JPS5935053A - Cementitious self-leveling material - 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 The present invention relates to a self-leveling material, and more particularly to a cement-based self-leveling material that has excellent water resistance, durability, and fluidity, exhibits extremely little shrinkage, and is resistant to cracking.

Gypsum-based materials are conventionally known as self-leveling materials, and are used for flooring materials and the like.

However, plaster has low water resistance, so it can be used on balconies, for example.
The drawback is that it cannot be used outdoors on rooftops or in humid basements. Cement-based materials have been proposed to eliminate these drawbacks, but no material has yet been developed that has good durability and fluidity and is resistant to cracking even after hardening.

The present invention provides a cement-based self-leveling material having these properties. That is, the present invention provides a self-leveling material containing cement, fly ash, and silica sand.
This is a cement-based self-leveling material made by blending the following components fa) to (cl) to O parts by weight.

(a) 80 particles with a particle size of 0.59 to 0.21 mm
2 to 15 parts by weight of gypsum hemihydrate (1)) 0.3 to 5 parts by weight of urea (C) 0.1 to 5 parts by weight of polymer emulsion or latex as a solid content, details of the present invention To explain, Semen, To,
Self-leveling materials containing fly ash and silica sand are known to improve water resistance and abrasion resistance. However, simply mixing these ingredients together will
Since the fluidity and adhesiveness as a self-leveling material are insufficient, components fa) to (C) are further blended.

In the present invention, from the viewpoint of fluidity and strength development, it is desirable that the proportions of cement, fly ash and silica sand be as follows. flf That is, the cement is 15 to 65, preferably 2 [1 to ! If c is less than 15%, which is 10 inches, sufficient strength cannot be obtained, and if it exceeds 55 inches, cracks tend to occur and fluidity decreases. Examples of cement include mixed cements such as various portland cements, blast furnace cements, fly ash cements, and silica cements.
and alumina cement. The fly ash is 50-50%, preferably 55-45%. 50%
If it is less than this, fluidity will decrease and drying shrinkage will also increase. Also 5
When it exceeds 0cIj, the viscosity increases, the fluidity decreases, and the strength also decreases. Silica sand is 25 to 50, and 2
If it is less than 5% or more than 50%, the fluidity will decrease.

Moreover, if the particle size exceeds 50, the strength also decreases, and the center particle size of the waxy silica sand is preferably around 250 μm from the viewpoint of fluidity.

(a) The gypsum hemihydrate as the component has a particle size of 0.59 to 0.
The particles were adjusted so that 80% or more of the particles were within the range of 21 mm. Gypsum includes anhydrous gypsum and industrial gypsum, but these are not preferred in terms of fluidity and strength. The amount of gypsum hemihydrate used is
The amount is 2 to 15 parts per 100 parts of the self-leveling material containing the three components. If it is less than 2 parts, the effect of preventing dry cracking will be small, and if it exceeds 15 parts, the strength will decrease or cracks will occur due to expansion pressure.

Furthermore, it is important to properly adjust the particles of gypsum hemihydrate used. This has a positive effect on the fluidity of the self-leveling material, and the formation of ettringite produced by the reaction with cement and fly ash occurs very slowly, which is almost as fast as the degree of hardening shrinkage of cement. It will be held in As a result, the expansion by ettringite smoothly compensates for the curing shrinkage of cement, resulting in a self-leveling material that is extremely resistant to cracking.

If the gypsum particle size exceeds 0.59 ms, dispersion will be poor, resulting in a decrease in strength after curing and poor surface smoothness.

(If it is less than 3,21+m, false coagulation tends to occur and the fluidity decreases significantly. Also, 0.59 to 0.2
If the particle ratio of 1+m++ is less than 80, expansion cracks will occur and the wear resistance will deteriorate. Component (b) is urea, which has a water-reducing effect and a crack-preventing effect. The amount used is 1 of the self-leveling material containing the above three components.
The amount is 0.5 to 6 parts per 00 parts. If the amount is less than 0.5 parts, the effect will be small, and if it exceeds 6 parts, no increase in the effect will be observed, and instead it will cause a delay in setting and a decrease in the strength of the cement.

Component (C) is a polymer emulsion or latex, which is useful for preventing solid-liquid separation, improving the water resistance of the cured product, and improving adhesion to the underlying concrete. The amount used is 0.1 to 5 parts as a solid content per 100 parts of the self-leveling material containing the above three components, and if it is less than 9.1 parts, there is almost no effect, and if it exceeds 5 parts. This will reduce the fluidity of the slurry.

Examples of the polymer emulsion include ethylene acetate emulsion, acetic acid vinyl emulsion, other polyvinyl acetate emulsions, acrylic emulsions, and polyethylene emulsions, among which powder emulsions are most suitable. In addition, as latex, natural rubber (NR), chloroprene rubber (
Rubber latexes such as styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), methyl methacrylate-butadiene rubber (MBR), and butadiene rubber (BFt) can be mentioned.

