Deck waterproofing composite and construction method thereof

Abstract

To provide a waterproof layer which takes the advantage of coating film waterproofing whose workability is comparatively easy, has affinity with asphalt mixture and high durability, and its construction method.SOLUTION: The present disclosure provides a deck slab waterproof composite which includes a layer of waterproof material formed on the deck slab and a leveling layer composed of asphalt mixture formed on the layer of waterproof material, the waterproof material constituting the waterproof material layer is an asphalt-based waterproof material having a dynamic complex shear elastic modulus of 9.5 MPa or more, and a binder contained in the asphalt mixture constituting the leveling layer is a binder showing a number of destruction of 89,000 or more when subjected to a bending fatigue test after being mixed with aggregate to form a mixture and cured. There is also provided a construction method therefor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a waterproofing composite deck constructed on concrete decks or steel decks used mainly in road bridges and the like, and a method for constructing the same. [Background technology]

[0002] On concrete decks, PC (prestressed concrete) decks, or steel decks used in road bridges, etc., a waterproof layer is usually constructed before the asphalt mixture is laid to prevent rainwater and melted snow water that permeates the asphalt pavement constructed on top of the deck from coming into direct contact with the deck or penetrating into the deck.

[0003] Deck waterproofing can be broadly divided into sheet-based waterproofing, pavement-based waterproofing, and coating-based waterproofing, each of which has its own advantages and disadvantages. That is, sheet-based waterproofing is a waterproof layer that is created by placing a sheet-type waterproofing material between the deck and the asphalt mixture, but it has generally been difficult to construct a sheet-type waterproofing layer that can maintain high resistance to horizontal displacement for a long period of time (e.g., for 30 years). In addition, when constructing a waterproof layer using a sheet-type waterproofing material, if air is left between the underside of the waterproofing material and the deck when spreading the sheet-type waterproofing material on the deck to which the primer has been applied, the waterproofing sheet will swell, hindering the adhesion between the waterproofing material and the deck, so spreading the sheet-type waterproofing material on the deck requires skilled techniques and meticulous care, and has the disadvantage of being time-consuming to install.

[0004] On the other hand, pavement waterproofing is based on the concept that the pavement itself has waterproofing properties, and has the advantage that the process of constructing a waterproof layer is unnecessary because the pavement itself has waterproofing properties. However, for example, when using goose asphalt, which is a typical pavement waterproofing, special transport vehicles and leveling machines are required for construction, and there is the inconvenience that construction cannot be carried out without these equipment.

[0005] In contrast, coating waterproofing is a method in which a coating film is formed by applying or spraying a waterproofing material onto a surface to be applied, and this coating film serves as a waterproof layer, and therefore has the advantage that it can be applied easily without requiring special equipment, etc. However, coating waterproofing generally has the disadvantage that it is relatively weak against repeated loads and deformations, and it is difficult to maintain high waterproof performance for a long period of time.

[0006] In order to eliminate this drawback, for example, Patent Documents 1 to 4 propose waterproofing materials containing polyurethane resins or polyurea resins, which have excellent fatigue resistance. However, polyurethane resins and polyurea resins lack affinity with asphalt, and the waterproofing layer formed by them has the drawback of poor adhesion to the asphalt mixture laid on top of it. For this reason, when forming a coating-type waterproofing layer using a waterproofing material containing polyurethane resin or polyurea resin, it is necessary to interpose some kind of adhesive layer between the waterproofing layer and the asphalt mixture to improve the adhesion between them, which requires an extra process, and is not necessarily fully satisfactory in terms of construction efficiency. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2000-170111 A [Patent Document 2] JP 2003-253608 A [Patent Document 3] JP 2003-166209 A [Patent Document 4] JP 2014-95284 A Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made to eliminate the drawbacks of the above-mentioned conventional technology, and has as its object to provide a waterproofing layer and a method for constructing the same, which has affinity with asphalt mixtures and is highly durable, while taking advantage of the advantage of coating-based waterproofing, that is, the relative ease of application. [Means for solving the problem]

[0009] In order to solve the above problems, the inventors of the present invention, through intensive research and trial and error, focused on the structure and technical concept of a bridge deck pavement equipped with a coating-type waterproof layer. As shown in Figure 5, a bridge deck pavement 11 is basically composed of a waterproof layer 14, a leveling layer 15, and a surface layer 16, which are constructed on a deck 12, and a primer layer 13 is usually provided between the deck 12 and the waterproof layer 14. An adhesive layer (not shown) may also be provided between the waterproof layer 14 and the leveling layer 15.

