JP6842124B2 - PC curtain wall concrete exfoliation prevention method - Google Patents

Description

The present invention relates to a concrete peeling prevention method for a PC curtain wall.

It has been almost 50 years since precast concrete was used as an outer wall, and it has been continuously used for maintenance. The first PC (precast concrete) curtain walls as an architectural expression are the Akasaka Chuo Building, Kishi Memorial Gymnasium, and Toyama Daiichi Seimei Building in 1964, but 35 years have already passed. In addition, there are many skyscrapers that have been actively used since 1971, Keio Brother Hotel, IBM Japan Building, and Hotel Pacific Tokyo, and have passed 20 years.

Many of these buildings have not reached the end of their life and will continue to be used in the future. However, if there is a life of 50 years, for example, a large-scale renovation will be required once, considering the life of equipment and interiors. Also, skyscrapers are not so easy to break and will need to be refurbished to keep them in use. It can be said that we are entering an era of renovation of buildings using the first precast concrete.

The problem with PC curtain walls is that the steel material corrodes due to salt damage, neutralization, etc., and the expansion pressure at that time causes cracks in the concrete structure, causing concrete pieces to peel off from the surface layer. Various exfoliation prevention methods have been proposed to solve various problems.

Most of them are construction methods in which a fiber sheet is adhered to the surface of a concrete structure to be repaired by using an adhesive to prevent concrete pieces from peeling off from the concrete structure.

Usually, after cleaning and roughening the concrete surface, a primer is applied, a net-like fiber sheet is attached, the adhesive is cured, and a weather-resistant paint is applied outdoors where there is concern about UV deterioration. Is being done.

If the concrete surface is uneven or has a lot of air bubbles, an adjusting material may be applied before applying the fiber sheet to smooth the surface.

The peeling prevention method includes (1) cleaning / roughening process, (2) primer process, (3) undercoating process, (4) fiber sheet bonding process, (5) topcoating process, and (6) weather resistant paint. Examples thereof include 6 to 7 steps (7 to 8 steps if there is a non-landing adjuster) of the coating step (1 to 2 times). This process consists of a lot of work.

The following patent document is also an example, and is a concrete structure characterized in that the protective layer and the adhesive coating layer are adhered and an adhesive layer is formed on the adhesive surface of the adhesive coating layer to the concrete structure. An adhesive layer that uses a repair / reinforcement / deterioration prevention sheet, a repair / reinforcement / deterioration prevention sheet for a concrete structure on a concrete structure, and an adhesive coating layer of the sheet on the adhesive surface to the concrete structure. Adhere using.
Japanese Unexamined Patent Publication No. 2004-27718

The prior art is not intended for PC curtain walls. In particular, in the PC curtain wall, the gap between the PC curtain walls becomes a narrow portion, and a concrete peeling portion is likely to occur here.

In such a PC curtain wall, the gap between them also serves as a place for installing a gondola rail (vertical rail), but in that case, it is a narrow portion where a spread is formed behind a narrow slit opening. It has been extremely difficult to adhere a fiber sheet such as the above to prevent the concrete pieces from peeling off from the concrete structure.

An object of the present invention is to eliminate the inconvenience of the above-mentioned conventional example and to simply attach a urethane or urea sheet with an adhesive, so that reinforcing fibers and the like are not required and the concrete is manually applied to the base concrete. In comparison, it is an object of the present invention to provide a concrete peeling prevention method for a PC curtain wall, which can be easily and quickly constructed even in a narrow space and can be safely constructed even in a high place work.

In order to achieve the above object, the present invention according to claim 1 applies to the surface layer of the corner of the PC curtain wall as a building exterior material at 23 ° C. in a narrow portion which is a gap between the PC curtain walls formed between the PC curtain walls. JIS A 6021 roof coating waterproofing material with a tensile strength of 10 N / mm ² or more and a tear strength of 30 N / mm or more. The gist is to make it stick with an adhesive.

According to the first aspect of the present invention, in order to eliminate the drawback of applying to the base concrete, the molded urethane or urea sheet is attached with an adhesive, and by attaching with an adhesive, it is desired. The peeling prevention performance can be satisfied.

After applying the primer, cure, dry and cure, apply urethane or urea sheet while applying adhesive, and even out the joint part to finish, so even when working on aerial work platforms, it is high in each process. Since it is not necessary to move the aerial work platform and the primer process to the finishing process can be completed, the construction period can be shortened, and the urethane or urea sheet with uniform thickness and performance manufactured at the factory is stable. The concrete peeling prevention performance can be guaranteed.

