JP5383469B2 - Adhesive structure and slip layer sheet having the adhesive structure - Google Patents

Description

  The present invention relates to a slip layer adhesive structure that reduces the force acting on the outer surface of the underground structure from the surrounding ground due to ground subsidence around the underground structure, and a slip layer sheet having the adhesive structure. .

  When underground structures such as foundation piles are constructed on soft ground such as coastal areas and landfills, a downward force is exerted on the contact surface of the underground structure with the ground due to ground subsidence of the surrounding ground. Works. This downward force is referred to as negative friction (hereinafter referred to as NF). NF occurs due to underground soil quality, groundwater flow or changes, and excavation of the surrounding ground after construction of the underground structure. These factors are accurately determined before construction of the underground structure. Therefore, it is difficult to accurately predict the amount of NF generated. In other words, the foundation pile is long and driven from 80 to 100 meters below the ground, and it is difficult to accurately grasp the underground structure up to that point. In some cases, the structure was damaged or the underground structure was destroyed.

  Therefore, it is necessary to reduce this NF. Conventionally, as an NF countermeasure for underground structures, especially in the field of foundation piles, countermeasures by increasing the pile diameter and the number of piles, A method called a group pile that constrains the ground, and a method that employs a double pipe pile in which the pile has a double structure and the outer cylinder receives NF and supports the building on the ground with the inner cylinder have been implemented. However, an increase in pile diameter and an increase in the number of piles will lead to an increase in material costs.In the method using group piles, an increase in material costs, an increase in residual soil due to an increase in the number of piles, and a design of the number of piles are required. There is a problem that it is necessary to predict NF, and it is not possible to reduce NF acting on the pile driven into the outermost periphery. Moreover, the method using a double pipe pile had the problem that the increase in material cost and the very difficult construction were accompanied.

  On the other hand, as another method, in recent years, asphalt material is applied around the foundation pile, the asphalt material is made to function as a slip layer, and NF is reduced by deformation of bitumen material (SL pile method) Has been implemented. In this SL pile method, it has been confirmed that if an appropriate asphalt material is applied as a slip layer around the foundation pile, NF acting on the foundation pile is reduced. However, in this case, it is necessary to apply a pre-melted asphalt material around the foundation pile at a dedicated factory to form a sliding layer, and apply the asphalt material at the site where the pile is placed. There was a problem that I could not. In forming the slip layer, there is a method of directly applying asphalt to the constituent material of the underground structure, but this method may not be applied depending on the shape of the constituent material. In other words, it could not be applied to vertical surfaces such as underground tunnels and outer walls of joint structures.

  Therefore, in order to broaden the application range of the SL pile method, for example, in Japanese Patent Application Laid-Open No. 55-154154 (Patent Document 1), an asphalt layer is formed by using the asphalt material as a sheet, and an acrylic emulsion is formed on one side thereof. There has been proposed a method in which an adhesive layer using rubber or asphalt is provided and attached to the surface of a structure or a constituent material (hereinafter referred to as a structure or the like). In addition, the adhesive layer used in this method needs to be strongly bonded to the asphalt layer. As such an adhesive layer, for example, JP-A-1-174721 (Patent Document 2) and JP The thing formed by the rubber | gum asphalt compound which the synthetic rubber | gum of SBS is added to the straight asphalt disclosed by 2004-74753 gazette (patent document 3) is known. In addition, what made the asphalt type material into a sheet form, and provided the adhesion layer there is called the slip layer sheet.

As a technique for forming an asphalt-based material into a sheet shape, a technique for improving the asphalt layer in addition to the adhesive layer has been proposed. For example, in Japanese Patent Laid-Open No. 2-48937 (Patent Document 4), asphalt compound is disclosed as a technique for reducing friction caused by misalignment occurring at an interface of a double wall structure such as concrete and concrete or concrete and steel plate. And a sheet comprising a layer of rubber asphalt compound. According to this sheet, ground subsidence (long loading time) and ground motion (short loading time) can be obtained by laminating asphalt compounds and rubber asphalt compounds with different stiffness coefficients depending on the loading time (time when the stress is applied). Friction caused by misalignment between concrete and concrete or between concrete and steel sheet can be reduced.
The stiffness coefficient is a measurement calculated as a value obtained by fixing one surface of the compound to be measured in the vertical direction, applying a constant load to the other surface in the vertical direction for a certain period of time, and dividing the load by the displacement at that time. Value.

