JPS6214515B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to a plastering material for thick application, which aims to improve the thickening performance of the plastering material by troweling by adding slag and lightweight spherical bodies as aggregates to the plastering material. . The standard coating thickness of conventionally used plastering materials for one troweling is about 1 mm to 6 mm depending on the type of plastering material, so a thick finished thickness (for example, 6 mm to 20 mm) is required.
In order to obtain this, it is usually necessary to trowel about 2 to 4 times, and due to the nature of the plastering material, it is difficult to apply multiple coats in succession, so the first coat (base coat) is sufficient. After curing and drying, 2
A second coat (intermediate coat) and a third coat (top coat) will be applied, which will delay the construction period. In addition, the causes of defects were complex, requiring consideration such as using a rich blend of inorganic binding materials in the undercoat to prevent peeling, and using a poor blend of inorganic binding materials in the top coat to prevent cracking. New plastering also has these problems, and even when repairing floating or peeling parts of the plastering base and plastering layer, the construction period may be shortened because parts need to be repainted two or three times.・There were problems such as high construction costs and the possibility of compromising consistency with healthy parts that do not require repair. Even if you try to apply a thick coat (e.g. 6mm to 20mm) using a conventional plastering material by troweling at one time, the trowel may not be enough to press the plastering material against the base surface, the plastering material may sag or slip easily, and the troweling may be difficult. Due to various factors such as the difficulty of the work, it has been virtually impossible to achieve a coating thickness greater than the standard coating thickness in one coat. However, the working performance of plastering materials can be expressed by the F value (equivalent to the force of holding the trowel), ψ value (equivalent to the resistance to slipping of the trowel), and M value (the moment applied to the grip of the trowel) shown in Figure 1. As a result of various studies on aggregates added to plastering materials, a plastering material for thick coating that has the desired work performance during thick coating was obtained. In other words, by mixing slag and lightweight spherical bodies in a predetermined proportion in addition to the conventionally known silica sand and similar sand, the aggregate improves the problems of the conventional plastering materials and is applied to the plastering base surface. Appropriate pressure with a sawing trowel can be easily applied, and there is no sagging or shearing of the plastering material during or after application, and if you try to apply thinly, the F value will increase, making it easier to apply thinly. This resulted in a plastering material that is difficult to apply and suitable for thick coating. A mixed aggregate of silica sand, slag and lightweight spherical bodies is suitable as the aggregate for this invention, and the particle size of each varies depending on the thickness of the coating layer after application and the application, but is preferably 3 mm or less. The slag used is blast furnace water slag slag and/or wind slag, and the lightweight spherules are vitreous microscopic hollow spheres, synthetic polymeric substance spheres, pozzolanic substance spheres, etc. Aggregates having physical properties similar to those of the above materials can be used. Next, the characteristics of plastering materials suitable for thick coating are listed. The coating thickness exceeds the standard coating thickness and can be applied up to 20mm in 2 to 4 coats. Or, it can be recoated in a short period of time in about 3 to 6 times on raw paint layers up to 50 mm. During and after application, the product should not sag or shear due to its own weight until it hardens. This means that the trowel must be properly tightened as soon as possible after the troweling process is completed, or that the thixotropy is large. It must have the deformability to absorb as much shrinkage strain as possible due to the restraint of the substrate. The trowel force F value is appropriately large, it blends well with the substrate, and it has high adhesion. The moment M value in the grip of the iron worn on the wrist is appropriately large, compacted, and solidified. Good trowel slippage. In other words, it does not stick to the iron surface and the iron easily slips. This means that the ψ value (resistance to iron slippage) is small. Difficult to apply thinly. In other words, when applied thinly,
The F value is large, and thick coating is easier for workers to apply with a trowel than thin coating. The above-mentioned ~ require mutually contradictory characteristics. For example, it may not shear and deform, but the trowel does not work well and the adhesion is poor, or the trowel may blend well with the substrate with a proper trowel, but the trowel does not slide well. In this invention, in addition to the effect of adding a synthetic polymer admixture to the inorganic binding material, slag and lightweight spherical bodies were mixed in addition to silica sand as aggregates, so the mixing of these aggregates was adjusted to an appropriate level. It is recognized that by determining the ratio, the above-mentioned contradictory characteristics have been shared. According to the results of the experiment, the ratio of the mixed aggregate to maintain the above properties is 70% or less (by weight) of silica sand and 25% to 75% slag.
% (by weight), lightweight spheres 5% to 50% (by weight). The lightweight spherical bodies include those with a water absorption rate of 10% or less (for example, vitreous micro hollow spheres) of 1% or more, and those with a water absorption rate of 40% or less (for example, glass balloons), and if the water absorption rate is 5% or more. good. In addition, the plastering material of this invention includes polymer dispersion of styrene-butadiene copolymer, ethylene-vinyl acetate copolymer, acrylic acid ester copolymer, vinyl chloride copolymer, and vinyl acetate polymer as synthetic polymer admixtures. and/or water-soluble cellulose ether and other polymers, the mixing ratio of which varies depending on the applied material.
The polymer/inorganic binding material ratio should be more than 0 and less than 45% (by weight) in terms of solid content. Further, the ratio of the inorganic binding material to the mixed aggregate is 1:1.0 to 4.0 (by volume). In this invention, as the inorganic binding material (hereinafter referred to as cement), ordinary Portland cement, early-strength Portland cement, alumina cement, mixed cement, plaster, lime, etc. are used. In order to further enhance the reinforcing effect, inorganic and/or organic fibrous materials can also be added. Table 1 shows the effect of each raw material used in this plastering material on the properties of thick plastering material.