[0010] The waterproof layer 14 performs a waterproofing function, the leveling layer 15 performs a base adjustment function by smoothing out any unevenness on the waterproof layer 14 to provide a flat construction surface when the surface layer 16 is paved, and the surface layer 16 performs the function of receiving and distributing traffic loads to ensure the function of the road surface. In this way, the conventional technical idea for bridge deck pavements is to guarantee the function and performance of the bridge deck pavement as a whole by sequentially stacking multiple layers each with a different role.

[0011] Based on this technical idea, until now, the waterproof layer 14 has been required to have a durable waterproof function on its own, that is, to follow well the deflection of the deck slab 12, have high fatigue resistance, and maintain excellent waterproof performance for a long period of time, and the materials that make up the waterproof layer 14 have been selected and prepared from this perspective.

[0012] However, in a bridge deck pavement, the waterproof layer 14 does not exist alone, but as shown in Figure 5, a leveling layer 15 always exists on top of the waterproof layer 14. Therefore, it is not necessary for the waterproof layer 14 alone to maintain the desired waterproof performance over the long term, and it would naturally be reasonable to think that the desired waterproof performance should be maintained over the long term with the leveling layer 15 laminated on top of it, that is, as a bridge deck pavement.

[0013] Based on the above idea, the inventors further conducted intensive research and trial and error, and discovered that by considering the waterproof layer and the leveling layer laminated on top of it as an integrated waterproof composite, and selecting materials for the waterproofing material and leveling layer on the premise that the leveling layer will always be present on top of the waterproof layer when in service, it is possible to provide a deck waterproof composite that reduces the excessive waterproofing performance that has previously been required of the waterproof layer alone and can maintain the desired waterproofing performance over the long term.

[0014] In other words, the present invention solves the above-mentioned problems by providing a deck waterproofing composite, which includes a layer of waterproofing material formed on a deck and a leveling layer composed of an asphalt mixture formed on the layer of waterproofing material, wherein the waterproofing material constituting the layer of waterproofing material is an asphalt-based waterproofing material having a dynamic complex shear modulus of 9.5 MPa or more, and the binder contained in the asphalt mixture constituting the leveling layer is a binder that exhibits a number of fractures of 89,000 or more when mixed with aggregate to form a mixture, hardened, and then subjected to a bending fatigue test.

[0015] The present invention also solves the above-mentioned problems by providing a method for constructing a deck slab waterproofing composite, comprising the steps of forming a layer of waterproofing material on a deck slab and forming a leveling layer composed of an asphalt mixture on the layer of waterproofing material, wherein the step of forming the layer of waterproofing material is carried out by applying or spraying an asphalt-based waterproofing material having a dynamic complex shear modulus of 9.5 MPa or more, and the step of forming the leveling layer is carried out by spreading evenly an asphalt mixture containing aggregate and a binder that shows a fracture frequency of 89,000 or more when mixed with aggregate to form a mixture, hardened, and subjected to a bending fatigue test.

[0016] Incidentally, the dynamic complex shear modulus of 9.5 MPa or more is a large value that has never been proposed before as the dynamic complex shear modulus of the asphalt-based waterproofing material that constitutes the waterproof layer, and it means that the waterproofing material is a material that does not easily deform elastically in response to external forces, i.e., a hard material. Using such a material that does not easily deform elastically for the waterproofing material is the exact opposite of the conventional idea of ​​using a material that easily deforms elastically in response to external forces (has a small dynamic complex shear modulus) in order to ensure compliance with the deflection of the deck slab.

[0017] On the other hand, when the binder contained in the asphalt mixture constituting the leveling layer is a binder that shows a breaking frequency of 89,000 or more when it is mixed with aggregate, hardened, and subjected to a bending fatigue test, it means that the binder has a certain level of adhesion to the aggregate, is relatively easy to deform, and has a certain level of deformation followability. Normally, a high dynamic stability is required for the leveling layer, and in order to ensure this, the conventional idea is to use a binder that is difficult to deform and relatively hard as the binder for the asphalt mixture constituting the leveling layer, so using a binder that has adhesion to the aggregate but is relatively easy to deform as described above is also the opposite of the conventional idea. The bending fatigue test refers to the fatigue test specified in "B018T Bending Fatigue Test Method for Asphalt Mixtures" in "Pavement Survey and Test Method Handbook," Japan Road Association, 2019 Edition, March 29, 2019, pp. [3]-169 to [3]179.

[0018] In this way, the present invention uses a relatively hard asphalt-based waterproofing material with a dynamic complex shear modulus of 9.5 MPa or more as the waterproofing material, and a relatively easily deformed binder that shows a breaking frequency of 89,000 or more when mixed with aggregate to form a mixture, hardened, and subjected to a bending fatigue test as the binder for the asphalt mixture that constitutes the leveling layer, thereby realizing a deck waterproofing composite that combines durable waterproofing performance that would be difficult to achieve by either alone, with the desired dynamic stability, through the cooperation of the waterproofing layer and the leveling layer. This technical idea did not exist before the present invention, and is a completely new technical idea that the inventors discovered independently.

