JP6594249B2 - Concrete crushing method and road repairing method - Google Patents

Description

  The present invention relates to a concrete crushing method and a road repairing method for crushing a hardened body of ultra-high speed hard concrete.

In repairing a concrete structure, after removing a deteriorated portion of concrete, a method of placing new concrete (repair material) at the removed portion is performed.
In addition, for example, repair (replacement) of a member fixed to concrete, such as a road bridge joint, is performed by crushing a hardened concrete body for fixing the joint, and then placing a new fixing concrete. .

If it is necessary to repair a road structure that is in service, traffic restrictions (blocks and lanes are closed during periods of relatively low traffic such as nights and holidays to avoid the occurrence of traffic congestion. In general, repair work is performed within a predetermined time.
In addition, there are many constructions that are subject to time restrictions even outside the road. For example, railway repair work is generally performed in the late-night hours from the last train to the first train. Also, in construction adjacent to a house, many residents avoid the time when they go home in the daytime. It is common to do work.

When crushing a part of concrete, a breaker, a concrete cutter, a water jet or the like (hereinafter referred to as “breaker or the like”) is generally used.
However, it is desirable that the concrete crushing operation using a breaker or the like be performed in a short period of time because of the noise caused by the impact sound (cutting sound) on the concrete and the mechanical noise of the compressor and generator.

  For this reason, Patent Document 1 discloses a repair method in which a concrete hardened body to be removed is weakened and then crushed and removed. The repair method described in Patent Document 1 heats a concrete removal target portion to 300 ° C. by raising the temperature at a rate of 7.5 ° C. per minute. When the concrete is heated to 300 ° C. or higher, the moisture inside the concrete expands as water vapor, so that cracks occur in the concrete at the portion to be removed due to the pressure of the water vapor. Therefore, according to the repair method of patent document 1, the removal object area | region is weakened by the crack, and shortening of the time which the operation | work which crushes can be aimed at.

It should be noted that ordinary concrete takes time to develop a predetermined strength. Therefore, when repairing a concrete structure or installing a new concrete structure with a time limit, use super fast hard concrete (so-called jet concrete) that develops a compressive strength of 24 N / mm ² or more in about 3 hours after placing. Sometimes.

Super fast hard concrete has high compressive strength (for example, strength at 28 days of age is 60 N / mm ² ) because strength continues to increase until the hydration reaction converges even after the necessary strength is developed.
In addition, a large amount of ettringite is precipitated in the ultra-fast hard concrete due to a hydration reaction, and the hardened concrete is densified by expansion due to the precipitation of ettringite.

Japanese Patent No. 3435493

When the repair method disclosed in Patent Document 1 is applied to a dense concrete hardened body such as ultra-high speed hard concrete, there is no escape space for water vapor inside the concrete caused by heating. May be scattered.
Moreover, since the repair method of patent document 1 weakens concrete by heating, it is necessary to restart use of the concrete member of repair object, after waiting for the intensity | strength of the repair material replaced with concrete to express. However, if the repair method of Patent Document 1 is employed in repair work with time constraints, there is a risk that the strength of the repair material will not be fully developed in time.

  From such a point of view, the present invention is a concrete that can safely and easily crush (cut) a hardened concrete body made of ultra-high speed hard concrete and can also be used at construction sites where there are time constraints. It aims at proposing the crushing method and the repair method of a road structure.

In order to solve the above-mentioned problems, the concrete crushing method of the present invention includes a heating step for heating the removal target range of the hardened body of ultra-high-speed hard concrete, and a crushing step for crushing the hardened body within the removal target range. In the heating step, heating is performed for 50 minutes or more, preferably 80 minutes or more, more preferably 190 minutes or more by a heating means of 200 ° C. or more and less than 250 ° C.
In the heating step, the temperature of the cured body in the removal target range is within a range of 100 ° C. or more and less than 250 ° C., preferably about 150 ° C., and is 50 minutes or more, preferably 80 minutes or more. It is preferable to heat for 190 minutes or more.

