JP6793016B2 - Hydraulic composition and anchor fixing capsule using it - Google Patents

Description

The present invention relates to a hydraulic composition containing cement and an anchor fixing capsule in which the composition is sealed in a container.

Reinforcement work is being carried out to improve shear strength in order to increase the seismic strength and durability of existing concrete man-made structures such as culverts, dam bodies, tunnels and buildings, and ground such as bedrock and natural cliffs. ing. In addition, construction work is being carried out to attach structures such as rockfall protection nets and avalanche prevention fences to so-called stretched concrete that covers the slope and prevents it from collapsing. In these works, a cylindrical hole is formed in the concrete skeleton or ground forming the concrete structure with a rotary tool such as a drill or a core boring machine, and an anchor fixing agent and a container containing the anchor fixing agent are formed. An anchor fixing capsule having a long shape formed from concrete is inserted, and an anchor bolt such as a reinforcing bar is driven into the capsule to crush the container and the anchor fixing agent is placed.

Such construction is called the post-construction anchor construction method. When the container is crushed by driving the anchor bolt, the anchor fixing agent is filled between the anchor bolt and the inner wall surface of the drilled hole, and then cured. As a result, the anchor bolts are fixed to the concrete skeleton, bedrock, etc., and the shear strength of the existing concrete structure can be increased, or a workpiece can be attached to the anchor bolt.

As such an anchor fixing agent, a fixing agent for fixing bolts containing a resin such as epoxy acrylate and a curing agent such as dimethylaniline or naphthenate is disclosed in Patent Document 1. The resin is sealed in a glass container, the curing agent is sealed in a second glass container smaller than the first glass container in which the resin is sealed, and the second glass container is housed in the first glass container. Has been done. As a result, the resin and the curing agent are isolated so as not to be mixed with each other until the time of use.

Such a fixing agent for fixing bolts causes an unpleasant odor when the organic solvent that dissolves the resin volatilizes and cures, which causes deterioration of the working environment of construction workers and pollution of the natural environment. In addition, in order to pierce the first and second glass containers with anchor bolts and crush them simultaneously and reliably, it is necessary to use hammer drills and vibration drills to hit and rotate the anchor bolts while driving them. It doesn't become. This imposes a burden on construction workers that when driving anchor bolts into concrete on steep slopes, the driving equipment must be operated with unstable scaffolding. Furthermore, since noise is generated from the driving equipment during operation, when there is a private house near the construction site, the vibration and noise are limited to the standard values or less, and it is difficult to use such driving equipment.

On the other hand, as an anchor fixing agent, Patent Document 2 discloses an anchor fixing capsule in which a hydraulic composition such as cement is sealed in a container. This anchor fixing agent is immersed in water immediately before use, and the hydraulic composition absorbs water to cause a curing reaction and cure. Such hydraulic compositions do not cause malodor or volatilization of organic solvents. However, when this anchor fixing capsule is used for the construction anchor method in winter or cold regions where the outside temperature is lower than 5 ° C, for example, the low outside temperature and the water in which the anchor fixing capsule is immersed are cold water. Because of this, the curing reaction is delayed and the initial strength is inferior, or the time until the desired strength is developed is prolonged. Therefore, it is necessary to use warm water to accelerate the curing reaction under low temperature conditions, or to cure the construction site while keeping the construction site warm in order to obtain the desired strength at an early stage, which complicates the construction procedure. ing.

In order to cure the hydraulic composition quickly and with high strength under low temperature conditions, a method of reducing the amount of water absorption can be considered. However, if the amount of water absorption is reduced, the hydraulic composition becomes difficult to flow, and the anchor bolts are hardened without being sufficiently spread between the anchor bolts and the inner wall surface of the drilled holes to form voids, resulting in insufficient anchoring force of the anchor bolts. To do.

Japanese Unexamined Patent Publication No. 60-28478 Japanese Unexamined Patent Publication No. 58-156698

The present invention has been made to solve the above-mentioned problems, and has a fast-hardening property that cures quickly even when cast at a low temperature using cold water and a fast-hardening property that develops high strength at the initial stage of casting. A hydraulic composition with excellent workability that can maintain high strength for a long period of time and is highly fluid during construction, so that the inside of the drilled hole can be reliably filled and anchor bolts can be inserted without the need for equipment. , And an anchor fixing capsule using the same.

