JP4869032B2 - Acid resistant strong anchor - Google Patents

Description

  The present invention relates to an acid-resistant strong anchor suitable for use in civil engineering facilities such as rockfall prevention and avalanche prevention.

Mainly as a measure to prevent falling rocks, landslides, and avalanches on slopes, wire ropes are laid in a grid and covered with a combination of wire rope and wire mesh. A method of placing a fence on the surface and suspending it with a wire rope from the mountain side is used.
In such a construction method, it is important to anchor the end of the wire rope firmly to the ground. However, if the construction site is a strong acid soil such as a volcanic area or a hot spring area, or an acidic gas atmosphere, further acid rain In recent years, it is said that acidification of groundwater proceeds and the deterioration of cement as a fixing material for anchoring is promoted, and the corrosion of the anchor body is accelerated by acid.

Conventionally, it has been proposed to use cement as a fixing material and to pierce it with an anchor, which eliminates the need for on-site metering and pouring, thus simplifying the work. However, because the main component is early strong Porland cement, in sewage, hot springs, acid rain, and other areas that have chemically severe ph values of about 3 or less, the durability of the cement is low and it is fixed by acidity. Strength reduction and surface defects were inevitable.
Moreover, since the anchor body to be fixed by the fixing material is generally made of steel, the corrosion resistance is impaired in severe corrosive environments such as those exposed to seawater and sea breeze as described above, and the acidic atmosphere of saltwater inflow rivers and volcanic areas. As a result, the strength is reduced, and the service life is shortened.

  The present invention has been made in order to solve the above-mentioned problems. The object of the present invention is to have extremely high acid resistance and high strength over a long period of time, and can be applied with good workability and severe corrosion. The object is to provide an acid-resistant strong anchor suitable for civil engineering facilities such as rock fall prevention and avalanche prevention installed in the environment.

In order to achieve the above object, the present invention is an anchor in which an anchor body is inserted into a drilling hole and fixed with a cement-based fixing material, and the fixing material is C ₃ A (tricalcium aluminate): 0. 2 to 1.5%, C ₃ S (tricalcium silicate): 60 to 70%, C ₂ S (dicalcium silicate): 15 to 25%, C ₄ AF (tetracalcium iron aluminate): 10 to 10% It is made of an acid-resistant constituent compound containing 15%, and the anchor body is powder coated with isoterephthalic acid copolymerized saturated polyester having 8-20 mol% isophthalic acid and 0.7-1.0% intrinsic viscosity on the surface of the main body. It is characterized by that.

Since the fixing material is a sulfate-resistant Portland cement in which the fixing material is different from the early-strength Portland cement, the tricalcium aluminate is greatly reduced. Therefore, the oxidation is reduced, the strength is hardly lowered and the surface defect is not easily caused. / Mm ² or more can be sufficiently satisfied. Moreover, the anchor body to be fixed has a powder coating film of isoterephthalic acid copolymerized saturated polyester having an isophthalic acid content of 8 to 20 mol% and an intrinsic viscosity of 0.7 to 1.0% on the surface, The powder coating film has strong adhesion to the anchor surface and at the same time has excellent adhesion to the fixing material, sulfate-resistant Portland cement. By combining the fixing material and the anchor body, high acid resistance can be obtained in the entire construction method, and the anchoring strength is high and it can be a stable anchor over a long period of time.