In addition, the urethane or urea sheet has the performance of a urethane rubber-based high-strength type of JIS A 6021 roof coating film waterproofing material ^{with a tensile strength of 10 N / mm 2 or more and a tear strength of 30 N / mm or more at 23 ° C.} Because it has, it is tough, and by attaching it to the surface layer of the corner of the PC curtain wall as a building exterior material, it is not necessary to reinforce with a fiber sheet or provide a displacement layer, Expressway Research Institute Co., Ltd. It is possible to satisfy the peeling prevention performance according to the issued structure construction management procedure (August 2007).

On the other hand, urethane or urea sheets are formed by heating the main material and curing agent with a special machine, pumping the hose, mixing at the tip of the hose, stirring and spraying on a flat, concave or convex mold. By doing so, it is possible to easily mold a product having a thickness of 0.5 mm or more and 3.0 mm or less.

Furthermore, urethane or urea sheet is molded as an angle material with an appropriate angle, and because it is flexible, it can be folded and unfolded, and it can be inserted through a narrow opening and unfolded to form a PC curtain wall in a narrow space. It can be easily attached to the surface layer of the corners. Moreover, it can be reliably covered by superimposing a part thereof and attaching it with an adhesive.

It is a cross-sectional plan view which shows one Embodiment of the concrete peeling prevention construction method of the PC curtain wall of this invention. It is a perspective view which shows one Embodiment of the concrete peeling prevention construction method of the PC curtain wall of this invention. It is explanatory drawing at the time of construction which shows 1 Embodiment of the concrete peeling prevention construction method of the PC curtain wall of this invention. It is a front view of the adhesive material used in the concrete exfoliation prevention method of the PC curtain wall of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional plan view showing an embodiment of the present invention, FIG. 2 is a perspective view of the same as above, FIG. 1 is a PC (precast concrete) curtain wall, and 2 is a gap between PC curtain walls 1 formed by each other. It is a narrow part.

Although not shown, a gondola rail is installed in the narrow portion 2, and the opening 2a is a narrow slit, and a space expands in the back thereof.

Further, a joint is formed in the back of the narrow portion 2, and a backup material 3 and a sealing material 4 are arranged.

The present invention prevents the concrete of such a PC (precast concrete) curtain wall 1 from peeling off, and prevents the corners where peeling is particularly likely to occur.

In the present invention, a part of the angle material of urethane or urea sheet is superposed on the surface layer of the corner portion of the PC curtain wall 1 and attached by the adhesive material 8. The angle material refers to a sheet material formed by giving an appropriate angle.

In the illustrated example, three types of urethane or urea sheet molded bodies of the angle material 5, the angle material 6, and the angle material 7 were partially overlapped and attached by the adhesive material 8.

First, the urethane or urea sheet for molding the angle material will be described. Diphenylmethane diisocyanate (hereinafter, abbreviated as "MDI") having an excess equivalent ratio to the hydroxyl group equivalent of polypropylene glycol (PPG) having two or more hydroxyl groups. In some cases), the NCO% obtained by reacting by mixing, heating and stirring is added to a plastic agent of 0% or more and 15% or less to an MDI-based prepolymer having two or more isocyanate groups. , 8% to 16% of main material, amines such as DETDA and POAPA having 2 or more amino groups, PPG having 2 or more hydroxyl groups, plasticizers, antiaging agents, reaction catalysts, antifoaming agents and pigments. The curing agent mixed with the above is heated by a dedicated machine, pumped by pressure from the hose, mixed at the tip of the hose, stirred, and sprayed onto the mold to form.

Urethane or urea sheet is a urethane coating film waterproofing material for JIS A 6021 roof with a thickness of 0.5 mm or more and 3.0 mm or less, a tensile strength of 10 N / mm ^{2 or more and a tear strength of 30 N / mm or more at 23 ° C.} It has the performance of rubber-based high-strength type.

The ratio of the amino group to the hydroxyl group of the curing agent is preferably amino group: hydroxyl group = 100: 0 to 60:40.

Since 100: 0 is all amino groups, it becomes a polyurea resin, and 40 parts of hydroxyl groups are contained at 60:40, and the reaction product with 40 parts thereof is urethane resin. The polyurea urethane resin is a mixture of a polyurea resin that reacts with an amino group and a urethane resin that reacts with a hydroxyl group.

The binding energy is different between the urea bond and the urethane bond, and the urea bond> the urethane bond, and a certain or more urea bond is required to ensure the performance.

The ratio of the NCO group of the main agent and the total group of the amino group and the hydroxyl group of the curing agent is NCO group: (amino group + hydroxyl group) = 1.0: 1.05-1.0: 0.75.

If the total number of amino groups + hydroxyl groups is too large compared to the NCO group of the main agent, the physical properties will deteriorate and curing will be poor, and if it is too small, the NCO groups will react with the moisture in the air and the coating film will foam. It ends up.

The surface of the urethane or urea sheet may be previously coated with a top coat to prevent deterioration by ultraviolet rays. By applying a top coat on the surface of the urethane or urea sheet in advance to prevent UV deterioration, concrete pieces can be prevented from peeling off, UV resistance can be exhibited, and deterioration can be prevented.

