Concrete pavement construction method

Abstract

To provide a construction method of a new concrete pavement that hardly generates chips at the corners of the joints.SOLUTION: A construction method of a concrete pavement 10 includes the following steps: installing a joint plate 1 at a planned paving location; pouring concrete into the paving area to bury the joint plate 1; forming a crack induction portion 6 in the poured concrete; curing the concrete in which the crack induction portion 6 is formed; removing the upper part of the joint plate 1 of the cured concrete; and putting joint filler 2 on top of the joint plate 1.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a concrete pavement construction method, and more particularly to a concrete pavement construction method that is less likely to cause chipped corners at joints between concrete pavements. [Background technology]

[0002] Compared to asphalt pavement, concrete pavement is more expensive and requires a longer curing period, which may result in long-term road closures, but it is less prone to rutting and has high durability and load-bearing capacity.

[0003] However, concrete pavements can develop cracks, and if left unchecked, the cracks will widen, connect, and cause concrete fragments to fly. As deterioration progresses, depressions known as potholes form. Potholes can also impede the safe operation of vehicles. Furthermore, if cracks or potholes reach the reinforcing bars, they can be corroded by the infiltrating rainwater.

[0004] Concrete pavement has joints at regular intervals to reduce stress and prevent cracks. These joints include contraction joints, which absorb shrinkage as the concrete hardens and prevent irregularly spaced cracks from occurring in the concrete slab, and expansion joints, which prevent stress from being generated by thermal expansion of the concrete. Expansion joints are usually about 25 mm wide.

[0005] A known method for forming joints in concrete pavements involves removing the concrete from the area where the joint board will be installed after the concrete has been poured and before it hardens, installing the joint board, and then replacing the concrete on both sides of the joint board and finishing the surface with a trowel.

[0006] With this method, if large aggregates such as 40mm diameter are placed around the joints, a clean finish cannot be achieved, so small aggregates must be placed around the joints. This can reduce the strength around the joints, causing chipped corners in the joints. Also, because this is a manual process, differences in the height of the concrete pavement at the joints can result in poor flatness.

[0007] Another known method of forming joints in concrete pavement is to first install a joint board such as a cedar board, pour concrete on top of it, and then, after the concrete has hardened, cut and remove the concrete above the joint board with a concrete cutter to create a gap, which is then filled with a waterproof joint filler.

[0008] With this method, even if large aggregates (e.g., 40 mm in diameter) are present, the concrete cutter cuts the entire aggregate, resulting in a clean finish and increased strength. However, this method makes it extremely difficult to time the cutting with the concrete cutter. The concrete must have hardened to a certain extent before the concrete cutter can be brought onto the poured concrete, but waiting too long for the concrete to harden can cause irregular cracks to form in the concrete. In particular, if irregular cracks have already appeared, trying to cut around them with the concrete cutter can chip the corners around the joints, which can lead to further destruction of the concrete pavement.

[0009] Patent Document 1 discloses a method for forming concrete pavement joints to prevent such corner chipping. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 2023-101428 Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention provides a new method for constructing concrete pavement that is less likely to cause chipped corners in joints. [Means for solving the problem]

[0012] The present inventors have discovered that a new concrete pavement construction method having the following features can solve the above problems.

[0013] That is, the present invention has the following aspects: <<Aspect 1>> Installing joint boards in areas where paving is planned, Pouring concrete into the planned paving area to fill in the joint boards; Forming a crack induction portion in the poured concrete; Curing the concrete in which the crack induction portion is formed; removing the upper portion of the joint plate of the cured concrete; and Putting a joint filler on top of the joint board A method for constructing a concrete pavement, including: <<Aspect 2>> 2. The concrete pavement construction method according to aspect 1, wherein the thickness of the joint board is in the range of 15 mm to 35 mm. Aspect 3 2. The method for constructing a concrete pavement according to claim 1, wherein the crack induction portion is formed by embedding a crack induction material. Aspect 4 4. The method for constructing a concrete pavement according to claim 3, wherein the crack inducer is a string-like material. [Effects of the Invention]

[0014] According to the present invention, a new concrete pavement construction method can be provided that is less likely to cause corner chipping. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 shows a cross section of one embodiment of a concrete pavement. [Figure 2] FIG. 2 illustrates the steps of a prior art concrete pavement construction method. [Figure 3] FIG. 3 illustrates the steps of a concrete pavement construction method according to one embodiment of the present invention. [Figure 4] FIG. 4 illustrates steps of a concrete pavement construction method according to another embodiment of the present invention. [Figure 5] FIG. 5 illustrates various embodiments of the joint plates used in the concrete pavement construction method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] Concrete pavement Concrete pavement has joint plates between the concrete slabs. Concrete pavement can have joint filler on top of the joint plates between the concrete slabs. In this specification, "pavement" refers to the structure of a paved road.

