JP5301297B2 - Joint material for paving - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection joint sealant for pavement which has basic performances as a joint sealant and which is not extruded to a paved surface even if compressed due to the expansion of the pavement. <P>SOLUTION: This air-milk cement joint sealant contains a 4-55 mass% very high-speed hardening cement, a 9-83 mass% calcium carbonate powder, 0.01-1 mass% foaming agent, and 10-45 mass% water. The joint sealant can maintain the shape as a joint when injected into the gap for joint and hardened, and forms a foam mortar which is easily collapsible by compression. The foam mortar is collapsed when subjected to a compression due to the expansion of the pavement, and absorbs the expansion when pulverized. Since the foam mortar is gradually collapsed into powder and falls on a road bed thereunder, it does not extrude to the paved surface. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a joint material for paving, and particularly to an injection type cement-based joint material suitable for a joint provided to absorb the expansion pressure of a roadbed using an expandable roadbed material.

Conventionally, as roadbed materials for roads and parking lots, in addition to natural materials, concrete waste materials and steel slag have been used. Hydrate with free CaO or free MgO if the roadbed material contains free CaO, free MgO, or ettringite (3CaO ・ Al ₂ O ₃・ 3CaSO ₄・ 32H ₂ O) minerals When the roadbed expands due to the generation of ettringite or the generation of ettringite, and the amount of expansion is large, problems such as the roadbed rising and the asphalt pavement rising and breaking, and structures adjacent to the pavement being destroyed. May occur.

As a preventive measure for such a problem, a measure of cutting the asphalt pavement to the road floor with a cutter to form joints can be considered. However, even if such joints are provided, the roadbed material collapses and blocks part of the joints, so that plate-like joint materials cannot be used. On the other hand, when a viscoelastic injection-type joint material is used, the joint material is compressed by expansion of the roadbed and protrudes to the pavement surface, which causes a problem that obstructs the passage of vehicles and pedestrians.
Such viscoelastic injection-type joint materials also cause the same problem even when used for joints provided as countermeasures against expansion and contraction of concrete pavements such as roads and parking lots.

On the other hand, a method of not injecting the injection type joint material to the vicinity of the pavement surface is also conceivable, but in this method, the groove trace of the joint becomes lower than the road surface and a step is generated.
Accordingly, the object of the present invention is to solve the above-mentioned problems of the prior art, and has the basic performance as a joint material, and does not protrude into the pavement surface even if compressed by the expansion of the pavement. The purpose is to provide joint materials.

As a result of repeated investigations to find an injection-type pavement joint material that can solve the above-mentioned problems, the present inventors have obtained a cement-based air (bubble) milk in which an appropriate amount of foaming agent, calcium carbonate, and super-hard cement is mixed in water. It discovered that the said subject could be solved by using as a joint material.
The present invention has been made on the basis of such knowledge, and is an air milk type cement-based joint material, which is super-hard cement: 4-55 mass%, calcium carbonate powder: 9-83 mass%, foaming agent: 0.01 It is the joint material for pavements characterized by including -1 mass% and water: 10-45 mass%.

  The joint material for paving of the present invention has a basic performance capable of maintaining the shape as a joint in a state where it is injected into a joint gap and cured, and forms a foam mortar that is easily crushed by compression. When compressed by the expansion of the pavement, it is crushed and pulverized to absorb the expansion. In addition, since this foam mortar is gradually crushed and powdered and collapses onto the lower roadbed, it may protrude from the pavement surface like conventional viscoelastic injection-type joint materials. Absent.