Preferably, the anchor body has irregularities on the surface where the ratio (a / b) of the cross-sectional circumferential length a before painting to the cross-sectional circumferential length b after painting ranges from 0.8% to 1.0%. The coating thickness of the convex portion is 300 microns or less.
According to this, it is possible to reinforce the adhesion between the specific fixing material and the anchor body in combination with the good adhesion of the anchor body coating film, and the coating film is thin and the anchor deformed state can be maintained. Therefore, the shear failure of the coating structure due to the anchor pull-out force does not occur, and strong integrity can be maintained.
The anchor body includes not only deformed reinforcing bars and bolts but also wire ropes. When the anchor body is composed of a wire rope, a wire rope that is a facility constituent member can be used, so that it is not particularly necessary to prepare a dedicated anchor body, and construction costs can be reduced.
Since the isoterephthalic acid copolymerized saturated polyester having an isophthalic acid content of 8 to 20 mol% and an intrinsic viscosity of 0.7 to 1.0%, which is a coating film, has a viscosity close to water when the melting temperature is reached, The fine irregularities and gaps between the twisted strands of the rope are well wetted and solidified. In addition, the weather resistance is good, the coating film is tough, and the coating does not peel off from the ground even with a strong impact at the time of breaking in a tensile test, for example, and the adhesion is excellent, and the adhesion strength is 3 to 5 times that of the epoxy resin Therefore, the coating surface does not crack and has excellent durability.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
1 to 4 show an example in which the acid-resistant strong anchor according to the present invention is applied to a rope net that is a natural protection type rock fall prevention work.
As shown in FIG. 1 and FIG. 2, this rope net is formed by connecting a large number of parallel vertical wire ropes 1 and horizontal wire ropes 2 in a grid pattern with a spacing of, for example, 2000 mm, and forming a rope net RN having a mesh shape as a slope. Since it can be cut down to the minimum by adjusting the mesh of the rope according to the position of the tree WO, it can effectively suppress the float stone ST and is naturally friendly It is said to be a construction method.

The intersecting portion of the vertical wire rope 1 and the horizontal wire rope 2 is coupled by a fastener 3 such as a cross clip or a cross clip. Further, between the vertical wire rope 1 and the horizontal wire rope 2, reinforcing ropes 1a and 2a are, for example, 500 mm. They are arranged at intervals, and the intersections are joined by the fasteners 3 in the same manner as described above.
The mountain-side end portion and the valley-side end portion of each vertical wire rope 1 are anchored to the ground, the left and right end portions of the horizontal wire rope 2 are anchored to the ground, and the mesh intersection is also anchored to the ground. When the ground is earth and sand, a pipe anchor PAK is used and driven into the ground and held by frictional force. However, the present invention is applied when the ground is rock. In FIG. 1, black squares indicate the anchor AK of the present invention.

  FIG. 3 shows an anchor portion to which the present invention of FIG. 2 is applied. An anchor body 5 is loaded into a cylindrical hole 4a drilled in the rock mass 4 and fixed by an acid-resistant cement-based fixing material 6. The anchor body 5 protrudes to the ground surface. In this example, as shown in FIG. 1 (c), the eye 100 (200) at the end of the wire rope 1 (2) is fitted, and the top and bottom are sandwiched between two plates. It is fixed by screwing a nut onto the upper end and tightening.

The anchor body 5 has a surface with irregularities, specifically, a deformed reinforcing bar, a threaded rod, a wire rope, or the like (in this example, a deformed reinforcing bar is used), and the surface has isophthalic acid 8. A powder coating film (baking coating film) 7 made of isoterephthalic acid copolymerized saturated polyester having a viscosity of ˜20 mol% and an intrinsic viscosity of 0.7 to 1.0% is applied. Preferably, the anchor body 5 is subjected to anticorrosion plating on the surface on which the powder coating film is applied. According to this, since double corrosion prevention is achieved by the anticorrosion plating and the resin coating thereon, durability can be improved.
The unevenness is preferably such that the ratio (a / b) of the cross-sectional circumferential length a before painting to the cross-sectional circumferential length b after painting is 0.8 to 1.0%. This is because if (a / b) is 0.8% or less, a sufficient corrosion resistance effect cannot be obtained, and if it exceeds 1.0%, there is a concern that the coating film may be broken by a tensile force. is there.

The reason why the isophthalaleic acid component is limited as described above is that if less than 8%, the adhesion is impaired, and if it exceeds 20%, the crystallinity decreases. The reason why the viscosity is limited is to suppress the progress of crystallization. However, a high molecular weight polymer is necessary to coat the surface with good fluidity.
When the modified saturated polyester resin reaches a certain temperature, the viscosity is remarkably lowered to a so-called “shabu-shabu” state like water. For this reason, it enters into a minute gap and wets and solidifies the solid there to form a film. Moreover, the adhesiveness is very good and the adhesive strength reaches 150 kg / cm ² .

