JPS59227764A - Aggregate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Technical field The present invention relates to aggregates, particularly lightweight aggregates.

BACKGROUND OF THE INVENTION Lightweight aggregates are often used for mortar as building coating materials in order to reduce the weight of construction.

All of the conventionally used lightweight aggregates, with the exception of obsidian pearlite, have a large amount of water absorption. When water-absorbing aggregate is used in mortar, the mortar after hardening repeatedly expands due to water absorption and shrinks due to drying, which may result in cracking or bursting accidents.

Furthermore, the amount of water required to be added during mortar kneading increases, causing increased drying shrinkage.

Obsidian pearlite, which has a low water absorption capacity, is made from natural obsidian, which is crushed and foamed, but it is difficult to supply in large quantities, at low cost, and stably. On the other hand, lightweight aggregates that are inexpensive and can be supplied in large quantities include pearlite pearlite, rosinite pearlite, vermiculite, cane clay, keraite, calcined 7-lion ashes, and wind-crushed blast furnace slag, all of which can be granulated in some cases. Alternatively, it may be ground and, in other cases, heated and expanded. Each particle of these aggregates is an aggregate of minute component particles, and therefore water is likely to be contained between the minute component particles, and the amount of water absorbed by the aggregate is large.

Purpose of the Invention In view of the above-mentioned conventional techniques, an object of the present invention is to reduce the water absorption of bulk aggregate.

Structure and details of the invention In order to achieve the above object, the present invention coats aggregate with an organic polymeric substance.

By using aggregates coated with such organic polymeric substances, the amount of mixed water in the mortar and the amount of water absorbed by the hardened material can be reduced.
Consequently, drying shrinkage can be reduced. Furthermore, by making the coating incomplete and allowing the aggregate to retain an appropriate amount of water absorption, it is possible to obtain a dew condensation prevention material that does not have a particularly large amount of water absorption.

The organic polymeric substance used in the present invention is not particularly limited as long as it can form a film on the surface of the aggregate.

Usually, ethylene vinyl acetate type, acrylic type, SBS
A polymer material such as a rubber material or a vinyl chloride material may be used.

The thickness of the organic polymer coating on the aggregate surface is generally 0.
．． I N is 1000 μm, preferably 50 to 200 μm. In order to make the aggregate non-water absorbent, 90% or more of the total surface area of the aggregate should be covered, and in order to obtain aggregate for anti-condensation material, 7
Cover 5% or more. As long as the outside of the aggregate is coated, it does not matter whether the voids inside the aggregate are impregnated with an organic polymer substance or not.

Coating the aggregate with the organic polymeric substance can be carried out by conventional means used for coating powder.

The suspension may be sprayed onto the aggregate and then coated by evaporating the solvent. Alternatively, the powder may be coated by mixing it with an organic polymer powder aggregate, adhering it to the surface of the aggregate, and then melting or softening the powder by heating or the like.The following will be explained using examples. .

Example The following materials were used in the following experiments.

〔aggregate〕

Fist Vermiculite (Hilcon Co., Ltd., product name "Hilcon +0", particle size 0.1-1.5 smoke), pearlite pearlite (Asa Tuba Light Co., Ltd., product name rP-IJ, particle size 0)
．． 1 to 1.5 listens) [Polymer, quality] Liquid emulsion silane type: - Ethylene-vinyl acetate polymer (Showa Denko Co., Ltd., trade name "Himol Emulsion") - Acrylic polymer (Showa Denko Co., Ltd., trade name "Petals") Powder emulsion type: - Melamine polymer (Hoechst Japan Co., Ltd., trade name "Movinyl Powder DM 2oOJ") - Vinyl acetate polymer (Denki Kagaku Kogyo Co., Ltd., trade name rD 100SJ) [Cement] - Ordinary Portland cement (Asano Cement Co., Ltd.) The above-mentioned aggregates coated with polymeric substances and those without coating were kneaded with cement and water, respectively, according to JIS R5201 (physical testing method for cement). At that time, flow 170
The water side required to achieve this was measured, and the water/cement ratio (W/C ratio) was determined based on it. Also, JISA
] 404 (Test method for cement waterproofing agents for construction), the water absorption amount of the hardened mortar was measured. Furthermore, the shrinkage rate was measured 28 days after placing the mortar.

Example 1 1. each of vermiculite and perlite aggregates. , e were mixed with 11 parts of powder emulsion DM200, stirred, and then heat treated at about 200° C. in a fluidized state to form a melamine polymer coating on the aggregate. The above-mentioned kneading test, water absorption test, and shrinkage test were conducted using the aggregates with and without a coating formed thereon. Results first
Shown in the table.

Table 1 When using aggregate with a polymer coating, the required W/C ratio during kneading is reduced compared to when using the same aggregate without coating, and as a result, mortar shrinkage is reduced. A decrease in the amount of water absorbed is observed.

Example 2 Nacreous perlite aggregate was coated with a high mole emulsion, and vermiculite aggregate was coated with Veculus. In both cases, emulsion was diluted with water, aggregate was added thereto, mixed, stirred, filtered, and dried.
However, the residual amount of polymer is 10.0 ml of residual emulsion solids per 1 pu of aggregate. It is. In this example, various cement/aggregate ratios were tested using coated and uncoated aggregates. Furthermore, for comparison purposes, mortar was prepared and tested in which liquid emulsicone was added during kneading so that a film was not formed on the aggregate, but the solid content of the emulsion was the same as that in the mortar. The results are shown in Table 2.

Table 2 below (Note) The mark * in the coating column indicates that the aggregate does not have a coating, but an amount of liquid emulsion that contains the same amount of solids during kneading is added.

From Table 2, it is clear that the effectiveness of the polymeric coating is maintained irrespective of the change in cement/aggregate ratio. Furthermore, even when a liquid emulsion containing a solid content equivalent to that of the coating was added to a mortar made of aggregate without a coating, no decrease in the WZC ratio was observed, indicating that the effect of creating a polymer coating on the aggregate is good. It is shown.

Example 3 Powder emulsion (DM 20
0 and DlooS) were mixed and stirred, and then heat treated in a fluid state at about 200°C to form a polymer film on the aggregate. Tests were conducted using these film-forming aggregates. For comparison, tests were conducted in which the powder emulsion was mixed and then added to the mortar without heat treatment, and the aggregate was heat treated at about 200° C. and then added to the mortar. Whistle the result 3
Shown in the table. The results of Example 1 are also shown in the table.

(Table 3), it can be seen that when a polymer film is formed, the WZC ratio during kneading and the water absorption amount of the curing mortar decrease as well as the emulsion concentration in the concentration range shown in the table. In addition, as in Example 2, it has been shown that a great effect can be obtained by forming a coating on the aggregate rather than simply mixing the emulsion tank into the mortar.

Incidentally, the aggregate according to the present invention can be effectively blended in other than the above-mentioned cement-based compositions, for example, in gypsum-based compositions.

patent applicant Showa Denko Co., Ltd. patent application agent Patent attorney Akira Aoki Patent attorney Kazuyuki Nishidate Patent attorney Yoshinari Koga Patent attorney Akira Yamaguchi

Claims (1)

[Claims] 1. Aggregate coated with an organic polymer film.