JP2011032694A - Concrete exfoliation preventing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a concrete exfoliation preventing method maintaining concrete exfoliation preventing performance over a long period of time and causing neither swelling nor exfoliation even with the occurrence of moisture of back face water or the like inside concrete. <P>SOLUTION: The concrete exfoliation preventing method includes processes for installing a mesh fiber sheet on a concrete structure, fixing the mesh fiber sheet with mortar with the amount of water permeability of 1 g or more and a bond strength of 1.5 N/mm<SP>2</SP>or more, and covering the surface with a covering material with the amount of water permeability of 20 ml/m<SP>2</SP>day or less, the amount of moisture permeability of 15 g/m<SP>2</SP>day or more and an elongation of 50% or more. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a concrete exfoliation prevention method, and more particularly to a concrete exfoliation prevention method that suppresses the influence of penetrating water for a long period of time and prevents blistering and peeling due to back water.

In concrete structures, concrete peels off due to the ingress of rainwater from the outside and corrosion of internal reinforcing bars due to deterioration factors such as salinity and neutralization in the natural environment over time. May occur.
As a measure for preventing concrete from peeling off due to deterioration of concrete structures, NEXCO “Structure Construction Management Guidelines” and the like have standardized performance checks for preventing peeling.

  For prevention of concrete peeling of concrete structures, a method that satisfies the above standards by adhering mesh fibers made of vinylon fiber or polypropylene fiber with an adhesive such as epoxy resin, urethane resin, or polyester resin Is popular.

  As a method for preventing peeling, one or more selected from (A) unsaturated polyester resin, vinyl ester resin, urethane (meth) acrylate resin and polyester (meth) acrylate resin in JP-A No. 2004-18719 (Patent Document 1) A resin composition containing 100 parts by weight of a resin, (B) a radical polymerization initiator: 0.01 to 20 parts by weight, and (C) an inorganic or organic filler: 0 to 200 parts by weight, a biaxial mesh, After applying a curable material for preventing concrete exfoliation impregnated into one or more selected from triaxial mesh and fiber layered body to a primer-treated concrete surface, or applying a resin composition to a primer-treated concrete surface, One or more types selected from biaxial mesh, triaxial mesh and fiber layered body are pasted, and the resin composition By applying forming a concrete surface that is primed concrete spalling prevention wherein the curing is disclosed.

  JP 2007-247290 A (Patent Document 2) discloses a primer layer (A), a main material layer (B), a concrete peeling prevention sheet (C), and a main material layer (B) on a concrete surface. And a concrete peeling prevention surface coating method for sequentially laminating a top coat layer (D), wherein the main material layer (B) is formed by an aqueous polyurethane paint (b) having a viscosity at 20 ° C. of 15 to 200 Pa · s. A concrete exfoliation preventing surface coating method is disclosed which is characterized by the above.

  Further, a method of applying a fiber mesh with a polymer cement mortar after construction with an epoxy crack impregnated material is described in Japanese Patent Application Laid-Open No. 2008-57146 (Patent Document 3). This is a concrete peeling prevention method in which a fiber mesh sheet is applied with a polymer cement mortar after applying and impregnating a crack-impregnated adhesive, and the polymer cement mortar is derived from (A) (meth) acrylic acid alkyl ester monomer A concrete cement mortar containing an epoxy-modified (meth) acrylic acid alkyl ester copolymer having a structural unit derived from a monomer having (B) an epoxy group as a functional group, and preventing concrete from peeling off It is a construction method.

  However, the conventional peeling prevention method conforms to the above-mentioned peeling prevention performance check provisions stipulated in the NEXCO “Structure Construction Management Guidelines”, but in the case where back water is generated in the long term in an actual environment, etc. May cause blistering or peeling. In particular, under floorboards and beams that need to be prevented from peeling off, they are easily affected by infiltrated water from the superstructure, causing concrete peeling and swelling of the surface coating material, which is insufficient for preventing concrete peeling. Met.