Explanatory drawing which shows one Embodiment of the repair method of the roadbed in which the joint material for paving of this invention is used suitably in order of a process. Explanatory drawing which shows other embodiment (state after completion of repair) of the repair method of the roadbed in which the joint material for paving of this invention is used suitably In the repair method of FIG. 1 and FIG. 2, the explanatory view which illustrated the installation form of the cutter groove G with respect to the plane of the roadbed material laying layer A

  The joint material for pavement of the present invention is an air cement milk type joint material, which is super-hard cement: 4-55 mass%, calcium carbonate powder: 9-83 mass%, foaming agent: 0.01-1 mass%, water: It contains 10 to 45 mass%. The air cement milk may be referred to as foam mortar, foam mortar, foam cement milk, foam cement milk, foam milk, cement-based foam material, or the like. Here, the joint material is an air cement milk type, which can be appropriately injected into the joint gap without causing material separation, and when cured as a joint, it becomes a foam mortar and compresses due to pavement expansion. It is because it is crushed when it receives, and can absorb expansion by pulverizing. As described above, the cement-based joint material of the present invention has a great feature in that a foamed mortar that is easily crushed by compression is formed in a cured state as a joint.

In the joint material for pavement of the present invention, the use of super-hard cement as the cement is to quickly and efficiently perform the construction work. This is to keep the shape.
If the added amount of super fast cement is less than 4 mass%, it is difficult to obtain a strength sufficient to maintain the shape as a joint. On the other hand, if the addition amount exceeds 55 mass%, the strength after curing becomes too large, and even if compressed due to the expansion of the pavement, it becomes difficult to be crushed and powdered.
Calcium carbonate powder is added to increase the fluidity of the joint material and prevent material separation. If the amount of calcium carbonate powder added is less than 9 mass%, material separation is likely to occur. On the other hand, if the added amount exceeds 83 mass%, the ratio of the super-hard cement is relatively lowered, so that it is difficult to obtain strength for maintaining the shape as a joint.

By adding a foaming agent (AE agent), the cement-based joint material can be made into air milk.
Examples of the foaming agent (AE agent) include carboxylic acid type (for example, resin acid salt, fatty acid salt), sulfuric acid ester type (for example, alcohol sulfuric acid ester salt), sulfonic acid type (for example, alkylbenzene sulfonic acid salt), ether. Type / ester ether type (for example, polyoxyethylene alkylphenyl ether) can be used. Examples of commercially available foaming agents include “Floric FA100” (trade name, manufactured by Floric Co., Ltd., alkyl sulfate surfactants).
When the amount of the foaming agent added is less than 0.01 mass%, foaming is insufficient, so that it hardens when cured, and is difficult to be crushed and powdered even when compressed due to pavement expansion. On the other hand, when the addition amount exceeds 1 mass%, foaming becomes excessive, so that it is difficult to obtain strength for maintaining the shape as a joint.
If the amount of water added is less than 10 mass%, the fluidity is insufficient, and uneven kneading or uneven injection tends to occur. On the other hand, if the addition amount exceeds 45 mass%, material separation tends to occur.

The joint material for pavement of the present invention needs to be crushed and pulverized by receiving compression due to expansion of the pavement in a cured state as a joint. For this reason, the compression rate is 90% or more in the cured state. Preferably there is. Here, the compression ratio (%) represents “a contractible amount (thickness) of the joint when the pavement expands when the joint is filled with a filler / a joint thickness before the pavement expands × 100”. Yes.
The joint material for paving of the present invention as described above has a basic performance capable of maintaining the shape as a joint in a state of being injected into the joint gap and cured, and forms a foam mortar that is easily crushed by compression, This cellular mortar is crushed when compressed by the expansion of the pavement and absorbs the expansion by being pulverized. In addition, since this foam mortar is gradually crushed and powdered and collapses onto the lower roadbed, it may protrude from the pavement surface like conventional viscoelastic injection-type joint materials. Absent.

The joint material for paving of the present invention can be produced as follows.
A foaming agent is added to the weighed water and foamed using an electric frothing device, and then calcium carbonate powder is added and kneaded for an appropriate time (for example, about 1 minute). Furthermore, a cement material of an air cement milk type can be obtained by adding a super fast cement and kneading for an appropriate time (for example, about 1 minute).
The joint material for pavement of the present invention can be applied to both asphalt concrete pavement and cement concrete pavement. Further, the present invention can be applied to joints provided at the time of pavement construction in cement concrete pavement and joints provided for the purpose of absorbing expansion after pavement construction in asphalt concrete pavement and the like.

