JP2023146742A - Concrete cure method - Google Patents

Abstract

To provide a concrete cure sheet that can obtain a high quality concrete structure capable of being quickly laid when curing a concrete structure with reinforcing-bars exposed and a concrete cure method used with its sheet.SOLUTION: A belt-like concrete cure sheet 1 that is laid on a concrete surface and cures concrete while keeping it in a wet state has multiple long gaps 1a in a width direction. The multiple gaps 1a are provided apart in a longer direction of the concrete cure sheet 1.SELECTED DRAWING: Figure 7

Description

The present disclosure relates to a concrete curing sheet and a concrete curing method for curing concrete poured on site.

In general, in concrete construction, in order to ensure the required quality of concrete such as strength, durability, and watertightness, it is necessary to maintain the temperature and humidity necessary for hardening for a certain period of time after concrete is poured, which is called curing. be.

There are various curing methods, and methods of curing concrete using concrete curing sheets are known, as disclosed in Patent Documents 1 to 3. The concrete curing sheet of Patent Document 1 has a plurality of protrusions on the side of the base sheet that is laid on the concrete surface. Each protrusion is composed of a wetting material that swells by absorbing water. Moreover, the concrete curing sheet of Patent Document 2 is a sheet in which a moisturizing sheet containing a swelling material and a heat insulating sheet made of a heat insulating member are integrated in a laminated state. Further, the concrete curing sheet disclosed in Patent Document 3 has a water retaining layer containing a swelling material and a heat dissipation layer integrated in a laminated state.

Japanese Patent Application Publication No. 2002-81210 Japanese Patent Application Publication No. 2010-196396 Japanese Patent Application Publication No. 2014-152559

By the way, each of the above-mentioned curing methods has its own problems. For example, at a concrete joint such as a joint between a floor and a wall, the reinforcing bars that connect the floor to the wall are exposed so as to protrude upward from the floor. In order to avoid reinforcing bars, it is necessary to make a notch in the curing sheet in the area corresponding to the reinforcing bar, and then lay the curing sheet while inserting the reinforcing bar into the notch.

Furthermore, for example, in the case of a ground-covered part of a bridge wall railing, if the length of concrete placement is long, the number of reinforcing bars becomes enormous. In such cases, if cuts are made in the concrete curing sheet to match the number of reinforcing bars on site, curing cannot be carried out promptly after the concrete is poured and the surface is finished, making it difficult to ensure the quality of the concrete. becomes difficult to do.

The present disclosure has been made in view of this point, and its purpose is to provide a concrete structure that can be quickly laid during curing of a concrete structure in which reinforcing bars are exposed, thereby obtaining a high-quality concrete structure. An object of the present invention is to provide a curing sheet and a concrete curing method using the sheet.

In order to achieve the above object, one aspect of the present disclosure can be based on a belt-shaped concrete curing sheet that is laid on a concrete surface and keeps the concrete in a moist state and cures it. The concrete curing sheet is provided with a plurality of widthwise long cuts spaced apart from each other in the longitudinal direction of the concrete curing sheet.

According to this configuration, when laying the concrete curing sheet on the exposed concrete surface so that the reinforcing bars protrude upward, the concrete curing sheet is provided with a long cut in the width direction in advance, so that the cut can be easily By placing reinforcing bars in the concrete, concrete curing sheets can be laid quickly while avoiding interference with the reinforcing bars. For example, when concrete is poured over a long period of time, such as in the ground-covered part of a bridge wall railing, a large number of reinforcing bars are exposed at intervals in the longitudinal direction of the wall railing. Since the reinforcing bars are pre-prepared at intervals in the longitudinal direction of the concrete curing sheet, even if there are a large number of reinforcing bars, there is no need to make numerous cuts on site, making the installation process quick and easy. I can do it. Note that additional cuts may be made on site.

Further, the plurality of cuts may be provided at intervals in the width direction of the concrete curing sheet. In this case, a plurality of cuts are lined up in the width direction of the concrete curing sheet, and the space between the cuts lined up in the width direction becomes a part where the concrete curing sheet is not cut, that is, a connected part. In other words, by leaving a part of the concrete curing sheet uncut when making long cuts in the width direction, the concrete curing sheet is less likely to turn over during transportation, for example, and handling becomes easier. At the time of laying, by cutting the connected parts of the concrete curing sheet on site, the cuts will be of sufficient length, and reinforcing bars can be inserted into the cuts. Incidentally, since long cuts in the width direction are provided in advance, the connected portions can be cut quickly on site, and the speed of the installation work is hardly hindered.

In addition, since there are connected parts between the cuts in the concrete curing sheet, if the cuts are left connected in places where they are not needed, the concrete curing sheet will be difficult to turn over due to wind, etc., and there is a possibility of curing failure. is lower than when there are no connected parts.

Moreover, the cut may be provided in a portion of the concrete curing sheet that is away from one end in the width direction toward the other end, and in a portion that is away from the other end in the width direction toward the one end. According to this configuration, since the cut does not reach one end and the other end of the concrete curing sheet, the concrete curing sheet becomes connected in the longitudinal direction at one end and the other end. This makes it difficult for one end and the other end of the concrete curing sheet to be turned over by wind or the like in places where cuts are not required. In addition, in places where a cut is required, a cut of sufficient length can be obtained by cutting one end or the other end of the concrete curing sheet on-site, and reinforcing bars can be inserted into the cut.

Alternatively, one end of the cut in the longitudinal direction may be provided so as to reach one end of the concrete curing sheet in the width direction. By providing a cut in advance that reaches one end of the concrete curing sheet, it becomes unnecessary to cut a part of the concrete curing sheet on site, and the laying work can be performed even more quickly.

Additionally, concrete curing sheets can be stored and transported in a rolled state. In addition, multiple concrete curing sheets cut to any length can be stored and transported in a stacked state in the thickness direction.

The concrete curing sheet may include a base material and a water retaining material provided on the side of the base material that is laid on the concrete. In this case, by impregnating the water retaining material with water, the concrete can be kept moist for a long period of time, and the quality of the concrete structure can be further improved.

As explained above, the concrete curing sheet has multiple long cuts in the width direction, spaced apart in the longitudinal direction of the concrete curing sheet, so that the concrete curing sheet can be quickly laid on the concrete where the reinforcing bars are exposed. This makes it possible to obtain high-quality concrete structures.

FIG. 1 is a plan view of a concrete curing sheet according to an embodiment of the present invention. 2 is a sectional view taken along line II-II in FIG. 1. FIG. It is a perspective view showing a concrete curing sheet in a rolled state. It is a perspective view showing concrete curing sheets in a stacked state. FIG. 2 is a diagram corresponding to FIG. 1 according to modification example 1; FIG. 2 is a diagram corresponding to FIG. 1 according to modification 2; It is a perspective view showing an example of a concrete joint part. This is a diagram equivalent to Figure 6 after the concrete curing sheet has been laid. It is a graph showing quality evaluation results based on air permeability coefficient. It is a graph showing quality evaluation results based on surface water supply amount.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings. Note that the following description of preferred embodiments is essentially just an example, and is not intended to limit the present invention, its applications, or its uses.

FIG. 1 is a plan view of a concrete curing sheet 1 according to an embodiment of the present invention. The concrete curing sheet 1 is a belt-shaped sheet that is laid on the concrete surface and keeps the concrete in a moist state for curing. Specifically, the concrete curing sheet 1 can be laid at a concrete joint 100 such as a joint between a floor and a wall as shown in FIG. 6, for example. A plurality of reinforcing bars 101 connected from the floor are exposed in the concrete joint part 100 so as to protrude upward. Concrete that will become a wall is cast so that the reinforcing bars 101 are buried, and a concrete structure in which the floor and walls are integrated is obtained. In short, the floor part that constitutes a part of the concrete structure has the concrete joint part 100.

Furthermore, examples of concrete structures include bridge wall railings and the like. Depending on the length of the bridge, the length of concrete pouring may be long for the ground covering part of the wall parapet. In this case, the number of reinforcing bars 101 becomes enormous, and a large number of reinforcing bars 101 are exposed at intervals from each other in the longitudinal direction of the wall railing. The spacing between the reinforcing bars 101 is approximately constant, and may be set to, for example, several tens of cm. Note that the concrete curing sheet 1 may be laid on the concrete surface other than the concrete joint 100.

