JP2610470B2 - Mortar and concrete surface improvement paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to paper used for various types of mortar / concrete for civil engineering and construction, concrete products, etc., and in particular to paper having improved surface properties, Slope) This relates to mortar / concrete surface property improving paper suitable for construction.

[Conventional technology and its problems]

The strength of mortar and concrete depends on the water / cement ratio, the smaller the value, the greater the strength. At the time of casting, the amount of water is reduced by using a cement dispersant or the like, but it is impossible to reduce the amount beyond the limit from the viewpoint of workability. In addition, if excess water is present, the water may become breathing water, voids may be formed in the concrete to cause a decrease in strength, or a defect called “avatar” may be generated on the concrete surface. The avatar is remarkably generated when the hitting surface, which is called a so-called slope, is an inclined portion, and may be increased by one step for repair.

In addition, an air entraining agent called an AE agent is used in concrete to prevent freezing and thawing, and contains about 4% of air. The avatar phenomenon is also caused by this air. For this reason, conventionally, immediately after casting, water or air has been absorbed by covering the surface with a water-absorbent resin, paper, or perforated cloth.

In particular, Japanese Patent Publication Nos. 49-18767 and 50-11692 have patent applications for similar purposes, but they have not been clarified from the relationship between the physical properties of the paper and the surface properties of concrete.
Rather, emphasis is placed on removability from concrete.

[Means for solving the problem]

As a result of various studies to solve these problems, the present inventors have developed a paper that allows excessive moisture and air to pass through the mortar / concrete at the time of casting and significantly improves the hitting surface.

The configuration is characterized in that a synthetic resin film having pores is laminated on a water-permeable sheet having a water time of 10 seconds or more and less than 1000 seconds, and the water time of the laminate is 100 to 10,000 seconds.

Water time is a value measured according to JIS P3801,
It is expressed as the time required for 00 ml of water to pass through the area of 10 cm ² of the sample sheet. If the water time of the laminate exceeds 10,000 seconds, the mortar / concrete will not be sufficiently dehydrated, and may cause avatars on the hitting surface. If the water time is shorter than 100 seconds, rapid dehydration is performed immediately after the casting, so that a favorable result such as formation of water in concrete cannot be obtained. Although the reason for the air avatar is not clear, it is sufficiently improved within the above water time range. Water time of permeable sheet is more than 10 seconds 1000
The reason for being less than a second is to make the water time of the laminate 100 to 10,000 seconds.

FIG. 1 is a cross-sectional view of a mortar / concrete surface property improving paper of the present invention.
FIG. 2 is a cross-sectional view of a mold used for casting on a slope, wherein 1 is paper, 2 is a synthetic resin film having pores,
3 is a mold.

The synthetic resin film having pores has a function of coming into contact with concrete, exhibiting water permeability, and facilitating separation from the concrete surface.

Examples of the synthetic resin film having pores include films made of polyethylene, polypropylene, polyester, vinyl chloride, polyurethane, cellulose derivatives, etc., which have perforations or slits, dialysis membranes, nets, cross yarns, flat yarns, etc. Can be used. The pores preferably have a total area occupying 5 to 80% of the total area and an interval between the pores of 0.5 to 10 mm. Outside this range, water absorption is insufficient and handling becomes difficult.

As the water-permeable sheet, paper having a water time of 10 seconds or more and less than 1000 seconds, mixed paper, or resin-impregnated paper can be used. Paper tends to occur wrinkles in the paper is suitable as a basis weight of 100 to 500 g / m ² Wori, basis weight is less than 100 g / m ^2, the wrinkles mortar
Since it remains on the concrete casting surface, it is not suitable for the purpose of improving the surface properties. Paper with a basis weight of more than 500 g / m ² is not practical.

As mixed paper, inorganic fiber and / or organic fiber 1
Those containing up to 50% have excellent dimensional stability and are unlikely to be wrinkled, and can be used without problems even if the basis weight is less than 100 g / m ² . As inorganic and organic fibers, glass fiber, carbon fiber,
Polyolefin fibers, aramid fibers, and polyester fibers can be used. When the mixing ratio is 1% or less, the dimensional stability is hardly improved. If it is more than 50%, the strength is reduced and there is a practical problem. In particular, the mixing rate is preferably 5 to 15%.

As resin-impregnated paper, paper impregnated with natural resins such as casein in addition to synthetic resins such as polyolefin, polyester, acrylic, urethane, epoxy, and vinyl acetate are excellent in dimensional stability and are unlikely to cause wrinkles. .

