JP2001270755A - Reinforcing fibrous sheet-protective mortar and method for applying the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protective mortar for reinforcing fibrous sheets to be used in antiseismic reinforcing work, directly applicable onto the adhesive surface of an epoxy resin adhesive, good in durability and high inadhesiveness, and capable of preventing such an epoxy resin-based adhesive from damage due to heat, impact, friction, etc., with a thickness of a minimum of 1 cm, a quarter or smaller compared to conventional ones, and to provide a method for applying the mortar. SOLUTION: This mortar for protecting reinforcing fibrous sheets through coating the sheets therewith comprises a mortar for lower layer formulated with a polymer dispersion or reemulsifiable powdery resin at 5-20 wt.% as solids and a mortar for upper layer formulated with the polymer dispersion or reemulsifiable powdery resin at <=2 wt.% as solids, each based on the total mortar solids freed from water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective mortar for a reinforcing fiber sheet used for seismic retrofitting and a method for applying the protective mortar.

[0002]

2. Description of the Related Art In general, as one type of seismic retrofitting means for a concrete structure, there is a means of reinforcing with a variety of fiber sheets such as carbon fiber and aramid fiber.

Conventionally, such reinforcement with a fiber sheet is performed by laminating and attaching a fiber sheet to a concrete surface to be reinforced by an epoxy resin adhesive a plurality of times.

[0004]

However, according to such a reinforcing means, since the final finished surface thus constructed is constituted by an epoxy resin adhesive, it is susceptible to heat,
If a fire or the like occurs, the epoxy resin adhesive may burn.

[0005] The bonding surface of the epoxy resin adhesive is also weak against physical damage factors such as impact and friction.

Therefore, in order to solve these problems, before the epoxy resin adhesive constituting the final finished surface is cured, dry silica sand is sprayed on the epoxy resin adhesive to form irregularities on the adhesive surface. The surface is then roughened, and a steel or stainless steel mesh is attached with an anchor or the like, and then a normal plaster mortar is applied by 4 cm or more.

However, plaster mortar is effective in protecting epoxy resin adhesive against heat such as fire,
Originally, the mortar hardly adhered to the surface of the epoxy resin adhesive, and there was a new problem that the mortar was easily peeled or lifted.

Further, there is another problem that the work of the construction is complicated because the plaster mortar is applied more than 4 cm.

The present invention has been made to solve all of the above problems, and can be directly applied to an adhesive surface of an epoxy resin adhesive, has good durability and has high adhesion. It is another object of the present invention to provide a reinforcing fiber sheet protective mortar having a minimum thickness of 1 cm or less, which is 1/4 or less of the conventional thickness, and which can prevent damage of an epoxy resin-based adhesive from heat, impact, friction and the like.

[0010]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a mortar obtained by changing the solid content of an organic substance of a polymer dispersion or a re-emulsifying type powder resin on an epoxy resin-based adhesive is used. Apply in layers and add 1
It has been found that a protective mortar layer capable of simultaneously solving two contradictory problems of adhesiveness with an epoxy resin adhesive and non-combustibility required for the entire mortar can be formed by coating more than 1 cm, and the present invention is completed. Reached.

That is, in order to solve such problems, the present invention has been made as a reinforcing fiber sheet protective mortar and a method of applying the protective mortar. A reinforcing fiber sheet protection mortar for protecting the fiber sheet for
5 to 20% by weight based on the total amount of mortar solids excluding water
A lower layer mortar containing a solid content polymer dispersion or re-emulsifying powder resin, and an upper layer mortar containing 2% by weight or less of solid content polymer dispersion or re-emulsifying powder resin. It is in.

Another feature of the method for applying the reinforcing fiber sheet protective mortar is the method for applying the reinforcing fiber sheet protecting mortar for protecting the reinforcing fiber sheet, which is based on the total amount of mortar solids excluding water. A lower layer mortar containing a polymer dispersion or a re-emulsifiable powder resin having a solid content of 5 to 20% by weight is applied or sprayed on a reinforcing fiber sheet, and then, after the lower layer mortar is hardened, water 2% by weight based on the total amount of mortar solids excluding
An object of the present invention is to apply or spray a mortar for an upper layer in which a polymer dispersion or a re-emulsifying type powder resin having the following solid content is blended.

