JPH052062B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to an asphalt sheet that is easy to install and has a sliding property, which is used to suppress uneven settlement of underground structures or prevent breakage of waterproof layers. [Prior art] Conventionally, in order to prevent uneven settlement of underground structures or to prevent rupture of the underground waterproof layer, a sheet or coating layer made of a slippery asphalt compound alone has been applied to the vertical walls of the structure. . However, the construction area is large and is subject to shear stress due to earth pressure, soil subsidence, flow, etc. under long-term loads, so the stress is reduced by displacement of the sliding layer to transmit this to the wall surface and waterproof layer. In order to cause displacement uniformly and extremely slowly, it is necessary to maintain the adhesive strength between the sliding layer and the structure greater than the shear stress acting on the sliding layer, but conventional methods do not have this point. cannot be resolved. [Problems to be Solved by the Present Invention] The present invention improves the above-mentioned conventional drawbacks and provides easy-to-handle sliding properties that allow the adhesive strength between the sliding layer and the frame to be greater than the shear stress acting on the sliding layer. The purpose is to provide an asphalt sheet having the following properties. [Means for Solving the Problems] The present invention has a stiffness coefficient of 10 ⁰ to 10 ³ N/m ² under a loading time of 1 year and a temperature of 20°C, and a thickness of 2 to
An asphalt compound of 10 mm is used as a sliding layer, and on the back side, an adhesive layer of a rubber asphalt compound with a stiffness coefficient of 10 ⁴ to 10 ⁷ N/m ² and a thickness of 0.5 to 3 mm under the same conditions as above is laminated. The asphalt sheet has sliding properties and has a woven or nonwoven fabric made of synthetic fibers or natural fibers whose stiffness coefficient is significantly higher than that of the sliding layer on the other side. [Function] The present invention is constructed as described above, and the process of reducing adhesive strength and shear stress to the building frame will be explained based on rheological theory. (1) Rheology of bond failure. Adhesive pieces A and B pasted together as illustrated in Figure 5
Assume that a load P is applied in the direction of shear, and the adhesive area S, the thickness of the adhesive layer C is h, and the displacement is x.
shall be. In this case, it is assumed that the adherend is hard and displacement occurs only in the adhesive. Shear stress σ is σ=
P/S, the strain ε of shear is ε=x/h, and the stress σ of this adhesive is "spring" (hook elastic body with rigidity G)
It is expressed as the sum of the stress of the "dashpot" (a Newtonian viscous body with a viscosity coefficient η) and the following equation. σ=σ ₁ +σ ₂ However, σ ₁ = εG, σ ₂ = η・dε/dt ∴σ=εG+ηdε/dt. Since the tensile speed V is V=dx/dt, dε/dt=1/h・dx/dt=V/h, so σ=εG+ηV/h. For convenience, let us denote the stress at which rupture occurs when the strain reaches ε = ε _c as σ _b , then σ _b = ε _c G + ηV/h. This destruction speed (here, adhesive strength) is linearly proportional to the speed, and converges to a constant value ε _c G when the speed is small, that is, when the loading time is very long. The amount of adhesive work at this time is on the order of 10 ² to ^{10 3} erg/cm ² . (2) Estimation of adhesive strength of asphalt compound with sliding properties (hereinafter referred to as SL). When calculating the adhesive breakage value in (1) above, σ _b = ε _c G, when the displacement is 0, ε _c G = 0, so if the displacement is 1
mm, and assuming for convenience that the thickness that acts as an adhesive is 1 mm, ε _c =x/h=1/1. In addition, the rigidity of SL compound (20℃ x 1 year)
Let G _s be the elastic modulus of the SL compound (20
℃ × 1 year) is expressed as E _s , then the stiffness modulus G _s is G _s = 1/3E _s If E _s is 20℃ and the loading time is 1 year, the stiffness coefficient is expressed as S _s . _s = 1/3S _s If we calculate S _s = 8×10 ⁰ N/m ² as the experimental value, E _s ≒ S _s , so ε _c G _s = 1/1×1/3×8×10 ⁰ = 8/3Nm ² So if the unit is g/cm ² then 1Kg/cm ² = 10 ⁵
Converted in N/m ² , ε _c G _s = 8/3 Nm ³ = 2.6×10 ^-5 Kg/cm ² ≒0.026 g/cm ² Also, adhesive work = 10 ₂ erg≒10 ^-4 Kg/cm ² =0.1
g/cm ² , which is close in order to the above value. Therefore, from this calculated value, the adhesive strength of the SL compound under long-term loading is determined to be approximately 0.1 g/cm ² . (3) Estimation of adhesive strength of rubber asphalt compound for adhesive layer. Rigidity coefficient G _RA : Value at 20℃ x 1 year Stiffness coefficient S _RA (Value at 20℃ x 1 year) is an experimental value for determining the adhesive failure value σ _b of rubber asphalt S _RA = 4.5 x 10 ⁴ N/ ^m2 was calculated. G _RA = 1/3S _RA = 1/3 x 4.5 x 10 ⁴ N/m ² Assuming that the displacement is 1 mm/1 mm as in equation (2), σ _b = ε _c G _RA = 1/1 x 1/3 x 4.5×10 ⁴ =1.5×10 ⁴ N/m ² =1.5×10 ^-1 Kg/cm ² =150g/cm ² is calculated. (4) Calculation of shear stress reduction of SL compound layer. If the SL compound layer is firmly adhered to the building frame, displacement will occur on the surface and the shear stress will be reduced. The calculation formula is τ _s = ds/3h. Here, τ _s : The value by which shear stress is reduced, d : Assuming that the displacement is 100 mm, 100 mm = 1
×10 ^-1 m. h: If the compound thickness is 4.5mm, 4.5mm=4.5
×10 ^-3 m. S ₈ : Stiffness coefficient at 20℃ x 1 year = 8 x 10 ⁰ N/
m ² = 8N/m ² = 8×10 ^-4 T/m ² ∴τ _s = dS/3h = 1×10 ^-1 ×8×10 ⁰ /3×4.5×10 ^-3 =8×10 ^-1 / 13.5×10 ^-3 59N/m ² = 5.9×10 ^-4 Kg/cm ² = 0.59g/cm ² . The following is clarified from the calculated values in (2), (3), and (4) above. In other words, (a) When (2) and (4) are combined, the value of (2) < the value of (4), and when the SL compound is applied as a sheet, the sheet will be smooth from the surface due to lack of adhesive strength. It is presumed that there is a concern that the sheet may bulge or wrinkle without sliding. (b) When (3) and (4) are combined, the value of (3) > the value of (4), and the SL sheet has almost no change on the adhesive surface.
It can be seen that only the SL layer slides from the surface and occurs uniformly and smoothly. (5) When constructing a waterproof layer on underground vertical walls. The waterproof layer has a large elastic modulus E, or stiffness coefficient, and this increases further when a core material is inserted, so the effect of shear stress due to earth pressure and soil sinking is large, but the adhesive surface follows the increasing displacement. Since there is a concern that the waterproof layer is likely to break, especially with shifting and peeling of the joints, it is necessary to take a method to reduce the shear stress acting on the surface by providing an SL layer. [Embodiment] FIGS. 1 and 2 show an embodiment of the present invention, and the present invention will now be described based on the illustrated example.
The sliding asphalt sheet (hereinafter referred to as SL sheet) (A) of the present invention has a 1SL compound layer,
2 adhesive layers, 3 polypropylene non-woven fabrics (100g/
m ² ) and 4 are release papers laminated on the surface of the adhesive layer 2, and their thicknesses are as follows. Polypropylene nonwoven fabric 0.6mm SL compound layer 4.5mm Adhesive layer 1.0mm Release paper 0.2mm Total 6.3mm The physical properties of the above examples are as follows.