The hydraulic composition of the present invention made to achieve the above object is a hydraulic composition for cold regions that cures at a working temperature of up to 10 ° C. and / or an ambient temperature upon contact with water. , Portland cement, and hydraulic component comprising alumina cement and quick-setting admixture, and strength enhancers mainly composed of kaolin, and Nde including a fluidizing agent, and a condensation modifier, the alumina cement 50 parts by weight 20 to 40 parts by mass of the Portland cement, 10 to 30 parts by mass of the quick-setting agent, 1 to 10 parts by mass of the kaolin, 0.1 to 1 part by mass of the coagulation adjuster, and the fluidization. The agent is 0.1 to 1 part by mass .

In the hydraulic composition, the kaolin is preferably calcined kaolin.

The water-hard composition comprises, for example, 20 to 40 parts by mass of the Portland cement, 30 to 50 parts by mass of the alumina cement, 10 to 30 parts by mass of the quick-setting admixture, 1 to 10 parts by mass of the kaolin, and the condensation. Examples thereof include those in which the adjusting agent is 0.1 to 1 part by mass and the fluidizing agent is 0.1 to 1 part by mass.

In the water-hardening composition, the quick-setting agent contains gypsum, the coagulation adjusting agent is at least one selected from oxycarboxylic acid, lignin sulfonic acid, citric acid, and salts thereof, and the fluidizing agent is It is preferably at least one selected from polycarboxylic acid ethers, alkylallyl sulfonic acids, melamine sulfonic acids, and salts thereof.

The anchor fixing capsule of the present invention is one in which any of the above hydraulic compositions is enclosed in a water-permeable tubular container.

The anchor fixing capsule preferably has a length of 200 to 450 mm and a diameter of 20 to 40 mm.

The hydraulic composition of the present invention is excellent in quick-hardening and quick-strength, in which it rapidly condenses by contacting with cold water at 10 ° C. or lower and absorbs water to change into a hydraulic paste, and then cures to high strength. Even when casting in a low temperature environment such as winter or cold regions, it is possible to eliminate the need for hot water and curing with heat retention.

Since the hydraulic paste produced by water absorption of the hydraulic composition is extremely fluid, anchor bolts can be manually driven without using equipment, improving workability on slopes such as stretched concrete. ing. Furthermore, due to its high fluidity, it is possible to fill the periphery of the anchor bolt inserted in the drilled hole in the concrete without a gap. As a result, a high pull-out load can be applied to the anchor bolt.

According to the anchor fixing capsule of the present invention in which this hydraulic composition is encapsulated, the water absorption rate becomes constant 3 to 5 minutes after immersion in cold water, and water absorption does not exceed the required amount, so that construction management is simple. Construction efficiency can be improved.

When the anchor fixing capsule has a length of 200 to 450 mm and a diameter of 20 to 40 mm, it is easy to transport and store, and it is excellent in handleability.

It is a schematic partial cross-sectional view which shows the use method of the anchor fixing capsule which sealed the hydraulic composition to which this invention is applied. It is a graph which shows the result of the water absorption test of the Example which applied this invention. It is a graph which shows the result of the tensile test of the anchor bolt fixed to the rock by the anchor fixing capsule of the Example to which this invention was applied, and the comparative example to which this invention is not applied.

Hereinafter, embodiments for carrying out the present invention will be described in detail, but the scope of the present invention is not limited to these embodiments.

The hydraulic composition of the present invention contains a hydraulic component containing Portland cement, alumina cement, and a quick-setting agent, a strength enhancer containing kaolin as a main component, a fluidizing agent, and a coagulation adjusting agent. It is hardened in contact with water at a working temperature of 10 ° C. or lower and / or an ambient temperature.

The hydraulic component of the hydraulic composition is M-type expansion cement containing Portland cement, alumina cement, and a quick-setting admixture as essential. Portland cement contains silica (SiO ₂ ) and calcia (CaO) as main components, and examples thereof include those containing 20 to 25% by mass of silica and 60 to 70% by mass of calcia. In addition, alumina (Al ₂ O ₃ ), magnesia (Mg O), and iron oxide (Fe ₂ O ₃ ) are each contained in an amount of 1 to 6% by mass. These components exist, for example, as calcium silicate, calcium aluminates, and calcium aluminate ferrite.