Even when a wire rope is used as the anchor body 5, the resin has a viscosity close to water when the melting temperature is reached, so that fine irregularities and gaps between twisted strands are well wetted. Solidified. In addition, the weather resistance is good, the coating film is tough, and the paint does not peel off from the background of the rope even in the case of a strong impact at the time of breakage in a tensile test. Since it reaches 3 to 5 times that of epoxy resin, cracks do not occur on the painted surface even when the rope is bent, and the durability is excellent.

In general, the powder coating film 7 preferably has a thickness of 40 to 300 μm, and particularly preferably 40 to 170 μm when the anchor body is a wire rope. The reason why the lower limit of the thickness is set to 40 μm is that when the thickness is reduced to 40 μm or less due to the particle size of the resin, open-pore pinholes that escape from the surface to the coating film surface are generated. The upper limit of the thickness is set to 170 μm. If the thickness exceeds this value, the rope becomes stiff, difficult to bend and handling becomes worse, and there is a risk of partial cracking when bent with a small bending radius. Because.

In order to obtain the powder coating film 7, the surface is first shot blasted, and then the resin powder is adhered to the anchor body surface using an electrostatic coating apparatus. The shot blasting process is for obtaining strong adhesion between the anchor body surface (plating layer) and the resin. The shot material is sprayed on the entire circumference of the anchor body surface, so that the surface is made into a satin finish with fine irregularities. It is processed.
The electrostatic coating apparatus uses, for example, electrostatic spraying, and is performed by charging resin powder and spraying the anchor body surface with an air gun. As a result, the resin powder is shot blasted and adhered to the surface of the anchor body 5 on which irregularities are scattered by static electricity. When the anchor body 5 is a wire rope, the resin powder has a particle size finer than 80 mesh pass, preferably finer than 120 mesh pass, in order to easily enter the gap between adjacent strands or the gap between strands. The coating conditions are controlled so that the thickness is 40 to 170 μm.

Thereafter, the anchor body 5 is heated (in the case of a rope, it is passed through a heating device), and is heated and melted to a predetermined temperature above the melting point of the resin powder, followed by cooling and fixing.
In the case of a rope, high-frequency heating is suitable. When a high frequency is applied to the rope by a high-frequency coil while the rope is running, heat is diffused from the surface of the rope to the inside to achieve a uniform heating state. The resin powder melts from the lower layer in contact with the rope surface, flows into innumerable irregularities by shot blasting, bites in and adheres like a rust, and forms a uniform film on the surface of the strand and the surface of the strand.

Since the rope has large irregularities unlike the round wire, when the high-temperature heating is suddenly applied to the rope at room temperature, the temperature difference between the peaks and valleys is large, causing uneven heating and making it difficult to obtain a stable coating surface. Therefore, preheating is performed before the electrostatic coating. This preheating may be high frequency heating or atmosphere heating. When two-step heating is performed using such a preheating process, since the temperature difference between the peak and valley of the rope can be reduced, unevenness in coating quality at the peak and valley is suppressed, As a whole, a uniform thin film having no pinhole can be obtained.

Next, the fixing material 6 will be described. The fixing material 6 is composed of a sulfate-resistant Portland cement having the following constituent compounds, and is normally in a powder form as shown in FIG. The fixing material 6 is packed in a capsule container 6a having a water-permeable cylindrical shape such as Japanese paper, cloth, or nonwoven fabric that dissolves when immersed in water for a certain period of time.
C ₃ A (tricalcium aluminate): 0.2 to 1.5%
C ₃ S (tricalcium silicate): 60-70%
C ₂ S (dicalcium silicate): 15-25%
C ₄ AF (tetracalcium iron aluminate): 10-15%
The remainder includes magnesium oxide (MgO), sulfur trioxide (SO3), chloride ions, total alkali, and the like.

As is well known, Portland cement is composed of calcium silicate compounds called tricalcium silicate (alite) and dicalcium silicate (belite), and trialuminate present to fill the gaps between these compound crystals. There is a porous phase consisting of calcium (aluminate phase) 3CaO.Al ₂ O ₃ and iron calcium tetraaluminate (ferrite phase), and early strength Portland cement is composed of tricalcium silicate in the calcium silicate compound. Is relatively increased, and the initial strength is increased.
However, in ordinary Portland cement and early-strength Portland cement, tricalcium aluminate hydrate, which accounts for a considerably high proportion of 5 to 10% of the chemical composition, is easily eroded by sulfate. Therefore, the present invention is one in which the composition ratio of tricalcium aluminate is reduced by 1/3 or more than that of early strong Portland cement, thereby improving the sulfate resistance. The reason why the above range is limited is that sufficient hydration activity cannot be obtained outside this range, and a predetermined strength cannot be obtained.

