JP2020200695A - Concrete curing sheet - Google Patents

Abstract

To provide a concrete curing sheet which can achieve both durability and water absorption property.SOLUTION: A white polyolefin-made fiber orthogonal laminate non-woven fabric is layered on one surface of a foam polyurethane resin having a width of 1 m, a thickness of 10 mm and a length of 20 m as a water retentive sheet, and a black polyolefin-made fiber orthogonal laminate non-woven fabric is layered on the other surface thereof. A lamination layer of the foam polyurethane resin and the fiber orthogonal laminate non-woven fabric is sewn at a pitch of 50 mm by a sewing machine.SELECTED DRAWING: Figure 1

Description

The present invention relates to a concrete curing sheet used in the construction of concrete.

Concrete used for roads and bridges is hardened by a hydration reaction. Therefore, it is necessary to maintain the moisture and temperature of the concrete surface in an appropriate state for a predetermined period after the concrete is placed, and to protect the concrete surface from natural conditions such as temperature difference, sunlight, and wind.

Conventionally, as a method of protecting the surface after placing concrete, a water-retaining or heat-retaining sheet is laid on the concrete surface.

For example, a wet heat-generating sheet containing a water-absorbing fiber and a moisture-absorbing heat-generating fiber, a heat-retaining sheet including a heat-insulating member, and a laminated wet heat-generating sheet and the heat-retaining sheet (see Patent Document 1), or heat insulating A heat insulating sheet made of a member and a waterproof sheet member surrounding the heat insulating member, and a wetting sheet provided on one side of the heat insulating sheet (see Patent Document 2), water. It is composed of a moisturizing sheet containing a moisturizing material that absorbs and moistens, and a heat insulating sheet made of a heat insulating member, and the moisturizing sheet and the heat insulating sheet are directly adhered and integrated in a laminated state. The moisturizing sheet and the heat insulating sheet are bonded and integrated by welding. Examples of the heat insulating sheet include those made of a soft resin foam such as polyethylene foam having a closed cell structure (see Patent Document 3).

However, these curing sheets have low water absorption when water is sprinkled on the surface of the curing sheet when trying to increase the durability that can be used repeatedly, and conversely, the durability becomes low when trying to obtain sufficient water absorption. There was a problem that it would end up.

Japanese Unexamined Patent Publication No. 2015-21345 Japanese Unexamined Patent Publication No. 6-285832 Japanese Unexamined Patent Publication No. 2010-196396

The problem to be solved is to provide a concrete curing sheet that can achieve both durability and water absorption.

The present invention is a curing sheet used for protecting the concrete surface for a predetermined period after placing concrete, and the curing sheet is made by laminating a foamed polyurethane resin or a foamed polyolefin resin and a fiber orthogonal laminated non-woven fabric. The most important feature is that it is made to do.

The concrete curing sheet of the present invention has an advantage that both durability and water absorption can be achieved at the same time.

FIG. 1 is a schematic cross-sectional view showing an example of the concrete curing sheet of the present invention.

The concrete curing sheet of the present invention is, for example, as follows.

As shown in FIG. 1, a white polyolefin fiber orthogonal laminated non-woven fabric is laminated on one side of a foamed polyurethane resin having a width of 1 m, a thickness of 10 mm, and a length of 20 m as a water-retaining sheet, and a black polyolefin fiber is laminated on the other side. Orthogonal laminated non-woven fabric is laminated. The laminated polyurethane foam resin and the fiber orthogonal laminated non-woven fabric are sewn with a sewing machine at a pitch of 50 mm.

The water-retaining sheet can be arbitrarily set as long as it is a rug having water absorption. For example, fibers such as hemp, straw, synthetic resin fiber, rock wool, and lightweight aggregates such as pearlite, vermiculite, and silas balloon may be packed in a water-permeable bag, or polyurethane foam resin and polyolefin foam resin may be used. , Porous foam such as foamed melamine resin, ceramic fiber board, diatomaceous earth cement board and the like may be used. Of these, it is preferable to use a porous foam such as a foamed polyurethane resin, a foamed polyolefin resin, and a foamed melamine resin, and it is more preferable to use a foamed polyurethane resin or a foamed polyolefin resin. By using the foamed polyurethane resin or the foamed polyolefin resin, when the curing of the concrete is completed and the curing sheet is removed, the retained water is removed more quickly and the mass of the curing sheet is reduced, which improves workability. Excellent.

The thickness of the water retention sheet is preferably 3 to 30 mm, more preferably 5 to 15 mm.

The fiber orthogonal laminated non-woven fabric is preferably laminated on at least one side of the water retention sheet, and more preferably on both the front and back surfaces. With such a configuration, the durability of the curing sheet is excellent, and the water retention when water is sprinkled on the surface of the curing sheet is excellent.

The fiber orthogonal laminated non-woven fabric is obtained by splitting and stretching a polyolefin film and orthogonally laminating it, and Warif, CLAF (both registered trademarks, manufactured by JX ANCI Co., Ltd.) and the like are known. By using the fiber orthogonal laminated non-woven fabric, the durability and water permeability of the curing sheet are excellent.

The sewing pitch of the fiber orthogonal laminated non-woven fabric on the water-retaining sheet is preferably 20 to 200 mm, more preferably 30 to 150 mm.

Lamination of the fiber orthogonal laminated non-woven fabric on the water-retaining sheet is not limited to sewing, and may be adhesive, ultrasonic lamination, extrusion lamination, dry lamination, or the like. Warif and CLAF are particularly preferable because they can be thermocompression bonded without an adhesive layer.