[0019] Moreover, in the deck waterproofing composite of the present invention, the waterproofing material constituting the waterproofing layer is an asphalt-based waterproofing material, so it has good affinity with the asphalt mixture that is spread on top of it as a leveling layer, and there is no need to interpose a special adhesive layer between the two layers. Therefore, since no adhesive layer is required, there are fewer steps, and it has the advantage of being able to be constructed efficiently in a short time.

[0020] The deck waterproofing composite and its construction method of the present invention are typically useful as a waterproofing composite and its construction method constructed on decks such as concrete decks, PC concrete decks, or steel decks used in road bridges, etc.; however, the construction surfaces targeted by the deck waterproofing composite and its construction method of the present invention are not limited to decks, but are intended for all construction surfaces on which it is necessary to construct a waterproofing layer and a leveling layer. Effect of the Invention

[0021] The deck waterproofing composite and its construction method of the present invention can provide a deck waterproofing composite that combines durable waterproofing function and high dynamic stability, and has the advantages of being able to efficiently construct a deck waterproofing composite that combines durable waterproofing function and high dynamic stability using the same construction process as conventional coating-type waterproofing, without the need for a special transport vehicle or leveling machine, and without the need to interpose an adhesive layer between the waterproofing layer and the leveling layer. [Brief description of the drawings]

[0022] [Figure 1] 1 is a cross-sectional view showing an example of a layer structure of a deck waterproof composite of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view showing an example of a test specimen when the deck waterproof composite of the present invention is subjected to a crack opening and closing load test. [Diagram 3] FIG. 1 is a plot of the relationship between the number of times to failure in a bending fatigue test and the number of times the crack is opened and closed under load. [Figure 4] This is a plot of the relationship between the dynamic complex shear modulus of a waterproofing material and the dynamic stability of a deck waterproofing composite. [Diagram 5] FIG. 2 is a cross-sectional view showing an example of a layer structure of a conventional bridge deck pavement. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The materials used in the method for constructing a deck waterproof composite of the present invention will be described below. 1.Waterproof material The waterproofing material used to construct the waterproofing layer may be an asphalt-based waterproofing material with a dynamic complex shear modulus of 9.5 MPa or more, and there are no particular restrictions on its composition, but the following is an explanation of the preferred case. The dynamic complex shear modulus is the dynamic complex shear modulus measured using a DSR (dynamic shear rheometer) at an angular velocity of 10 rad / s and a test temperature of 23°C.

[0024] As the asphalt to be mixed into the waterproofing material used in the present invention, basically any type of asphalt may be used so long as it has good affinity with the asphalt contained in the asphalt mixture that is laid as a leveling layer on top of the waterproofing layer, but it is preferable to use straight asphalt, artificial asphalt, or a mixture of both.

[0025] Artificial asphalt is a mixture of petroleum resin and oil in a mass ratio of petroleum resin:oil = 100:0 to 0:100, preferably 50:50. As the oil, aromatic oil, naphthenic oil, and paraffin oil can be used, and as the petroleum resin, aromatic, aliphatic, aliphatic aromatic, coumarone, indene, styrene, coumarone indene styrene, alicyclic, terpene, terpene phenol, and rosin petroleum resin can be used. Straight asphalt and artificial asphalt may be used alone or in combination.

[0026] It is preferable to add a thermoplastic resin such as SEBS (styrene ethylene butylene styrene block copolymer), SBS (styrene butadiene block copolymer), SBR (styrene butadiene rubber), SEPS (styrene ethylene propylene styrene block copolymer), EVA (ethylene vinyl acetate copolymer), PE (polyethylene), EPDM (ethylene propylene diene terpolymer), or PA (polyamide) to the asphalt, and among these, SBS, SEBS, SEPS, etc. are preferably used.

[0027] The ratio of the thermoplastic resin to asphalt is preferably in the range of 10 to 50 parts by mass, more preferably 20 to 40 parts by mass, of the thermoplastic resin per 100 parts by mass of asphalt. Note that the above 100 parts by mass of asphalt means 100 parts by mass of asphalt or artificial asphalt when asphalt or artificial asphalt is used alone, and means 100 parts by mass of the total of both when asphalt and artificial asphalt are mixed and used in combination.

[0028] The dynamic complex shear modulus of the waterproofing material can be adjusted by changing the type of asphalt used and the type and mixing ratio of the thermoplastic resin. Basically, the higher the mixing ratio of the thermoplastic resin, the higher the dynamic complex shear modulus of the resulting asphalt-based waterproofing material. Therefore, while measuring the dynamic complex shear modulus, the type and mixing ratio of the thermoplastic resin are changed to prepare an asphalt-based waterproofing material having the desired dynamic complex shear modulus of 9.5 MPa or more. If the dynamic complex shear modulus is too high, the adhesion and durability of the waterproofing layer may be poor, so it is desirable to keep the upper limit of the dynamic complex shear modulus at 30 MPa or less.