The reason why the amount of the polymer dispersion or the re-emulsifying type powder resin in the lower layer mortar is set to 5 to 20% by weight is that the adhesion of the lower layer mortar is good under ordinary weather conditions, When exposed to a high temperature due to a fire or the like, the adhesive strength is reduced, and there is a risk of peeling. Therefore, the blending amount of the polymer dispersion or the re-emulsifying type powder resin with respect to the total amount of the mortar solid content is 5 to 20% by weight. %, It is possible to cope with such peeling in the event of an emergency.

That is, when the blending amount of the polymer dispersion or the re-emulsifying type powder resin is 5% by weight or less, the adhesive force is reduced when exposed to a high temperature, and there is a risk of peeling. This is because the adhesive force (member strength) is reduced and the polymer dispersion or the re-emulsifiable powder resin is expensive, which is uneconomical.

The mortar for the lower layer has a working thickness of 2 mm or less on the assumption that the polymer dispersion or the re-emulsifying type powder resin having a solid content of 5 to 20% by weight is blended as described above. It is preferable to maintain the adhesion to the epoxy resin adhesive, and it is preferable that the mortar for the upper layer has a construction thickness of 8 mm or more from the viewpoint of maintaining the nonflammability.

The reason why the amount of the polymer dispersion or the re-emulsifying powder resin in the mortar for the upper layer is set to 2% by weight or less is that when the thickness of the mortar for the upper layer to be applied is about 8 mm, If the re-emulsifiable powder resin is blended in an amount of 2% by weight or more, it is not always possible to ensure nonflammability.

In the present invention, as the cement, portland cement, ultra-rapid hardening cement, or a mixed cement obtained by mixing these cements with a mixed material such as blast furnace slag, fly ash, silica fume, limestone powder, and gypsum are used.

The polymer dispersion or re-emulsifiable powder resin is, for example, a polymer dispersion or re-emulsifiable type resin used for cement admixture, such as polyacrylate, styrene butadiene, ethylene vinyl acetate, etc. shown in JIS A 6203. Powder resin is used.

Further, as the aggregate, silica sand, limestone sand,
One or more materials that can be blended with the mortar, such as lightweight aggregate, can be used.

Further, short fibers can be blended for the purpose of suppressing the occurrence of cracks in the mortar.

As the short fiber, a short fiber made of alkali-resistant glass, carbon, aramid, vinylon, polypropylene, polyethylene, acrylic or the like can be used.
The length and diameter are not particularly limited, but when the length of the fiber is shortened, the effect of suppressing cracking is reduced, and when the length is increased, the kneading property with water and workability are deteriorated. Preferably it is 3 to 20 mm.

It is also possible to add and mix admixtures such as high-performance water reducing agents, thickeners, and antifoaming agents that can be used for cement concrete, which are necessary for imparting fluidity and workability functions.

The above materials are kneaded with water necessary for construction and sprayed directly on the cured epoxy resin adhesive after reinforcing the fiber sheet or applied with a trowel, a roller or the like. It is necessary to limit the total solid amount of the polymer dispersion or the re-emulsified powder resin to the total amount.

That is, in order to exhibit sufficient adhesiveness to the adhesive surface of the epoxy resin adhesive, it is necessary to incorporate a large amount of polymer dispersion or re-emulsifying type powder resin. It must be reduced to prevent the burning of the system adhesive.

Therefore, in the present invention, as described above, the required solid content of the polymer dispersion or the re-emulsifiable powder resin relative to the total amount of the mortar solid content is directly applied to the adhesive surface of the epoxy resin adhesive or It is 5 to 20% by weight in the mortar for the lower layer sprayed, and 2% by weight in the mortar for the upper layer sprayed or sprayed on the mortar for the lower layer.
We found that:

[0026]

Embodiments of the present invention will be described below.

(Test Example 1) A concrete board laminated and adhered to the surface in the order of an epoxy resin primer, an epoxy resin adhesive, a carbon fiber sheet, an epoxy resin adhesive, a carbon fiber sheet, and an epoxy resin adhesive, Two types of the mortar for the lower layer and the mortar for the upper layer, which were blended at the ratio shown in No. 1, were repeatedly applied, and the adhesive strength of the protective mortar was measured at the age of 28 days.