According to such a concrete crushing method, the ettringite water is dehydrated by heating by dehydrating the water molecules of the ettringite in the hardened super fast hardened concrete (hardened super fast concrete), and as a result, the super fast hardened concrete within the range to be removed. The strength of the cured body can be reduced. By reducing the strength of the hardened ultra-hard concrete, the time required for crushing (cutting) the hardened ultra-hard hard concrete can be shortened.
In addition, since super strength hardened concrete is increased in strength by ettringite (3CaO ・ Al ₂ O ₃・ 3CaSO ₄・ 32H ₂ O) precipitated by the hydration reaction, if the ettringite disappears, the super speed hardened concrete hardens. The strength of the body can be reduced.
Further, in the concrete crushing method of the present invention, since the temperature of the heating means is less than 250 ° C., the super-hard hard concrete cured body is not heated to 300 ° C. For this reason, the moisture inside the hardened ultra-high-hardness concrete does not become high-pressure water vapor that causes explosion.

  The first road repairing method of the present invention includes a heating step of heating a removal target range of a super fast hard concrete hardened body by a heating means of 200 ° C. or higher and lower than 250 ° C. for 50 minutes or more, and the hardened body within the removal target range. A crushing step for crushing and removing the material, and a filling step for filling the removed portion of the cured body with a repair material.

  Further, the second road repairing method of the present invention comprises a heating step of heating the removal target range of the super fast hardened concrete hardened body by a heating means of 200 ° C. or more and less than 250 ° C. for 50 minutes or more, and heating for removing the heating means. A stopping step, a crushing step for crushing and removing the cured body within the range to be removed after a predetermined time has elapsed from the heating stopping step, and a filling step for filling the removed portion of the cured body with a repair material. It is said.

  According to this road repairing method, the strength of the ultra-high speed hardened concrete body can be reduced by removing the ettringite in the ultra-high speed hardened concrete body by heating. The hardened super-hard concrete has only the internal ettringite disappeared by the heating process, and the shape is maintained without causing cracks and the like, so that the road can be temporarily opened. Therefore, in the repair work of the road with time restrictions, the heating process and the crushing process can be performed separately on different days.

  According to the concrete crushing method and the road repairing method of the present invention, a hardened concrete body made of ultrafast hard concrete can be crushed safely and easily, and even if there are time constraints, repair work is carried out. be able to.

It is a figure which shows the outline | summary of the road repair method of embodiment of this invention, Comprising: (a) is a cross-sectional view, (b) is a top view. It is a flowchart of the road repair method which concerns on embodiment of this invention. (A) is a perspective view which shows a heating process typically, (b) is a perspective view which shows a crushing process typically. (A) is a perspective view which shows typically the crushing process following FIG.3 (b), (b) is a perspective view which shows typically a filling process. It is a graph which shows the relationship between the compression strength for every heating temperature and the heating time in the demonstration experiment of embodiment of this invention, Comprising: (a) is 105 degreeC, (b) is 200 degreeC, (c) is 300 degreeC temperature. It is a graph of.

In the present embodiment, as an example, a case will be described in which an old or damaged road joint (extension device) 1 is repaired (replaced). First, the structure of the joint 1 will be described, and then the procedure for repairing the joint 1 will be described.
As shown to Fig.1 (a), the joint 1 is arrange | positioned ranging over the edge parts of the adjacent floor slabs 2,2. The joint 1 is disposed so as to cover the upper surface of the gap 3 between the adjacent floor slabs 2 and 2.

  A step portion 22 having an upper surface lower than the general portion 21 is formed at the end of the floor slab 2. When the end portions of the adjacent floor slabs 2 and 2 are brought into contact with each other, a concave groove 23 having a concave shape is formed by both stepped portions 22 and 22. The joint 1 is disposed in the concave groove 23 and is fixed by a hardened body 4 of ultrafast hard concrete filled in the concave groove 23. In addition, the connection part which is not shown in figure protrudes in the level | step-difference part 22, and the hardening body 4 and the floor slab 2 are integrated via the connection line.

The joint 1 of the present embodiment includes a pair of joint main bodies 11, 11, a sealing material 12, and anchors 13, 13,.
The joint body 11 is made of a steel member, and as shown in FIG. 1 (b), irregularities are formed at the end on the other joint body 11 side. The concave and convex portions of the joint main body 11 are configured such that the concave portions 11a and the convex portions 11b have the same shape, and the concave portions 11a and the convex portions 11b are engaged with each other in a state where the joint main bodies 11 are abutted with each other. In the present embodiment, the unevenness having a trapezoidal shape in plan view is formed, but the shape of the unevenness formed at the end of the joint body 11 is not limited, and may be, for example, a triangular shape.