When the cement-based self-leveling material of the present invention having the above ratio is further combined with the following water-soluble resin as required, it not only improves chemical resistance such as acid resistance, but also improves adhesive strength, water retention, and bending strength. and liquidity will improve. Water-soluble resins include casein and some salts, gelatin, protein thickeners such as glue, and methylcellulose (M, O
), polyvinyl alcohol (PTA), polyacrylate, furfuryl alcohol, and other water-soluble polymers, and powdered versions of these may also be added. ``The amount of the water-soluble resin used is about 0.05 to 1 part as solid content per 100 parts of Selzle perifluorocarbon material containing the above three components.

The effects of using the self-leveling material of the present invention are as follows: (1) Since it has high fluidity, it can be pumped.

(2) It has excellent self-leveling properties, so when used for flooring, construction costs are low and construction can be done quickly.

(3) Because it is highly water resistant, it can be used outdoors, which was not possible with conventional plaster-based leveling Linma 1.
It can now be used for construction on homes, balconies, and rooftops, as well as in basements and underground pits that tend to get damp.

(4) Since it has excellent wear resistance, it can be used on warehouse floors, aisles, etc. where transport vehicles such as forklifts come in and out, where this is required.

(5) Durability is significantly increased because cracks are less likely to occur.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Note that all units and parts described in the specification are expressed on a weight basis.

Examples Ordinary Portland cement, fly ash, silica sand, α-type hemihydrate gypsum with different particle sizes, urea, Vinnapa R1538Z as vinyl acetate emulsion [vinyl acetate-vinyl versatate-vinyl laurate copolymer] (WA
OKI! Jj Co., Ltd.) and water were blended as shown in Table 1.

Table 1 1
11(2) (3) (4) Note 1 0.21 + a full-length α-type hemihydrate gypsum Note 2 0.59
α-type hemihydrate gypsum Note 50.59 to 0.21 exceeding +c++
(5) α-type hemihydrate gypsum with particles within the range of (5) 75 yen. The non-impact flow, pleating, dry cracking, expansion cracking, abrasion resistance, and strength of these mortars were measured.

The results are shown in Table 2.

In addition, each physical property was measured as follows.

Fromm: Non-impact flow is the spread diameter in a non-impact state on a smooth acrylic resin horizontal surface of 6vf Rutar using a flow cone specified in JIS R5201.

Pleasing: 4 x 4 x 16 crn of kneaded mortar
The surface condition was observed 50 minutes after the kneading was completed.

Dry Crack 2 A Q-crack test specimen having the dimensions shown in the drawing was prepared using kneaded mortar, and the presence or absence of cracking was observed when it was cured under conditions of Φ 20° C. and 601 RH.

A specimen with expansion cracks = 4 x 4 x 16 cIn was molded,
After air-drying at 20° C. and 80° RH, it was immersed in water at 20° C. and observed.

Abrasion resistance: A 10ψ x 20cm test piece that had been air-dried for 28 days was packed in a vibrating pot mill equipped with a 145ψ inner diameter x 225T tatami stainless steel container together with 7kg of 10ψ steel balls at a frequency of 1110V and an amplitude of 10m. After operating for 30 minutes, the wear status of the specimen was observed.

(6) Strength: A 4x4x16m specimen was molded and 20
Air-drying was performed at 80° C. and RH, and the compressive strength was measured after 1 day and 28 days.

Table 2 Note 4 Dry cracks: Comparative example 1 was aged 7 days, comparative example 2
Cracks occurred at the age of 10 days in Comparative Example 5, and at 15 days after the age of the material in Comparative Example 5, and no cracking occurred in the other samples even after 4 months of age.

Note 5 Expansion cracks: Comparative example 4 was aged 5 days, comparative example 6
Cracks occurred at the age of 7 days in Comparative Example 7, and at 4 days after the age of the materials in Comparative Example 7, and no cracks occurred in the others even after 4 months of age.

Note 6 Wear resistance: Good (surface wear less than 1W) Mouth surface 11 points υbi! l mountain j?゛”Sadako 6 printing 1o0i1isugono)
.

Patent applicant Denki Kagaku Kogyo Co., Ltd.

Claims (1)

[Claims] In a self-leveling material containing cement, fly ash and silica sand, the self-leveling material 100
A cement-based self-leveling material containing the following components (a) to (C) based on parts by weight. (+1.) Particle size 0.59-0.21 tttm (
') 2 to 15 parts by weight of gypsum hemihydrate whose particles have an 80i content of 1 or more (1) J Urea [J, 3 to 6 parts by weight (C) 0.1 to 5 parts by weight of polymer emulsion or latex as solid content