JPH0678678B2 - Mortar wall construction method - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improved mortar wall construction method in which cracks do not occur.

[Conventional technology]

Conventionally, so-called undercoated plywood (hereinafter referred to as "laminate"), in which cement mortar containing a polymer is applied in a concavo-convex shape with a thickness of 2 to 3 mm on a wall foundation plywood, is manufactured in advance in a factory, and this laminate is used at a construction site. It was used as a wall base material.

That is, the mortar wall construction method in which the mortar layer of the laminated board is placed outside, but the laminated boards are abutted, nailed to the pillars to form the wall base surface, and then ordinary mortar is intermediately coated and overcoated to a required thickness The so-called non-laser construction method was used.

[Problems to be solved by the invention]

In the non-laser method, after nailing the laminate, the joints between the laminate and the laminate are coated with caulking material to close the gap, and then ordinary mortar is applied. Due to the distortion of the plywood due to the deformation of the structural body due to its own contraction strain and wind pressure and other external forces, the bonding surface between the mortar layer of the laminate and the caulking material,
Alternatively, the caulking material itself was cracked, and the overcoated ordinary mortar was also cracked due to shrinkage of the cement used. In other words, the mortar wall produced by the non-laser method had cracks in both the undercoat layer and the overcoat layer after a long time had passed, and the cracks propagated to the overcoat layer and the undercoat layer, respectively, resulting in cracks penetrating in the mortar thickness direction. .

Therefore, not only does the appearance of the mortar wall deteriorate, but especially in the case of the outer wall, rainwater penetrates inside the building through cracks and corrodes the underlying plywood, columns, and metal fittings, reducing the durability of the building. Was.

Therefore, in order to eliminate the above-mentioned drawbacks, the present inventors have studied a mortar wall construction method in which cracks do not occur,
The inventors have found that cracking can be suppressed by integrally undercoating the entire surface of the base plywood nailed with polymer cement mortar and nailing the mortar with a small shrinkage, and the occurrence of cracks can be suppressed.

[Means for solving problems]

That is, the present invention is a mortar wall construction method in which mortar is applied to a base plywood, and polymer cement mortar is then applied to the entire surface of the base plywood in which staples, nails, etc. (hereinafter collectively referred to as “nails etc.”) are struck on the wall framework. A mortar wall construction method for applying a mortar mixed with a shrinkage reducing agent (hereinafter referred to as "shrinkage reducing mortar").

The present invention will be described in detail below.

The polymer cement mortar of the present invention is obtained by mixing cement, polymer dispersion and sand.

Examples of the cement include Portland cement and mixed cement. The polymer dispersion conforms to JIS A 6203 "Cement mixing polymer dispersion", for example ethylene vinyl acetate copolymer, modified vinyl acetate polymer, vinyl acetate-Veova copolymer, styrene butadiene rubber, acrylic rubber, It is used by appropriately selecting it from a dispersion of cation or anion acrylic. An antifoaming agent is usually added to commercially available polymer dispersions, but this has no adverse effect on the practice of the present invention.

The blending ratio of the polymer dispersion is preferably 10 to 50% by weight based on the solid content of the cement. If the solid content is less than 10% by weight, the adhesion between the polymer cement mortar and the base plywood is weak, which is not preferable. If it is blended in an amount of more than 50% by weight, the adhesive strength of the polymer cement mortar to the base plywood and the elasticity of the cured product thereof are increased, but the viscosity becomes too large and the workability is deteriorated, which is not preferable.

Sand is appropriately selected and used from river sand, mountain sand, silica sand, lightweight fine aggregate, etc., which are used for making ordinary cement mortar and concrete. The mixing ratio is preferably 50 to 300% by weight with respect to the cement. If it is less than 50% by weight, it is not preferable since it is difficult to roughen the surface after applying the polymer cement mortar.
If it exceeds 0% by weight, the amount of the polymer dispersion becomes relatively small and the adhesion to the base plywood becomes weak, which is not preferable.

The above cement, polymer dispersion and sand are mixed using a conventional equipment to prepare a polymer cement mortar. At that time, the mortar needs to have a viscosity that allows plastering, but if a mortar having an appropriate viscosity cannot be obtained only by the amount of water contained in the polymer dispersion, water is appropriately added to adjust.

It should be noted that, when making polymer cement mortar, it is possible to add and mix an extender, for example, silica powder, calcium carbonate powder, or aluminum silicate powder, if necessary, within a range that does not hinder the coating operation.

Next, the shrinkage-reducing mortar will be described.

This product is used for intermediate coating (may be omitted depending on the wall thickness; the same meaning unless otherwise stated) and for top coating.

Shrinkage reduction mortar is made by adding cement, organic shrinkage reducing agent, sand, thickener and water and kneading.

The cement used for the mortar is usually Portland cement or mixed cement, and the sand is river sand, mountain sand, sea sand or the like.

Organic shrinkage reducing agents are used as ordinary cement mortar and concrete admixtures, for example, lower alcohol alkylene oxide compounds (eg Nippon Cement Co., Ltd. “Tetraguard AS20”), glycol ether compounds (eg Fujisawa Pharmaceutical Co., Ltd. ) “FC1610”), polypropylene glycol-based compounds (for example, “Hibidan” from Takemoto Yushi Co., Ltd.), and the like.

