JPS648123B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a road pavement construction method, and particularly to a method for forming contraction joints on a concrete pavement surface.

(Prior Art) Concrete pavement, which is one type of road pavement, is generally widely adopted because the traffic load is borne by the bending resistance of the concrete slab, and the load on the roadbed and roadbed is small.

In concrete pavement, the stress is reduced by allowing the concrete pavement slab to contract freely, and in order to prevent cracks from occurring in the concrete slab, the concrete pavement is It is common practice to provide contraction joints.

Conventionally, when creating contraction joints in concrete pavement, concrete is placed on the roadbed, and after the concrete hardens, a narrow groove is formed in the concrete slab in a straight line in the road width direction using a concrete cutter. A commonly used method is to inject a joint material into the grooves. However, the use of concrete cutters is not only dangerous, but also has the problem of scattering chips and poor workability.

Therefore, recently, as exemplified in Japanese Patent Publication No. 48-9337, a linear joint material is inserted from above into the poured concrete before it hardens, and after the concrete hardens, the joint material A construction method has been proposed to remove this.

(Problems to be Solved by the Invention) However, since the contraction joint formed by the conventional construction method is straight in the longitudinal direction, the entire tire width direction of a passing vehicle faces the contraction joint at the same time. For this reason, the contraction joints are subjected to shock, so
There is a problem in that the corners on both sides of the shrinkage joint are prone to chipping, and the cracks at the corners gradually grow larger, leading to destruction of the joint.

In addition, the contraction joint is linear, and if a crack occurs at the bottom of the contraction joint, this crack is naturally linear, so it tends to propagate in the longitudinal direction, and the crack spreads in the longitudinal direction of the contraction joint. There is a problem of slowing down.

In view of the above, the present invention makes it difficult for linear cracks to occur in shrinkage joints, and even if they occur, the wavy shape prevents the cracks from expanding, thereby improving the durability of shrinkage joints. The purpose is to achieve this goal.

(Means for Solving the Problems) In order to achieve the above object, the present invention bends a contraction joint in a waveform in its longitudinal direction.

Specifically, the solution taken by the present invention is to improve the road pavement construction method by placing chairs on both sides of the position where contraction joints are to be formed on the roadbed, which is formed by spreading earth, sand, fine stones, etc. on the roadbed. , after placing slip bars on both chairs, concrete is cast on the roadbed to a height that reaches the path surface to cover the slip bars, and before the concrete hardens,
A corrugated template, in which both side plate surfaces rising approximately vertically from the lower end are similarly bent in a waveform in the longitudinal direction of the contraction joint, is inserted into the concrete above the slip bar from above to create concrete with a corrugated joint gap. The configuration is such that a plate is formed.

(Function) With the above configuration, on the surface of the concrete slab,
Since contraction joints are formed that are bent in a wave shape, when one point in the width direction of the tire reaches the contraction joint, other points in the width direction have not yet reached the contraction joint, and when other points reach the contraction joint, Since the first point reached has already passed the contraction joint, the entire width of the tire does not face the contraction joint at the same time, so the contraction joint receives less impact.

In addition, since the contraction joints are bent in a wave shape, even if cracks occur at the bottom of the contraction joints, the
Since this crack is wave-shaped, it is difficult to propagate in the longitudinal direction of the contraction joint.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings.

First, the template 2 used for construction of the road pavement 1 will be explained. The template 2 is used to form joint gaps, and is made of styrofoam, rubber, wood, etc.
It is made of steel or the like, and the plate surfaces 2a, 2a rise substantially perpendicularly from the lower end and are bent in the same waveform in the longitudinal direction. In other words, this template 2 has a wavy shape in the longitudinal direction from its lower end to its upper end.

When constructing road pavement, chairs 4, 4 are placed on both sides of the position where contraction joints are to be formed on the roadbed 3, which is formed by spreading earth, sand, fine stones, etc. on the roadbed, and slip bars 5 are placed on top of the chairs 4, 4. Fix it. Subsequently, concrete is poured from the upper surface of the roadbed 3 to the road surface to cover the slip bar 5.

Before the concrete cast in this manner hardens, a corrugated template 2 is inserted from above into the concrete to a depth of about 50 mm at the position where the contraction joint is to be formed. At this time, if the upper end of the template 2 is made to protrude upward from the surface of the poured concrete, the template 2 can be easily removed after the concrete has solidified.

After the concrete has solidified, the template 2 is removed to form a concrete slab 6 having corrugated joint gaps formed by the template 2.

Thereafter, a joint material is injected into the gap between the joints to form a corrugated contraction joint 7.

By doing this, the concrete plate 6
The end faces of the joints facing each other via the corrugated contraction joints 7 are formed to be uneven, and the convex portions 6a, 6a are engaged with each other via the contraction joints 7.

In addition, when using an elastic material such as a rubber plate or a foamed polystyrene plate for the template 2, after inserting the template 2 into the concrete before hardening, leave it as it is and use the elastic template 2. May be used as a base plate.

Further, the contraction joint 7 does not necessarily need to be filled with a joint material, a joint plate, etc., and may be left empty as it is after removing the template 2.

Furthermore, the depth of the contraction joint can be determined as necessary for each construction.

(Effects of the Invention) As explained above, according to the road pavement construction method according to the present invention, a corrugated template is inserted into the concrete before solidification to form a joint clearance, so that the tire Because the width direction does not face the contraction joint at the same time, the contraction joint receives less impact, making it difficult for cracks to occur at the bottom of the contraction joint.Also, even if cracks do occur, the cracks are wave-shaped and will not be affected by contraction. It is difficult to propagate in the longitudinal direction of the joint. Therefore, according to the method of the present invention, the durability of the shrinkage joint is significantly improved compared to the conventional method.

Furthermore, although the durability of the contraction joint is improved as described above, there is no need for a concrete cutter as in the past, so work efficiency can be improved.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the invention.
The figure is a longitudinal cross-sectional perspective view of a road showing a state in which a template is inserted into poured concrete, and FIG. 2 is a longitudinal cross-sectional perspective view of a completed road pavement. 1... Road pavement, 2... Template, 3... Roadbed, 4
...Cheer, 5...Slip bar, 6...Concrete plate, 7...Joint.

Claims (1)

[Claims] 1. Placing chairs on both sides of the position where shrinkage joints are to be formed on the roadbed formed by spreading earth, sand, fine stones, etc. on the roadbed, and after bridging the both chairs with slip bars, concrete is placed on the roadbed. The concrete is poured to a height that reaches the surface to cover the slip bar, and before the concrete hardens, each of the plate surfaces on both sides rising approximately vertically from the bottom end is similarly bent into a wave shape in the longitudinal direction of the contraction joint. A road pavement construction method comprising the step of inserting a corrugated template into the concrete on the slip bar from above to form a concrete pavement slab having corrugated joint gaps.