Adhesive material 8 has a sway-modifying property that can fix urethane or urea sheet, and is a one-component or two-component urethane or urea type that adheres to the base primer 9 and urethane or urea sheet, and is a building sealant JIS A 5758. : 2016 type F-12.5, class 8020 conformity or better performance.

Specifically, as the adhesive 8, the trade name SU Sealant QUICK NB of Tohoku Sangyo Co., Ltd., the trade name Hiflex US-1 of Daiflex Co., Ltd. (Hiflex is a registered trademark of Daiflex Co., Ltd.) and the like can be used.

The thickness to which the adhesive 8 is applied is 0.2 mm or more and 2.0 mm or less, preferably 0.5 mm or more and 1.5 mm or less, but is not particularly limited thereto.

The performance and workability of the adhesive are important for attaching the molded urethane or urea sheet to satisfy the desired peeling prevention performance.

If the adhesive 8 is a one-component or two-component urethane or urea type adhesive that has the performance of JIS A 5758: 2016 type F-12.5, class 8020 or higher, the building sealant, urethane. Alternatively, since the adhesive strength and elongation to the urea sheet and the base primer 9 are high, the durability is high, the physical properties do not deteriorate with time, and the urethane or urea sheet does not peel off with time.

Next, the construction procedure will be described. A primer 9 is applied to the surface of the PC (precast concrete) curtain wall 1, and urethane or urea sheet angle members 5, 6 and 7 are partially superposed on the surface of the PC (precast concrete) curtain wall 1 in order and attached by the adhesive material 8.

In the sticking order, the angle member 5 is pasted first, then the angle member 6 is pasted with its end overlapped with the angle member 5, and then the angle member 7 is pasted with its end overlapped with the angle member 6.

At that time, each angle material aligns its bent portion with the corner portion of the PC (precast concrete) curtain wall 1.

The adhesive material 8 is applied by a roller, but when it is difficult to insert the roller through the opening 2a of the narrow portion 2, the adhesive material by the tube 10 to which the bending nozzle 11 is attached as shown in FIG. 4 is used. You can also.

The thickness of the adhesive 8 applied is 0.2 mm or more, 2.0 mm or less, preferably 0.5 mm or more and 1.5 mm or less. Therefore, it is not necessary to secure a uniform thickness, and the surface is surfaced against the unevenness of the base. By applying it smoothly or in a comb shape, the urethane or urea sheet on the front surface can also be finished smoothly.

Further, when the angle material 5, the angle material 6, and the angle material 7 are attached in order, they can be folded so as to pass through the opening 2a of the narrow portion 2 and expanded inside, and since it is an angle material, the PC curtain wall 1 The corners may be aligned with the corners of the wall.

Further, as shown in FIG. 2, the joint portions of the angle member 5, the angle member 6, and the angle member 7 in the vertical direction are bonded by the adhesive member 8 by shifting the positions of the joints 12 and superimposing them.

The pasted state is confirmed by inserting a visual mirror 13 as shown in FIG.

The urethane or urea sheet forming the angle material 5, the angle material 6, and the angle material 7 has a displacement of 10 mm or more when the maximum punching load per φ10 cm of the JHS 424-2004 peeling prevention punching test method is 1.5 kN or more. What can be confirmed, or bridge structure design procedure Concrete piece peeling prevention edition (August 2006) Evaluation criteria for peeling prevention work of Tokyo Metropolitan Expressway Co., Ltd. Punching per φ10 cm of type B peeling prevention punching test method It conforms to any of the cases where a maximum load of 0.3 kN or more and a displacement of 10 mm or more can be confirmed.

In the above embodiment, an example in which three types of angle materials are used has been described, but since the PC curtain wall 1 has various shapes and the shape of the narrow portion varies accordingly, three types in particular. It is not limited to the angle material of.

Further, in the portion protruding from the narrow portion, it is possible to superimpose the urethane or urea sheet with a flat sheet.

1 ... PC (precast concrete) curtain wall 2 ... Narrow part 2a ... Opening 3 ... Backup material 4 ... Sealing material 5, 6, 7 ... Angle material 8 ... Adhesive material 9 ... Primer 10 ... Tube 11 ... Bending nozzle 12 ... Joint 13 …mirror

Claims (1)

In a narrow space formed between ^{PC curtain walls, the tensile strength is 10 N / mm 2} or more and the tear strength is 30 N on the surface layer of the corner of the PC curtain wall as a building exterior material at 23 ° C. / Mm or more JIS A 6021 Urethane rubber for roof coating waterproof material PC curtain wall characterized by partially superimposing urethane or urea sheet angle material with high-strength performance and pasting with adhesive Concrete peeling prevention method.