FIG. 4 shows a process of constructing an anchor using the fixing material 6 and the anchor body 5. First, as shown in FIG. 4 (a), a cylindrical hole 4a is formed in the rock mass 4 to a predetermined depth by a rock drill or the like. On the other hand, as shown in FIG. 4 (b), water is put into the dish-like container 6b and the capsule container 6a is immersed therein to absorb water for about 4 to 5 minutes, so that the fixing material 6 can be hydrated. Put it in a state.
Since the fixing material 6 is filled in the capsule-like container 6a, it is convenient to carry on the construction site, easy to manage the immersion of water in the cement, and to obtain stable quality. This eliminates the need for simplification of work and enables construction for a short time.

Next, the fixing material 6 that has absorbed water as shown in FIG. 4 (c) is inserted into several cylinder holes 4a, and the anchor body 5 is inserted from above as shown in FIG. 4 (d) and moved up and down. The capsule container 6a is broken to cause the fixing material 6 to flow and diffuse around the anchor body 5 in the cylindrical hole 4a. As a result, the fixing material 6 is sufficiently adhered to the anchor body 5 in the cylindrical hole 4a and integrated by solidification curing.
As described above, the anchor body 5 has irregularities on the surface, the powder coating film 7 has very good adhesion, and the powder coating film 7 is composed of the specific component (constituent compound) sulfate-resistant Portland cement. Since the affinity is good, the degree of adhesion stress (N / mm ²⁾ is very high and it is integrated tightly and firmly.

And in the obtained anchor, since the oxidation resistance of the fixing material 6 as a solidified filler in contact with groundwater or acid rain is high, the strength reduction and surface defects are eliminated, and the anchor body 5 is also a powder coating film 7. Since it exhibits higher corrosion resistance, it can be made into a rope net with stable yield strength over a long period even under acidic conditions.

FIGS. 5 to 8 show an example in which the present invention is applied to an anchor for a curtain net for preventing falling rocks, wherein a is a swamp, N is a curtain net installed in a swarm a, and many are arranged at intervals. A wire mesh M is stretched over a flexible grid-like skeleton composed of a plurality of horizontal ropes 2 spaced apart from a vertical rope 1, and the mountain side is the most along the upper edge of the curtain net N. Posts S that support the upper rope RT are erected at a predetermined interval.

The uppermost rope RT is extended to the left and right of the swab portion a, and in this example, the portion on the right side of the paper surface is connected to the anchor AK of the present invention embedded in the rock. The left portion of the uppermost rope RT is connected to the earth and sand anchor device A.
Further, in the portion on the right side with respect to the paper surface, about two vertical ropes 1 are led to the mountain side and connected to the anchor AK of the present invention. And in the part on the left side with respect to the paper surface, the vertical rope 1 is guided to the mountain side and connected to the anchor device A for earth and sand.

The anchor AK according to the present invention is shown in FIGS. 6 to 8, and is an anchor composed of a wire rope inserted into the rock mass 4 at a required angle, for example, 25 to 90 degrees with respect to the horizontal line, and fixed by the fixing material 6. It comprises a body 5 and a rope portion 5a that extends on the surface side and extends to the ground surface side. In this embodiment, a saddle receiver 8 disposed on the ground surface portion of the rope portion, and a load direction placed on the saddle receiver 8 A conversion saddle 9 is provided.
The rope portion 5a extends along the surface of the load direction changing saddle 9 and extends in a direction crossing the longitudinal direction of the saddle, and the top end of the rope is directly or via a connecting portion such as an eye, the uppermost rope RT, A main rope such as a vertical rope 1 or a horizontal rope 2 is connected. Of course, the rope portion 5a may be extended as it is to form the uppermost rope RT, the vertical rope 1, and the horizontal rope 2.