[Table] In the above, the mixing ratio of lightweight spherical bodies is 5%.
If the weight is less than (weight), the plastering material will not come easily with the trowel and workability will deteriorate, making it impractical.
If it exceeds 50% (weight), the force of pressing the plastering material with the trowel decreases, making it impossible to apply the necessary pressure to the underlying surface, and making it impractical due to lack of adhesion. Furthermore, if the slag content is less than 25% (by weight), thin coating is possible and thick coating is not necessary, making it unsuitable as a plastering material for thick coating. Also, if the slag exceeds 75% (weight), compaction will accelerate,
Pot life becomes shorter. Furthermore, inorganic and/or organic fibrous materials can be added to increase the reinforcing effect. Next, an experimental example of this invention will be explained. Experimental example 1 First, the quality of the aggregate used is as shown in Table 2.

[Table] Table 3 shows the composition ratio of the mixed aggregate used in the experiment.

[Table] Cement mortar is made by using the above three types of mixed aggregates A, B, and C and adding ordinary Portland cement, polymer dispersion of styrene-butadiene rubber, and water, and this is shown in Figure 1. The F
When the value, ψ value and M value were measured, the results shown in FIGS. 2 to 6 were obtained. In this case, the polymer/cement ratio was 7% (weight) in terms of solid content, the cement/mixed aggregate ratio was 1:2 (volume), and the water/cement ratio was 48% (weight). Also, the room temperature is 20±2℃,
The humidity was 60±5%RH, and the water temperature used was 18°C. Considering the results of the above experiment, the characteristics of thick coating with a trowel were determined after 5 minutes of kneading. According to Figures 2 to 4, mortar using mixed aggregate A had a thick coating property (20 mm) F value is abnormally small,
The ψ value is abnormally large and difficult to paint. On the other hand, in the case of thin coating (5 mm), the ψ value was small and the F value and M value were appropriate, making it suitable as a mortar for thin coating, but unsuitable for thick coating. This was presumed to be due to the lack of glassy microscopic hollow spheres in the mixed aggregate. In addition, for mixed aggregate B, F is applied between thick coating and thin coating.
Since the difference in value, M value, and ψ value is not very large, it can also be used for thin coating. Therefore, even if thick coating is supported, there is a possibility that workers will inevitably apply thin coating. Therefore, although it can be used as mortar for thick coating, it is not optimal. Next, even when mixed aggregate C is thickly coated (20 mm), the F value and M
The value is appropriately large, and the trowel can be properly pressed against the base, and the ψ value is small, so the trowel slips easily and is easy to apply thickly. Furthermore, if you try to apply a thin coat, the F value and M value will increase dramatically, so in the field, workers naturally apply a thick coat with one stroke of the trowel. This point C is considered to be due to the fact that a large amount of slag was mixed into the mixed aggregate, and the effect of the mixing of glassy microscopic hollow spheres was also added. Figures 5 and 6 show the ease of thick coating work,
Appropriate characteristic value ranges (shaded areas) are predicted after considering the balance between improving the performance of the finished layer after hardening due to the ability to press against the base. In the apparatus used in the above experiment (Fig. 1), the length l (progressing direction) of the blade 1 (corresponding to the iron surface) is 200 mm, the width is 90 mm, and the shortest distance h between the iron surface and the center of the grip is 35 mm. , the angle θ between the blade and the sample is 1.4 degrees, the speed of the blade υ is 25 cm/sec,