JP-A-55-154154 Japanese Patent Laid-Open No. 1-174721 JP 2004-74753 A JP-A-2-48937

The property required for the slipping layer is required to be free from deviation during construction. If it is displaced at the time of construction, for example, if it is provided on the outer peripheral surface of the foundation pile, it will be deformed during the driving work of the foundation pile, and it will be deformed to reduce NF at the time of use after completion of construction of the foundation pile. This is because there is no part to be left and the original function cannot be exhibited. In order to obtain this required property, it is generally required that the stiffness coefficient is large. On the other hand, resistance to cracking during construction is also required. This is because, if the slip layer is damaged during construction, it naturally does not perform its function during operation. In addition, in order to obtain this required property, it is said that the stiffness coefficient at 10 ⁻² seconds needs to be 1 × 10 ⁸ Pa or less. That is, it can be said that there is a conflict between the difficulty of slipping and the difficulty of cracking during construction.

  In the conventional sliding layer formed in consideration of the necessity of having such a complicated relationship, the rubber asphalt compound that should be an adhesive layer to a structure or the like does not function well as an adhesive material, At the time of construction at about ° C., there was a problem that the adhesive layer did not adhere to the underground structure, and the adhesive layer had to be heated and welded with a burner.

  Therefore, the present invention provides an adhesive structure having sufficient adhesive force to a structure or the like in a temperature range of about 10 ° C. and a slip layer sheet provided with the adhesive structure in a slip layer that satisfies characteristics required for the entire slip layer The purpose is to provide.

The adhesive structure according to the present invention comprises an asphalt layer facing the soil and an adhesive layer for an underground structure, and the adhesive layer has a storage elastic modulus of 1 at a loading time of 1 second (frequency: 1 Hz) at 10 ° C. × 10 ⁵ Pa or less, and loss tangent tan δ is 1 or more.

The slip layer sheet according to the present invention has an asphalt layer and an adhesive layer laminated, and the adhesive layer has a storage elastic modulus of 1 × 10 ⁵ Pa or less at a loading time of 1 second (frequency: 1 Hz) at 10 ° C. And the loss tangent tan δ is 1 or more. A protective layer for keeping the surface state of the adhesive layer normal may be laminated on the surface of the adhesive layer until construction. As the protective layer, a nonwoven fabric produced from polyester, rayon, polypropylene, nylon or the like may be used.

また、本発明における損失正接ｔａｎδは、上記試験法により得た、正弦波歪みと正弦波応力との位相差δの正接である。 The storage elastic modulus in the present invention can be measured by a dynamic viscoelasticity tester. Specifically, a binder is sandwiched between two parallel disks, a sine wave distortion γ of a predetermined frequency is added to one disk, and a sine stress σ and sine wave distortion transmitted to the other disk via the binder. The phase difference δ between the sine wave stress and the sine wave stress is measured. And based on a measurement result, it can obtain | require from following Formula (1).

The loss tangent tan δ in the present invention is the tangent of the phase difference δ between the sine wave distortion and the sine wave stress obtained by the above test method.

The material of the adhesive layer is not limited as long as it satisfies the above properties, but for example, a mixture of asphalt material and butyl rubber is suitable. The asphalt material to be mixed with butyl rubber is straight asphalt obtained as a residue obtained by distilling crude oil under reduced pressure, propane deasphalted asphalt obtained by removing crude oil under reduced pressure distillation residue with propane or the like, or crude oil vacuum distillation residue. It can be composed of asphalt raw materials such as extracts obtained by solvent extraction of solvent-removed oil obtained by removing oil with a solvent such as propane. Instead of this extract, you may make it comprise aroma system oil. This aroma-based oil is specified in JISK6200 and is a hydrocarbon-based process oil containing at least 35% by mass of aromatic hydrocarbons.
In addition, in order to improve the mixability of butyl rubber and asphalt material, the adhesives include pigments such as calcium carbonate, barium sulfate, calcium hydroxide, mica, talc, silicic acid, titanium oxide, and carbon black as inorganic fillers. It may be added.
Further, rosin resin, terpene resin, coumarone indene resin, aliphatic petroleum resin, aromatic petroleum resin and the like may be added to the adhesive as resins.