The anchor body 5 is made of, for example, a wire rope (including a cable) having a length of 2000 to 4500 mm, and the fixing material that has absorbed water in the hole 4a formed in the rock mass 4 as shown in FIG. 6 (capsule-like container 6a) is inserted, and then the anchor body 5 is inserted as shown in FIG. And the part 5a which extended the anchor body 5 is direction-changed by the saddle 9, and is extended like FIG.8 (c).
The fixing material 6 is the same as that shown in the first embodiment, and the fixing process is the same as that shown in FIG.

The wire rope as the anchor body 5 has a rope portion 5a having a required length extending to the ground surface, and the rope portion and the anchor portion are integrally formed of a single kind of member. By adopting such a configuration, the number of members is reduced, and since it is more flexible than being a rope, it can be rolled up on a drum and carried to the site, and cut to the required length at the site. Since the anchor body can be made, there is an advantage that it can be easily adapted to the situation in the field.
The rope portion and the anchor portion are optional, such as a 7 × 7 structure, and the entire surface is subjected to corrosion-resistant plating, such as zinc plating, preferably zinc-aluminum alloy plating, and the specific powder described in the first embodiment on the surface. It has a body coating film 7.

The anchor body 5 in the second embodiment is required to have a powder coating film 7 on the surface, but the main rope such as the uppermost rope RT, the vertical rope R1 or the horizontal rope R2, the first embodiment It is preferable that the vertical wire rope 1, the horizontal wire rope 2, and the reinforcing ropes 1 a and 2 a also have the powder coating film 7.
9 to 10 show examples of such an anchor body 5 and a wire rope connected thereto, 10 is a rope body having a diameter of 6 mm or more, and a plurality of strands 10b obtained by twisting a plurality of strands 10a. In this example, it is a 3 × 7 structure, and a trough 11 is formed between the strands.

The material of the element wire 10a is required to have corrosion resistance, and is usually made of iron or steel, and the surface thereof is plated with zinc, zinc aluminum alloy or the like.
The entire surface of the rope body is baked and coated with a saturated polyester-based synthetic resin containing isophthalic acid in an amount of 8 to 20 mol% and an intrinsic viscosity of 0.7 to 1.0.

In this example, the resin powder is not directly applied to each strand constituting the rope, but directly on the entire surface of the rope formed by twisting a plurality of strands 10b obtained by twisting three or more strands. After adhering and melting the body, it is solidified and adhered.
According to this, it is possible to produce an efficient operation in one step. In addition, the entire rope created by twisting the strands is coated directly, and the entire rope is covered with a coating, rather than being coated on the strands and twisting the strands. No peeling or damage occurs. Therefore, good corrosion resistance can be obtained.

  The baked coating film 7 is thin so that irregularities on the rope surface can be visually confirmed, and is applied so that the peaks and valleys of the adjacent strands 10a and 10a are clearly visible. That is, as shown in FIGS. 10 (a) and 10 (b), a V-shaped film 7a is formed in the valley between adjacent strands 10a and 10a. The film is formed along the outer contour of the adjacent strand. The film is continuous along the contour of the cross section and is a uniform thin film without pinholes.

  The thickness of the coating film is 300 μm or less, preferably 40 to 170 μm. The reason is as described above. Then, as shown in FIG. 10 (b), if the length of the coating film dent between the adjacent strands 10a and 10a on the outermost surface is L and the strand diameter is d, (L / d) × 100 ( %) Is 6% or more. This is an index for the thin and uniform coating thickness at any location on the rope cross section, and by satisfying this condition, uniform corrosion resistance and flexibility (ease of bending) of the rope are maintained.

If L / d is less than 6%, the unevenness of the strands becomes invisible, and the gap between the adjacent strands 1a and 1a is filled with resin, which is not appropriate because the rope becomes rigid and difficult to bend. Moreover, because the coating film has a thin, uniform and sharp contour due to the indentation condition of the coating film between the strands, the slippage of the rope is prevented when the ropes are crossed and clamped with clamp fittings during use, It becomes possible to fix in an orthogonal shape reliably.

FIG. 11 shows another example of the rope according to the present invention, in which the entire rope body 1 having a 7 × 19 structure is provided with the baked coating film 7 so that the trough portion 11 is buried and becomes a rod shape. And evenly coated. Since other configurations are the same as described, the description is incorporated.