The lower layer mortar is a powder obtained by mixing 100 parts by weight of ordinary Portland cement, 100 parts by weight of dry silica sand, and 0.2 part by weight of a naphthalene sulfonate-based high-performance water reducing agent.
A polyacrylate polymer dispersion (solid content: 45%) and water were mixed at the ratio shown in Table 1, kneaded with a hand mixer for 2 minutes, and applied to the concrete plate with a trowel.

Further, after the lower layer mortar has hardened, an early-strength Portland cement is used as the upper layer mortar.
For 100 parts by weight, 100 parts by weight of dry silica sand, fiber length 6 mm
1.0 parts by weight of vinylon fiber, 0.4 parts by weight of a naphthalene sulfonate-based high-performance water reducing agent, and a methylcellulose-based thickener 0.
02 parts by weight of powder, polyacrylate polymer dispersion (solid content: 45%), and water were blended in the proportions shown in Table 1, kneaded with a hand mixer for 2 minutes, and cured to form a protective mortar for lower layer. I smeared it up with a trowel.

As Comparative Examples 1 to 4, the same test was carried out for the compounds shown in Table 1.

The results are shown in Table 1.

[0032]

[Table 1]

As is clear from Table 1, the adhesive strength was good in Examples 1 and 2, and Comparative Examples 2 and 4, but Comparative Examples 1 and 2 in which the polymer dispersion was not compounded. In Comparative Example 3 in which a large amount of polymer dispersion was blended, the adhesive strength was very low.

(Test Example 2) Epoxy resin primer, epoxy resin adhesive, carbon fiber sheet, epoxy resin adhesive, carbon fiber sheet, epoxy resin adhesive , Table 1
The two types of mortar for the lower layer and the mortar for the upper layer, which were blended in the proportions shown in the following, were applied repeatedly, and when the protective mortar was 28 days old, the Ministry of Construction Notification No. 1828 in 1970
A nonflammability test was performed according to the surface test method for nonflammable materials specified in the above item.

As Comparative Examples 1 to 4, similar tests were performed on the compounds shown in Table 1.

The results are shown in Table 1.

As is clear from Table 1, in Examples 1 and 2, and Comparative Examples 1, 3, and 4, the non-combustion evaluation was good, but 15 parts by weight of the polymer dispersion was blended. In Comparative Example 2, the non-combustion evaluation was poor.

In Comparative Examples 1, 2, and 4 in which the amount of the polymer dispersion in the lower layer mortar was small, it was confirmed that the adhesion was low.

In the above embodiment, the mortar for the upper layer and the mortar for the lower layer are formed by coating, but may be formed by spraying instead of coating.

[0040]

As described above, when the fiber sheet protective mortar of the present invention is used, the workability and adhesion to the final epoxy resin surface reinforced with the fiber sheet are excellent, and the non-flammability and impact resistance are protected. It is possible to protect fiber sheet reinforced epoxy resin which has excellent function.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) C04B 16:06 C04B 16:06 E 16:04) 16:04) 111: 00 111: 00 (72) Invention Person Keiichi Osaki 7-55 Minamionkajima, Taisho-ku, Osaka Sumitomo Osaka Cement Co., Ltd. C-Concrete Research Laboratory F-term (reference) 4G012 PA20 PA23 PA24 PA24 PE04

Claims (2)

[Claims] 1. A reinforcing fiber sheet protecting mortar for protecting a reinforcing fiber sheet, comprising a polymer dispersion or a re-emulsified type having a solid content of 5 to 20% by weight based on the total mortar solid content excluding water. A mortar for a lower layer containing a powdered resin, and a mortar for an upper layer containing a polymer dispersion or a re-emulsifying type powder resin having a solid content of 2% by weight or less, a protective mortar for a reinforcing fiber sheet, characterized in that 2. A method for applying a reinforcing fiber sheet protective mortar for protecting a reinforcing fiber sheet, comprising a polymer dispersion having a solid content of 5 to 20% by weight based on the total mortar solid content excluding water. The lower layer mortar containing the re-emulsified powder resin is applied or sprayed on a reinforcing fiber sheet, and then the lower layer mortar is cured, and then 2% by weight or less based on the total amount of the mortar solids excluding water. A method for constructing a reinforcing fiber sheet protective mortar, which comprises applying or spraying an upper layer mortar containing a polymer dispersion or a re-emulsifying type powder resin having a solid content of 1.