[0029] The dynamic complex shear modulus may be measured based on "A062 Dynamic Shear Rheometer Test Method" described in the "Pavement Survey and Test Method Handbook," Japan Road Association, 2019 Edition, March 29, 2019, pp. [2]-335 to [2]-345.

[0030] 2. Asphalt mixture The asphalt mixture used to construct the leveling layer may be a mixture containing aggregate and a binder that, when mixed with the aggregate to form a mixture, hardened, and then subjected to a bending fatigue test, exhibits a breaking frequency of 89,000 or more. There are no particular restrictions on the composition of the mixture, but the following is an explanation of the preferred cases.

[0031] As described above, the binder used in the present invention may be any asphalt-based binder that exhibits a breaking frequency of 89,000 or more when mixed with aggregate and subjected to a bending fatigue test. Basically, any type of asphalt may be used, but it is preferable to use straight asphalt, artificial asphalt, or a mixture of both.

[0032] These asphalts are preferably modified asphalts modified by adding thermoplastic resins, rubbers, etc., and by adjusting the type of asphalt used and the types and amounts of thermoplastic resins and rubbers used for modification, it is possible to adjust the number of times to break in a bending fatigue test of the resulting mixture of asphalt-based binder and aggregate to 89,000 or more. The ratio of thermoplastic resin or rubber used for modification is preferably in the range of 1 to 40 parts by mass, more preferably in the range of 3 to 25 parts by mass, per 100 parts by mass of asphalt.

[0033] Whether the obtained binder satisfies the predetermined level of the number of fractures when mixed with aggregate can be confirmed by actually mixing the binder and aggregate, rolling, hardening, and subjecting the mixture to a bending fatigue test according to the procedure set forth in the above-mentioned "Pavement Survey and Testing Method Handbook," Japan Road Association, 2019 Edition, March 29, 2019, [3]-169 to [3]179 pages, "B018T Bending Fatigue Test Method for Asphalt Mixtures." In addition, if the mixture of the binder and aggregate has already hardened, a specimen can be cut out from the hardened part using an appropriate tool and subjected to the above-mentioned bending fatigue test for confirmation. Note that the number of fractures in the bending fatigue test referred to in this specification is measured under the conditions of a repeated bending strain amplitude of 600 μm and a test temperature of 15 ° C. in the bending fatigue test.

[0034] In addition, when preparing a specimen for a bending fatigue test, there is no particular restriction on the particle size of the aggregate mixed with the binder, but it is preferable to use aggregate with the same particle size as the aggregate to be used in the expected leveling layer, for example, it is good to prepare a specimen using dense aggregate with a maximum particle size of 13 mm. There is no particular restriction on the mixing ratio of aggregate and binder in the specimen, and it may be in the usual range, but it is preferable to use the same mixing ratio as in the asphalt mixture to be used in the expected leveling layer, and it is preferable to mix and mix in the range of 5 to 7 parts by mass of binder per 100 parts by mass of aggregate.

[0035] There are no particular restrictions on the particle size of the aggregate used in the asphalt mixture used to construct the leveling layer, and dense-grained aggregate with a maximum particle size of 13 mm may be used, but from the perspective of providing a flat construction surface as a leveling layer, it is preferable to use dense-grained aggregate with a maximum particle size of 5 mm.

[0036] There is also no particular restriction on the mixing ratio of the binder and aggregate, and it may be within a normal range, but it is preferable to mix, for example, 5 to 7 parts by mass of binder per 100 parts by mass of aggregate.

[0037] Next, the layer structure of the deck waterproof composite according to the present invention and the outline of the construction method will be described. FIG. 1 is a cross-sectional view showing an example of a bridge deck pavement equipped with a deck waterproof composite constructed by the construction method of the present invention. In FIG. 1, 11 indicates a bridge deck pavement, 2 indicates a deck, 3 indicates a primer layer, 4 indicates a waterproofing material layer, 5 indicates a leveling layer, 6 indicates a surface layer, and 7 indicates an adhesion prevention layer, and the primer layer 3, the waterproofing material layer 4, the adhesion prevention layer 7, and the leveling layer 5 form the deck waterproof composite 1 according to the present invention. Note that the deck waterproof composite 1 according to the present invention only needs to include at least the waterproofing material layer 4 and the leveling layer 5, and if the adhesion prevention layer 7 does not exist, it does not need to include the adhesion prevention layer 7. In addition, the primer layer 3 may or may not be included in the deck waterproof composite 1 according to the present invention.