  Among these applications, the joint material for paving of the present invention is an asphalt concrete pavement using an inflatable roadbed material, for the purpose of releasing strain due to roadbed expansion after pavement construction and absorbing absorption after repairing. It is particularly suitable as a joint material for a repair method for providing joints. The joint material for such applications is highly required to have a performance that appropriately absorbs the expansion of the pavement and does not protrude onto the pavement surface even if compressed due to the expansion of the pavement. The material can reliably satisfy such required performance.

The repair method described above is a repair method for a roadbed in which an asphalt concrete layer B is provided on the upper layer of an inflatable roadbed material laying layer A, and the cutter is obtained by cutting the roadbed material laying layer A together with the asphalt concrete layer B with a cutter. After forming the groove G, the filler F that can absorb the expansion of the roadbed material laying layer A is filled in the cutter groove G (at least in the cutter groove G formed in the roadbed material laying layer A), As the filler F, the joint material for paving of the present invention is used.
In a preferred embodiment of the repair method, a filler F (pavement joint material of the present invention) that can absorb expansion of the roadbed material laying layer A is filled in the cutter groove G formed in the roadbed material laying layer A. Then, another filler is filled in the cutter groove G formed in the asphalt concrete layer B.

Here, the inflatable roadbed material laying layer A means that the roadbed material contains one or more types of expansion-causing components such as components that generate free CaO, free MgO, and ettringite. ).
According to this repair method, a part of the expansible roadbed material laying layer A constituting the roadbed is removed by the cutter groove G in almost the entire layer thickness direction, so that accumulation by the expansion of the roadbed material laying layer A is achieved so far. Since the strain (expansion pressure) that has been released is released and the filler F (pavement joint material of the present invention) filled in the cutter groove G absorbs the expansion of the repaired roadbed material laying layer A, the roadbed It is possible to appropriately prevent uplift / destruction caused by expansion of the material laying layer A.

1 (a) and 1 (b) show an embodiment of the repair method described above in the order of steps. In the figure, A is a roadbed material laying layer constituting the roadbed (hereinafter simply referred to as “laying layer A”), B is an asphalt concrete layer provided above the laying layer A, and C is a roadbed provided with the laying layer A. It is. The laying layer A has expansibility (expanding property) when a roadbed material (for example, steel slag) constituting the laying layer A includes a component that generates free CaO, free MgO, or ettringite.
In the present embodiment, as shown in FIG. 1 (a), a cutter is inserted from the surface of the asphalt concrete layer B, and the entire thickness of the laying layer A is cut together with the asphalt concrete layer B to form the cutter groove G. .
Next, as shown in FIG. 1 (b), the joint material for paving of the present invention is filled as the filler F that can absorb the expansion of the laying layer A in the cutter groove G.
The filler F does not necessarily fill the cutter groove G completely, but it is necessary to fill at least the cutter groove G formed in the laying layer A.

The filler F (pavement joint material of the present invention) may be filled in the entire cutter groove G as shown in FIG. 1 (b), but in particular, in the embodiment shown in FIG. Is preferred.
The embodiment of FIG. 2 is the same as the embodiment of FIG. 1 in that the cutter groove G is formed, but the filler F (pavement joint of the present invention) is only in the cutter groove G formed in the laying layer A. Material) and the other filler D is filled in the cutter groove G formed in the asphalt concrete layer B thereon.
There is no particular restriction on the material of the filler D, but a liquid injection type filler containing asphalt (for example, a heat injection type filler mainly composed of asphalt, resin, and / or rubber) is preferable. Further, when such a liquid injection type is used as the filler, it is preferable to install a backup material E for supporting the filler D at the lower end position of the filler D in advance. The backup material E is composed of, for example, a rod-like body that is elastically deformable and made of rubber or resin (for example, polyurethane, polyethylene, etc.).