As shown in FIG. 1A, the sealing material 12 is adhered to the lower surface of the butt portion between the joint bodies 11, 11, and the gap between the joint bodies 11, 11 and the gap between the floor slabs 2, 2. 3 is covered.
Although the sealing material 12 of this embodiment is exhibiting a cross-sectional portal shape, the shape of the sealing material 12 is not limited and may be, for example, a flat plate shape.
Moreover, the material which comprises the sealing material 12 is although it is not limited, It is desirable that it is resin provided with the elasticity.

The anchor 13 protrudes from the back surface of the joint body 11 (the surface on the opposite side of the other joint body 11).
The joint 1 is fixed by the anchor 13 being embedded in the cured body 4.
Although the anchor 1 of this embodiment is formed by deformed reinforcing bars, the material constituting the anchor 13 is not limited to deformed reinforcing bars, and may be, for example, a plate-shaped member. Moreover, the joint 1 does not necessarily need to be provided with the anchor 1, and for example, may be provided with an attachment member attached to a connecting bar (not shown) instead of the anchor 13.

A pavement 5 having a predetermined thickness is laminated on the upper surface of the general portion 21 of the floor slab 2. The upper surfaces of the joint 1 and the cured body 4 are flush with the upper surface of the pavement 5.
In addition, the material which comprises the pavement 5 is not limited, For example, asphalt pavement, concrete pavement, etc. may be sufficient.
Moreover, the layer thickness of the pavement 5 is not limited and may be set as appropriate.

The joint 1 is repaired by removing the hardened body 4 and exchanging the joint 1 and then placing a repair material (super-hard hard concrete) around the joint.
In the present embodiment, repair work is performed in a state where traffic is restricted in a time zone where the traffic volume is low (for example, at night), and in the time zone where the traffic volume is high, the repair work is interrupted and the traffic regulation is released. Work so that you can.
Since the joint 1 is fixed to the two floor slabs 2 and 2 by the hardened body 4 of super fast hard concrete, the hardened body 4 is removed when the joint 1 is repaired.

As shown in FIG. 2, the road repair method of the present embodiment includes a first preparation step S1, a heating step S, a heating stop step S3, a second preparation step S4, a crushing step S5, and a filling step S6. Yes.
In the first preparation step S1, road traffic is regulated to secure a work area for repair work. In this embodiment, as shown in FIG.1 (b), traffic regulation is performed with respect to one lane (lane containing removal target range A1) of two lane roads, and the other lane (removal target range A1 is set to the same). (Excluding lanes) Keep the road open.

The heating step S <b> 2 is a step of heating the removal target range of the cured body 4 around the joint 1 by the heating means 6.
In the present embodiment, the heating means 6 heated to a temperature of 200 ° C. or higher and lower than 250 ° C. is heated by being placed on the upper surface of the repair (removal) target range A1, as shown in FIG.

As shown in FIGS. 1A and 1B, in the present embodiment, a steel plate 61 having a heating wire 62 wired therein is used as the heating means 6.
The heating means 6 (heating wire 62) is connected to the generator 63 via the power transmission line 64 and is heated by the power transmitted from the generator 63. In the present embodiment, the generator 63 is installed on the road under traffic regulation, but the installation location of the generator 63 is not limited, and may be mounted on a vehicle such as a truck, for example. It may be installed on the side of the road.

The steel plate 61 has an area smaller than the surface area of the removal target range A1 (the area of the upper surface of the hardened body 4), and here, there is a gap between the outer periphery of the removal target range A1 and the outer periphery of the steel plate 62. is doing. The steel plate 61 may have an area equal to or greater than the surface area of the removal target range A1, and may cover the entire surface of the removal target range A1.
In addition, the structure of the heating means 6 is not limited. For example, in the present embodiment, the heating means 6 placed on the removal target range A1 is adopted, but a rod-like heating means inserted into a hole formed by drilling the hardened body 4 may be used. .