JP 2004-18719 A JP 2007-247290 A JP 2008-57146 A

  The object of the present invention is to solve the above problems and maintain the concrete peeling prevention performance for a long period of time, and even if moisture such as back water is generated inside the concrete, it does not swell or peel off. It is to provide a peeling prevention method.

In order to solve the above-mentioned problems, the invention according to claim 1 includes a step of installing a mesh fiber sheet on a concrete structure, the mesh fiber sheet having a water permeability of 1 g or more and an adhesive strength of 1.5 N / mm ² or more. And a step of covering the surface with a coating material having a water permeability of 20 ml / m ² · day or less, a moisture permeability of 15 g / m ² · day or more and an elongation of 50% or more. This is a concrete peeling prevention method.

The concrete exfoliation preventing method according to claim 2 is a step of applying a mortar having a water permeability of 1 g or more and an adhesion strength of 1.5 N / mm ² or more to a concrete structure, and installing a mesh fiber sheet on the mortar. The step of further fixing the installed mesh fiber sheet with the mortar, the surface has a water permeability of 20 ml / m ² · day or less, the moisture permeability is 15 g / m ² · day or more, and the elongation is 50% or more. A concrete peeling prevention method characterized by including a step of covering with a covering material.

  The concrete exfoliation preventing method according to claim 3 is characterized in that in the concrete exfoliation preventing method according to claim 1 or 2, the concrete is covered with the covering material after the mortar to which the mesh fiber sheet is fixed is cured. This is a concrete peeling prevention method.

  The concrete peeling prevention method according to claim 4 is a concrete peeling prevention method according to any one of claims 1 to 3, wherein the mortar is a polymer cement mortar. .

  The concrete exfoliation preventing method according to claim 5 is a concrete exfoliation preventing method according to any one of claims 1 to 4, wherein the coating material is polymer cement mortar. is there.

The concrete peeling prevention method of the present invention can maintain the concrete peeling prevention performance for a long period of time, and even if moisture such as water on the back surface is generated inside the concrete, it does not swell and does not peel off the concrete. Can be prevented.
In particular, by using polymer cement mortar as the covering material, it becomes possible to follow the deformation of the installed mesh fiber sheet.

It is a figure explaining the concrete peeling prevention construction method of the present invention. It is a figure explaining the peeling prevention method of other concrete of this invention. It is a figure which shows the state which tests the effect of this invention.

The present invention will be described below with reference to the drawings, but is not limited thereto.
FIG. 1 is a diagram illustrating an example of a concrete peeling prevention method according to the present invention.
An example of the concrete peeling prevention method of the present invention is a step of previously installing the mesh fiber sheet 2 on the concrete peeling prevention target portion (FIG. 1A) in the concrete structure 1 (see FIG. 1B), The step of fixing the installed mesh fiber sheet with a mortar having a water permeability of 1 g or more and an adhesion strength of 1.5 N / mm ² or more (FIG. 1 (c)), and further the surface has a water permeability of 20 ml / m ² · day or less. This is a concrete peeling prevention method including a step of covering with a coating material having a moisture permeability of 15 g / m ² · day or more and an elongation of 50% or more (FIG. 1 (d)).

FIG. 2 is a diagram for explaining another example of the concrete peeling prevention method according to the present invention.
Another example of the concrete exfoliation preventing method according to the present invention is that a concrete permeation prevention target portion (FIG. 2A) in the concrete structure 1 has a water permeability of 1 g or more and an adhesion strength of 1.5 N / mm ² or more. Applying the mortar (see FIG. 2 (b)), placing the mesh fiber sheet 2 on the mortar (see FIG. 2 (c)), and then further water permeability on the mortar on which the mesh fiber sheet is placed A step of fixing with a mortar of 1 g or more and an adhesion strength of 1.5 N / mm ² or more (FIG. 2 (d)), and further its surface has a water permeability of 20 ml / m ² · day or less and a moisture permeability of 15 g / m ² · day. This is a concrete peeling prevention method including the step of covering with a covering material having an elongation rate of 50% or more (FIG. 2E).