The mass of the fiber orthogonal laminated non-woven fabric is preferably 10 to 50 g / m ² , and more preferably 20 to 40 g / m ² .

The tensile strength of the fiber orthogonal laminated non-woven fabric is preferably 50 to 500 N / 50 mm, more preferably 100 to 300 N / 50 mm.

The color of the fiber orthogonal laminated non-woven fabric can be set arbitrarily. By making the color of the fiber orthogonal laminated non-woven fabric white, it is possible to reduce the direct sunlight in summer and suppress the temperature rise of the concrete surface. Further, by changing the color of the fiber orthogonal laminated non-woven fabric to black, sunlight can be efficiently absorbed in winter, so that the temperature drop on the concrete surface can be suppressed.

It is preferable that the colors of the fiber orthogonal laminated non-woven fabric are different on the front and back sides. With such a configuration, since the front and back surfaces of the curing sheet can be visually observed, it becomes easy to use the front and back surfaces alternately, and the number of times the curing sheet can be used repeatedly increases.

By making the color of the fiber orthogonal laminated non-woven fabric white on one side of the water-retaining sheet and black on the other side, the white side is on the outside in summer to suppress the temperature rise of the concrete surface, and in winter. Since the temperature drop of the concrete surface can be suppressed by turning the black surface to the outside, the concrete can be cured under appropriate conditions in both summer and winter with one curing sheet.

The width of the curing sheet is preferably 0.8 to 1.2 m, more preferably 0.9 to 1.1 m.

The length of the curing sheet is preferably 5 to 60 m, more preferably 10 to 30 m.

The curing sheet is preferably rolled and stored before and after use, and is spread out when installed on a concrete casting surface.

The curing sheet configured as described above is used as follows.
The day after concrete was placed on the floor surface with a width of 16 m and a length of 200 m as a road, a white polyolefin fiber orthogonal laminated non-woven fabric was sewn on the surface of a water-retaining sheet made of foamed polyurethane resin on the surface of the concrete. Spread a concrete curing sheet with a length of 20 m and a thickness of 8 mm and sprinkle water. The sprinkled water permeates through the opening of the polyolefin fiber orthogonal laminated non-woven fabric on the surface of the curing sheet, and the water-retaining sheet made of foamed polyurethane resin is moistened. Even in the direct sunlight of summer, the direct sunlight is reflected by the polyolefin fiber orthogonal laminated non-woven fabric on the surface, the moisture contained in the water retention sheet is hard to evaporate, and the moisture content of the concrete surface after casting is appropriately maintained. Can be done. Watering is done regularly until the concrete has been cured, during which the curing sheet remains laid on the concrete surface. At the end of the concrete curing period, which lasts from weeks to months, the curing sheet is removed. The curing sheet is wound again in a roll shape, and the water retained in the winding operation is easily removed, so that the winding operation is easy.

Hereinafter, the present invention will be described with reference to Examples and Comparative Examples. In the water retention test, a curing sheet cut to the same size was placed on the surface of a mortar plate having a size of 70 mm × 70 mm × thickness 10 mm, and the outer circumference was covered with an aluminum tape having a width of 50 mm to prepare a test piece. Subsequently, 50 g of water was poured from the curing sheet of the test body, and the test body was left outdoors in direct sunlight for 4 hours in fine weather to measure the mass change of the test body. In the evaluation, the mass reduction of 25 g or less was evaluated as 〇, the mass reduction of more than 25 g and 40 g or less was evaluated as Δ, and the mass reduction of more than 40 g was evaluated as x.

The durability test was carried out by cutting out a curing sheet into a width of 50 mm and a length of 300 mm and measuring the tensile strength. The evaluation was 0 for 100N or more, Δ for less than 100N, and × for less than 50N.

In the temperature measurement test, a curing sheet cut to the same size is placed on the surface of a mortar plate of 70 mm x 70 mm x 10 mm thickness to make a test piece, and the test piece is left in direct sunlight for 4 hours to measure the temperature of the surface of the water retention sheet. went. In the evaluation, as compared with the test piece on which the curing sheet was not placed (Comparative Example 1), the one having a temperature lower than 5 ° C. was evaluated as 0, the one having a temperature of 3 ° C. or more and less than 5 ° C.

In the ease of removal test, 50 g of water is poured from the top of the curing sheet of the test piece into the same test piece as the water retention test, left indoors for 24 hours, and then only the curing sheet is pulled up to measure the mass of the curing sheet. I went by. In the evaluation, the mass increase of 25 g or less was evaluated as 〇, the mass increase of more than 25 g and 40 g or less was evaluated as Δ, and the mass increase of more than 40 g was evaluated as x.
The test results are shown in Table 1.

1 Curing sheet 2 Water retention sheet 3 Fiber orthogonal laminated non-woven fabric

Claims (3)

It is a curing sheet used to protect the concrete surface for a predetermined period after placing concrete, and is characterized in that the curing sheet is a laminate of a water-retaining sheet and a fiber orthogonal laminated non-woven fabric. Concrete curing sheet to do. The concrete curing sheet according to claim 1, wherein the water-retaining sheet is a foamed polyurethane resin or a foamed polyolefin resin, and fiber orthogonal laminated non-woven fabrics are laminated on the front surface and / or the back surface of the water-retaining sheet. The concrete curing sheet according to claim 2, wherein the fiber orthogonal laminated non-woven fabric laminated on the front and back surfaces of the foamed polyurethane resin or the foamed polyolefin resin is white on one side and black on the other side. ..

Images