JPH0967906A - Freezing damage preventing construction for concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent water from invading into concrete and from staying therein by laminating waterproof moisture permeable sheets as a waterproof moisture permeable layer on the position apt to contact with water and be repeatedly frozen and melted by the use of adhesive and the like. SOLUTION: At a new construction work of a building, a waterproof moisture permeable sheet 12 is stuck on the surface of concrete 11 as a mending work for preventing freezing damage. At this time, rain water or snow water is prevented from invading into concrete 11, and from staying therein, even if it is submerged from the joint of the sheet 12 or a broken position. When the waterproof moisture permeable sheet 12 is stuck on the surface of concrete 11 of eaves, submersion is prevented even when snow water is supplied from fallen snow on the eaves for a long term. Even if concrete is invaded by water, water is discharged in the state of water vapor, and stay of water in the concrete 11 is obstructed so as to previously prevent freezing damage of the eaves.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a structure capable of preventing frost damage of a concrete structure.

[0002]

2. Description of the Related Art In cold regions, concrete structures are sometimes damaged by frost damage. Frost damage is a phenomenon in which the water in the concrete repeatedly freezes and thaws, causing cracks and peeling of the surface layer, and the concrete deteriorates from the part near the surface, but it does not contribute to the cement hydration reaction. In particular, the degree of deterioration due to water remaining in concrete is generally slight, and the permeation of water from the outside is a major factor causing frost damage.

Therefore, a place which is constantly wet due to poor drainage of snowmelt water and is susceptible to temperature changes due to sunlight, that is, horizontal projections such as eaves, eaves, balconies, parapets, rooftop slabs, outer stairs, etc. Freezing damage is likely to occur in. In addition, civil engineering structures are vulnerable to frost damage on road bridges and breakwaters.

FIG. 4 shows the deterioration of concrete due to such frost damage as an example of a parapet. As can be seen in FIG. 4, the water that has infiltrated from the inside of the parapet 1 flows along the spit 2 into the concrete. To cause frost damage to the portion 3 facing the outer wall.

In order to prevent frost damage, consideration should be given to a draining method and a heat insulation method at the time of designing, and methods such as introducing fine air bubbles into concrete using an AE agent and reducing the water-cement ratio. Is also effective, and there is also known a method of covering the concrete surface with a metal plate or a waterproof sheet in order to cut off the supply of water into the concrete.

[0006]

However, in the method using a metal plate, a waterproof sheet or the like, when water penetrates into the concrete for some reason, the water is exposed to the outside air due to the presence of the waterproof sheet and the like. There was a problem that evaporation was hindered and it stayed in the concrete.

The present invention has been made in consideration of the above-mentioned circumstances, and provides a structure for preventing frost damage of concrete which can prevent the infiltration of water into the concrete and can prevent the retention of the water once invaded. With the goal.

[0008]

In order to achieve the above object, the structure for preventing frost damage of concrete according to the present invention has a waterproof and moisture permeable layer laminated on the surface of concrete as described in claim 1.

The structure for preventing frost damage of concrete according to the present invention has a waterproof and moisture permeable layer laminated on the surface of the concrete through a predetermined moisture permeable heat insulating layer.

In the structure for preventing frost damage of concrete according to the present invention, the waterproof and moisture permeable layer cuts off the supply of water into the concrete, and the water in the concrete is diffused into the outside air in the form of steam to release the water in the concrete. Do not let it stay. Therefore, the amount of water contained in concrete is greatly reduced.

Here, when a moisture permeable heat insulating layer is sandwiched between the waterproof moisture permeable layer and the concrete surface, the temperature in the concrete is relaxed and the water in the concrete easily evaporates.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a frost damage prevention structure for concrete according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 (a) shows an example in which the structure for preventing frost damage of concrete according to the present invention is applied to a parapet of a building structure. As can be seen in the figure, the frost damage prevention structure according to the present embodiment is a part of the surface of the concrete 11 forming the parapet, which is easy to come into contact with water and is susceptible to repeated freezing and thawing, that is, the outer wall part, the head part, the inner side. A waterproof / moisture permeable sheet 12 as a waterproof / moisture permeable layer is laminated on the rising portion and the rooftop portion using an adhesive or the like.

The waterproof / moisture-proof sheet 12 is made of a material having a characteristic that it is difficult for water droplets to pass through and water vapor easily pass through.
For the purpose of preventing dew condensation in the wall, various commercially available building sheets with excellent durability may be used. Specifically, polyethylene ultrafine fibers are processed into a sheet by applying high pressure and high heat (trade name: Tyvek, manufactured by DuPont), and a strong non-woven fabric is laminated on a porous film having micro uniform pores. There are products (trade name Tough Sheet, manufactured by Mitsui Toatsu Chemicals), etc. Also, polytetrafluoroethylene (PTFE) is stretched to have a fine continuous porous structure, and a nonwoven fabric is laminated on this to give a predetermined strength (trade name GORE-TEX Laminate). Good.