The coating thickness T was 5 mm, 10 mm, 15 mm, and 20 mm. Fifth
In the figure and Figure 6, △ is 5 mm, ○ is 10 mm, ◇ is 15
mm and □ are symbols indicating a coating thickness of 20 mm. That is, according to the present invention, the above-mentioned mixed aggregate is used as the aggregate, and 25% to 75% (by weight) of slag and 5% to 50% (by weight) of lightweight spherical bodies are mixed, so that a moderate F.
It has a small ψ value and has the effect of satisfying various characteristics required for thick plastering plastering materials. Next, we determined the tensile adhesive strength of the mortar finish layer of mixed aggregate C, which was applied once to the RC building wall with a coating thickness of 15 mm, after 4 weeks of age, and found that it was 12.5 with 5 tests.
~15.7Kgf/ ^cm2 was obtained. The cement mortar layer in the above experiment exhibited reliable adhesion after hardening and did not crack or crack even after three months. Next, we prepared mortar test specimens in accordance with JISR5201 and cured them for 4 weeks in an environment of 20°C and 60% RH.The bending strength and bending elastic modulus of the specimens were determined, and the results shown in Table 4 were obtained. It was found that the bending strength and bending elastic modulus were lower than that of Mixed Aggregate D, and that it had excellent deformability and was able to alleviate stress caused by movement.

[Table] For the water absorption test, mortar test specimens were prepared in accordance with JISA6203, and air-dried specific gravity and water absorption rate (after 48 hours of water absorption) were prepared at 20℃ and 60% RH for 4 weeks.
The results were as shown in Table 5. It was found that the waterproofness was satisfactory.

【table】 Experimental example 2 The quality of the aggregate used is as shown in Table 6.

[Table] Table 7 shows the composition ratio of the mixed aggregate used in the experiment.

[Table] Using the above two types of mixed aggregates E and F, we added ordinary Portland cement, styrene-butadiene rubber polymer dispersion, and water to make cement mortar, and determined various properties. Table 8 The results shown in Table 9 were obtained. In this case, the polymer/cement ratio is 4% solids (by weight), and the cement to mixed aggregate ratio is 1:
2.5 (volume), water/cement ratio is 56 for mixed aggregate E
% (weight), and 55% (weight) for the same F. The room temperature was 25±3°C, the humidity was 65±5%RH, and the water temperature used was 21°C. The test method and test conditions were the same as in Experimental Example 1.

【table】

[Table] Table 10 shows the results of the tensile bond strength after 4 weeks of age for walls with the same polymer cement mortar applied to a concrete base to a thickness of 25 mm.

[Table] The above polymer cement mortar finish had a high deformability and no cracks or cracks appeared even after 3 months. Experimental Example 3 Using mixed aggregates E and F, which are the same as Type B mixed aggregate used in Experimental Example 2, ordinary Portland cement, water-soluble cellulose ether, and water were added to each to make cement mortar, and its properties were investigated. The results shown in Table 11 and Table 12 were obtained. The polymer cement ratio in this case is 0.3%
(weight), cement and mixed aggregate ratio is 1:2.5 (volume), water and cement ratio is mixed aggregate E and F,
Both were set at 67% (weight). The room temperature was 25±3°C, the humidity was 65±5%RH, and the water temperature used was 21°C. The test method and test conditions were the same as in Experimental Examples 1 and 2.