Specific examples of Portland cement include ordinary Portland cement, early-strength Portland cement, ultra-early-strength Portland cement, moderate heat Portland cement, sulfate-resistant Portland cement, and white Portland cement. Among them, early-strength Portland cement is preferable. Only one type of these Portland cements may be used, or a plurality of types may be mixed and used.

Alumina cement is a special cement composed mainly of calcium aluminate _{(CaO · Al 2 O 3)} , for example, calcia 20-40 wt%, 40-80 wt% of alumina include those containing each ..

Fast-setting agents include sulfates such as sodium sulphate, potassium sulphate, aluminum sulphate, and calcium sulphate. As calcium sulfate, anhydrous gypsum (CaSO _4), hemihydrate gypsum _{(CaSO 4 · 1 / 2H 2} O), gypsum such as gypsum _(CaSO 4 · _2H 2 O) is increased production of which will be described later ettringite It is preferable from the viewpoint of developing high rapid toughness and quick hardening. These quick-setting agents may be used alone or in admixture of a plurality of types.

In the hydraulic composition of the present invention, the main component of the strength enhancer is kaolin. Kaolin contains silica and alumina. Specific examples of kaolin include calcined kaolin (2SiO ₂ · Al ₂ O ₃ ). Calcined kaolin, kaolin which is a natural clay mineral _{(2SiO 2 · Al 2 O 3} · 2H 2 O), was charged into the kiln such as a rotary kiln, at 700 to 750 ° C., or 20 to 25 minute residence time Obtained by baking. In addition to calcined kaolin, the strength enhancer may include siliceous powders such as blast furnace slag powder, fly ash, and / or silica fume.

When the water-hard component in the water-hard composition absorbs water, it disperses in water and changes into a fluid water-hard paste, which causes a hydration reaction to condense and then cure. Specifically calcium aluminate in an alumina cement, gypsum, and the reaction proceeds in water to form ettringite is calcium aluminate sulphate hydrate _{(3CaO · Al 2 O 3 ·} 3CaSO 4 · 32H 2 O). Ethringite is a bulky, water-insoluble acicular crystal, and as it grows, the water-hard paste expands and hardens. Moreover, the gypsum contained in the hydraulic composition serves as a source of calcium sulfate, increases the amount of ettringite produced, and forms a high-strength cured product.

The water-hard paste contains a large amount of calcium hydroxide (Ca (OH) ₂ ) in which calcia in alumina cement is dissolved in water. Kaolin contained in the strength enhancer causes a so-called pozzolan reaction with this calcium oxide to produce a hydrate insoluble in water. Thus, for example, calcium silicate hydrate _{(3CaO · 2SiO 2 · 3H 2} O) and, is fine and dense crystals of calcium aluminate hydrates _{(3CaO · Al 2 O 3 ·} 6H 2 O) to generate , Hardens hydraulic paste to high strength. In particular, compared to blast furnace slag that is pulverized by crushing and fly ash that has a relatively large spherical shape due to coal ash, the calcined kaolin particles are finer and therefore have a larger surface area per unit mass. There is. Therefore, calcined kaolin has much higher pozzolanic activity than other siliceous powders, so that dense hydrate crystals are rapidly formed. This gives the hydraulic composition early toughness.

As described above, the hydraulic composition contains an alumina cement, a quick-setting agent such as gypsum, and a strength enhancer containing kaolin as a main component, so that the cured product can be produced for several hours to 1 day after casting. It is excellent in quick-hardening and fast-strength, which develops high strength to some extent.

Further, the formation of ettringite and the pozzolan reaction proceed rapidly without delay even at a working temperature of 10 ° C. or lower and / or a low temperature such as an ambient temperature. Therefore, since this hydraulic composition does not require the use of hot water or curing accompanied by heat retention, it can be suitably used for the post-construction anchor method in winter or cold regions. The working temperature is, for example, the air temperature at the work site when the anchor fixing capsule using the hydraulic composition is cured at the work site, and the ambient temperature is, for example, the anchor fixing capsule using the hydraulic composition. The temperature around the surface, specifically the temperature of the water in contact with the hydraulic composition, the temperature inside the drilling holes made in the concrete skeleton to drive the anchor bolts (see Figure 1), and the curing temperature. The temperature of the environment in which the hydraulic composition comes into contact when it condenses and hardens.