[0038] To construct the deck waterproofing composite 1 on the deck 2, first, the surface of the deck 2 is cleaned, and then an appropriate primer is applied to form a primer layer 3 on the deck 2. Any material may be used as the primer as long as it can bond the asphalt-based waterproofing material layer 4 to the deck slab 2, but for example, a solvent-based primer is preferably used. Depending on the condition of the surface of the deck slab 2, the primer layer 3 may be omitted.

[0039] After the primer layer 3 is formed, an asphalt-based waterproofing material is applied or sprayed thereon to form the waterproofing layer 4. There is no particular limit to the thickness of the waterproofing layer 4 formed, but if it is too thin, the desired waterproofing performance may not be achieved, and conversely, if it is too thick, the dynamic stability of the leveling layer 5 may fall below the desired value, so it is preferable to form it to a thickness of 1.0 mm or more and less than 4.0 mm. It goes without saying that the asphalt-based waterproofing material applied or sprayed at this time has a dynamic complex shear modulus of 9.5 MPa or more.

[0040] After the waterproofing layer 4 is formed, suitable fine aggregate is scattered on top of it to prevent adhesion, forming an anti-adhesion layer 7. There are no particular limitations on the type or particle size of the fine aggregate to be scattered, but for example, No. 4 silica sand can be used. If not necessary, the formation of the anti-adhesion layer 7 may be omitted.

[0041] Next, an asphalt mixture is laid on the adhesion prevention layer 7 and spread evenly to form the leveling layer 5. The binder of the asphalt mixture laid at this time is a binder that shows a breaking frequency of 89,000 times or more when it is mixed with aggregate to form a mixture, hardened, and then subjected to a bending fatigue test. There is no particular limit to the thickness of the leveling layer to be formed, and it is sufficient if it is a normal thickness for a leveling layer, and it is preferably in the range of 30 mm to 50 mm. In this way, a deck slab waterproof composite 1 consisting of the primer layer 3, the waterproofing material layer 4, the adhesion prevention layer 7, and the leveling layer 5 is formed. After the leveling layer 5 is formed, another asphalt mixture is laid on it to form the surface layer 6.

[0042] The present invention will now be described in more detail based on experiments.

[0043] <Experiment 1> A test deck waterproof composite was created using the following three types of waterproofing materials A to C, and the durability of the waterproofing performance was tested.

[0044] [Waterproof material] Asphalt-based waterproofing material A (coating-based waterproofing material: product name "Celloseal SS-B", manufactured by Nichireki Co., Ltd.): Dynamic complex shear modulus (23°C) 2.8 MPa Asphalt-based waterproofing material B (coating-based waterproofing material: product name "Fresh Coat", manufactured by Nichireki Co., Ltd.): Dynamic complex shear modulus (23°C) 8.1 MPa Asphalt-based waterproofing material C (coating-based waterproofing material: product name "Super Fresh Coat", manufactured by Nichireki Co., Ltd.): Dynamic complex shear modulus (23°C) 19.7 MPa

[0045] [Asphalt mixture] A mixture of 100 parts by mass of aggregate with a maximum particle size of 5 mm and 6.5 parts by mass of modified asphalt type II (polymer modified asphalt, product name "Polyphalt SS", manufactured by Nichireki Co., Ltd.) was used as a binder. The penetration (25°C) of the modified asphalt type II used as the binder was 51 (1 / 10 mm).

[0046] A primer ("Kachicoat", manufactured by Nichireki Co., Ltd.) was applied onto a test concrete deck (300mm x 300mm x 60mm), and then one of the above asphalt-based waterproofing materials A, B, or C was applied to a thickness of 2.0mm. No. 4 silica sand was then spread on top to prevent adhesion, and the above asphalt mixture was paved and spread to a thickness of 40mm as a leveling layer, to create three types of test composites 1, 2, and 3 with different types of waterproofing material, A, B, and C. After curing, each test composite was subjected to the crack opening and closing load test described below to examine the durability of the waterproofing ability.

[0047] [Crack opening and closing load test] This test was conducted based on "14. Crack Opening and Closing Load Test" described in "Highway Bridge Deck Waterproofing Handbook 2007," published by Japan Road Association on March 20, 2007, pages 153-155. However, while the official rule states that "In order to induce cracks in the specimen for crack loading, cuts should be made on the top and bottom of the specimen," as shown in Figure 2, this test was conducted by making a cut V only on the bottom of the specimen, in the concrete deck 2, and not on the leveling layer. This is because, while the purpose is usually to test the crack durability of a single waterproofing layer, in this test, the waterproofing layer and the leveling layer on top of it are treated as an integrated composite, and the purpose is to test the crack durability of that composite.