12 and 13 show another example of the rope with a powder coating film according to the present invention, 10 is a rope having a diameter of 6 mm or more, and a plurality of strands 10a are arranged as shown in FIGS. A twisted strand body 10b is coated with a stranded coating film 7 provided on the surface thereof, and a plurality of these strands are twisted together to form a 7 × 7 structure in this example. The baking coating film 72 is applied so that the peaks and valleys of the adjacent strands 10a and 10a are clearly visible.
FIG. 14 shows an example of the rope of the present invention, in which three coated strands 10b each having a baked coating film 7 applied to the surface of the strand body are twisted to form a 3 × 7 structure. Since other configurations are the same as described, the description is incorporated.

Although there is no limitation in the manufacturing method of the resin powder coating metal rope of the present invention, in FIGS. 9 to 11, a rope body formed by twisting a plurality of strands further is created, and while running the rope, First, shot blasting is performed on the surface, and then resin powder is adhered to the rope surface using an electrostatic coating apparatus. 12-14, while running the strand main body which twisted three or more strands, the surface is first shot blasted, and then the resin powder is attached to the strand surface using an electrostatic coating apparatus. .

After that, it is rapidly heated by passing through a high-frequency heating device, heated up to a predetermined temperature above the melting point of the resin powder, and then cooled and fixed. It becomes a state. The resin powder melts from the lower layer in contact with the strand surface, flows into countless irregularities by shot blasting, bites in and adheres like rust, and forms a uniform film on the surface of each strand and the strand that aggregates it. Form.
Since the strands have large irregularities unlike the round wires, when the strands at room temperature are suddenly subjected to high-frequency heating, the temperature difference between the peaks and valleys is large, so that heating unevenness occurs and it is difficult to obtain a stable coating surface. Therefore, preheating is performed before the electrostatic coating. This preheating may be high frequency heating or atmosphere heating. When two-step heating is performed using such a preheating process, the temperature difference between the peak and valley of the rope can be reduced, so that uneven film thickness at the peak and valley is suppressed. As a whole, a uniform thin film having no pinhole can be obtained.

In FIGS. 12 to 14, a plurality of coated strands 10b are twisted together by a known twisting machine to form a rope, which is a two-step process of coating the strands → twisting the ropes. Since the twisting after coating is less than the three steps of coating to strands, twisting to strands, and twisting to ropes, it is possible to reduce the occurrence of peeling and damage of the coating film due to the wound of the strands.

Further, since the strands are coated, it is possible to make a rope with a colorful pattern by making two or more different coating colors of the strands and twisting the strands of different colors. For example, if you combine black and yellow strands, it will become a safety alert rope, twisting strands that have all the colors will make a rainbow-colored rope, and combining strands painted in green or skin color will make a camouflage rope It can be said.

Specific examples of the anchor body 5 of the present invention and the wire rope connected thereto are as follows.
Example 1:
A wire rope body with a diameter of 30mm and a 3x7 structure in which three strands of seven strands of galvanized wire are twisted together are very uniform with an average coating thickness of 120μm (L / d) A baked coating of isoterephthalic acid copolymerized saturated polyester having an intrinsic viscosity of 0.7 to 1.0 and containing 100 to 8.2 mol% of isophthalic acid having no pinhole of 8 to 20 mol%. This coating does not peel even when subjected to a strong impact at the time of tensile break, and the adhesion of the coating film is good, and it is confirmed that peeling and cracking do not occur even when wound on a drum used for winding ordinary non-painted ropes It was done. Even after 5000 hours passed through a salt spray tester, no rust or cracks were generated.

Example 2:
In addition, 7 strands of 19 strands galvanized and 7 strands are twisted together. As shown in FIG. An isoterephthalic acid copolymerized saturated polyester having an intrinsic viscosity of 0.7 to 1.0 was baked and applied.
The coating thickness averaged 70 μm, no pinholes, and (L / d) × 100 was 7.9 (%). This coating does not peel even when subjected to a strong impact at the time of tensile break, and the adhesion of the coating film is good, and it is confirmed that peeling and cracking do not occur even when wound on a drum used for winding ordinary non-painted ropes It was done. Even after 5000 hours passed through a salt spray tester, no rust or cracks were generated.