In parallel with the formation of ettringite and the pozzolan reaction, the hydration reaction of calcium silicate in Portland cement proceeds to produce a cured product of calcium silicate hydrate. As a result, the hydration reaction of calcium silicate is slower than that of calcium aluminates, so that although the quick strength and quick hardening of Portland cement are somewhat inferior to those of alumina cement, for example, 7 days to several days after casting. Excellent in maintaining strength for a long period of time after months.

Meanwhile, ettringite derived from alumina cement may gradually converted into a plate-like crystals of stable et Trinh Gaito monosulfate _{(3CaO · Al 2 O 3 ·} CaSO 4 · 12H 2 O), results in a decrease in strength than the initial .. Even in such a case, the strength of the cured product of calcium silicate hydrate derived from Portland cement does not cause a decrease in strength of the cured product of the hydraulic composition as a whole.

As described above, the hydraulic composition of the present invention contains Portland cement, alumina cement, and gypsum as hydraulic components, so that the hydraulic composition quickly cures even when cast in cold water at a low temperature. It has an early strength that develops high strength at the initial stage of casting, and can maintain high strength for a long period of time after casting.

The fluidizing agent is a surfactant that improves the fluidity of the water-hardened paste and ensures workability. Examples of the fluidizing agent include polycarboxylic acid ethers such as polymers of (meth) acrylic acid polyalkylene glycol ester, alkylallyl sulfonic acid, melamine sulfonic acid, and alkali metal salts and alkaline earth metal salts thereof. Of these, polycarboxylic acid ether is preferable. It is considered that the fluidizing agent generates extremely fine bubbles in the hydraulic paste, and these bubbles inhibit the aggregation of the hydraulic components in the hydraulic paste, promote the dispersion and improve the fluidity. Be done. By using the fluidizing agent, the amount of water required to impart the desired fluidity to the hydroponic paste can be reduced. As a result, the fluidizing agent can reduce the water / cement ratio, which is the mass ratio of water to the hydraulic component, to, for example, 27 to 32%, imparting high strength to the cured product of the hydraulic composition and cooling. Suppresses the occurrence of cracks in the hardened material caused by freezing water in the ground.

The coagulation adjuster is for controlling the coagulation time of the water-hardened paste and maintaining the pot life. As coagulation regulators, oxycarboxylic acids such as citric acid, gluconic acid, tartaric acid, malic acid, salicylic acid, m-oxybenzoic acid, and p-oxybenzoic acid, lignin sulfonic acid, and sorbitol, pentitol, and hexitol. Examples of sugar alcohols such as. The coagulation modifier may be an alkali metal salt such as a sodium salt, a lithium salt, and a potassium salt of an oxycarboxylic acid or a lignin sulfonic acid, and an alkaline earth metal salt such as a magnesium salt and a calcium salt. Of these, sodium citrate is preferable, and trisodium citrate is more preferable.

The coagulation modifier adsorbs to the particles of the water-hard component in the water-hard paste and coats the surface thereof. As a result, the coagulation modifiers generate electrostatic repulsion, and the particles of the water-hard component are dispersed without agglomeration, and contact with water is suppressed. As a result, the start of the hydration reaction of the water-hard component can be appropriately delayed to prevent the water-hard paste from instantly condensing, and the length of time from water absorption of the water-hard composition to the onset of condensation of the water-hard paste can be adjusted.

In such a hydraulic composition, the preferable content of each component is parts by mass. Portland cement: Alumina cement: Rapid binder: Strength enhancer: Coagulation adjuster: Fluidizer = 20-40: 30-50: It is preferably 10 to 30: 1 to 10: 0.1 to 1: 0.1 to 1, and is preferably 20 to 30:30 to 45:10 to 20: 1 to 5: 0.1 to 0.5: 0. .1 to 0.5 is more preferable, and 20 to 25:30 to 40: 10 to 18: 2 to 4: 0.2 to 0.5: 0.2 to 0.5 is even more preferable. preferable.