  The asphalt layer is not particularly limited as long as it is sufficiently responsible for the main function of the sliding layer, that is, the function of reducing NF generated in the structure, and can be formed of a known asphalt compound. The asphalt raw material constituting the asphalt compound is produced by any of the above-described vacuum distillation method, blowing (air blowing method), and blending method (blending method). That is, the asphalt compound contains at least one of propane-desorbed asphalt, straight asphalt, and extract asphalt raw materials.

The propane deasphalted asphalt is a so-called solvent deasphalted asphalt obtained by using a propane or a mixture of propane and butane as a solvent for the vacuum distillation residual oil. As the propane deasphalting asphalt suitable for the present invention, for example, under JISK2207, the penetration at 25 ° C. is 8 (1/10 mm), the softening point is 66.5 ° C., and the density at 15 ° C. is 1.028 g / cm ³ . Some may be used. Any asphalt such as straight asphalt or blown asphalt may be used in addition to this propane deasphalted asphalt.

Further, as the straight asphalt, for example, a straight asphalt having a penetration of 65 (1/10 mm) at 25 ° C., a softening point of 48.5 ° C., and a density at 15 ° C. of 1.034 g / cm ³ is used. It may be. For example, a blown asphalt having a penetration of 32 (1/10 mm) at 25 ° C., a softening point of 102.0 ° C., and a density of 15 ° C. of 1.032 g / cm ³ is used. Also good.

Extracts are extracted oils used to obtain heavy lubricating oil as refined oil by further solvent extraction of the solvent-depleted oil obtained by removing the vacuum distillation residue of crude oil with propane, etc. It is. Extract, for example, as the kinematic viscosity at 100 ° C. kinematic viscosity at 119.2mm ² / s, 40 ℃ to use a density of 3970mm ² / s, 15 ℃ is is 0.9764g / cm ³ May be.

  The adhesive structure and slip layer sheet of the sliding layer according to the present invention are provided with sufficient adhesive force to a structure or the like in a temperature range of about 10 ° C. In addition, the formed sliding layer can maintain its shape without causing deformation at high temperatures and without being deformed even in the operation of being driven into the soil, and as a result, NF generated in the structure is reduced. It will be equipped with functions.

Here, the size of NF acting on the structure or the like on which the slip layer is formed is proportional to the amount of ground subsidence and inversely proportional to the thickness of the slip layer. Moreover, NF which acts on a structure etc. can be reduced, so that a slip layer becomes easy to plastically deform. Conventionally, the ease of plastic deformation of the slip layer was expressed using a stiffness coefficient. The stiffness coefficient was obtained as a value obtained by fixing one surface of the sliding layer in the vertical direction, applying a constant load to the entire other surface in the vertical direction for a certain time, and dividing the load by the displacement at that time. The time when the load is applied is called loading time.
However, this stiffness coefficient can be measured with relatively high accuracy in the case of a loading time of about 100 seconds or more due to the structure of the measuring device, but in the case of a loading time of 10 seconds or less, the measurement error is large, and slipping occurs. The property of the actual sliding layer was not accurately represented, for example, the Poisson's ratio, which is a physical property value of the asphalt material constituting the layer, was regarded as an assumed value.
Therefore, the present inventor conducted research on a method for more accurately grasping the properties of the slip layer, and applied the storage elastic modulus, loss elastic modulus, and loss tangent (tan δ) in rheological theory. Thus, the present inventors have found that the adhesive performance of the sliding layer can be expressed more accurately than the conventional stiffness coefficient. The present invention is based on this new finding.

The present invention proposes the optimum physical properties of the adhesive layer. In other words, it was necessary to clarify the physical properties of the adhesive layer during loading time (about 1 to 10 seconds) when trying to adhere the adhesive layer to a structure or the like at the actual construction site. It is not the material design based on the stiffness coefficient that has been used, but the adhesive layer is optimized using the storage elastic modulus and loss tangent tan δ.
Specifically, as the physical properties of the adhesive layer, at a loading speed of 1 second (frequency 1 Hz), the storage elastic modulus (that is, the elastic modulus measured as an elastic body that returns to its original shape when the applied displacement is removed with respect to the elastic modulus of the adhesive layer) ), And is well adapted to fine irregularities on the adherend surface. Further, the lower limit value of the loss tangent tan δ is established, that is, it is easy to be plastically deformed. The shape of the adhesive layer is maintained, and the function of the adhesive layer is improved.
In addition, since the adhesive layer in the present invention is used together with the slip layer, after being attached to a structure or the like together with the slip layer, that is, when the loading time is 100 seconds or more, the adhesive layer is plastically deformed and slips more than necessary. In order to prevent the function of the layer from being deteriorated, an upper limit value of the loss tangent tan δ is provided, that is, it is difficult for plastic deformation.