[0017] FIG. 1 shows a cross-section of an example of a typical concrete pavement 10. In this specification, the positive Z direction in this figure is referred to as the aboveground direction, and the negative Z direction is referred to as the underground direction. The X direction is the direction of travel of automobiles, and the Y direction is the width direction of the road, and in this specification, these are also referred to as the automobile travel direction and the road width direction, respectively. However, the orientation of the joint board 1 used in the construction method of the concrete pavement 10 of the present invention is not limited to the orientation specifically shown in FIGS. 1 to 4. That is, in FIGS. 1 to 4, the longitudinal direction of the joint board 1 is oriented perpendicular to the direction of travel of the automobile, but the orientation of the joint board 1 used in the present invention may be oriented parallel to the direction of travel of the automobile.

[0018] This concrete pavement 10 has a joint 13 between a first concrete slab 11 and a second concrete slab 12 .

[0019] The joint 13 is composed of a joint board 1 and a joint filler 2. The joint 13 can be an expansion joint, and can absorb the thermal expansion of the first concrete slab 11 and the second concrete slab 12 when they mutually expand in the summer, etc.

[0020] In the plane defined by the X and Y directions in Fig. 1, the two sides of the joint board 1 extending in the Y direction are chamfered. That is, the corners of the joint board 1 facing above ground on the surface sandwiched between the first concrete slab 11 and the second concrete slab 12 are chamfered. This makes it possible to prevent the occurrence of irregular cracks originating from the corners of the joint board as the first concrete slab 11 and the second concrete slab 12 harden and shrink.

[0021] There are no particular limitations on the material of the joint board 1. The joint board 1 may be a hard board, for example, a wooden board such as a cedar board, or an asphalt-based material board such as Elastite (trademark) or Kentite (trademark), a resin-based material board, a foamed resin-based board, or the like.

[0022] A material well known in the art, such as a waterproof flexible material, can be used for the joint filler 2. The joint filler may be a heat-type sealant such as a rubber asphalt-based sealant, or a two-component cold-type sealant such as a urethane-based, polysulfide-based, or silicone-based sealant.

[0023] The concrete pavement 10 may have slip bars (or dowel bars) 3 in the first concrete slab 11 and the second concrete slab 12, respectively, which transmit loads across the joints, and chairs 4 for fixing the joint plates and arranging the slip bars 3 regularly. Although not shown, if the joints are formed in the direction of vehicle travel, tie bars may be provided to prevent the joints from opening and the concrete slabs from shifting. The concrete pavement 10 may also have reinforcing bars 5 in the first concrete slab 11 and the second concrete slab 12.

[0024] The concrete pavement 10 may have a foundation 20 beneath the first concrete slab 11 and the second concrete slab 12. The foundation 20 may be one known in the art, but may have, for example, a subgrade and a roadbed from underground to above ground, with an asphalt interlayer between the roadbed and the concrete slab. The roadbed may be composed of a subgrade and an upper subgrade.

[0025] <Concrete pavement construction method> The concrete pavement construction method of the present invention includes installing a joint board in the area to be paved, pouring concrete into the area to be paved to fill the joint board, forming a crack guide portion in the poured concrete, curing the concrete with the crack guide portion formed therein, removing the upper part of the joint board from the cured concrete, and inserting a joint filler material into the upper part of the joint board.

[0026] FIG. 2 illustrates the steps of a prior art concrete pavement construction method.

[0027] Figure 2(a) shows the process of pouring concrete so as to fill in the joint board 1, slip bar 3, chair 4, and reinforcing bar 5. When the poured concrete is cured and hardened, cracks tend to form diagonally from the corners of the upper part of the joint board 1, moving away from the joint, as shown in Figure 2(b). Then, as shown in Figure 2(c), the concrete above the joint board 1 is cut and removed using a concrete cutter or similar tool. Then, as shown in Figure 2(d), joint filler 2 is injected into the part of the joint board 1 from which the concrete was removed.

