powder. .

Hydraulic wax, particularly hemihydrate wax, when kneaded with an appropriate amount of water, quickly undergoes a hydration reaction to form a hardened product.

Since this cured product has excellent mold stability (low expansion and contraction due to hydration and drying), it is widely used in various stone wax products such as stone wax boards, molds, ceramics, and medical products.

However, conventional stone wax, such as β-type hemihydrate stone wax, which is used in the largest quantities as a molding material, has the disadvantages of lower strength development than cement, lack of water resistance, and lack of rust prevention properties for reinforcing bars. Therefore, its use was subject to many restrictions.

In order to improve these drawbacks, methods have been proposed in the past, such as mixing polymeric substances or impregnating and polymerizing polymerizable materials, but these methods result in higher costs and lower nonflammability and fire resistance. There were drawbacks.

The present inventor conducted research on a composition based on stone wax that is particularly excellent in water resistance and strength without blending organic materials, and found that 60 to 90 parts of stone wax powder and 30 parts of calcium aluminate were added. ~5 parts and C2S and or C3
The present invention was achieved by discovering that a composition containing 20 to 2 parts of cement powder containing S as a main component forms a cured product exhibiting particularly excellent water resistance and high strength.

Here, the limestone wax may be semi-hydrous or anhydrous stone wax which itself has hydraulic properties, or dihydrate stone wax which does not exhibit hydraulic properties.

The degree of fineness is not particularly limited, but the Blaine value is 30.
00 crit/g or more is preferable.

Calcium aluminate is usually obtained by calcining or melting lime and bauxate, and its mineral composition is Cl2A7, C11A7CaF2, C3A3CaF.
2 and C3A (where C represents CaO and A represents Ag2O3).

Of course, this includes C5A3, but this is difficult to manufacture under normal conditions.

Even when -CA or CA2 is used, the strength development as in the present invention is not observed.

The fineness is not restricted by this like stone wax, but the normal Brain value is 3000 cr? t/g or more, especially 5oooi/, 9 or more is preferable.

If the fineness is too low, initial strength development will be poor.

In addition, cements mainly composed of C2S and/or C3S include commonly used Portland cement, fly ash cement, blast furnace cement, etc.
The hydrate exhibits water resistance.

The fineness of this powder is preferably a Blaine value of 3 ooffl/, 9 or more.

The blending ratio of these is 30~30 for calcium aluminate.
5 parts; otherwise, the strength, particularly the bending strength, decreases.

The amount of cement is 20 to 2 parts, and if it is less than 2 parts, water resistance cannot be imparted, and if it exceeds 20 parts, expandability will occur and strength will decrease.

Based on this background, Ishiro limited the number of copies to 60 to 90 copies.

The masonry wax, calcium aluminate, and cement powder may be mixed in powder form, or each may be mixed in a suspended state in water.

Further, hydration accelerators or retarders can be added as necessary.

Such retardants include citric acid, gluconic acid, tartaric acid, or salts thereof, and accelerators include potassium carbonate, sodium carbonate, sodium sulfate, aluminum chloride, and the like.

The plaster composition of the present invention exhibits high strength as well as water resistance, and because it fixes a large amount of water compared to a hardened body of stone wax alone, the fire resistance of a molded body using it is The surface of a molded product made of stone wax alone becomes sticky when it contains water, which lowers its value as a molded product, but the hardened product according to the present invention has a rough state similar to cement. Therefore, it has a high value as a molded product, and since it is Alka IJ l'lE and exhibits rust prevention properties, it can be used as a structure manufacturing material similar to cement, etc. There is.

The present invention will be explained below with reference to Examples, in which parts described in the specification are expressed on a weight basis.

Example 1 CaO and Ae obtained by melting β-type hemihydrate powder, bauxite and quicklime manufactured by Haruno Seiso Sales Co., Ltd. in an electric furnace
Blaine value of calcium aluminate mainly composed of C12A7 with a 2o, p weight ratio of 1.2 and a Blaine value of 5500 crit
/ g of powder, and Blaine value 3300 cyrt/
Add 80 parts of water to 100 parts of a mixture of 1.5 g of ordinary Portland cement in various proportions, mix well, and mix 4X4X.
Pour into a 16CrfL mold and heat at 20°C.

At the 1st and 7th day of 5o% Rn curing and the 1st day of age, the specimens were immersed in running water for 1 day, and the weights before and after were measured.

Table 1 shows the blending ratios and the results.

Experiments/I64-6 are examples of the present invention.

In addition, when we observed the surface of the specimens after immersion in water, we found that the specimens of Experiments 161-3 were sticky and had sprouting at the corners, but the specimens of Experiments A64-6 were found to be sticky. These were completely unrecognized and remained in their original form.

Example 2 In the experiment/164 formulation, when C3A was used as the calcium aluminate and similarly measured, the daily compressive strength was 103 kg/cr? L, 1 day bending strength is 40k
y/crit, 7-day compressive strength is 260 kg/ffl, and the weights before and after soaking are 400 g and 405, respectively.
It was g.

Furthermore, in this example, C11A7Ca instead of C3A
Similar measurements were made using F2 and C3A3CaF2, and the values were almost the same as in this example.

Claims (1)

[Claims] 1 60 to 90 parts by weight of stone wax powder, 30 to 5 parts by weight of calcium alumina powder, and C2S and or C
A water-resistant high-strength masonry wax composition comprising 20 to 2 parts by weight of cement powder containing 3S as a main component.