In order to more effectively prevent the mesh fiber sheet from being peeled off, it is desirable that the mesh fiber sheet is installed over the entire surface so as to cover the part to be peeled off, that is, the entire surface is stretched.
As the fibers constituting the mesh fiber sheet, known fibers such as carbon fibers, aramid fibers, polyparaphenylene benzbisoxazole fibers (PBO), glass fibers, vinylon fibers, and polypropylene fibers can be used.
Moreover, the shape is not specifically limited, For example, arbitrary mesh fiber sheets, such as a triaxial assembly fabric and a biaxial assembly fabric, can be used.
In order to obtain air permeability, the mesh opening between the installed mesh fiber sheets is preferably 5 mm or more, and more preferably 10 mm or more.

The mesh fiber sheet is fixed using a mortar having a water permeability of 1 g or more and an adhesion strength of 1.5 N / mm ² or more.
Here, the water permeability is a value measured according to JIS A 1404, and the adhesion strength is a value measured according to JIS A 6909.
As the fixing method, after the mesh fiber sheet is placed on the concrete, the mortar is placed and fixed by curing, or after the mortar is applied to the concrete and before the mortar is cured. The mesh fiber sheet is installed so as to be pushed into the mortar, and the mortar is further placed from above and fixed by curing. Any process may be used as long as the mesh fiber sheet can be fixed. .
The mesh fiber sheet is covered with mortar and fixed by the mortar placing process. In addition, the mortar is placed over the entire part to be peeled off of the concrete structure including the mesh fiber sheet.

The mortar for fixing the mesh fiber sheet to the concrete structure is a mortar having a water permeability of 1 g or more and an adhesion strength of 1.5 N / mm ² or more.
The mortar has a water permeability of 1 g or more and has a good water dispersion. Preferably, it is more desirable that the mortar is a polymer cement mortar because it has excellent elasticity and deformation followability of the mesh fiber sheet. As the polymer cement mortar, acrylic resin polymer cement mortar and the like can be used.
Further, when the mesh fiber sheet uses a mesh having low fiber strength such as vinylon fiber or polypropylene fiber, the adhesion strength is 1.5 N / mm ² or more and less than ^2.5 N / mm ² , in particular. It is desirable to be.

If the water permeation amount is less than 1 g, moisture may accumulate at the interface with the frame concrete and may cause peeling.
Moreover, when the adhesion strength is less than 1.5 N / mm ² , there is a risk of peeling when stress is applied. Furthermore, when using a mesh with low fiber strength such as vinylon fiber or polypropylene fiber, for example, as described above, it is particularly desirable that the adhesion strength is less than ^2.5 N / mm ² , which is a mesh fiber sheet. This is because stress is locally applied to the metal and there is a risk of breakage.

Here, before fixing the mesh fiber sheet to the concrete structure with the mortar, it is possible to pre-treat the concrete structure to prevent the concrete structure from being peeled off, cleaned, or polished as necessary. is there.
Furthermore, if necessary, the primer is applied as a base to the location where the concrete structure is to be prevented from peeling off by applying a primer, etc., and then hardened. Corrections may be made.

Next, after fixing the mesh fiber sheet with mortar, it is further coated with a coating material.
After the mortar is cured, the mortar is covered with a coating material.
As the covering material, a covering material having a water permeability of 20 ml / m ² · day or less, a moisture permeability of 15 g / m ² · day or more and an elongation of 50% or more can be used.
Since the covering material has such performance of water permeability and moisture permeability, in addition to the peeling prevention effect by the mesh fiber sheet, the internal moisture of the concrete structure is effectively released to the outside by the coating material, and the external moisture and Since harmful factors are prevented from entering, the durability of the mesh fiber sheet is improved. And especially when base-material concrete causes an alkali aggregate reaction, the suppression effect of the expansion deterioration is also acquired.