Since the concrete curing sheet 1 is strip-shaped, the longitudinal direction and the width direction can be defined. Further, the lower end in FIG. 1 is defined as one end in the width direction of the concrete curing sheet 1, and the upper end in FIG. 1 is defined as the other end in the width direction of the concrete curing sheet 1. The length of the concrete curing sheet 1 is not particularly limited, but should be longer than the spacing between the reinforcing bars 101 that are generally arranged at regular intervals, such as 1 m or more, 3 m or more, or 5 m or more. has been set for a long time. The width of the concrete curing sheet 1 is set to be larger than the dimension in the depth direction of the concrete joint 100, and specifically, is several tens of cm or more.

The concrete curing sheet 1 has a plurality of long cuts 1a in the width direction of the concrete curing sheet 1, and as shown in FIG. 7, one reinforcing bar 101 can be inserted into each cut 1a. It has become. Note that when a plurality of reinforcing bars 101 are provided side by side in the depth direction, the plurality of reinforcing bars 101 lined up in the depth direction can also be inserted into one cut 1a.

The lower end of the cut 1a in FIG. 1 is defined as one longitudinal end of the cut 1a, and the upper end of the cut 1a in FIG. 1 is defined as the other longitudinal end of the cut 1a. The cut 1a extends linearly along the width direction of the concrete curing sheet 1, and therefore the longitudinal direction of the cut 1a and the longitudinal direction of the concrete curing sheet 1 are perpendicular to each other. Note that the cut 1a may extend in a direction intersecting the width direction of the concrete curing sheet 1. Moreover, the cut 1a does not have to be linear, and may be, for example, bent or curved.

The cut 1a is after being cut with a knife, and can also be called a cut with a knife. When creating the cut 1a, it is sufficient to pass a cutter through the concrete curing sheet 1 from the front surface to the back surface in the thickness direction, and the cut 1a of a desired length can be easily provided at a targeted position. The plurality of cuts 1a are provided at intervals in the longitudinal direction of the concrete curing sheet 1. The interval between the cuts 1a can be set, for example, in a range of 20 mm or more and 100 mm or less, or can be set in a range of 30 mm or more and 60 mm or less. If the interval between the cuts 1a is narrowed, it can be easily adapted to various positions of reinforcing bars 101, but the parts of the concrete curing sheet 1 where the cuts 1a are formed tend to fall apart, making storage and transportation difficult. Therefore, the interval between the cuts 1a is set to 20 mm or more.

In addition, widening the interval between the cuts 1a makes it difficult for the part of the concrete curing sheet 1 where the cuts 1a are formed to fall apart, making storage and transportation easier. This may reduce the effect of providing the cuts 1a, so the distance is set to 100 mm or less to at least correspond to the spacing between the reinforcing bars 101 in general. In consideration of the above, in this embodiment, as will be described later, the intervals between the cuts 1a are set to two types, 30 mm and 50 mm.

The cut 1a is provided such that one end in the longitudinal direction of the cut 1a reaches one end in the width direction of the concrete curing sheet 1. Further, the other end in the longitudinal direction of the cut 1a does not reach the other end in the width direction of the concrete curing sheet 1, but is located at a part of the concrete curing sheet 1 away from the other end in the width direction toward one end side. The longitudinal dimension of the cut 1a is 1/2 or more of the widthwise dimension of the concrete curing sheet 1, and can be, for example, 2/3 or more, 4/5 or more. The longitudinal dimension of the cut 1a may be set according to the position in the depth direction of the reinforcing bar 101 shown in FIG. 6, and is not limited to the above-described dimension.

Since one end in the longitudinal direction of the cut 1a reaches one end in the width direction of the concrete curing sheet 1, an operator can easily turn over the portion of the concrete curing sheet 1 between the adjacent cuts 1a. On the other hand, since the cut 1a does not reach the other end in the width direction of the concrete curing sheet 1, the concrete curing sheet 1 is not completely separated due to the formation of the cut 1a, and can be handled as one sheet.

As shown in FIG. 2, the concrete curing sheet 1 has a multilayer structure. Specifically, the concrete curing sheet 1 includes a base material 11 and a water retaining material 12 provided on the side of the base material 11 that is laid on concrete. The base material 11 is a non-air permeable sheet, and is made of, for example, a reinforced vinyl chloride sheet containing fibers, a polyethylene film, etc., although it is not particularly limited. The base material 11 may have a multilayer structure, or may be made of a sheet that is a combination of a non-breathable sheet and a nonwoven fabric.

The water retaining material 12 is made of a water-absorbing polymer, fiber, or the like that can absorb and retain water. As the water-absorbing polymer, for example, a polyethylene oxide-based polymer absorbent such as crosslinked polyethylene oxide can be used. The amount of water retained by the water retaining material 12 is not particularly limited, but is an amount capable of continuously replenishing water that is removed from the surface as the material ages after being laid on concrete for a predetermined period of time. In addition, the concrete curing sheet 1 may have a heat dissipation layer or a heat insulation layer.

As shown in FIG. 3A, one concrete curing sheet 1 can be stored and transported in a rolled state. For example, by rolling the concrete curing sheet 1 in the longitudinal direction, it can be made into a single roll, which facilitates storage and transportation. Furthermore, more concrete curing sheets 1 can be transported with a smaller volume than in the case shown in FIG. 3B, which will be described later.

Further, as shown in FIG. 3B, a plurality of concrete curing sheets 1 cut into predetermined lengths can be stored and transported in a state where they are stacked in the thickness direction. In this case, the sides of each concrete curing sheet 1 on which the cuts 1a are formed are aligned. A plurality of concrete curing sheets 1 can be stacked and packed in a bag (not shown). By packing in this way, before laying the concrete curing sheets 1, you can fill the bag with water and let the water retaining material 12 of each concrete curing sheet 1 absorb the water all at once, making it easier to carry out work at the site. Improves sex.

FIG. 4 shows a concrete curing sheet 1 according to a first modification of the embodiment. In this modification 1, a plurality of cuts 1a are provided at intervals in the longitudinal direction of the concrete curing sheet 1, and are also provided at intervals in the width direction of the concrete curing sheet 1. The spaces between the cuts 1a arranged in the width direction of the concrete curing sheet 1 are uncut parts of the concrete curing sheet 1, that is, connected parts. That is, by leaving a part of the concrete curing sheet 1 uncut when making the long cuts 1a in the width direction, the concrete curing sheet 1 is less likely to turn over during transportation, for example, and handling becomes easier. Further, in the case of Modification 1, it is easy to roll the sheets as shown in FIG. 3A and to stack them as shown in FIG. 3B.

The dimension between the cuts 1a arranged in the width direction is not particularly limited, but is set shorter than the length of the cut 1a, and in Modification 1, it is 1/5 or less of the length of the cut 1a, and It can be reduced to 1/10 or less. At the time of laying, by cutting the connected part between the cuts 1a arranged in the width direction of the concrete curing sheet 1 on site, one cut 1a having sufficient length is obtained, so reinforcing bars 101 are inserted into the cut 1a. Just put it in. In the case of modification 1, since the long cuts 1a are provided in advance in the width direction of the concrete curing sheet 1, cutting the connected parts between the cuts 1a arranged in the width direction can be quickly performed on site. There is almost no impediment to the speed of the installation work.

Further, since there is a connected portion between the cuts 1a in the concrete curing sheet 1, the cuts 1a can remain connected at unnecessary laying locations. This makes it difficult for the concrete curing sheet 1 to turn over due to wind or the like, and the possibility of poor curing is lower than in the case where there are no connected parts (as shown in FIG. 1).

A plurality of cuts 1a lined up in the width direction of the concrete curing sheet 1 are provided so as to be located on the same imaginary straight line extending in the width direction of the concrete curing sheet 1. The lengths of the cuts 1a arranged in the width direction of the concrete curing sheet 1 may all be the same or may be different. The plurality of cuts 1a arranged in the width direction of the concrete curing sheet 1 are provided in a part of the concrete curing sheet 1 away from one end in the width direction to the other end side, and in a part away from the other end in the width direction to the one end side. . That is, since the cut 1a does not reach one end and the other end of the concrete curing sheet 1 in the width direction, the concrete curing sheet 1 is connected in the longitudinal direction at one end and the other end in the width direction. This makes it difficult for one end and the other end of the concrete curing sheet 1 in the width direction to be turned over by wind or the like at the installation location where the cut 1a is not required.