  In this repair method, the form of providing the cutter groove G is basically arbitrary, but from the viewpoint of appropriately absorbing the expansion of the laying layer A, the cutter groove G is provided in parallel or in a lattice shape with respect to the plane of the laying layer A It is preferable. Moreover, since the laying layer A can be divided into small sections by providing the cutter grooves G in a lattice shape, it is preferable because the expansion of the laying layer A can be more appropriately absorbed. When the cutter grooves G are provided in parallel, the grooves do not necessarily have to be parallel. Further, when the cutter grooves G are provided in a lattice shape, the shape is not necessarily limited to a grid pattern. Therefore, the size and shape of the portion partitioned in a lattice shape may be different, and the partitioned portion may have a shape other than a square.

FIG. 3 exemplifies the installation form of the cutter groove G with respect to the plane of the laying layer A, FIG. 3 (a) shows the cutter groove G provided in parallel, and FIG. 3 (b) shows the cutter groove G. It is provided in a grid pattern (in this example, a grid pattern). As described above, from the viewpoint of appropriately absorbing the expansion of the laying layer A, the cutter grooves G are particularly preferably provided in a lattice shape. However, in the case of an elongated roadbed such as a road, for example, It may be sufficient if the cutter grooves G along the roadbed width direction are provided in parallel in the form shown in FIG.
Here, the width w _G of the cutter groove G and the installation interval p (distance between adjacent cutter grooves G) as shown in FIG. 3 are the residual expansion amount α in the horizontal direction of the laying layer A (the cutter groove G after repair). It is preferable that α ≦ β is determined according to the expansion amount generated in the width direction) and the expansion absorption amount β of the filler F (expansion amount that can be absorbed in the width direction of the cutter groove G). When α> β, the expansion absorption by the filler F or the void H is not in time, and there is a possibility that a bulge is generated.

For example, in the embodiment shown in FIGS. 1 and 2, if a filler F (pavement joint material of the present invention) having a compression rate of 90% is used, the laying layer corresponding to 90% of the width w _G of the cutter groove G is used. When the expansion amount of A can be absorbed and the width w _G of the cutter groove _G is 10 mm, the expansion absorption amount β is 9 mm. On the other hand, the residual linear expansion coefficient (residual expansion strain) of the inflatable laying layer A can be calculated based on the component analysis of the roadbed material that causes expansion, and the residual linear expansion coefficient is 0.14%. If it is, it will suffice if the installation interval p of the cutter groove G is about 6.4 m or less.
Generally, the width w _G of the cutter groove is about 10 to 30 mm, and therefore the installation interval p of the cutter groove G defined from the above viewpoint is usually about 6 to 20 m.

Incidentally, the residual linear expansion coefficient of the laying layer A, for example, in the case hydration of free CaO (Ca _{(OH) 2} product) is the cause of expansion, Ca _{(OH) 2} produced in the laying layer A in Possible amount x (mass%) (= production amount when the total amount of free CaO becomes Ca (OH) ₂ ), Ca (OH) ₂ production amount y (mass%) before repair, Ca (OH) ₂ production Based on the expansion coefficient z (mass%) per 1 mass%, it can obtain | require by residual linear expansion coefficient = (xy) * z.

A joint material for paving having the composition shown in Table 1 was produced. The joint material was manufactured according to the procedure of the manufacturing method described above. As the ultrafast cement, a curing time adjustable ultrafast cement (trade name “mild jet cement”, manufactured by Sumitomo Osaka Cement Co., Ltd.) was used. Further, as the foaming agent, an alkyl sulfate surfactant (trade name “Floric FA100”, manufactured by Floric Co., Ltd.) was used.
About the obtained joint material, the compressive strength after hardening was measured based on JIS-A1216 "Soil uniaxial compressive strength test method". The results are also shown in Table 1.

A Laying layer B Asphalt concrete layer C Road floor D Filler E Backup material F Filler G Cutter groove

Claims (1)

  It is an air milk type cement-based joint material, and includes super-hard cement: 4-55 mass%, calcium carbonate powder: 9-83 mass%, foaming agent: 0.01-1 mass%, water: 10-45 mass% A joint material for paving.

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