Example 3:
A strand obtained by twisting together seven galvanized strands using isoterephthalic acid copolymer saturated polyester containing 8 to 20 mol% of isophthalic acid as a resin powder and having an intrinsic viscosity of 0.7 to 1.0. A thin resin without pinholes with a 1 × 7 structure of FIG. 13 twisted together and a 10 mm diameter strand with an average coating thickness of 118 μm and an average (L / d) × 100 of 7.2 (%) Powdered paint was applied. This coating was not peeled even by an impact at the time of tensile fracture, and the adhesion of the coating film was good.
Seven strands obtained were further twisted to produce a 7 × 7 rope having a diameter of 30 mm in FIG. Even if the rope is tightly wound around a drum having a diameter of 710 mm, which is used for winding an ordinary unpainted rope, no peeling or cracking of the coating occurs, and no abnormality is observed even when the rope is unrolled. There was no rust or cracking over time.

Example 4:
14 is coated in the same way on the entire circumference of a 1 × 7 strand with a diameter of 8.9 mm, in which seven strands that have been galvanized are twisted together, and the three coated strands are twisted together to form the 3 × 7 structure in FIG. A rope with a diameter of 18 mm was manufactured. As the resin powder, isoterephthalic acid copolymerized saturated polyester was blended with 3% titanium oxide and a pigment and stirred and mixed.
The coating thickness of the strand was 103 μm on average, no pinholes, and (L / d) × 100 was 7.6 (%). This coating was not peeled even by impact at the time of tensile fracture, and the adhesion of the coating film was good. Even when it was tightly wound around a drum having a diameter of 540 mm, peeling and cracking did not occur. Even if the rope was returned to the straight state, no abnormality was observed, and no rust or cracks occurred even after 5000 hours passed through the salt spray tester.

Next, specific examples of the fixing material 6 of the present invention will be shown.
Constituent compounds:
Tricalcium aluminate: 0.7%, tricalcium silicate: 64%, dicalcium silicate: 19%, iron tetracalcium aluminate: 13%, balance ( magnesium oxide, sulfur trioxide, chloride ions, total alkali Etc.) 3.3%
A specimen was prepared based on the fixing material and tested. For comparison, a test specimen was also prepared and tested for a conventional fixing material (Haya strong Portland cement). In the conventional fixing material, the constituent compounds are tricalcium aluminate: 5%, tricalcium silicate: 50%, dicalcium silicate: 28%, iron calcium aluminate: 12%, and the remaining 5%.
Each specimen was made to have a W / C ratio of 36% with respect to the cement paste, cured in a mold for 24 hours (20 ° C., 80 rh%), taken out from the mold, and subjected to a test after end face cutting. The dimension of the specimen is 30 mm in diameter and 60 mm in height. .

The specimen was n = 3, and the acid resistance test was immersed in 10 liters of sulfuric acid aqueous solution (0.5 wt%) adjusted to about pH 2.7, and the appearance change state was confirmed. In addition, the solution was exchanged in whole amount every week in consideration of pH increase due to cement.
The appearance changes greatly after 4 weeks of immersion. After 13 weeks of immersion, the conventional product showed surface peeling, precipitation, and discoloration, but the product of the present invention had no change and was immersed for 4 weeks. As a result of observing the internal cross section, the conventional product showed fine crack-like aqueous solution penetration traces, but the product of the present invention was not changed.

As a result of the compressive strength test, the conventional product was higher than the product of the present invention up to 14 days, but on the 28th, the average of the conventional product was 60.4 N / mm ^2. The average of the invention exceeded 62.3 N / mm ² , and on the 91st day, the average of the conventional product was 36.4 N / mm ² , whereas the average of the present invention was significantly different from 63.8 N / mm ^2. , 114 days later, the product of the present invention completely satisfied the compression strength standard value of 24 N / mm ² or more, and no decrease in compression strength was seen, but it was confirmed that the conventional product was below the standard value. . FIG. 15 shows the relationship between the number of days of immersion in sulfuric acid solution and the rate of change in compressive strength, and the product of the present invention shows no change in compressive strength. From this result, it can be seen that the constituent compound has excellent characteristics as an anchor fixing material.