The number of cuts 1a arranged in the width direction of the concrete curing sheet 1 is not limited to two, and may be three or more as in Modification 2 shown in FIG. 5. In this modification 2, cuts 1a lined up in the width direction are provided like perforations. In the case of this modification 2 as well, if necessary, the cuts 1a arranged in the width direction and the connected portions between the cuts 1a may be cut on site. Furthermore, in the case of Modification 2, it is also easy to roll up as shown in FIG. 3A and to stack as shown in FIG. 3B.

(Concrete curing method)
Next, a concrete curing method using the concrete curing sheet 1 will be explained. Cuts 1a in the concrete curing sheet 1 are already provided at the time of shipment from the factory. After the concrete curing sheet 1 with the cuts 1a previously provided is transported to the site, a water absorption process is performed to cause the water retaining material 12 to absorb water. In the case shown in FIG. 3A, the water retaining material 12 may absorb water while the concrete curing sheet 1 is being rolled up, or may be made to absorb water after being spread. Moreover, in the case shown in FIG. 3B, the water retaining material 12 may absorb water while the concrete curing sheets 1 are stacked, or may be allowed to absorb water after being separated.

Thereafter, as shown in FIG. 7, the concrete curing sheet 1 is laid on the concrete joint 100. This is the laying process. At this time, in the case of the concrete curing sheet 1 shown in FIG. 1, since the cut 1a is provided, the concrete curing sheet 1 must be deformed so as to widen the cut 1a or to turn over the part between the cuts 1a and 1a. Thus, the reinforcing bar 101 can be easily inserted into the cut 1a. Depending on the spacing between the reinforcing bars 101, there may be cuts 1a where the reinforcing bars 101 cannot fit, but in FIG. It shows that it is in. By laying it in this way, most of the parts of the concrete joint 100 that require curing can be covered with the concrete curing sheet 1. Note that the gap created by providing the cut 1a is so small that it can be ignored.

In addition, in the case of the concrete curing sheet 1 of Modification 1 shown in FIG. 4 and in the case of the concrete curing sheet 1 of Modification 2 shown in FIG. Cut with. This is the cutting process. By doing so, a long cut 1a similar to the concrete curing sheet 1 shown in FIG. 1 is formed, so that the reinforcing bars 101 can be easily inserted into the cut 1a. In the case of the concrete curing sheet 1 of Modification Example 2 shown in FIG. 5, it is not necessary to cut all the cuts 1a arranged in the width direction of the concrete curing sheet 1, and only a part thereof may be cut.

After laying the concrete curing sheet 1 as described above, wait for a predetermined curing period to elapse. Water is supplied only at the beginning, and there is no need to supply water in the middle. The reason for this is that most of the parts of the concrete joint 100 that require curing are covered with the concrete curing sheet 1, and the concrete curing sheet 1 suppresses the evaporation of moisture from the concrete joint 100. . In addition, water may be supplied in the middle as necessary.

(Test examples and test results)
In order to verify the effects of concrete curing sheet 1, the following tests were conducted. As Example 1, a concrete curing sheet 1 as shown in FIG. 1 was prepared, and a concrete joint 100 was covered with the longitudinally aligned cuts 1a having an interval of 30 mm. As Example 2, a concrete curing sheet 1 as shown in FIG. 1 was prepared, and the interval between the cuts 1a arranged in the longitudinal direction of the concrete curing sheet 1 was set to 50 mm to cover the concrete joint 100. As Comparative Example 1, an example (sheet curing) was prepared in which the concrete joint 100 was covered with a sheet that had no breaks and was non-ventilated. As Comparative Example 2, an example in which no curing sheet was used (an example in which no curing measures were taken) was prepared.

The curing period was one week. The test period was midsummer, and the test was conducted under harsh conditions for concrete curing. The curing age is 7 days. Further, the quality evaluation described below was performed after 7 days and 28 days had passed from the start of the test. Note that water is only supplied at the beginning, and no water is supplied in the middle.

FIG. 8 shows the measurement results of the air permeability coefficient in the surface layer of concrete. An example of a test for determining the air permeability coefficient is the Trent method. The upper graph in FIG. 8 is the measurement result when the material age is 7 days, and the lower graph is the measurement result when the material age is 28 days. In both measurement results, it can be seen that Examples 1 and 2 have significantly lower air permeability coefficients than Comparative Examples 1 and 2, that is, the quality of the concrete is higher.

FIG. 9 shows the measurement results of the surface water supply amount of concrete. This surface water supply amount can be measured using, for example, a commercially available water content meter, and the measuring method is conventionally well known. The upper graph in FIG. 9 is the measurement result when the material age is 7 days, and the lower graph is the measurement result when the material age is 28 days. In both measurement results, it can be seen that the amount of surface water supply in Examples 1 and 2 is significantly smaller than in Comparative Examples 1 and 2, that is, the quality of the concrete is higher.

(effect)
As explained above, since the concrete curing sheet 1 is provided with a plurality of widthwise long cuts 1a at intervals in the longitudinal direction, the concrete curing sheet 1 is placed on the exposed concrete surface so that the reinforcing bars 101 protrude upward. When laying the reinforcing bars 101, the reinforcing bars 101 can be laid quickly and over a wide range while avoiding interference with the reinforcing bars 101. Thereby, a high quality concrete structure can be obtained.

The embodiments described above are merely illustrative in all respects and should not be interpreted in a limiting manner. Furthermore, all modifications and changes that come within the scope of equivalents of the claims are intended to be within the scope of the present invention.

As explained above, the present invention can be used, for example, by being laid in a concrete joint where reinforcing bars protrude upward.

1 Concrete curing sheet 1a Cut 100 Concrete joint 101 Rebar

The present disclosure relates to a concrete curing method for curing concrete poured on site.

In general, in concrete construction, in order to ensure the required quality of concrete such as strength, durability, and watertightness, it is necessary to maintain the temperature and humidity necessary for hardening for a certain period of time after concrete is poured, which is called curing. be.

There are various curing methods, and methods of curing concrete using concrete curing sheets are known, as disclosed in Patent Documents 1 to 3. The concrete curing sheet of Patent Document 1 has a plurality of protrusions on the side of the base sheet that is laid on the concrete surface. Each protrusion is composed of a wetting material that swells by absorbing water. Moreover, the concrete curing sheet of Patent Document 2 is a sheet in which a moisturizing sheet containing a swelling material and a heat insulating sheet made of a heat insulating member are integrated in a laminated state. Further, the concrete curing sheet disclosed in Patent Document 3 has a water retaining layer containing a swelling material and a heat dissipation layer integrated in a laminated state.

Japanese Patent Application Publication No. 2002-81210 Japanese Patent Application Publication No. 2010-196396 Japanese Patent Application Publication No. 2014-152559

By the way, each of the above-mentioned curing methods has its own problems. For example, at a concrete joint such as a joint between a floor and a wall, the reinforcing bars that connect the floor to the wall are exposed so as to protrude upward from the floor. In order to avoid reinforcing bars, it is necessary to make a notch in the curing sheet in the area corresponding to the reinforcing bar, and then lay the curing sheet while inserting the reinforcing bar into the notch.

Furthermore, for example, in the case of a ground-covered part of a bridge wall railing, if the length of concrete placement is long, the number of reinforcing bars becomes enormous. In such cases, if cuts are made in the concrete curing sheet to match the number of reinforcing bars on site, curing cannot be carried out promptly after the concrete is poured and the surface is finished, making it difficult to ensure the quality of the concrete. becomes difficult to do.

The present disclosure has been made in view of this point, and its purpose is to provide a concrete structure that can be quickly laid during curing of a concrete structure in which reinforcing bars are exposed, thereby obtaining a high-quality concrete structure. An object of the present invention is to provide a curing sheet and a concrete curing method using the sheet.

In order to achieve the above object, one aspect of the present disclosure provides a concrete curing method using a band-shaped concrete curing sheet, the concrete curing sheet having a plurality of long cuts in the width direction of the concrete curing sheet. , the concrete curing sheets are provided at intervals in the longitudinal direction, and a laying process is performed in which the concrete curing sheets are laid at concrete joints, and in the laying process, the concrete curing sheets are placed in the breaks in the concrete curing sheets. It is characterized by the inclusion of reinforcing bars that protrude upward from the joint.

Alternatively, the laying process can be performed after the water retention material of the concrete curing sheet absorbs water.