[0048] The test composites 1, 2, and 3 with the notches introduced were set in a testing machine, and a crack opening and closing load was applied with an initial crack width of 0.25 mm, a crack amplitude of ±0.15 mm, and a sine wave of 10 Hz. Test pieces were cut out from the test composite at appropriate times, and water pressure was applied from above to check the durability of the waterproofing ability by detecting the presence or absence of water leakage through the waterproofing layer. The maximum number of crack opening and closing loads at which no water leakage through the waterproofing layer was detected within the tested range was defined as the "crack opening and closing load number." The results are shown in Table 1.

[0049] [Table 1]

[0050] Generally, if the crack opening and closing load count is 4.8 million or more, it is considered that the durability as a deck waterproofing is at a satisfactory level, but as shown in Table 1, none of the composites tested reached 4.8 million crack opening and closing load counts, and it cannot be said that they have a satisfactory level of durability in terms of waterproofing. However, among the three types of waterproofing materials used in the test, waterproofing material C showed the greatest crack opening and closing load count.

[0051] Waterproofing materials A and B are coating-type waterproofing materials that have traditionally been used to waterproof decks and the like, and their dynamic complex shear moduli are relatively small at 2.8 MPa and 8.1 MPa, respectively, and are waterproofing materials that are thought to follow the deflection of the deck well, but when evaluated as a composite with a leveling layer, the number of crack opening and closing loads was limited to 500,000 at most. Thus, it was a surprising result that waterproofing materials A and B, which have a relatively small dynamic complex shear modulus and are thought to follow the deflection of the deck well, have inferior durability to waterproofing material C, which has a large dynamic complex shear modulus of 19.7 MPa and is thought to be less likely to deform under external forces, when evaluated as a composite with a leveling layer.

[0052] <Experiment 2> In experiment 1, waterproofing material C, which has a large dynamic complex shear modulus of 19.7 MPa, showed the largest crack opening and closing load number when evaluated as a composite with the leveling layer, so an experiment was conducted to examine the crack opening and closing load number using waterproofing material C as the waterproofing material and changing the binder of the asphalt mixture that constitutes the leveling layer. In addition, the same test composite was subjected to a wheel tracking test to examine the dynamic stability (DS) of the leveling layer. The wheel tracking test was measured based on "B003 Wheel Tracking Test Method" described in "Pavement Survey and Test Method Handbook," Japan Road Association, 2019 Edition, March 29, 2019, pp. [3]-44 to [3]-55. However, the test specimen was created based on "Appendix-1 Test Method," "1. Test Specimen Creation," "Highway Bridge Deck Waterproofing Handbook 2007," Japan Road Association, March 20, 2007, pp. 111 to 113.

[0053] The asphalt mixture used to construct the leveling layer was as follows: [Asphalt mixture] The asphalt mixture was made by mixing 100 parts by mass of dense aggregate with a maximum particle size of 13 mm with 5.5 parts by mass of binder. The following four types of binder were used. Binder α (polymer modified asphalt, product name "Rekifalt", manufactured by Nichireki Co., Ltd.): Penetration (25°C) 51 (1 / 10 mm) Binder β (polymer modified asphalt, product name "Containerphalt Super", manufactured by Nichireki Co., Ltd.): Penetration (25°C) 47 (1 / 10 mm) Binder γ (polymer modified asphalt, product name "Sinophalt M", manufactured by Nichireki Co., Ltd.): Penetration (25°C) 78 (1 / 10 mm) Binder δ (polymer modified asphalt, product name "Non-Crack Asphalt", manufactured by Nichireki Co., Ltd.): Penetration (25°C) 92 (1 / 10 mm)

[0054] Test composites 4, 5, 6, and 7 were prepared in the same manner as in Experiment 1, except that waterproofing material C was used as the waterproofing material, and the leveling layer was constructed using an asphalt mixture containing any of the above binders α, β, γ, or δ instead of the modified type II binder. The test composites 4 to 7 prepared were subjected to a crack opening and closing load test to determine the crack opening and closing load count, and were also subjected to a wheel tracking test to measure the dynamic stability (DS). (However, the dynamic stability (DS) was not measured for test composite 5.) The results are shown in Table 2.

[0055] [Table 2]

[0056] As shown in Table 2, when waterproofing material C, which has a large dynamic complex shear modulus of 19.7 MPa, was used, and relatively hard binders α, β, and γ with a penetration of less than 80 (1 / 10 mm) were used for the asphalt mixture that constitutes the leveling layer (test composites 4, 5, and 6), the crack opening and closing load cycle was a maximum of 4 million cycles, which did not reach the 4.8 million cycles that are considered to have a satisfactory level of durability. In contrast, when a relatively soft binder δ with a large penetration of 92 (1 / 10 mm) was used for the asphalt mixture that constitutes the leveling layer (test composite 7), the crack opening and closing load cycles reached 10 million cycles, and the waterproofing ability of the composite, which is a laminate of a waterproofing material layer and a leveling layer, showed extremely excellent durability.