Using the fixing material of the chemical component and the constituent compound, an allowable adhesion stress test with an anchor body (wire rope) was performed.
As the anchor body, a diameter of 30 mm having a 7 × 7 structure shown in FIG. This anchor body with a powder resin coating is set on a bottomed pipe having a diameter of 114.3 mm, a thickness of 4.5 mm, and a height of 300 mm, filled with the fixing material, fixed, and after a week or more, a tensile test Carried out. For comparison, a plating-only anchor body without a powder resin coating on the surface was prepared, and the above experiment was also conducted on this. The tensile test was performed by subjecting the other end of the anchor body to end alloy processing, fixing the pipe with the bottom, and pulling the end alloy processed portion with a tensile tester.

As a result, the comparative product had a tensile strength of 227.5 kN and an adhesion stress of 8.9 N / mm ² , but the product of the present invention reached a tensile strength of 356.5 kN and an adhesion stress of 11.4 N / mm 2. ² , a good result 7.1 times as large as the allowable adhesion stress degree of deformed reinforcing bar 1.6 N / mm ² was obtained. This is thought to be due to the very good adhesion between the powder resin coating film and the fixing material.
In addition, although the said test was done also about the thing with a diameter of 24 mm and 20 mm as an anchor body, the adhesion stress degree was 11.4-11.5 N / mm < ² > in all.

What is shown is a few examples of the present invention and is not limited thereto. For example, in the first embodiment, a deformed reinforcing bar is used as the anchor body, but this may be replaced with a wire rope as in the second embodiment.
Further, the present invention can be applied not only to anchors in rocks but also to anchors in earth and sand.

Industrial applicability

  The present invention supports and reinforces an anchor device, a rockfall prevention fence, an avalanche prevention fence, and the like that fix both ends of a rope stretched vertically and horizontally on a slope together with a wire net for rockfall prevention such as a curtain net. The present invention is applied to an anchor device for fixing a part of a rope, a wire rope net anchor device stretched in a net shape in the vertical and horizontal directions to prevent falling rocks, and the like.

(a) is a plan view of a rope net to which the anchor of the present invention is applied, (b) is a partial perspective view thereof, and (c) is a perspective view of the anchor portion. It is sectional drawing of FIG. (a) is the elements on larger scale of FIG. 2, (b) is an expanded cross-sectional view. (a)-(d) is explanatory drawing which shows a construction state in steps. It is a partial notch top view which shows the example which applied the anchor of this invention to the curtain net for rockfall prevention. It is an expanded sectional view of FIG. It is a schematic diagram of the anchor part of FIG. (a)-(c) is sectional drawing which shows a construction state in steps. It is a perspective view which shows an example of the rope used as an anchor body of this invention, or also a net component. (a) is the expanded sectional view of FIG. 9, (b) is the partially expanded view of (a). It is an expanded sectional view showing other examples of the rope of the present invention. It is an expanded sectional view which shows the other example of the rope used as an anchor body of this invention, or also a net component. (a) is an expanded sectional view of a strand, (b) is an enlarged view. It is an expanded sectional view showing other examples of the rope of the present invention. It is a diagram which shows the test result of this invention.

Explanation of symbols

5 Anchor body 6 Fixing material 7 Powder resin coating film 10 Rope body

Claims (3)

An anchor in which an anchor body is inserted into a drilling hole and fixed with a cement-based fixing material, and the fixing material is C ₃ A (tricalcium aluminate): 0.2 to 1.5%, C ₃ S (Tricalcium silicate): 60 to 70%, C ₂ S (dicalcium silicate): 15 to 25%, C ₄ AF (tetracalcium iron aluminate): 10 to 15% The anchor body is powder-coated with isoterephthalic acid copolymerized saturated polyester having an isophthalic acid content of 8 to 20 mol% and an intrinsic viscosity of 0.7 to 1.0% on the surface of the main body. Strong anchor.   The anchor body has irregularities with a ratio (a / b) of the cross-sectional circumference length a before painting to the cross-sectional circumference length b after painting in the range of 0.8% to 1.0%. The acid-resistant strong anchor according to claim 1, having a thickness of 300 microns or less.   3. The acid-resistant strong anchor according to claim 1, wherein the anchor body includes a case where the anchor body is made of a deformed reinforcing bar or bolt and a wire rope.

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