About the said water permeation amount of a coating | covering material, it is the value measured according to JISA6909B method. If the water permeability exceeds 20 ml / m ² · day, other harmful factors such as moisture may be taken into the inside from the outside. Furthermore, according to the quality standards for concrete coating materials proposed by NEXCO, “the water permeation amount of the coating film is 20 ml / m ² · day or less” as a water permeation inhibiting property for concrete in which cracks are progressing. It is prescribed.

Further, the moisture permeability of the covering material is a value measured according to JIS Z 0208. If the moisture permeation amount is less than 15 g / m ² · day, the internal moisture release is not sufficient, and there is a risk of swelling and peeling.

Moreover, about the said elongation rate, the value measured according to JISA6909 is represented.
When the elongation is 50% or more, even if cracks occur in the concrete structure, it is possible to prevent the entry of harmful factors, and it is possible to further improve the durability.
When the elongation percentage is less than 50%, the followability to deformation of the mesh fiber sheet is not sufficient, the stress dispersion for peeling is not sufficient, and there is a possibility that the peeling prevention performance may be hindered.

Moreover, by imparting flame retardancy to the covering material, combustion during a fire can be suppressed and the protective effect can be enhanced.
Examples of the coating material having these performances include acrylic resin-based polymer cement mortar.

  In this way, by fixing the mesh fiber sheet with water-dispersible mortar, further affixing, and covering with a covering material having water-imperviousness and moisture permeability, in the conventional construction method, moisture such as back water is separated from concrete. Even if the mesh fiber sheet is formed between the layer fixed with the mortar, it is possible to remove moisture such as back water from the inside, and to prevent entry of harmful factors such as moisture from the outside. .

  The concrete peeling-off prevention method of the present invention will be described with reference to the following examples and comparative examples.

(Mesh fiber fixing material)
・ Permeable mortar for fixing mesh fibers 39.6 parts by weight of ordinary Portland cement (manufactured by Sumitomo Osaka Cement Co., Ltd.), 50 parts by weight of silica sand 7 and re-emulsifying powder resin (vinyl acetate / veova / acrylic acid copolymer re-emulsifying type) Powder resin, trade name: LDM7000P, manufactured by Nippon Synthetic Chemical Co., Ltd.) 10 parts by weight and further 21 parts by weight of water were added and kneaded to prepare a mesh fiber fixing mortar.
The mesh fiber fixing mortar obtained had a water permeability (JIS A 1404) of 1.5 g and an adhesion strength (JIS A 6909) of 2.4 N / mm ² .

-Water-blocking epoxy resin for fixing mesh fibers As the water-blocking epoxy resin for fixing mesh fibers, a trade name of a two-pack type epoxy resin;
The water permeability (JIS A 1404) of the epoxy resin was 0.1 g, and the adhesion strength (JIS A 6909) was 2.4 N / mm ² .

(Surface coating material)
・ Water barrier / moisture permeable surface covering material 50 parts by weight of ordinary Portland cement (Sumitomo Osaka Cement Co., Ltd.), 50 parts by weight of calcium carbonate powder (trade name: KD-100, Calfine Co., Ltd.), Emulsion Polytron Z871 (Asahi Kasei) 100 parts by weight (made by Co., Ltd.) (however, 50 parts by weight in terms of solid) was added and kneaded to prepare a water-impervious and moisture-permeable surface coating material.
The obtained water-impermeable and moisture-permeable surface covering material has a water permeability of 11 ml / m ² · day (JIS A 6909 water permeability test B method), a moisture permeability of 48 g / m ² · day (JIS Z 0208), and elongation rate. Was 180% (JIS A 6909).

-Moisture-proof elastic epoxy resin surface coating material As a moisture-proof elastic epoxy resin surface coating material, the brand name which is a two-pack type epoxy resin;
The epoxy resin coating material has a water permeability of 1 ml / m ² · day (JIS A 6909 water permeability test B method), a moisture permeability of 5 g / m ² · day (JIS Z 0208), and an elongation of 60% (JIS A). 6909).