[0057] In addition, when any binder was used (except for binder β), the dynamic stability (DS) exceeded 1,000 (times / mm), which is required for a leveling layer, and test composites 4, 6, and 7 all had the required dynamic stability.

[0058] <Experiment 3> In experiment 2, when waterproofing material C, which has a large dynamic complex shear modulus of 19.7 MPa, was used as the waterproofing material, depending on the type of binder used in the asphalt mixture, a dynamic stability (DS) of over 1,000 (times / mm) and a crack opening and closing load count of over 4.8 million were obtained. Therefore, the following experiment was conducted to investigate the effect of the physical properties of the asphalt mixture, rather than the physical properties of the binder alone, on the crack opening and closing load count.

[0059] That is, the binder β or γ, which did not reach 4.8 million crack opening and closing load cycles, and the binder δ, which exceeded 4.8 million crack opening and closing load cycles, were used, and mixed with the same dense-grained aggregate with a maximum particle size of 13 mm as used in Experiment 2 in the same mixing ratio as in Experiment 2 to produce test mixtures 8, 9, and 10. Each of the test mixtures 8, 9, and 10 produced was poured into a mold of a predetermined size, rolled, and hardened, and mixture specimens 8, 9, and 10 with a size of 40 mm x 40 mm x 400 mm were cut out from each. The cut mixture specimens 8, 9, and 10 were subjected to a bending fatigue test as specified in "B018T Bending Fatigue Test Method for Asphalt Mixtures" in "Pavement Survey and Test Method Handbook," Japan Road Association, Heisei 31 Edition, March 29, 2019, pp. [3]-169 to [3]179, and the number of times until destruction was measured. The amplitude of bending strain was 600 μm, and the test temperature was 15° C. The results are shown in Table 3. Table 3 also shows the crack opening and closing load cycles, which are the values ​​transcribed from Table 2 for test composites 5, 6, and 7 using the corresponding binders.

[0060] [Table 3]

[0061] As shown in Table 3, the binder with a higher number of failures in the bending fatigue test when used as a mixture tends to have a higher crack opening and closing load number when used as a composite, and in the case of the binder used in the asphalt mixture that constitutes the leveling layer, it was thought that the number of failures in the bending fatigue test when used as a mixture affects the crack opening and closing load number when used as a composite with the waterproof layer. When the number of failures and the crack opening and closing load number in the bending fatigue test shown in Table 3 are plotted with the former on the horizontal axis and the latter on the vertical axis, the result is as shown in Figure 3, and when the correlation between the two was calculated from the plot shown in Figure 3, it was found that there is a correlation between the number of failures (x) and the crack opening and closing load number (y) as shown in the following formula 1. y=6.8625x 0.373 (Formula 1)

[0062] The correlation coefficient R in Eq. 2 is 0.9869, which is considered to be a highly reliable correlation, so if we calculate the number of times to fracture (x) in a bending fatigue test that corresponds to the 4.8 million crack opening and closing load cycles (y) required for deck waterproofing based on formula 1, we get x = 8.9 (million cycles).From this, it was concluded that in order to achieve the 4.8 million or more crack opening and closing load cycles required for deck waterproofing, it is best to use a binder for the asphalt mixture that makes up the leveling layer that shows a number of times to fracture of 89,000 or more when mixed with aggregate to form a mixture and subjected to a bending fatigue test after hardening.

[0063] <Test 4> In experiment 2, when waterproofing material C was used, the binder δ, which showed a fracture frequency of 89,000 or more, was used as the binder for the asphalt mixture constituting the leveling layer when it was mixed with aggregate to form a mixture, hardened, and then subjected to a bending fatigue test. As a result, a deck waterproofing composite was obtained that satisfied both the crack opening and closing load frequency and dynamic stability (DS). Therefore, test composites 11, 12, and 13 were prepared using waterproofing materials A, B, or C in the same manner as in experiment 1, except that binder δ was used instead of modified asphalt type II as the binder for the asphalt mixture, and their dynamic stability (DS) was measured. The measurement of dynamic stability (DS) was performed in the same manner as in experiment 2. The results are shown in Table 4.

[0064] [Table 4]

[0065] As shown in Table 4, when the binder δ showing a number of fractures of 89,000 or more was used as the binder for the asphalt mixture constituting the leveling layer, the mixture was mixed with aggregate, the mixture was hardened, and then subjected to a bending fatigue test. When the dynamic complex shear modulus of the waterproofing material was small, at 2.8 MPa (waterproofing material A) or 8.1 MPa (waterproofing material B), the dynamic stability (DS) was below 1,000 (times / mm), and a composite having a leveling layer with the desired dynamic stability was not obtained. In contrast, when the binder δ showing a number of fractures of 89,000 or more was used as the binder for the asphalt mixture constituting the leveling layer, the mixture was mixed with aggregate, the mixture was hardened, and then subjected to a bending fatigue test. When the dynamic complex shear modulus of the waterproofing material was large, at 19.7 MPa, the dynamic stability was significantly higher than 1,000 (times / mm), and a composite having a leveling layer with the desired dynamic stability was obtained.