The compounding ratio of the organic shrinkage reducing agent is 1.5 to 10 with respect to the cement.
Weight percent is suitable. If the blending ratio is less than 1.5% by weight, cracks are generated along the joints, which is not preferable. On the contrary, even if the amount is more than 10% by weight, the shrinkage reducing effect is almost unchanged, which is economically disadvantageous.

The mixing ratio of sand is usually the ratio for making plaster mortar, and about 100 to 400% by weight of cement is a standard.

As the thickener, substances and compounding ratios which are usually used in making plaster mortar are adopted in the present invention. That is, as the thickener, methyl cellulose, carboxymethyl cellulose and the like are shown, and the mixing ratio thereof is preferably 0.05 to 0.3% by weight with respect to the cement.

Water is added to the above materials and kneaded by a conventional method to form a shrinkage-reducing mortar, but the amount of water at that time should be appropriately blended in consideration of the coating thickness and workability (iron spread, iron separation, etc.). Good.

In addition, when making shrinkage-reducing mortar, depending on the case, "Denka CSA" of Denki Kagaku Co., Ltd., Nippon Cement Co., Ltd.
Shrinkage reduction is further improved and effective if an expansive material for cement such as "Zipcal" or "Expan" manufactured by Onoda Cement Co., Ltd. is appropriately blended.

Next, a wall construction method using each of the above mortars will be described.

The wall plywood is made by nailing the plywood while abutting the plywood so that the pillars have as little gaps as possible. After the polymer cement mortar is troweled to a thickness of several mm on the finished wall-base plywood and left for several hours, this shrink-coated mortar is intermediately coated and left for several days with roughening. After that, the intermediate coated surface is wetted with water, and the shrinkage-reducing mortar is overcoated and cured to form a mortar wall without cracks.

[Action]

In the present invention, the polymer cement mortar is used as the undercoating mortar because it is well adhered to the base plywood and the cured mortar has elasticity. The polymer cement mortar is undercoated on the entire surface of the wall-base plywood that is struck on the pillars with nails or the like, and the mortar layer (undercoat layer) is integrated as a single plate by curing. As a result, (1) the polymer cement mortar cured product adheres to the base plywood, and the adjacent base plywoods are firmly connected to each other, and (2) the elasticity of the mortar cured product absorbs the strain generated in the base plywood. The first feature of the present invention is to suppress the generation of cracks that have conventionally occurred in the undercoat layer.

The second feature of the present invention is that the shrinkage-reducing mortar is used on the polymer cement mortar for intermediate coating and overcoating, thereby suppressing cracks generated in the overcoat layer.

Next, the present invention will be described with reference to examples.

[Examples] Examples 1-2 and Comparative Examples 1-2 A wall framework is made according to the framework wall construction method of Ministry of Construction Notification No. 56, and two 910 x 1820 x 12 mm base plywoods are abutted on one side thereof Then, nails of CN50 were struck to produce three 3.3 m ² wall surfaces.

Next, three kinds of undercoating polymer cement mortar (Examples 1 and 2 and Comparative Example 1) having the materials and compositions shown in Table 1 were prepared, and each wall was applied with a trowel to a thickness of 1.5 mm.
It was left for 3 hours.

Then, apply a shrinkage-reducing mortar for intermediate coating with the composition shown in the same table with a trowel to about 8.5 mm, and make a rough look with a gold comb.
It was left to cure for a period of time.

After that, after water-moistening each wall that has been intermediately coated, apply the shrinkage-reducing mortar for top-coating shown in the same table with a trowel to a total mortar thickness of 20 mm, and finish the coating surface flat after 3 hours. It was

On the other hand, two commercially available laminates (“Nodalus Cut”, Noda Plywood Co., Ltd.) coated with polymer cement mortar with a thickness of 2 to 3 mm as a base plywood on the wall frame made according to the above notification Then, using the nail of NC50, it was struck from above and the wall of 3.3mm was made. After that, caulking material was applied to the joint with a trowel and cured for 2 days.

A wall surface was prepared by applying shrinkage-reducing mortar for intermediate coating and top coating on the laminated plate according to the formulation and working procedure of Example 1 in the same table (Comparative Example 2).

The four types of wall surfaces obtained as described above were left for 4 weeks after overcoating, each wall surface was observed, and the state of crack generation was examined. The results are also shown in the table.

EFFECTS OF THE INVENTION The present invention applies a polymer cement mortar to a base plywood nailed to a wall frame to cure it, thereby integrally forming an undercoat layer, and the elasticity of the cured product has an undercoat layer due to distortion of the plywood. Achieved the purpose by combining the performance of each mortar, which suppresses the occurrence of cracks and suppresses the occurrence of cracks on the surface by using shrinkage-reducing mortar for intermediate coating and top coating. This is an excellent mortar wall construction method that cannot be seen with conventional methods.

Claims (1)

[Claims] 1. A mortar wall construction method in which mortar is applied to a base plywood, characterized in that polymer cement mortar and then mortar mixed with an organic shrinkage reducing agent are applied to the base plywood struck on the wall framework. .