(Mesh fiber sheet)
Vinylon fiber (trade name: Trineo 1810, manufactured by Unitika Ltd.) was used.

Example 1 and Comparative Examples 1-2
As shown in FIG. 1, the mesh fiber sheet was attached to the entire surface of a 20 cm square slate plate, and then the mesh fiber sheet shown in Table 1 was used to fix the mesh fiber sheet. . After curing, it was further coated with each of the above surface coating materials shown in Table 1 and cured at 20 ° C. and 60% RH for 14 days.
Next, as shown in FIG. 3A, a Φ5 cm × h5 cm vinyl chloride pipe is installed on the back surface of the slate plate, water is poured up to the upper end of the vinyl chloride pipe, The change in appearance after the day was visually confirmed.
In addition, as shown in FIG.3 (b), evaluation of the floating of a mesh fiber stationary phase in Table 1 confirms adhesion of a covering material by making a cut and removing a portion surrounded by the cut. It was evaluated. In addition, as shown in FIG.3 (c), the depth of cut was made into the depth to the extent which reaches a slate board.
The case where the floating of the mesh fiber stationary phase could not be confirmed by visual observation was marked with ◯, and the case where the mesh fiber stationary phase was confirmed was marked with ×.
Further, the swelling of the covering material was evaluated by visual observation of the appearance, and the case where the swelling could not be confirmed was evaluated as “◯” and the case where the swelling was observed as “X”.
The results are shown in Table 1.

From Table 1 above, after 28 days elapsed, as a result of visually confirming the floating of the mesh fiber stationary phase and the swelling of the coating material, the test body according to the present invention in which the water-permeable mortar of Example 1 was coated with the moisture-permeable coating material floated, Neither swollen nor seen.
On the other hand, in Comparative Example 1 in which a water-permeable epoxy resin is coated with a water-permeable and moisture-permeable coating material, the fixed layer of the mesh fiber sheet is peeled off, and in Comparative Example 2 in which a water-permeable mortar is coated with a moisture-proof coating material, The material was swollen.

  As described above, according to the present invention, the effect of preventing the concrete from peeling off using a mesh fiber sheet for a long period of time can be appropriately controlled by appropriately controlling the water entering the concrete structure and the back water generated in the structure. It is possible to provide a concrete peeling prevention method that can be maintained. The construction method can be applied to any concrete structure such as civil engineering and construction fields.

DESCRIPTION OF SYMBOLS 1 Concrete structure 2 Mesh fiber sheet 3 Mortar 4 Coating | covering material 5 Vinyl chloride pipe 6 Cutting

Claims (5)

A step of installing a mesh fiber sheet on a concrete structure, a step of fixing the mesh fiber sheet with a mortar having a water permeability of 1 g or more and an adhesion strength of 1.5 N / mm ² or more, and further, the surface has a water permeability of 20 ml / m ^2. A concrete peeling prevention method comprising a step of coating with a coating material having a moisture permeability of 15 g / m ² · day or more and an elongation of 50% or more. A step of applying a mortar having a water permeability of 1 g or more and an adhesion strength of 1.5 N / mm ² or more to a concrete structure and installing a mesh fiber sheet on the mortar, and a mesh fiber sheet installed in the mortar with the mortar A step of further fixing, and a step of covering the surface with a covering material having a water permeability of 20 ml / m ² · day or less, a moisture permeability of 15 g / m ² · day or more and an elongation of 50% or more. A concrete peeling prevention method.   The concrete exfoliation preventing method according to claim 1 or 2, wherein the concrete is covered with the covering material after the mortar to which the mesh fiber sheet is fixed is cured.   4. The concrete peeling prevention method according to claim 1, wherein the mortar is a polymer cement mortar.   5. The concrete exfoliation preventing method according to claim 1, wherein the coating material is polymer cement mortar.

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