In the structure for preventing frost damage of concrete according to the present embodiment, the waterproof / moisture permeable sheet 12 is attached to the surface of the concrete 11 at the time of new construction of a building or as repair work for preventing frost damage with an adhesive or the like. It

Then, the waterproof / moisture permeable sheet 12 is shown in FIG.
As shown in, while preventing rainwater and snow melting water from entering the concrete 11 (solid line arrow), even if water enters the concrete 11 from the seam of the sheet or the damaged part, the It serves to release to the atmosphere in the form of water vapor (dashed arrow). Therefore, concrete 11
Water does not stay inside.

As described above, according to the structure for preventing frost damage of concrete according to the present embodiment, the waterproof and moisture permeable sheet prevents water from entering into the concrete and stagnation of water in the concrete. The amount of water is
It will also decrease significantly in winter.

Therefore, it is possible to prevent frost damage even without using an AE agent or adjusting the water-cement ratio, and the need to give special consideration to draining is reduced. The degree of freedom of is also increased.

In the present embodiment, the frost damage prevention structure according to the present invention is applied to the parapet portion of a building structure. Can be applied to any part that is susceptible to repeated use.

FIG. 1 (b) shows concrete 1 forming an eaves.
1 shows a state in which the above-mentioned waterproof / moisture permeable sheet 12 is attached to the surface of 1. According to such a configuration, even if the snowmelt water is supplied from the snow accumulated on the eaves for a long period of time, the waterproof / moisture permeable sheet 12 does not penetrate into the concrete 11, and even if it does, it stays inside. As it evaporates without being frozen, frost damage to the eaves is prevented.

The present invention is not limited to a building structure,
It can also be applied to civil engineering structures such as road bridges, dams, and port facilities. FIG. 2 is a perspective view showing an example in which the present invention is applied to a road bridge, and the above-mentioned waterproof / moisture permeable sheet 12 is attached to the upper and side surfaces of the ground cover 21 of the superstructure and both end portions of the abutment 22 of the substructure. There is.

According to this structure, it is possible to prevent frost damage to the ground cover 21 and damage to the balustrade 23 in advance, thereby ensuring the safety of pedestrians and the like. In addition, even if water flows down from the side of the ground cover 21 and wets the abutment 22,
It is possible to prevent the frost damage of the.

Further, in this embodiment, the waterproof / moisture permeable sheet is directly laminated on the surface of concrete.
As shown in, a heat insulating material 31 as a moisture permeable heat insulating layer may be attached to the surface of the concrete 11, and the waterproof moisture permeable sheet 12 may be laminated thereon. According to such a configuration, the temperature inside the concrete 11 is relieved by the heat insulating material 31, so that it becomes possible to effectively prevent frost damage in combination with the effect of preventing water from entering by the waterproof and moisture permeable sheet 12.

A spacer may be attached to the surface of the concrete 11 and the waterproof / moisture permeable sheet 12 may be disposed thereon. In such a configuration, concrete 1
1 and the waterproof / moisture permeable sheet 12 form a breathable layer as a moisture permeable heat insulating layer, so that the moisture in the concrete is easily diffused to the outside air.

[0025]

As described above, since the structure for preventing freezing damage of concrete according to the present invention has a waterproof and moisture-permeable layer laminated on the surface of concrete, it prevents water from entering the concrete and prevents water from entering once. It becomes possible to prevent frost damage from occurring by preventing the accumulation of

Further, in the structure for preventing frost damage of concrete according to the present invention, since the waterproof and moisture permeable layer is laminated on the concrete surface through the predetermined moisture permeable heat insulating layer, water is prevented from entering the concrete and It becomes possible to prevent frost damage by preventing the invading water from staying.

[0027]

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a frost damage prevention structure for concrete according to the present invention, where (a) is a cross-sectional view when applied to a parapet and (b) is a cross-sectional view when applied to an eaves.

FIG. 2 is a perspective view of a concrete frost damage prevention structure according to the present invention applied to a road bridge.

FIG. 3 is a cross-sectional view showing a modified example according to the present embodiment.

FIG. 4 is a diagram showing how frost damage occurs in a concrete structure.

[Explanation of symbols]

 11 Concrete 12 Waterproof Breathable Sheet (Waterproof Breathable Layer) 31 Insulation Material (Breathable Insulation Layer)

Claims (2)

[Claims] 1. A structure for preventing frost damage of concrete, characterized in that a waterproof and moisture-permeable layer is laminated on the surface of the concrete. 2. A structure for preventing frost damage of concrete, characterized in that a waterproof and moisture permeable layer is laminated on the concrete surface through a predetermined moisture permeable heat insulating layer.