[0028] In the conventional technology, the cracks that appear diagonally in Figure 2(b) cause cracks in the corners of the joints of the final concrete slab. These cracks in the corners of the joints can easily destroy the concrete slab.

[0029] FIG. 3 illustrates the steps of a concrete pavement construction method according to one embodiment of the present invention.

[0030] As shown in Figure 3(a), in the construction method of the present invention, as in the prior art of Figure 2(a), concrete is poured to bury the joint board 1, slip bar 3, chair 4, and reinforcing bar 5. However, in the construction method of this embodiment, a crack guide portion 6 is formed on top of the joint board 1.

[0031] The crack guide portions 6 can be formed across the width of the road above the portions where the joint boards 1 are present. The crack guide portions 6 can be formed, for example, by embedding string-shaped material into the poured concrete by pressing it in with a trowel after the concrete has been poured and before the concrete has hardened. As shown in FIG. 3(a), the crack guide portions 6 are preferably formed so that the crack guide material is completely embedded in the poured concrete. However, the crack guide portions 6 may also be formed so that the crack guide material is only slightly embedded in the poured concrete, or may be formed by simply digging a groove.

[0032] As shown in Figure 3(b), when crack guide portions 6 are formed, cracks tend to extend straight from joint plate 1 to crack guide portions 6 toward the ground. The reason why cracks form straight toward the ground when crack guide portions 6 are formed is that when the concrete slabs sandwiching the joint harden and shrink, shrinkage stress is applied in both the positive and negative X-direction (left and right in the drawing) as shown by the arrows in Figure 3(b). When shrinkage stress is applied, the distance from the apex of joint plate 1 to crack guide portions 6 becomes shorter, which is thought to make the concrete more likely to crack in both the positive and negative directions. In contrast, in Figure 2(b), when the concrete slab shrinks in the positive and negative X-direction, the distance from the top of joint plate 1 toward the ground to the top of the concrete slab (i.e., the ground surface) is long. This is thought to make the corners of joint plate 1, where large stress is likely to be applied, more likely to crack, especially when there is a difference in the stress applied due to shrinkage in the positive and negative directions.

[0033] The crack guide 6 is not particularly limited as long as it performs the above-mentioned function, and can be formed using various crack guide materials such as rope or other string-like materials, rod-shaped materials, plate-shaped materials, etc. However, in some cases, the central part of the road in the width direction is slightly higher to give the road a semi-cylindrical cross section in the width direction, and in such cases, it is preferable to use a flexible string-shaped crack guide material. The string-shaped material is not particularly limited as long as it can function as the crack guide 6, and can be a traffic rope or the like that is often used at construction sites.

[0034] When the crack guide portion 6 is a string-like or rod-like crack guide material, the diameter thereof can be, for example, 5 mm to 20 mm, or 10 mm to 15 mm, so that the distance from the top of the joint board 1 above ground to the bottom of the crack guide portion 6 can be in the range of 20 mm to 40 mm, or 25 mm to 30 mm.

[0035] The thickness of the concrete slab (height from the foundation to the ground surface) is in the range of 150 mm to 500 mm. In the prior art, the length from the top of the joint board 1 above ground to the top of the concrete slab (i.e., the ground surface) is usually in the range of 30 mm to 50 mm or 35 mm to 45 mm.

[0036] In Figure 3(c), the concrete on top of the joint board 1 is cut and removed using a concrete cutter or similar tool. The cracks that occurred in the process of Figure 3(b) and that extend straight toward the ground are removed in this process. Then, as shown in Figure 3(d), joint filler 2 is injected into the area of ​​the joint board 1 from which the concrete was removed. This makes it possible to form a concrete pavement with no or few cracks at the corners of the joints in the concrete slab.

[0037] Figure 4 illustrates the steps of a concrete pavement construction method according to another embodiment of the present invention. This method is more advantageous than the construction method shown in Figure 3, as cracks are more likely to extend straight from the joint board 1 toward the ground, making it less likely that chipped corners will occur in the joint area.