It is a graph which shows the change of the loss tangent with respect to the loading time of the Example of the adhesive material in the adhesion structure which concerns on this invention. It is a graph which shows the change of the loss tangent with respect to the loading time of the conventional adhesive material (rubber asphalt compound).

  Examples of the adhesive structure according to the present invention will be described. However, the present invention is not limited to the following examples.

  As the adhesive material for the slip layer sheet, a mixture of butyl rubber, asphalt material, resins and inorganic filler was prepared. As a comparative example, a rubber asphalt compound of SBS and asphalt material, which is a conventional adhesive material, was prepared.

As the asphalt material to be mixed with the adhesive material and the rubber asphalt compound, a mixture of straight asphalt, propane deasphalted asphalt, and extract was used.
The pressure-sensitive adhesives of the examples were prepared by dispersing and kneading 15% by weight of butyl rubber, 15% by weight of resins, 50% by weight of inorganic filler, and 20% by weight of asphalt material using a Banbury type mixer or the like.
The rubber asphalt compound of the comparative example is an asphalt material composed of a mixture of straight asphalt 10% by weight, blown asphalt 23% by weight, propane deasphalted asphalt 25% by weight, and extract 30% by weight at a temperature of about 195 ° C. While maintaining the condition, 12% by weight of SBS was added, and the mixture was prepared by mixing and stirring with a homomixer. Table 1 shows the properties of the prepared adhesive and rubber asphalt compound.

The penetration shown in Table 1 was obtained by the method shown in JIS K 2207. The storage modulus and loss tangent were obtained by the following methods.
First, a binder having a thickness of 2 mm is sandwiched between two parallel disks having a diameter of 8 mm, and a 10% sine wave distortion is applied to one of the disks using a dynamic viscoelasticity tester. The sinusoidal stress σ transmitted to the other disk and the phase difference δ between the sine wave distortion and the sine wave stress were measured. And storage elastic modulus G 'was calculated | required from above-described Formula (1) based on the measurement result. The loss tangent tan δ was calculated based on the phase difference δ between the sine wave distortion and the sine wave stress.

About the said Example and comparative example, the test sheet | seat was produced and the 90 degree peel strength test was done. The test results are shown in Table 2. The procedure for producing the test sheet and the procedure for the 90 ° peel peel strength test are as follows.
<Preparation of test sheet>
The pressure-sensitive adhesive material of the example and the rubber asphalt compound of the comparative example were kept at 160 ° C., a 1.5 mm thick sheet was prepared using a release paper using silicone and a press, and allowed to cool to room temperature. Next, the release paper at the top of the sheets was peeled off, and the asphalt compound for the SL layer maintained at 80 ° C. was placed thereon, and a 4 mm thick SL layer was formed over the entire surface using a press. Thereafter, a polyester non-woven fabric was immediately put on top of the SL layer and lightly pressed to prepare a test sheet. And this test sheet | seat was cut | disconnected to 25 mm x 150 mm, and it was set as the test sheet. As the asphalt compound for the SL layer, SL compound B grade (penetration 43) manufactured by Showa Shell Sekiyu KK, which is a conventional asphalt compound, was adopted.
<90 ° peel peel strength test (unit: N / 25 mm)>
The test sheet and the test steel sheet (cold rolled steel sheet) of Examples and Comparative Examples were left in an air oven maintained at the test temperature for 1 hour, and then the release paper of the 25 × 50 mm portion of the test sheet was peeled off, and 35 mm × 150 mm ( Affixed to a test steel plate having a thickness of 0.8 mm. The upper part of the pasted portion was pressure-bonded by reciprocating 3 kg of a 1 kg weight roller to obtain a specimen.
After pressure bonding, the film was peeled in a 90 ° peeling direction at a tensile speed of 200 mm / min in a tensile tester, and the maximum peel load (N) was determined. The peeling load was measured as N / 25 mm. The test was conducted at 5 ° C, 25 ° C, and 50 ° C.