According to this configuration, when laying the concrete curing sheet on the exposed concrete surface so that the reinforcing bars protrude upward, the concrete curing sheet is provided with a long cut in the width direction in advance, so that the cut can be easily By placing reinforcing bars in the concrete, concrete curing sheets can be laid quickly while avoiding interference with the reinforcing bars. For example, when concrete is poured over a long period of time, such as in the ground-covered part of a bridge wall railing, a large number of reinforcing bars are exposed at intervals in the longitudinal direction of the wall railing. Since the reinforcing bars are pre-prepared at intervals in the longitudinal direction of the concrete curing sheet, even if there are a large number of reinforcing bars, there is no need to make numerous cuts on site, making the installation process quick and easy. I can do it. Note that additional cuts may be made on site.

Further, the plurality of cuts may be provided at intervals in the width direction of the concrete curing sheet. In this case, a plurality of cuts are lined up in the width direction of the concrete curing sheet, and the space between the cuts lined up in the width direction becomes a part where the concrete curing sheet is not cut, that is, a connected part. In other words, by leaving a part of the concrete curing sheet uncut when making long cuts in the width direction, the concrete curing sheet is less likely to turn over during transportation, for example, and handling becomes easier. At the time of laying, by cutting the connected parts of the concrete curing sheet on site, the cuts will be of sufficient length, and reinforcing bars can be inserted into the cuts. Incidentally, since long cuts in the width direction are provided in advance, the connected portions can be cut quickly on site, and the speed of the installation work is hardly hindered.

In addition, since there are connected parts between the cuts in the concrete curing sheet, if the cuts are left connected in places where they are not needed, the concrete curing sheet will be difficult to turn over due to wind, etc., and there is a possibility of curing failure. is lower than when there are no connected parts.

Moreover, the cut may be provided in a portion of the concrete curing sheet that is away from one end in the width direction toward the other end, and in a portion that is away from the other end in the width direction toward the one end. According to this configuration, since the cut does not reach one end and the other end of the concrete curing sheet, the concrete curing sheet becomes connected in the longitudinal direction at one end and the other end. This makes it difficult for one end and the other end of the concrete curing sheet to be turned over by wind or the like in places where cuts are not required. In addition, in places where a cut is required, a cut of sufficient length can be obtained by cutting one end or the other end of the concrete curing sheet on-site, and reinforcing bars can be inserted into the cut.

Alternatively, one end of the cut in the longitudinal direction may be provided so as to reach one end of the concrete curing sheet in the width direction. By providing a cut in advance that reaches one end of the concrete curing sheet, it becomes unnecessary to cut a part of the concrete curing sheet on site, and the laying work can be performed even more quickly.

Additionally, concrete curing sheets can be stored and transported in a rolled state. In addition, multiple concrete curing sheets cut to any length can be stored and transported in a stacked state in the thickness direction.

The concrete curing sheet may include a base material and a water retaining material provided on the side of the base material that is laid on the concrete. In this case, by impregnating the water retaining material with water, the concrete can be kept moist for a long period of time, and the quality of the concrete structure can be further improved.

As explained above, the concrete curing sheet has multiple long cuts in the width direction, spaced apart in the longitudinal direction of the concrete curing sheet, so that the concrete curing sheet can be quickly laid on the concrete where the reinforcing bars are exposed. This makes it possible to obtain high-quality concrete structures.

FIG. 1 is a plan view of a concrete curing sheet according to an embodiment of the present invention. 2 is a sectional view taken along line II-II in FIG. 1. FIG. It is a perspective view showing a concrete curing sheet in a rolled state. It is a perspective view showing concrete curing sheets in a stacked state. FIG. 2 is a diagram corresponding to FIG. 1 according to modification example 1; FIG. 2 is a diagram corresponding to FIG. 1 according to modification 2; It is a perspective view showing an example of a concrete joint part. This is a diagram equivalent to Figure 6 after the concrete curing sheet has been laid. It is a graph showing quality evaluation results based on air permeability coefficient. It is a graph showing quality evaluation results based on surface water supply amount.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings. Note that the following description of preferred embodiments is essentially just an example, and is not intended to limit the present invention, its applications, or its uses.

FIG. 1 is a plan view of a concrete curing sheet 1 according to an embodiment of the present invention. The concrete curing sheet 1 is a belt-shaped sheet that is laid on the concrete surface and keeps the concrete in a moist state for curing. Specifically, the concrete curing sheet 1 can be laid at a concrete joint 100 such as a joint between a floor and a wall as shown in FIG. 6, for example. A plurality of reinforcing bars 101 connected from the floor are exposed in the concrete joint part 100 so as to protrude upward. Concrete that will become a wall is cast so that the reinforcing bars 101 are buried, and a concrete structure in which the floor and walls are integrated is obtained. In short, the floor part that constitutes a part of the concrete structure has the concrete joint part 100.

Furthermore, examples of concrete structures include bridge wall railings and the like. Depending on the length of the bridge, the length of concrete pouring may be long for the ground covering part of the wall parapet. In this case, the number of reinforcing bars 101 becomes enormous, and a large number of reinforcing bars 101 are exposed at intervals from each other in the longitudinal direction of the wall railing. The spacing between the reinforcing bars 101 is approximately constant, and may be set to, for example, several tens of cm. Note that the concrete curing sheet 1 may be laid on the concrete surface other than the concrete joint 100.

Since the concrete curing sheet 1 is strip-shaped, the longitudinal direction and the width direction can be defined. Further, the lower end in FIG. 1 is defined as one end in the width direction of the concrete curing sheet 1, and the upper end in FIG. 1 is defined as the other end in the width direction of the concrete curing sheet 1. The length of the concrete curing sheet 1 is not particularly limited, but should be longer than the spacing between the reinforcing bars 101 that are generally arranged at regular intervals, such as 1 m or more, 3 m or more, or 5 m or more. has been set for a long time. The width of the concrete curing sheet 1 is set to be larger than the dimension in the depth direction of the concrete joint 100, and specifically, is several tens of cm or more.

The concrete curing sheet 1 has a plurality of long cuts 1a in the width direction of the concrete curing sheet 1, and as shown in FIG. 7, one reinforcing bar 101 can be inserted into each cut 1a. It has become. Note that when a plurality of reinforcing bars 101 are provided side by side in the depth direction, the plurality of reinforcing bars 101 lined up in the depth direction can also be inserted into one cut 1a.

The lower end of the cut 1a in FIG. 1 is defined as one longitudinal end of the cut 1a, and the upper end of the cut 1a in FIG. 1 is defined as the other longitudinal end of the cut 1a. The cut 1a extends linearly along the width direction of the concrete curing sheet 1, and therefore the longitudinal direction of the cut 1a and the longitudinal direction of the concrete curing sheet 1 are perpendicular to each other. Note that the cut 1a may extend in a direction intersecting the width direction of the concrete curing sheet 1. Moreover, the cut 1a does not have to be linear, and may be, for example, bent or curved.

The cut 1a is after being cut with a knife, and can also be called a cut with a knife. When creating the cut 1a, it is sufficient to pass a cutter through the concrete curing sheet 1 from the front surface to the back surface in the thickness direction, and the cut 1a of a desired length can be easily provided at a targeted position. The plurality of cuts 1a are provided at intervals in the longitudinal direction of the concrete curing sheet 1. The interval between the cuts 1a can be set, for example, in a range of 20 mm or more and 100 mm or less, or can be set in a range of 30 mm or more and 60 mm or less. If the interval between the cuts 1a is narrowed, it can be easily adapted to various positions of reinforcing bars 101, but the parts of the concrete curing sheet 1 where the cuts 1a are formed tend to fall apart, making storage and transportation difficult. Therefore, the interval between the cuts 1a is set to 20 mm or more.

In addition, widening the interval between the cuts 1a makes it difficult for the part of the concrete curing sheet 1 where the cuts 1a are formed to fall apart, making storage and transportation easier. This may reduce the effect of providing the cuts 1a, so the distance is set to 100 mm or less to at least correspond to the spacing between the reinforcing bars 101 in general. In consideration of the above, in this embodiment, as will be described later, the intervals between the cuts 1a are set to two types, 30 mm and 50 mm.

The cut 1a is provided such that one end in the longitudinal direction of the cut 1a reaches one end in the width direction of the concrete curing sheet 1. Further, the other end in the longitudinal direction of the cut 1a does not reach the other end in the width direction of the concrete curing sheet 1, but is located at a part of the concrete curing sheet 1 away from the other end in the width direction toward one end side. The longitudinal dimension of the cut 1a is 1/2 or more of the widthwise dimension of the concrete curing sheet 1, and can be, for example, 2/3 or more, 4/5 or more. The longitudinal dimension of the cut 1a may be set according to the position in the depth direction of the reinforcing bar 101 shown in FIG. 6, and is not limited to the above-described dimension.