〔Effect of the invention〕

As described above, the present invention is made by laminating an adhesive layer on one side of a slippery asphalt compound and laminating a woven fabric or non-woven fabric on the other side, so it can be used for structures constructed on soft ground, coastal reclaimed land, etc. In other words, it can be applied to underground buildings, subways, public ditches, sunken boxes, etc.
It can be made into an epoch-making civil engineering material that can prevent uneven settlement of buildings and also prevent rupture of waterproof layers. Furthermore, since the present invention is easy to handle, it can be easily applied to concrete support piles and steel sheet piles at construction sites, and work efficiency can be improved. The asphalt compound of the present invention is a compound containing asphalt as a main component and mixed with paraffin, grease, and other inorganic fillers. A rubber asphalt compound is a compound whose main component is a mixture of asphalt and synthetic rubber, which also contains a synthetic resin and an inorganic filler.

[Brief explanation of the drawing]

Fig. 1 is a side view of one embodiment of the present invention, Fig. 2 is a perspective view thereof, Figs. 3 and 4 are explanatory diagrams of the state in which it is applied to a vertical wall, respectively, and Fig. 5 is an adhesive based on rheological theory. It is an explanatory view of fracture. 1...SL compound layer, 2...Adhesive layer, 3
...Polypropylene nonwoven fabric, 4...Release paper, 5...
...Vertical wall surface, 6...Rubber asphalt primer, 7...Waterproof layer.

Claims (1)

[Claims] 1 The sliding layer is an asphalt compound having a stiffness coefficient of 10 ⁰ to 10 ³ N/m ² and a thickness of 2 to 10 mm at 20°C and a loading time of 1 year. coefficient
An adhesive layer of rubber asphalt compound with a thickness of 0.5 to 3 mm is laminated at 10 ⁴ to 10 ⁷ N/m ² , and a release paper is adhered to the surface of the adhesive layer, and the other surface has a stiffness coefficient of 0.5 to 3 mm. An asphalt sheet having sliding properties, characterized in that woven or nonwoven fabrics made of synthetic fibers or natural fibers having a stiffness coefficient significantly higher than the stiffness coefficient of the layers are laminated and bonded.