  Moreover, about the adhesive material of an Example and a comparative example, the loss tangent at the time of changing loading time was calculated | required. 1 and 2 show changes in loss tangent with respect to loading time. In rheological theory, the loss tangent at a certain loading time under a high temperature environment is equivalent to the loss tangent at a longer loading time when replaced under a low temperature environment, that is, temperature and loading time. (For example, Oka Kotenhen, Introduction to Rheology, pp. 164, Industrial Research Institute, Inc. (1970)). Here, using the shift factor derived by the WLF formula proposed by Williams-Landel-Ferry et al., The property at a long loading time was measured by increasing the measurement temperature.

  Specifically, the loss tangent when the loading time is long was measured in an environment higher than 10 ° C., specifically in an environment of 20 ° C. and 30 ° C. In FIG. 1 and FIG. 2, rhombus marks indicate measurement points at 10 ° C., square marks indicate measurement points at 20 ° C., and triangle marks indicate measurement points at 30 ° C.

According to Table 2, it was confirmed that the Examples had a high peel strength at any test temperature and were well adhered to the adherend as compared with the Comparative Examples. In addition, it was confirmed that the peeling mode of the examples was cohesive failure at any test temperature, and was well adapted to the surface of the adherend because the storage elastic modulus was reduced and tan δ was increased. On the other hand, the comparative example has an interfacial peeling at any test temperature, and has a large storage elastic modulus and a small tan δ. It could be confirmed. That is, the storage modulus is less than 1 × ¹⁰ 5 Pa, Example loss tangent tanδ is 1 or more, the storage elastic modulus is 1 × ¹⁰ 5 Pa or more, than the comparative examples the loss tangent tanδ is less than or equal to 1 It was confirmed that the adhesive strength was excellent. According to the theory of rheology, when the storage elastic modulus G ′ is 1 × 10 ⁵ Pa or more, the pressure-sensitive adhesive body cannot be deformed to fit the minute unevenness present on the surface of the pressure-sensitive adhesive body, and the loss tangent tan δ It is said that the deformed state is less likely to be maintained and the adhesive force to the adherend is reduced, but according to the examples and comparative examples, it was confirmed that this theory also applies to the adhesive layer of the sliding layer. . From Table 1, it can be seen that it is impossible to capture the change in storage elastic modulus and loss tangent due to the loading time with the penetration that has been conventionally used for property evaluation.
In addition, it is effective to add a molecule having a polar group in order to further improve the adhesive strength within the range satisfying these physical property values. For example, it is also effective to use a rosin having a carboxylic acid, a maleated resin, a terpene resin or the like.

Further, according to FIG. 1, the adhesive layer of the example has a loss tangent tan δ that decreases as the loading time becomes longer (that is, the behavior as an elastic body increases and plastic deformation becomes difficult), and the conventional adhesive layer Similar to the layer, it was confirmed that when the adhesive layer was stored (corresponding to a loading time of about 2 × 10 ⁶ seconds in about one month), it was difficult to be plastically deformed. In addition, since the conventional asphalt compound is employ | adopted as an asphalt layer, it can be anticipated that it has the function which reduces the NF which generate | occur | produces the characteristic required for the whole sliding layer, ie, a structure.

Claims (4)

An asphalt layer facing the soil and an adhesive layer for underground structures, the adhesive layer has a storage elastic modulus of 1 × 10 ⁵ Pa or less at a loading time of 1 second (frequency: 1 Hz) at 10 ° C., The adhesive structure is characterized in that the loss tangent tan δ is 1 or more.   The pressure-sensitive adhesive structure according to claim 1, wherein the loss tangent tan δ at a loading time of 100 seconds at 10 ° C is 1 or less. The asphalt layer and the adhesive layer are laminated, the storage layer has a storage elastic modulus of 1 × 10 ⁵ Pa or less and a loss tangent tan δ of 1 or more at a loading time of 1 second (frequency: 1 Hz) at 10 ° C. A slip layer sheet characterized by that.   The slip layer sheet according to claim 3, wherein a loss tangent tan δ of the adhesive layer at a loading time of 100 seconds at 10 ° C is 1 or less.

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