Since one end in the longitudinal direction of the cut 1a reaches one end in the width direction of the concrete curing sheet 1, an operator can easily turn over the portion of the concrete curing sheet 1 between the adjacent cuts 1a. On the other hand, since the cut 1a does not reach the other end in the width direction of the concrete curing sheet 1, the concrete curing sheet 1 is not completely separated due to the formation of the cut 1a, and can be handled as one sheet.

As shown in FIG. 2, the concrete curing sheet 1 has a multilayer structure. Specifically, the concrete curing sheet 1 includes a base material 11 and a water retaining material 12 provided on the side of the base material 11 that is laid on concrete. The base material 11 is a non-air permeable sheet, and is made of, for example, a reinforced vinyl chloride sheet containing fibers, a polyethylene film, etc., although it is not particularly limited. The base material 11 may have a multilayer structure, or may be made of a sheet that is a combination of a non-breathable sheet and a nonwoven fabric.

The water retaining material 12 is made of a water-absorbing polymer, fiber, or the like that can absorb and retain water. As the water-absorbing polymer, for example, a polyethylene oxide-based polymer absorbent such as crosslinked polyethylene oxide can be used. The amount of water retained by the water retaining material 12 is not particularly limited, but is an amount capable of continuously replenishing water that is removed from the surface as the material ages after being laid on concrete for a predetermined period of time. In addition, the concrete curing sheet 1 may have a heat dissipation layer or a heat insulation layer.

As shown in FIG. 3A, one concrete curing sheet 1 can be stored and transported in a rolled state. For example, by rolling the concrete curing sheet 1 in the longitudinal direction, it can be made into a single roll, which facilitates storage and transportation. Furthermore, more concrete curing sheets 1 can be transported with a smaller volume than in the case shown in FIG. 3B, which will be described later.

Further, as shown in FIG. 3B, a plurality of concrete curing sheets 1 cut into predetermined lengths can be stored and transported in a state where they are stacked in the thickness direction. In this case, the sides of each concrete curing sheet 1 on which the cuts 1a are formed are aligned. A plurality of concrete curing sheets 1 can be stacked and packed in a bag (not shown). By packing in this way, before laying the concrete curing sheets 1, you can fill the bag with water and let the water retaining material 12 of each concrete curing sheet 1 absorb the water all at once, making it easier to carry out work at the site. Improves sex.

FIG. 4 shows a concrete curing sheet 1 according to a first modification of the embodiment. In this modification 1, a plurality of cuts 1a are provided at intervals in the longitudinal direction of the concrete curing sheet 1, and are also provided at intervals in the width direction of the concrete curing sheet 1. The spaces between the cuts 1a arranged in the width direction of the concrete curing sheet 1 are uncut parts of the concrete curing sheet 1, that is, connected parts. That is, by leaving a part of the concrete curing sheet 1 uncut when making the long cuts 1a in the width direction, the concrete curing sheet 1 is less likely to turn over during transportation, for example, and handling becomes easier. Further, in the case of Modification 1, it is easy to roll the sheets as shown in FIG. 3A and to stack them as shown in FIG. 3B.

The dimension between the cuts 1a arranged in the width direction is not particularly limited, but is set shorter than the length of the cut 1a, and in Modification 1, it is 1/5 or less of the length of the cut 1a, and It can be reduced to 1/10 or less. At the time of laying, by cutting the connected part between the cuts 1a arranged in the width direction of the concrete curing sheet 1 on site, one cut 1a having sufficient length is obtained, so reinforcing bars 101 are inserted into the cut 1a. Just put it in. In the case of modification 1, since the long cuts 1a are provided in advance in the width direction of the concrete curing sheet 1, cutting the connected parts between the cuts 1a arranged in the width direction can be quickly performed on site. There is almost no impediment to the speed of the installation work.

Further, since there is a connected portion between the cuts 1a in the concrete curing sheet 1, the cuts 1a can remain connected at unnecessary laying locations. This makes it difficult for the concrete curing sheet 1 to turn over due to wind or the like, and the possibility of poor curing is lower than in the case where there are no connected parts (as shown in FIG. 1).

A plurality of cuts 1a lined up in the width direction of the concrete curing sheet 1 are provided so as to be located on the same imaginary straight line extending in the width direction of the concrete curing sheet 1. The lengths of the cuts 1a arranged in the width direction of the concrete curing sheet 1 may all be the same or may be different. The plurality of cuts 1a arranged in the width direction of the concrete curing sheet 1 are provided in a part of the concrete curing sheet 1 away from one end in the width direction to the other end side, and in a part away from the other end in the width direction to the one end side. . That is, since the cut 1a does not reach one end and the other end of the concrete curing sheet 1 in the width direction, the concrete curing sheet 1 is connected in the longitudinal direction at one end and the other end in the width direction. This makes it difficult for one end and the other end of the concrete curing sheet 1 in the width direction to be turned over by wind or the like at the installation location where the cut 1a is not required.

The number of cuts 1a arranged in the width direction of the concrete curing sheet 1 is not limited to two, and may be three or more as in Modification 2 shown in FIG. 5. In this modification 2, cuts 1a lined up in the width direction are provided like perforations. In the case of this modification 2 as well, if necessary, the cuts 1a arranged in the width direction and the connected portions between the cuts 1a may be cut on site. Furthermore, in the case of Modification 2, it is also easy to roll up as shown in FIG. 3A and to stack as shown in FIG. 3B.

(Concrete curing method)
Next, a concrete curing method using the concrete curing sheet 1 will be explained. Cuts 1a in the concrete curing sheet 1 are already provided at the time of shipment from the factory. After the concrete curing sheet 1 with the cuts 1a previously provided is transported to the site, a water absorption process is performed to cause the water retaining material 12 to absorb water. In the case shown in FIG. 3A, the water retaining material 12 may absorb water while the concrete curing sheet 1 is being rolled up, or may be made to absorb water after being spread. Further, in the case shown in FIG. 3B, the water retaining material 12 may absorb water while the concrete curing sheets 1 are stacked, or may be allowed to absorb water after being separated.

Thereafter, as shown in FIG. 7, the concrete curing sheet 1 is laid on the concrete joint 100. This is the laying process. At this time, in the case of the concrete curing sheet 1 shown in FIG. 1, since the cut 1a is provided, the concrete curing sheet 1 must be deformed so as to widen the cut 1a or to turn over the part between the cuts 1a and 1a. Thus, the reinforcing bar 101 can be easily inserted into the cut 1a. Depending on the spacing between the reinforcing bars 101, there may be cuts 1a where the reinforcing bars 101 cannot fit, but in FIG. It shows the state in which it is inserted. By laying it in this way, most of the parts of the concrete joint 100 that require curing can be covered with the concrete curing sheet 1. Note that the gap created by providing the cut 1a is so small that it can be ignored.

In addition, in the case of the concrete curing sheet 1 of Modification 1 shown in FIG. 4 and in the case of the concrete curing sheet 1 of Modification 2 shown in FIG. Cut with. This is the cutting process. By doing so, a long cut 1a similar to the concrete curing sheet 1 shown in FIG. 1 is formed, so that the reinforcing bars 101 can be easily inserted into the cut 1a. In the case of the concrete curing sheet 1 of Modification Example 2 shown in FIG. 5, it is not necessary to cut all the cuts 1a arranged in the width direction of the concrete curing sheet 1, and only a part thereof may be cut.

After laying the concrete curing sheet 1 as described above, wait for a predetermined curing period to elapse. Water is supplied only at the beginning, and there is no need to supply water in the middle. The reason for this is that most of the parts of the concrete joint 100 that require curing are covered with the concrete curing sheet 1, and the concrete curing sheet 1 suppresses the evaporation of moisture from the concrete joint 100. . In addition, water may be supplied in the middle as necessary.

(Test examples and test results)
In order to verify the effects of concrete curing sheet 1, the following tests were conducted. As Example 1, a concrete curing sheet 1 as shown in FIG. 1 was prepared, and a concrete joint 100 was covered with the longitudinally aligned cuts 1a having an interval of 30 mm. As Example 2, a concrete curing sheet 1 as shown in FIG. 1 was prepared, and the interval between the cuts 1a arranged in the longitudinal direction of the concrete curing sheet 1 was set to 50 mm to cover the concrete joint 100. As Comparative Example 1, an example (sheet curing) was prepared in which the concrete joint 100 was covered with a sheet that had no breaks and was non-ventilated. As Comparative Example 2, an example in which no curing sheet was used (an example in which no curing measures were taken) was prepared.

The curing period was one week. The test period was midsummer, and the test was conducted under harsh conditions for concrete curing. The curing age is 7 days. Further, the quality evaluation described below was performed after 7 days and 28 days had passed from the start of the test. Note that water is only supplied at the beginning, and no water is supplied in the middle.

FIG. 8 shows the measurement results of the air permeability coefficient in the surface layer of concrete. An example of a test for determining the air permeability coefficient is the Trent method. The upper graph in FIG. 8 is the measurement result when the material age is 7 days, and the lower graph is the measurement result when the material age is 28 days. In both measurement results, it can be seen that Examples 1 and 2 have significantly lower air permeability coefficients than Comparative Examples 1 and 2, that is, the quality of the concrete is higher.

FIG. 9 shows the measurement results of the surface water supply amount of concrete. This surface water supply amount can be measured using, for example, a commercially available water content meter, and the measuring method is conventionally well known. The upper graph in FIG. 9 is the measurement result when the material age is 7 days, and the lower graph is the measurement result when the material age is 28 days. In both measurement results, it can be seen that the amount of surface water supply in Examples 1 and 2 is significantly smaller than in Comparative Examples 1 and 2, that is, the quality of the concrete is higher.

(effect)
As explained above, since the concrete curing sheet 1 is provided with a plurality of widthwise long cuts 1a at intervals in the longitudinal direction, the concrete curing sheet 1 is placed on the exposed concrete surface so that the reinforcing bars 101 protrude upward. When laying the reinforcing bars 101, the reinforcing bars 101 can be laid quickly and over a wide range while avoiding interference with the reinforcing bars 101. Thereby, a high quality concrete structure can be obtained.

The embodiments described above are merely illustrative in all respects and should not be interpreted in a limiting manner. Furthermore, all modifications and changes that come within the scope of equivalents of the claims are intended to be within the scope of the present invention.

As explained above, the present invention can be used, for example, by being laid in a concrete joint where reinforcing bars protrude upward.

1 Concrete curing sheet 1a Cut 100 Concrete joint 101 Rebar

The present disclosure relates to a concrete curing method for curing concrete poured on site.

In general, in concrete construction, in order to ensure the required quality of concrete such as strength, durability, and watertightness, it is necessary to maintain the temperature and humidity necessary for hardening for a certain period of time after concrete is poured, which is called curing. be.

There are various curing methods, and methods of curing concrete using concrete curing sheets are known, as disclosed in Patent Documents 1 to 3. The concrete curing sheet of Patent Document 1 has a plurality of protrusions on the side of the base sheet that is laid on the concrete surface. Each protrusion is composed of a wetting material that swells by absorbing water. Moreover, the concrete curing sheet of Patent Document 2 is a sheet in which a moisturizing sheet containing a swelling material and a heat insulating sheet made of a heat insulating member are integrated in a laminated state. Further, the concrete curing sheet disclosed in Patent Document 3 has a water retaining layer containing a swelling material and a heat dissipation layer integrated in a laminated state.

Japanese Patent Application Publication No. 2002-81210 Japanese Patent Application Publication No. 2010-196396 Japanese Patent Application Publication No. 2014-152559

By the way, each of the above-mentioned curing methods has its own problems. For example, at a concrete joint such as a joint between a floor and a wall, the reinforcing bars that connect the floor to the wall are exposed so as to protrude upward from the floor. In order to avoid reinforcing bars, it is necessary to make a notch in the curing sheet in the area corresponding to the reinforcing bar, and then lay the curing sheet while inserting the reinforcing bar into the notch.

Furthermore, for example, in the case of a ground-covered part of a bridge wall railing, if the length of concrete placement is long, the number of reinforcing bars becomes enormous. In such cases, if cuts are made in the concrete curing sheet to match the number of reinforcing bars on site, curing cannot be carried out promptly after the concrete is poured and the surface is finished, making it difficult to ensure the quality of the concrete. becomes difficult to do.

The present disclosure has been made in view of this point, and its purpose is to provide a concrete structure that can be quickly laid during curing of a concrete structure in which reinforcing bars are exposed, thereby obtaining a high-quality concrete structure. An object of the present invention is to provide a curing sheet and a concrete curing method using the sheet.

In order to achieve the above object, one aspect of the present disclosure provides a concrete curing method using a band-shaped concrete curing sheet, the concrete curing sheet having a plurality of long cuts in the width direction of the concrete curing sheet. , the concrete curing sheets are provided at intervals in the longitudinal direction, and a laying process is performed in which the concrete curing sheets are laid at concrete joints, and in the laying process, the concrete curing sheets are placed in the breaks in the concrete curing sheets. In parallel with the work of inserting reinforcing bars that protrude upward from the joint, the edges of the cuts are brought into contact with the outer surface of the reinforcing bars to deform them, and then the concrete is inserted between the adjacent cuts in the concrete curing sheet. It is characterized by covering the joint .

Alternatively, the laying process can be performed after the water retention material of the concrete curing sheet absorbs water.

According to this configuration, when laying the concrete curing sheet on the exposed concrete surface so that the reinforcing bars protrude upward, the concrete curing sheet is provided with a long cut in the width direction in advance, so that the cut can be easily By placing reinforcing bars in the concrete, concrete curing sheets can be laid quickly while avoiding interference with the reinforcing bars. For example, when concrete is poured over a long period of time, such as in the ground-covered part of a bridge wall railing, a large number of reinforcing bars are exposed at intervals in the longitudinal direction of the wall railing. Since the reinforcing bars are pre-prepared at intervals in the longitudinal direction of the concrete curing sheet, even if there are a large number of reinforcing bars, there is no need to make numerous cuts on site, making the installation process quick and easy. I can do it. Note that additional cuts may be made on site.

Further, the plurality of cuts may be provided at intervals in the width direction of the concrete curing sheet. In this case, a plurality of cuts are lined up in the width direction of the concrete curing sheet, and the space between the cuts lined up in the width direction becomes a part where the concrete curing sheet is not cut, that is, a connected part. In other words, by leaving a part of the concrete curing sheet uncut when making long cuts in the width direction, the concrete curing sheet is less likely to turn over during transportation, for example, and handling becomes easier. At the time of laying, by cutting the connected parts of the concrete curing sheet on site, the cuts will be of sufficient length, and reinforcing bars can be inserted into the cuts. Incidentally, since long cuts in the width direction are provided in advance, the connected portions can be cut quickly on site, and the speed of the installation work is hardly hindered.

In addition, since there are connected parts between the cuts in the concrete curing sheet, if the cuts are left connected in places where they are not needed, the concrete curing sheet will be difficult to turn over due to wind, etc., and there is a possibility of curing failure. is lower than when there are no connected parts.

Moreover, the cut may be provided in a portion of the concrete curing sheet that is away from one end in the width direction toward the other end, and in a portion that is away from the other end in the width direction toward the one end. According to this configuration, since the cut does not reach one end and the other end of the concrete curing sheet, the concrete curing sheet becomes connected in the longitudinal direction at one end and the other end. This makes it difficult for one end and the other end of the concrete curing sheet to be turned over by wind or the like in places where cuts are not required. In addition, in places where a cut is required, a cut of sufficient length can be obtained by cutting one end or the other end of the concrete curing sheet on-site, and reinforcing bars can be inserted into the cut.

Alternatively, one end of the cut in the longitudinal direction may be provided so as to reach one end of the concrete curing sheet in the width direction. By providing a cut in advance that reaches one end of the concrete curing sheet, it becomes unnecessary to cut a part of the concrete curing sheet on site, and the laying work can be performed even more quickly.

Additionally, concrete curing sheets can be stored and transported in a rolled state. In addition, multiple concrete curing sheets cut to any length can be stored and transported in a stacked state in the thickness direction.

The concrete curing sheet may include a base material and a water retaining material provided on the side of the base material that is laid on the concrete. In this case, by impregnating the water retaining material with water, the concrete can be kept moist for a long period of time, and the quality of the concrete structure can be further improved.

As explained above, the concrete curing sheet has multiple long cuts in the width direction, spaced apart in the longitudinal direction of the concrete curing sheet, so that the concrete curing sheet can be quickly laid on the concrete where the reinforcing bars are exposed. This makes it possible to obtain high-quality concrete structures.