【table】

[Table] Table 13 shows the results of the tensile bond strength after 4 weeks of age for walls with the same polymer cement mortar applied to a concrete base to a thickness of 22 mm.

[Table] The above polymer cement mortar finish has deformability, and only some cracking was observed after 3 months. No cracks occurred. Next, embodiments of this invention will be described. Example 1 Mixed aggregate made by mixing 50% (by weight) of silica sand, 40% (by weight) of blast furnace water slag, and 10% (by weight) of glassy microscopic hollow spheres was mixed to 1:2.5 of cement.
(by volume), and then add styrene-butadiene rubber latex to cement at a solid content of 10%.
(by weight) and mix the cement mortar at a water/cement ratio of 35% (by weight) to a thickness of 15 mm to 25 mm.
It was applied to an approximately 5 m ² RC exterior wall surface for repair purposes after one to two additional coats, and no abnormalities such as cracks, crazing, or lifting were observed after 3 months. Example 2 Mixed aggregate made by mixing 30% (by weight) of silica sand, 50% (by weight) of blast furnace water slag, and 20% (by weight) of vitreous micro hollow spheres was mixed at a ratio of 2 (by volume) to 1 part of cement. Then, add 7% solids (weight) of ethylene-vinyl acetate resin copolymer emulsion to the cement, making the water/cement ratio 45% (weight).
Cement mortar mixed with 30 mm to 50 mm was applied two to three times to cover an area of approximately 10 m ² and to repair the missing horizontal reinforcing bars at the lower end of the RC beam in the ceiling. No abnormalities were observed after several months had passed. The tensile adhesive strength at 4 weeks of age was 10 Kgf/cm ² or more. Example 3 Mixed aggregate made by mixing 40% (by weight) of silica sand, 55% (by weight) of blast furnace water slag, and 5% (by weight) of vitreous micro hollow spheres was mixed to 1.5% of cement.
(by volume), and then add styrene-butadiene rubber latex to cement at a solid content of 7%.
(by weight) and a cement mortar mixed at a water/cement ratio of 38% (by weight) was used as mortar for tiling. The base is 12 mm thick waterproof plywood, and on top of that is a polymer/cement ratio of 12% (solid weight of styrene-butadiene rubber latex), cement: mixed aggregate = 1:0.7 (volume), water/cement ratio.
After applying 30% (by weight) cement-rich and polymer-rich mortar, apply the above mortar.
108×60mm, 16mm thick exterior tile with adhesive layer thickness 8
After 6 months of crimping at ~12mm, no abnormalities such as lifting or cracking were found. The tensile adhesive strength of the same material was 8 to 10 kgf/cm ² .

[Brief explanation of the drawing]

Figure 1 is a diagram of the principle of the apparatus for testing the characteristics of plastering materials according to the present invention, Figure 2 is a graph of the relationship between the F value and coating thickness, Figure 3 is a graph of the relationship between the M value and coating thickness, and Figure 4 is a graph of the relationship between the M value and coating thickness. 5 is a graph of the relationship between the F value and the φ value, and FIG. 6 is a graph of the relationship between the F value and the M value.

Claims (1)

[Scope of Claims] 1. A plastering material consisting of an inorganic binder material/mixed aggregate and a synthetic polymer admixture, wherein the ratio of the inorganic binder material to the mixed aggregate is 1:1.0 to 4.0 (by volume); The aggregate includes silica sand, blast furnace water slag, and inorganic, microscopic, hollow, lightweight spherical bodies with a specific gravity of 1.70 or less and a nominal sieve size of 3 mm or less, and blast furnace water slag accounts for 25% to 70% (by weight) of the mixed aggregate. A thick plastering material characterized by: 2 Slag in the mixed aggregate is 25% or more of the mixed aggregate
75% (by weight), lightweight spheres from 5% to 50% (by weight)
A plastering material for thick coating according to claim 1, characterized by: