Concrete pavement, and construction method thereof

Abstract

To provide a new concrete pavement that hardly generates chips at the corners of the joints, and a construction method thereof.SOLUTION: A concrete pavement 10 has a joint plate 1. In the concrete pavement 10, the ground-facing corners of the joint plate 1 are chamfered. The construction method of the concrete pavement 10 includes the following steps: installing joint plate 1 at the planned paving location; pouring concrete into the paving area to bury the joint plate 1; curing of the poured concrete; 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. The ground-facing corners of the joint plate 1 are chamfered.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a concrete pavement and a construction method thereof, and more particularly to a concrete pavement and a construction method thereof that are less likely to cause chipped corners at the joints of the concrete pavement. [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 concrete pavement that is less likely to develop chipped corners in joints, and a construction method thereof. [Means for solving the problem]

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

[0013] That is, the present invention has the following aspects: <<Aspect 1>> A concrete pavement having joint plates between concrete slabs, the corners of the joint plates facing the ground being chamfered. <<Aspect 2>> 2. The concrete pavement according to claim 1, wherein the thickness of the joint board is in the range of 15 mm to 35 mm. Aspect 3 Installing joint boards in areas where paving is planned, Pouring concrete into the planned paving area to fill in the joint boards; Curing the poured concrete; removing the upper portion of the joint plate of the cured concrete; and Putting a joint filler on top of the joint board Including, A method for constructing a concrete pavement, wherein the corners of the joint board facing the ground are chamfered. [Effects of the Invention]

[0014] According to the present invention, a new concrete pavement that is less likely to develop chipped corners and a construction method thereof can be provided. [Brief explanation of the drawings]

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

[0016] Concrete pavement The concrete pavement of the present invention has joint plates between the concrete slabs with chamfered corners facing the ground. This 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] Conventionally, joint fillers have been rectangular plates with a thickness equal to the width of the joint. However, the inventor discovered that cracks occurring around the joints in concrete pavement tend to originate from the corners of the joint filler. The inventor then constructed concrete pavement using joint fillers with chamfered corners and, to his surprise, discovered that cracks in the concrete pavement tended to occur in a straight line from the top of the joint filler toward the ground. The top of the joint filler is the part that will later be removed with a concrete cutter, and even if cracks occur in this part, there is no problem with the quality of the final concrete pavement. Therefore, the fact that cracks in the concrete pavement tend to occur at the top of the joint filler is a great advantage.

[0018] FIG. 1 shows a cross-section of one embodiment of a concrete pavement 10 of the present invention. 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, which 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 concrete pavement 10 of the present invention is not limited to the orientation specifically shown in FIG. 1 and FIGS. 3 to 5. That is, while the longitudinal direction of the joint board 1 is oriented perpendicular to the direction of travel of automobiles in FIG. 1 and FIGS. 3 to 5, the orientation of the joint board 1 used in the concrete pavement 10 of the present invention may be oriented parallel to the direction of travel of automobiles.

[0019] This concrete pavement 10 has a joint 13 between a first concrete slab 11 and a second concrete slab 12 .

[0020] 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.

[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] 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.

[0023] 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.

[0024] In this specification, "chamfered" refers to a state in which there are no corners in the joint 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.

[0025] For example, as shown in Fig. 2, the chamfered joint plate 1 may have various cross-sectional shapes. As shown in Fig. 2(a), the joint plate 1 may have a chamfered shape with a cross section shaped like Mount Fuji, as shown in Fig. 2(b), the joint plate 1 may have a chamfered shape with a triangular cross section, and as shown in Fig. 2(c), the joint plate 1 may have a chamfered shape with a semicircular or semi-elliptical cross section.

[0026] 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.

[0027] 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 1 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.

[0028] 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.

[0029] <Concrete pavement construction method> The concrete pavement construction method of the present invention includes installing a joint board at the planned paving location, pouring concrete into the planned paving location to fill the joint board, curing the poured concrete, removing the upper part of the joint board from the cured concrete, and placing a joint filler material on top of the joint board, and the corners of the joint board facing above ground are chamfered.

[0030] FIG. 3 illustrates the steps of a prior art concrete pavement construction method.

[0031] Figure 3(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 3(b). Then, as shown in Figure 3(c), the concrete above the joint board 1 is cut and removed using a concrete cutter or similar tool. Then, as shown in Figure 3(d), joint filler 2 is injected into the part of the joint board 1 from which the concrete was removed.

[0032] In the conventional technology, the cracks that appear diagonally in Figure 3(b) cause cracks in the corners of the joints of the final concrete slab. Such cracks in the corners of the joints can easily destroy the concrete slab.

[0033] FIG. 4 illustrates the steps of a concrete pavement construction method according to one embodiment of the present invention.

[0034] As shown in Figure 4(a), in the construction method of the present invention, as in the conventional technique of Figure 3(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 the present invention, the corner of the joint board 1 facing above ground is chamfered.

[0035] When this poured concrete is cured and hardened, cracks tend to extend straight from the joint board 1 toward the ground, as shown in Figure 4(b). The reason that cracks appear straight toward the ground when a joint board 1 with chamfered corners is used is that when the concrete slabs sandwiching the joint harden and shrink, they shrink in both the positive and negative X-direction (left and right in the drawing) as shown by the arrows in Figure 4(b), and stress is applied. When stress is applied, the joint board 1 is likely to crack equally in both the positive and negative directions from the vertex of the joint board 1. In contrast, in Figure 3(b), when the concrete slab shrinks in the positive and negative X-direction, especially if there is a difference in the stress applied due to shrinkage in the positive and negative directions, large stress is likely to be applied to the corners of the joint board 1, making it more likely to crack from those positions.

[0036] The thickness of the concrete slab (height from the foundation to the ground surface) is in the range of 150 mm to 500 mm, while the length from the top of the joint board 1 above ground to the top of the concrete slab (i.e., the ground surface) can be in the range of 30 mm to 50 mm or 35 mm to 45 mm.

[0037] In Figure 4(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 4(b) and that extend straight toward the ground are removed in this process. Then, as shown in Figure 4(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.

[0038] Figure 5 illustrates the steps of a concrete pavement construction method according to another embodiment of the present invention. This method is even more advantageous than the construction method shown in Figure 4, as cracks are more likely to extend straight from the joint board 1 toward the ground, making it even less likely that chipped corners will occur in the joint area.

[0039] As shown in Figure 5(a), in the construction method of the present invention, as in the method of Figure 4(a), concrete is poured so as to fill in the joint board 1, slip bar 3, chair 4, and reinforcing bar 5, whose corners facing the ground are chamfered. However, in the construction method of this embodiment, a crack guide portion 6 is formed on top of the joint board 1.

[0040] The crack guide portions 6 can be formed across the width of the road above the portions where the joint plates 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. 5(a), the crack guide portions 6 are preferably formed so that the crack guide material is completely embedded in the poured concrete, but 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.

[0041] As shown in Figure 5(b), when crack guide portion 6 is formed, the tendency for cracks to extend straight toward the ground from joint plate 1 to crack guide portion 6 becomes even stronger. 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 X directions (left and right directions in the drawing) as shown by the arrows in Figure 5(b), and stress is applied; when stress is applied, the distance from the apex of joint plate 1 to crack guide portion 6 becomes very short, making it even more likely for cracks to occur even more evenly in the positive and negative directions.

[0042] 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.

[0043] 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.

[0044] Figures 5(c) and 5(d) can be performed in substantially the same manner as Figures 4(c) and 4(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] The present invention provides a new concrete pavement that is less likely to develop chipped corners in joints, and a construction method thereof, 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. A concrete pavement having joint plates between concrete slabs, the corners of the joint plates facing the ground being chamfered.

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

3. Installing joint boards in areas where paving is planned, Pouring concrete into the planned paving area to fill in the joint boards; Curing the poured concrete; removing the upper portion of the joint plate of the cured concrete; and Putting a joint filler on top of the joint board Including, A method for constructing a concrete pavement, wherein the corners of the joint board facing the ground are chamfered.

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