FIG. 1 is a plan view of a concrete curing sheet according to an embodiment of the present invention. 2 is a sectional view taken along line II-II in FIG. 1. FIG. It is a perspective view showing a concrete curing sheet in a rolled state. It is a perspective view showing concrete curing sheets in a stacked state. 2 is a diagram corresponding to FIG. 1 according to modification example 1. FIG. FIG. 2 is a diagram corresponding to FIG. 1 according to modification 2; It is a perspective view showing an example of a concrete joint part. This is a diagram equivalent to Figure 6 after the concrete curing sheet has been laid. It is a graph showing quality evaluation results based on air permeability coefficient. It is a graph showing quality evaluation results based on surface water supply amount.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings. Note that the following description of preferred embodiments is essentially just an example, and is not intended to limit the present invention, its applications, or its uses.

FIG. 1 is a plan view of a concrete curing sheet 1 according to an embodiment of the present invention. The concrete curing sheet 1 is a belt-shaped sheet that is laid on the concrete surface and keeps the concrete in a moist state for curing. Specifically, the concrete curing sheet 1 can be laid at a concrete joint 100 such as a joint between a floor and a wall as shown in FIG. 6, for example. A plurality of reinforcing bars 101 connected from the floor are exposed in the concrete joint part 100 so as to protrude upward. Concrete that will become a wall is cast so that the reinforcing bars 101 are buried, and a concrete structure in which the floor and walls are integrated is obtained. In short, the floor part that constitutes a part of the concrete structure has the concrete joint part 100.

Furthermore, examples of concrete structures include bridge wall railings and the like. Depending on the length of the bridge, the length of concrete pouring may be long for the ground covering part of the wall parapet. In this case, the number of reinforcing bars 101 becomes enormous, and a large number of reinforcing bars 101 are exposed at intervals from each other in the longitudinal direction of the wall railing. The spacing between the reinforcing bars 101 is approximately constant, and may be set to, for example, several tens of cm. Note that the concrete curing sheet 1 may be laid on the concrete surface other than the concrete joint 100.

Since the concrete curing sheet 1 is strip-shaped, the longitudinal direction and the width direction can be defined. Further, the lower end in FIG. 1 is defined as one end in the width direction of the concrete curing sheet 1, and the upper end in FIG. 1 is defined as the other end in the width direction of the concrete curing sheet 1. The length of the concrete curing sheet 1 is not particularly limited, but should be longer than the spacing between the reinforcing bars 101 that are generally arranged at regular intervals, such as 1 m or more, 3 m or more, or 5 m or more. has been set for a long time. The width of the concrete curing sheet 1 is set to be larger than the dimension in the depth direction of the concrete joint 100, and specifically, is several tens of cm or more.

The concrete curing sheet 1 has a plurality of long cuts 1a in the width direction of the concrete curing sheet 1, and as shown in FIG. 7, one reinforcing bar 101 can be inserted into each cut 1a. It has become. Note that when a plurality of reinforcing bars 101 are provided side by side in the depth direction, the plurality of reinforcing bars 101 lined up in the depth direction can also be inserted into one cut 1a.

The lower end of the cut 1a in FIG. 1 is defined as one longitudinal end of the cut 1a, and the upper end of the cut 1a in FIG. 1 is defined as the other longitudinal end of the cut 1a. The cut 1a extends linearly along the width direction of the concrete curing sheet 1, and therefore the longitudinal direction of the cut 1a and the longitudinal direction of the concrete curing sheet 1 are perpendicular to each other. Note that the cut 1a may extend in a direction intersecting the width direction of the concrete curing sheet 1. Moreover, the cut 1a does not have to be linear, and may be, for example, bent or curved.

The cut 1a is after being cut with a knife, and can also be called a cut with a knife. When creating the cut 1a, it is sufficient to pass a cutter through the concrete curing sheet 1 from the front surface to the back surface in the thickness direction, and the cut 1a of a desired length can be easily provided at a targeted position. The plurality of cuts 1a are provided at intervals in the longitudinal direction of the concrete curing sheet 1. The interval between the cuts 1a can be set, for example, in a range of 20 mm or more and 100 mm or less, or can be set in a range of 30 mm or more and 60 mm or less. If the interval between the cuts 1a is narrowed, it can be easily adapted to various positions of reinforcing bars 101, but the parts of the concrete curing sheet 1 where the cuts 1a are formed tend to fall apart, making storage and transportation difficult. Therefore, the interval between the cuts 1a is set to 20 mm or more.

In addition, widening the interval between the cuts 1a makes it difficult for the part of the concrete curing sheet 1 where the cuts 1a are formed to fall apart, making storage and transportation easier. This may reduce the effect of providing the cuts 1a, so the distance is set to 100 mm or less to at least correspond to the spacing between the reinforcing bars 101 in general. In consideration of the above, in this embodiment, as will be described later, the intervals between the cuts 1a are set to two types, 30 mm and 50 mm.

The cut 1a is provided such that one end in the longitudinal direction of the cut 1a reaches one end in the width direction of the concrete curing sheet 1. Further, the other end in the longitudinal direction of the cut 1a does not reach the other end in the width direction of the concrete curing sheet 1, but is located at a part of the concrete curing sheet 1 away from the other end in the width direction toward one end side. The longitudinal dimension of the cut 1a is 1/2 or more of the widthwise dimension of the concrete curing sheet 1, and can be, for example, 2/3 or more, 4/5 or more. The longitudinal dimension of the cut 1a may be set according to the position in the depth direction of the reinforcing bar 101 shown in FIG. 6, and is not limited to the above-described dimension.

Since one end in the longitudinal direction of the cut 1a reaches one end in the width direction of the concrete curing sheet 1, an operator can easily turn over the portion of the concrete curing sheet 1 between the adjacent cuts 1a. On the other hand, since the cut 1a does not reach the other end in the width direction of the concrete curing sheet 1, the concrete curing sheet 1 is not completely separated due to the formation of the cut 1a, and can be handled as one sheet.

As shown in FIG. 2, the concrete curing sheet 1 has a multilayer structure. Specifically, the concrete curing sheet 1 includes a base material 11 and a water retaining material 12 provided on the side of the base material 11 that is laid on concrete. The base material 11 is a non-air permeable sheet, and is made of, for example, a reinforced vinyl chloride sheet containing fibers, a polyethylene film, etc., although it is not particularly limited. The base material 11 may have a multilayer structure, or may be made of a sheet that is a combination of a non-breathable sheet and a nonwoven fabric.

The water retaining material 12 is made of a water-absorbing polymer, fiber, or the like that can absorb and retain water. As the water-absorbing polymer, for example, a polyethylene oxide-based polymer absorbent such as crosslinked polyethylene oxide can be used. The amount of water retained by the water retaining material 12 is not particularly limited, but is an amount capable of continuously replenishing water that is removed from the surface as the material ages after being laid on concrete for a predetermined period of time. In addition, the concrete curing sheet 1 may have a heat dissipation layer or a heat insulation layer.

As shown in FIG. 3A, one concrete curing sheet 1 can be stored and transported in a rolled state. For example, by rolling the concrete curing sheet 1 in the longitudinal direction, it can be made into a single roll, which facilitates storage and transportation. Furthermore, more concrete curing sheets 1 can be transported with a smaller volume than in the case shown in FIG. 3B, which will be described later.

Further, as shown in FIG. 3B, a plurality of concrete curing sheets 1 cut into predetermined lengths can be stored and transported in a state where they are stacked in the thickness direction. In this case, the sides of each concrete curing sheet 1 on which the cuts 1a are formed are aligned. A plurality of concrete curing sheets 1 can be stacked and packed in a bag (not shown). By packing in this way, before laying the concrete curing sheets 1, you can fill the bag with water and let the water retaining material 12 of each concrete curing sheet 1 absorb the water all at once, making it easier to carry out work at the site. Improves sex.

FIG. 4 shows a concrete curing sheet 1 according to a first modification of the embodiment. In this modification 1, a plurality of cuts 1a are provided at intervals in the longitudinal direction of the concrete curing sheet 1, and are also provided at intervals in the width direction of the concrete curing sheet 1. The spaces between the cuts 1a arranged in the width direction of the concrete curing sheet 1 are uncut parts of the concrete curing sheet 1, that is, connected parts. That is, by leaving a part of the concrete curing sheet 1 uncut when making the long cuts 1a in the width direction, the concrete curing sheet 1 is less likely to turn over during transportation, for example, and handling becomes easier. Further, in the case of Modification 1, it is easy to roll the sheets as shown in FIG. 3A and to stack them as shown in FIG. 3B.