[0038] As shown in Figure 4(a), in this construction method, as in the method of Figure 3(a), concrete is poured to fill in the joint board 1, slip bar 3, chair 4, and reinforcing bar 5, whose corners facing above ground are chamfered, and a crack guide portion 6 is formed on top of the joint board 1. However, in this construction method, the corners of the joint board 1 facing above ground are chamfered.

[0039] Conventionally used joint filler boards 1 have been rectangular parallelepiped plates with a thickness equal to the width of the joint, but the inventor discovered that cracks that occur around the joints of concrete pavement 10 originate from the corners of joint filler board 1. Therefore, the inventor constructed concrete pavement 10 using joint filler board 1 with chamfered corners, as in this embodiment, and surprisingly found that cracks in concrete pavement 10 tended to occur in a straight line from the top of joint filler board 1 toward the ground. The top of joint filler board 1 is the part that will be removed later with a concrete cutter, and even if cracks occur in this part, there is no problem with the quality of the final concrete pavement 10. Therefore, the fact that cracks in concrete pavement tend to occur in the top of joint board 1 is extremely advantageous.

[0040] In other words, when this poured concrete is cured and hardened, the tendency for cracks to extend straight from the joint board 1 toward the ground becomes even stronger, as shown in Figure 4(b). The reason why such cracks become even more likely to occur is that when the concrete slabs sandwiching the joint harden and shrink, they shrink in both the positive and negative directions of the X axis (left and right directions in the drawing), as shown by the arrows in Figure 4(b), and when stress is applied, cracks tend to occur evenly in both the positive and negative directions from the apex of the joint board 1. This tendency is thought to be further strengthened by the shorter distance from the apex of the joint board 1 to the crack induction part 6.

[0041] The thickness of the joint board 1, the thickness of the portion sandwiched between the first concrete slab 11 and the second concrete slab 12, for example, the dimension in the X direction in Figure 1, may be 5 mm or more, 10 mm or more, 15 mm or more, 20 mm or more, 25 mm or more, or 30 mm or more, or may be 50 mm or less, 45 mm or less, 40 mm or less, 35 mm or less, 30 mm or less, 25 mm or less, 20 mm or less, or 15 mm or less. For example, the thickness of the joint board 1 may be 15 mm or more and 35 mm or less.

[0042] In this specification, "chamfered" refers to a state in which there are no corners in the joint base board 1. Therefore, the shape of the chamfer is not particularly limited as long as there are no corners. The degree of chamfering may be slight as long as it is within a range in which the advantageous effects of the present invention can be obtained.

[0043] For example, as shown in Fig. 5, the chamfered joint plate 1 may have various cross-sectional shapes. As shown in Fig. 5(a), the joint plate 1 may have a chamfered shape with a cross section shaped like Mount Fuji, as shown in Fig. 5(b), the joint plate 1 may have a chamfered shape with a triangular cross section, and as shown in Fig. 5(c), the joint plate 1 may have a chamfered shape with a semicircular or semi-elliptical cross section.

[0044] Figures 4(c) and 4(d) can be performed in substantially the same manner as Figures 3(c) and 3(d) above, which makes it possible to form a concrete pavement with no or few cracks at the corners of the joints of the concrete slab. [Industrial Applicability]

[0045] According to the present invention, a new concrete pavement construction method can be provided that is less likely to cause corner chipping in joints, and therefore has high industrial applicability. [Explanation of symbols]

[0046] 1…Joint board 2...Joint filler 3...Slip bar 4. Chair 5...Reinforcing bars 6...Crack induction section 10...Concrete pavement 11...First concrete slab 12...Second concrete slab 20…Basics

Claims

1. Installing joint boards in areas where paving is planned, Pouring concrete into the planned paving area to fill in the joint boards; Forming a crack induction portion on the upper part of the joint plate of the poured concrete; Curing the concrete in which the crack guide portion is formed to cause cracks to occur from the joint plate toward the crack guide portion; Removing the upper portion of the joint plate of the cured concrete together with the crack and the crack guide portion; and Putting a joint filler on top of the joint board A method for constructing a concrete pavement, including:

2. 2. The method for constructing a concrete pavement according to claim 1, wherein the thickness of the joint board is in the range of 15 mm to 35 mm.

3. 2. The method for constructing a concrete pavement according to claim 1, wherein the crack inducer is formed by embedding a crack inducer.

4. 4. The method for constructing a concrete pavement according to claim 3, wherein the crack inducer is a string-like material.

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