In this embodiment, it heats so that the temperature of the hardening body 4 in removal object range A1 may become in the range of 100 to 250 degreeC as a whole.
In addition, although it will not be limited if heating time is 50 minutes or more, in this embodiment, it enables it to heat for 50 minutes or more in the state which maintained the temperature of the bottom part of the hardening body 4 at 100 degreeC or more. That is, the heating time by the heating means 6 is the time until the heating means 6 reaches 200 ° C. or more, the time until the bottom of the cured body 4 is heated to 100 ° C. or more, and the temperature at the bottom is 100 ° C. or more. It is set as the time which added the time to heat in the state which maintained this.
In addition, you may install a thermometer as needed, and may measure the temperature inside the hardening body 4 (bottom part).
By performing heating process S2, the water molecule | numerator of the ettringite in the hardening body 4 is dehydrated by heating, and the ettringite has disappeared.

The heating stop step S3 is a step of removing the heating means 6 from the removal target range A1.
In this embodiment, if the hardening body 4 of removal object range A1 is heated for a predetermined period, the heating means 6 will be removed and traffic regulation will be cancelled | released.
It should be noted that the release of traffic regulation may be carried out as necessary.

The second preparation step S4 is a step of regulating road traffic and securing a work area for repair work. The traffic regulation is performed on the same lane as the lane regulated in the first preparation step S1.
In addition, 2nd preparatory process S4 is implemented when traffic regulation is cancelled | released in heating stop process S3. Therefore, the second preparation step S4 is omitted when the traffic restriction is not canceled in the heating stop step S3.

As shown in FIG. 3B, the crushing step S5 is a step of crushing and removing the cured body 4 in the removal target range A1.
In the present embodiment, the crushing step S4 is performed after a predetermined time has elapsed from the heating stop step S3 (after the road is once opened), but the timing of performing the crushing step S4 is not limited.
The hardened body 4 is crushed manually using a concrete breaker 7. In addition, the means for crushing the hardening body 4 is not limited, For example, you may employ | adopt a water jet.
The glass generated by crushing the cured body 4 is removed. Moreover, if the hardening body 4 is removed, as shown to Fig.4 (a), the exposed joint 1 will be exchanged for a new joint 1a.

The filling step S6 is a step of filling the repair material 8 into the removed portion of the cured body 4 as shown in FIG.
The repair material 8 is filled in the gap between the replaced joint 1a, the floor slab 2 and the pavement 5.
Although the material which comprises the repair material 8 is not limited, In this embodiment, super-high-speed hard concrete is employ | adopted. Further, as the repair material 8 is placed, reinforcing bars may be arranged as necessary.
When the repair material 8 is cured until a predetermined strength is developed, the traffic regulation is canceled.

As mentioned above, according to the road repair method (concrete crushing method) of this embodiment, the ettringite disappears by dehydrating the water molecules of the ettringite in the hardened body 4 of the super fast-hardened concrete, and as a result, the removal target range A1. The intensity | strength of the inside hardening body 4 can be reduced.
If the strength of the cured body 4 is reduced, the time required for crushing the cured body 4 can be shortened. Therefore, adverse effects on the surrounding environment can be minimized by minimizing the time during which noise, vibration, and the like associated with crushing of the cured body 4 occur.
The strength of the hardened body 4 is increased by ettringite (3CaO · Al ₂ O ₃ · 3CaSO ₄ · 32H ₂ O) precipitated by the hydration reaction. The strength can be reduced.

Moreover, since the road repair method (concrete crushing method) of this embodiment sets the temperature of the heating means 6 to less than 250 degreeC, the hardening body 4 is not heated to 300 degreeC. Therefore, the moisture inside the cured body 4 does not become high-pressure water vapor that causes cracks or the like. Therefore, the road after heating can be temporarily opened, and the heating process S2 and the crushing process S5 can be performed separately on different days in the repair work of the road with time restrictions.
Furthermore, in heating process S2, since the whole hardening body 4 in removal object range A1 is heated for a predetermined time at predetermined temperature, crushing of hardening body 4 is comparatively easy.