[0066] From the above results, it was considered that the dynamic complex shear modulus of the waterproofing material used in the waterproofing composite, which is a laminate of a waterproofing material layer and a leveling layer, affects the dynamic stability (DS) of the entire waterproofing composite. When the dynamic complex shear modulus and dynamic stability shown in Table 4 are plotted with the former on the horizontal axis and the latter on the vertical axis, the result is shown in Figure 4. When the correlation between the two was calculated from the plot shown in Figure 4, it was found that there is a correlation between the dynamic complex shear modulus (x) and the dynamic stability (y) as shown in the following formula 2. y=456.37032x 0.34766 (Formula 2)

[0067] The correlation coefficient R in Eq. 2 is 0.98925, which is considered to be a highly reliable correlation, so if we calculate the dynamic complex shear modulus (x) corresponding to the dynamic stability (DS) of 1,000 (times / mm) or more (y) required for a deck waterproofing composite based on formula 2, we get x = 9.5 MPa. Therefore, it was concluded that in order to achieve the dynamic stability of 1,000 (times / mm) or more required for a deck waterproofing composite, it is best to use a waterproofing material with a dynamic complex shear modulus of 9.5 MPa or more at 23°C. [Industrial Applicability]

[0068] As explained above, the deck waterproofing composite of the present invention is a composite consisting of a layer of waterproofing material constructed on the deck and a leveling layer laminated on top of that, and has excellent waterproofing performance with excellent durability and the required dynamic stability. The deck waterproofing composite of the present invention has the advantage that it does not require a special transport vehicle or leveling machine, and can be constructed using the same equipment and construction process as conventional coating-type waterproofing. The deck waterproofing composite of the present invention and its construction method bring about a new technological advancement in the field of deck waterproofing, and have great industrial applicability. [Explanation of symbols]

[0069] 1 Floor slab waterproofing complex 2, 12 floor slab 3, 13 Primer layer 4, 14 Waterproofing layer 5, 15 Leveling layer 6, 16 Surface layer 7 Anti-adhesive layer 11 Bridge surface pavement V notch

Claims

1. The waterproofing composite includes a layer of waterproofing material having a thickness of 1.0 mm or more and less than 4.0 mm formed on a deck slab, and a leveling layer having a thickness of 30 mm to 50 mm composed of an asphalt mixture formed on the layer of waterproofing material, and further includes a primer layer located between the deck slab and the layer of waterproofing material, and / or an anti-adhesion layer located between the layer of waterproofing material and the leveling layer, the waterproofing material constituting the layer of waterproofing material is an asphalt-based waterproofing material having a dynamic complex shear modulus of 9.5 MPa or more, and the binder contained in the asphalt mixture constituting the leveling layer is a binder that shows a number of fractures of 89,000 or more when subjected to a bending fatigue test defined in "B018T Bending Fatigue Test Method for Asphalt Mixtures" in "Pavement Survey and Test Method Handbook" (Japan Road Association, 2019 Edition, March 29, 2019) after being mixed with aggregate to form a mixture and hardened.

2. The method includes a step of forming a layer of waterproofing material having a thickness of 1.0 mm or more and less than 4.0 mm on a deck slab, and a step of forming a leveling layer of 30 mm to 50 mm thick composed of an asphalt mixture on the layer of waterproofing material, and further includes a step of applying or spraying a primer on the deck slab prior to the step of forming the layer of waterproofing material, and / or a step of spraying fine aggregate on the layer of waterproofing material prior to the step of forming the leveling layer, the step of forming the layer of waterproofing material being carried out by applying or spraying an asphalt-based waterproofing material having a dynamic complex shear modulus of 9.5 MPa or more, and the step of forming the leveling layer being carried out by mixing the asphalt-based waterproofing material with aggregate to form a mixture and hardening the mixture, and then performing the step of forming the leveling layer by applying or spraying the asphalt-based waterproofing material having a dynamic complex shear modulus of 9.5 MPa or more according to "B018T" in "Pavement Survey and Testing Method Handbook" (Japan Road Association, 2019 Edition, March 29, 2019). A method for constructing a deck waterproofing composite, comprising spreading evenly an asphalt mixture containing a binder and aggregate that exhibits a fracture frequency of 89,000 or more when subjected to a bending fatigue test specified in the "Bending Fatigue Test Method for Asphalt Mixtures."

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