The mortar / concrete surface-improving paper is fixed to the formwork by applying a pressure-sensitive adhesive on the entire surface or a part of a metal surface such as a rivet or a stapler, and in some cases, a surface on which the synthetic resin film is not laminated. This is possible.

[Effects of Examples and the Invention]

 Hereinafter, the effects of the present invention will be described with reference to examples.

Example 1 Pores having a pore diameter of 0.5 mm and a number of 49 / cm ² (area ratio 9.6%)
Was laminated on a paper having a water time of 300 seconds and a basis weight of 160 g / m ² to obtain a mortar / concrete surface property improving paper in which the water time of the laminate was 1000 seconds. This product was fixed with a stapler so that the paper surface was in contact with the plywood formwork, the formwork was assembled so that the polyethylene film surface was in contact with the mortar and concrete, and the mold was removed one day later. A hit surface was obtained.

Example 2 Pores with a pore diameter of 1 mm and a number of 16 / cm ² (area ratio 12.6%)
A mortar / concrete surface having a thickness of 30 μm laminated on a mixed paper containing 3% glass fiber for 120 seconds in water time and 110 g / m ^{2 in} basis weight, and having a water time of 500 seconds for the laminate An improved paper was obtained. An adhesive is applied to the surface of the laminate opposite to the polyethylene film surface, and the adhesive is fixed to a plywood formwork, cast as in Example 1, and removed one day later. Surface was obtained.

Example 3 pore diameter 0.5 mm, the number of 49 pieces / cm ² pore (area ratio 9.6%)
Mortar / concrete surface with 25μm thick polyethylene film having a water content of 30% aramid fiber for 30 seconds and a basis weight of 50g / m ² Improved paper was obtained. When the casting was performed in the same manner as in Example 1 and the mold was removed one day later, a hitting surface free of avatars and wrinkles was obtained.

Example 4 Pores having a pore diameter of 1 mm and a number of 16 / cm ² (area ratio 12.6%)
Mortar / concrete in which a 30 μm-thick polyethylene film having a thickness of 5 g / m ² is impregnated with a urethane resin 5 g / m ² for 400 seconds and a paper weight of 60 g / m ² A surface-improved paper was obtained. It was cast in the same manner as in Example 1, and was removed from the mold one day later.

Comparative Example 1 Pores with a pore diameter of 0.5 mm and a number of 49 / cm ² (area ratio 9.6%)
Was laminated on paper having a water time of 1000 seconds and a basis weight of 160 g / m ² , and the water time of the laminate was 12000 seconds. When the casting was performed in the same manner as in Example 1 and the mold was removed one day later, avatar generation was observed on the hitting surface.

Comparative Example 2 pore diameter 0.5 mm, pore that number of 49 pieces / cm ² (area ratio 9.6%)
Was laminated on a polyester nonwoven fabric having a water time of 0 seconds, and the water time of the laminate was 10 seconds. The casting surface was cast in the same manner as in Example 1, and the mold was removed one day later.

Comparative Example 3 Pores with a pore diameter of 0.5 mm and a number of 49 / cm ² (area ratio 9.6%)
Was laminated on paper having a water time of 500 seconds and a basis weight of 65 g / m ² , and the water time of the laminate was 2,000 seconds. When the casting was carried out in the same manner as in Example 1 and the mold was removed one day later, no avatar was found on the hitting surface, but wrinkles were found.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of the mortar / concrete surface property improving paper of the present invention, and FIG. 2 is a cross-sectional view of a mold used for casting on a slope. In the drawing, 1 ... paper 2 ... synthetic resin film having pores 3 ... mold

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Makoto Yamada 1551 Higashidaira, Higashimatsuyama-shi, Saitama Prefecture Sanyo Kokusaku Pulp Co., Ltd. (56) References Hikaru 1-67244 (JP, U) Tokiko Hei 7-103685 ( JP, B2)

Claims (4)

(57) [Claims] The total area of the small holes is 5 to 80 times the total area of the film.
% Of the synthetic resin film having pores occupying 0.5% to 10% and having a pore interval of 0.5 to 10 mm is laminated on a water-permeable sheet having a water time of 10 seconds or more and less than 1000 seconds.
Mortar / concrete surface property improvement paper characterized by 0000 seconds. 2. The mortar / concrete surface property improving paper according to claim 1, wherein the water permeable sheet is a paper having a basis weight of 100 to 500 g / m ² . 3. The mortar / concrete surface-improving paper according to claim 1, wherein the water-permeable sheet is a mixed paper comprising 1 to 50% of inorganic fibers and / or organic fibers and 99 to 50% of cellulosic stock. 4. The mortar / concrete surface property improving paper according to claim 1, wherein the water permeable sheet is a resin impregnated paper.