Here, a description will be given of the results of a demonstration experiment conducted in order to confirm that the strength of the hardened body 4 is reduced by heating the hardened body 4 of super fast hard concrete.
In this experiment, after heating a cylindrical specimen manufactured from ultra-high speed hard concrete in a drying furnace at 105 ° C., 200 ° C., and 300 ° C., the compressive strength of each specimen is measured, thereby hardening the ultra-high speed hard concrete. Changes in strength due to body heating were measured.
The compressive strength test was performed according to JIS A1108.
The results of the compressive strength test are shown in FIGS. 5A to 5C for each heating temperature (105 ° C., 200 ° C., 300 ° C.).
In addition, the composition of the concrete used for the production of the specimen is as shown in Table 1.

As shown in FIG. 5A, when the heating temperature was 105 ° C., it was necessary to heat for 24 hours before the compressive strength was reduced to 50% or less. Therefore, in repair work with time restrictions such as road construction, when the heating temperature is 105 ° C., the work is hindered.
On the other hand, when the heating temperature was 200 ° C., the compressive strength was reduced to 50% or less by heating for 50 minutes as shown in FIG. Therefore, if it heats at 200 degreeC, even if it is a case where there exists time restrictions, it can fully employ | adopt. Further, when the heating temperature is 200 ° C., the compressive strength of 10 N / mm ² or more is maintained even when the heating time is 300 hours. Therefore, it can be seen that the road can be temporarily released even when the compressive strength is reduced by heating the cured body for the necessary heating time.
Furthermore, when the heating temperature was 300 ° C., as shown in FIG. 5 (c), the compressive strength was drastically decreased, and explosion occurred in about 50 minutes. Therefore, heating at 300 ° C. or higher may cause explosion in the cured body 4.
As a result of the above, it is understood that the compression strength of the hardened body 4 of super-hard-hardened concrete can be lowered by heating for 50 minutes or more with a heating means of 200 ° C. or higher. Moreover, in order to avoid explosion of the hardened body 4, it is desirable to set the temperature of the heating means to less than 250 ° C.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and the above-described constituent elements can be appropriately changed without departing from the spirit of the present invention.
In the above embodiment, the repair of the joint has been described, but the object to which the concrete crushing method and the road repair method of the present invention can be applied is not limited. For example, it is used for repairing a pavement made of super high-speed hard concrete. May be.

The concrete crushing method of the present invention is not limited to road repair work, but can be used for dismantling / repairing any concrete structure constructed of super-hard hard concrete.
What is necessary is just to set suitably the heating means used at a heating process according to the member thickness, the property, etc. of the hardening body 4. FIG.
Although the said embodiment demonstrated the case where the whole hardening body 4 was heated, the hardening body 4 may be divided into several layers and a heating and crushing may be repeated for every layer.

DESCRIPTION OF SYMBOLS 1 Joint 2 Floor slab 3 Crevice 4 Hardened body (super-hard-hardened concrete)
5 Pavement 6 Heating means 7 Breaker 8 Repair material S2 Heating process S3 Heating stop process S5 Crushing process S6 Filling process

Claims (4)

A heating process for heating the removal target range of the hardened body of super-hard-hardened concrete;
A crushing step of crushing the cured body within the removal target range, and a concrete crushing method comprising:
In the heating step, the concrete crushing method is characterized by heating for 50 minutes or more by a heating means of 200 ° C. or higher and lower than 250 ° C.   2. The method for crushing concrete according to claim 1, wherein in the heating step, heating is performed for 50 minutes or more in a state where the temperature of the hardened body within the removal target range is maintained at 100 ° C. or more and less than 250 ° C. 3. A heating step of heating the target for removal of the hardened body of super fast hard concrete for 50 minutes or more by a heating means of 200 ° C. or more and less than 250 ° C .;
Crushing step of crushing and removing the cured body within the removal target range;
A road repairing method comprising: a filling step of filling the removed portion of the cured body with a repair material. A heating step of heating the target for removal of the hardened body of super fast hard concrete for 50 minutes or more by a heating means of 200 ° C. or more and less than 250 ° C .;
A heating stop step of removing the heating means;
A crushing step of crushing and removing the cured body in the removal target range after a predetermined time has elapsed from the heating stop step;
A road repairing method comprising: a filling step of filling the removed portion of the cured body with a repair material.