The dimension between the cuts 1a arranged in the width direction is not particularly limited, but is set shorter than the length of the cut 1a, and in Modification 1, it is 1/5 or less of the length of the cut 1a, and It can be reduced to 1/10 or less. At the time of laying, by cutting the connected part between the cuts 1a arranged in the width direction of the concrete curing sheet 1 on site, one cut 1a having sufficient length is obtained, so reinforcing bars 101 are inserted into the cut 1a. Just put it in. In the case of modification 1, since the long cuts 1a are provided in advance in the width direction of the concrete curing sheet 1, cutting the connected parts between the cuts 1a arranged in the width direction can be quickly performed on site. There is almost no impediment to the speed of the installation work.

Further, since there is a connected portion between the cuts 1a in the concrete curing sheet 1, the cuts 1a can remain connected at unnecessary laying locations. This makes it difficult for the concrete curing sheet 1 to turn over due to wind or the like, and the possibility of poor curing is lower than in the case where there are no connected parts (as shown in FIG. 1).

A plurality of cuts 1a lined up in the width direction of the concrete curing sheet 1 are provided so as to be located on the same imaginary straight line extending in the width direction of the concrete curing sheet 1. The lengths of the cuts 1a arranged in the width direction of the concrete curing sheet 1 may all be the same or may be different. The plurality of cuts 1a arranged in the width direction of the concrete curing sheet 1 are provided in a part of the concrete curing sheet 1 away from one end in the width direction to the other end side, and in a part away from the other end in the width direction to the one end side. . That is, since the cut 1a does not reach one end and the other end of the concrete curing sheet 1 in the width direction, the concrete curing sheet 1 is connected in the longitudinal direction at one end and the other end in the width direction. This makes it difficult for one end and the other end of the concrete curing sheet 1 in the width direction to be turned over by wind or the like at the installation location where the cut 1a is not required.

The number of cuts 1a arranged in the width direction of the concrete curing sheet 1 is not limited to two, and may be three or more as in Modification 2 shown in FIG. 5. In this modification 2, cuts 1a lined up in the width direction are provided like perforations. In the case of this modification 2 as well, if necessary, the cuts 1a arranged in the width direction and the connected portions between the cuts 1a may be cut on site. Furthermore, in the case of Modification 2, it is also easy to roll up as shown in FIG. 3A and to stack as shown in FIG. 3B.

(Concrete curing method)
Next, a concrete curing method using the concrete curing sheet 1 will be explained. Cuts 1a in the concrete curing sheet 1 are already provided at the time of shipment from the factory. After the concrete curing sheet 1 with the cuts 1a provided in advance is transported to the site, a water absorption process is performed to cause the water retaining material 12 to absorb water. In the case shown in FIG. 3A, the water retaining material 12 may absorb water while the concrete curing sheet 1 is being rolled up, or may be made to absorb water after being spread. Further, in the case shown in FIG. 3B, the water retaining material 12 may absorb water while the concrete curing sheets 1 are stacked, or may be allowed to absorb water after being separated.

Thereafter, as shown in FIG. 7, the concrete curing sheet 1 is laid on the concrete joint 100. This is the laying process. At this time, in the case of the concrete curing sheet 1 shown in FIG. 1, since the cut 1a is provided, the concrete curing sheet 1 must be deformed so as to widen the cut 1a or to turn over the part between the cuts 1a and 1a. Thus, the reinforcing bar 101 can be easily inserted into the cut 1a. Depending on the spacing between the reinforcing bars 101, there may be cuts 1a where the reinforcing bars 101 cannot fit, but in FIG. It shows that it is in. By laying it in this way, most of the parts of the concrete joint 100 that require curing can be covered with the concrete curing sheet 1. Note that the gap created by providing the cut 1a is so small that it can be ignored.

In addition, in the case of the concrete curing sheet 1 of Modification 1 shown in FIG. 4 and in the case of the concrete curing sheet 1 of Modification 2 shown in FIG. Cut with. This is the cutting process. By doing so, a long cut 1a similar to the concrete curing sheet 1 shown in FIG. 1 is formed, so that the reinforcing bars 101 can be easily inserted into the cut 1a. In the case of the concrete curing sheet 1 of Modification Example 2 shown in FIG. 5, it is not necessary to cut all the cuts 1a arranged in the width direction of the concrete curing sheet 1, and only a part thereof may be cut.

After laying the concrete curing sheet 1 as described above, wait for a predetermined curing period to elapse. Water is supplied only at the beginning, and there is no need to supply water in the middle. The reason for this is that most of the parts of the concrete joint 100 that require curing are covered with the concrete curing sheet 1, and the concrete curing sheet 1 suppresses the evaporation of moisture from the concrete joint 100. . In addition, water may be supplied in the middle as necessary.

(Test examples and test results)
In order to verify the effects of concrete curing sheet 1, the following tests were conducted. As Example 1, a concrete curing sheet 1 as shown in FIG. 1 was prepared, and a concrete joint 100 was covered with the longitudinally aligned cuts 1a having an interval of 30 mm. As Example 2, a concrete curing sheet 1 as shown in FIG. 1 was prepared, and the concrete joint portion 100 was covered with the intervals between the cuts 1a arranged in the longitudinal direction of the concrete curing sheet 1 being 50 mm. As Comparative Example 1, an example (sheet curing) was prepared in which the concrete joint 100 was covered with a sheet that had no breaks and was non-ventilated. As Comparative Example 2, an example in which no curing sheet was used (an example in which no curing measures were taken) was prepared.

The curing period was one week. The test period was midsummer, and the test was conducted under harsh conditions for concrete curing. The curing age is 7 days. Further, the quality evaluation described below was performed after 7 days and 28 days had passed from the start of the test. Note that water is only supplied at the beginning, and no water is supplied in the middle.

FIG. 8 shows the measurement results of the air permeability coefficient in the surface layer of concrete. An example of a test for determining the air permeability coefficient is the Trent method. The upper graph in FIG. 8 is the measurement result when the material age is 7 days, and the lower graph is the measurement result when the material age is 28 days. In both measurement results, it can be seen that Examples 1 and 2 have significantly lower air permeability coefficients than Comparative Examples 1 and 2, that is, the quality of the concrete is higher.

FIG. 9 shows the measurement results of the surface water supply amount of concrete. This surface water supply amount can be measured using, for example, a commercially available water content meter, and the measuring method is conventionally well known. The upper graph in FIG. 9 is the measurement result when the material age is 7 days, and the lower graph is the measurement result when the material age is 28 days. In both measurement results, it can be seen that the amount of surface water supply in Examples 1 and 2 is significantly smaller than in Comparative Examples 1 and 2, that is, the quality of the concrete is higher.

(effect)
As explained above, since the concrete curing sheet 1 is provided with a plurality of widthwise long cuts 1a at intervals in the longitudinal direction, the concrete curing sheet 1 is placed on the exposed concrete surface so that the reinforcing bars 101 protrude upward. When laying the reinforcing bars 101, the reinforcing bars 101 can be laid quickly and over a wide range while avoiding interference with the reinforcing bars 101. Thereby, a high quality concrete structure can be obtained.

The embodiments described above are merely illustrative in all respects and should not be interpreted in a limiting manner. Furthermore, all modifications and changes that come within the scope of equivalents of the claims are intended to be within the scope of the present invention.

As explained above, the present invention can be used, for example, by being laid in a concrete joint where reinforcing bars protrude upward.

1 Concrete curing sheet 1a Cut 100 Concrete joint 101 Rebar

Claims (6)

A belt-shaped concrete curing sheet that is laid on the concrete surface to keep the concrete in a moist state and cure it,
The concrete curing sheet has a plurality of long cuts in the width direction,
A concrete curing sheet, wherein the plurality of cuts are provided at intervals in the longitudinal direction of the concrete curing sheet. In the concrete curing sheet according to claim 1,
The plurality of cuts are provided at intervals in the width direction of the concrete curing sheet. The concrete curing sheet according to claim 1 or 2,
The cut is provided in a part of the concrete curing sheet that is away from one end in the width direction to the other end, and in a part that is away from the other end in the width direction to the one end. The concrete curing sheet according to claim 1 or 2,
The cut is a concrete curing sheet, the cut being provided such that one end in the longitudinal direction of the cut reaches one end in the width direction of the concrete curing sheet. The concrete curing sheet according to any one of claims 1 to 4,
base material and
A concrete curing sheet comprising: a water retaining material provided on the side of the base material to be laid on concrete. A concrete curing method using the concrete curing sheet according to any one of claims 1 to 5.