The hydraulic composition contains a somewhat larger amount of alumina cement than Portland cement in the hydraulic component, so that it can impart fast strength and quick hardness even in a low temperature environment such as a cold region. preferable. If the amount of Portland cement is larger than that of alumina cement, quick strength and quick hardening in a low temperature environment cannot be obtained.

If the content of the quick-setting agent is less than the above lower limit, the amount of ettringite produced is insufficient and the desired strength cannot be obtained. On the other hand, if the upper limit is exceeded, the amount of ettringite produced becomes excessive, which causes excessive expansion of the cured product and causes cracks in the concrete skeleton.

If the content of the strength enhancer is less than the above lower limit, the initial strength of the cured product is insufficiently developed and the early strength is impaired. If the value exceeds the limit value, unreacted fine powder of kaolin remains in the cured product and hinders the crystal growth of the hydrate, thus reducing the strength of the cured product.

Further, if the contents of the coagulation adjuster and the fluidizing agent are less than the above lower limit values, the water-hardened paste does not flow sufficiently and the coagulation termination is reached during casting, so that the coagulated water-hardened paste becomes It clings to the anchor bolt and the insertion resistance of the anchor bolt increases, which makes manual construction difficult and impairs workability (see FIG. 1 (c)). In addition, poor filling of the gap between the inner wall of the drilled holes made in the concrete skeleton or stretched concrete and the anchor bolt causes a decrease in the pull-out strength of the anchor bolt. In particular, the content of the fluidizing agent is preferably at least 0.4 parts by mass with respect to 100 parts by mass in total of the water-hardening component containing Portland cement, alumina cement, and the quick-setting admixture and the strength enhancer. On the other hand, if the content of the fluidizing agent exceeds the upper limit, the hydration reaction of the water-hard component is inhibited, so that the condensation and curing of the water-hard paste are delayed and the rapid strength and quick-hardness of the cured product are impaired. In addition, the long-term strength is reduced.

Among them, the content of the coagulation adjuster is preferably 3.7 parts by mass at the maximum, and more preferably 1.2 parts by mass, with respect to 100 parts by mass in total of the water-hardening component and the strength enhancer. .. If this content is exceeded, the temperature of the water in contact with the water-hardening composition will rise during construction, or the temperature of the hardened body will rise slightly when the hardened body is exposed to direct sunlight, for example. Due to such a change in temperature, the onset of condensation of the water-hardened paste is delayed, the setting time is prolonged, and the quick-hardening property is impaired, and the desired strength cannot be obtained at the initial stage of curing of the cured product.

As described above, the hydraulic composition contains Portland cement, alumina cement, a quick-setting agent, a strength enhancer, a coagulation adjuster, and a fluidizing agent as essential, and these are combined in a certain composition ratio. As a result, under a low temperature such that the working temperature and / or the ambient temperature is 10 ° C. or lower, the fast-hardening property is exhibited, in which the onset of condensation is 10 to 80 minutes and the end is 12 to 100 minutes. In curing of a low-temperature environment, its compressive strength (according to JIS A1108 (2006)) is reached 20-30 N / mm ² after after casting only one day, increased to after 28 days in 40~50N / mm ² To do. Further, the hydraulic paste obtained by absorbing water in this hydraulic composition has a flow value of 10 to 30 seconds (JSCE-F 541-2013 filling mortar fluidity test method (J14 funnel test) specified in the concrete standard specification). ), And a flow test value of 280 to 300 mm (according to JIS R5201 (2015)), which has high fluidity. Therefore, the anchor bolt can be driven by hand without using a tool such as a hammer drill.

If the working temperature and / or the ambient temperature exceeds 10 ° C., the hydraulic composition is condensed remarkably rapidly, so that the condensation is completed and the composition is hardened before the completion of casting.

The hydraulic composition may include fine aggregate. Fine aggregates include sands such as silica sand, river sand, sea sand, and crushed sand; inorganic materials such as alumina clinker, silica powder, and limestone; crushed urethane, EVA foam, and / or crushed foamed resin. Of these, silica sand is preferable, and Nos. 1 to 9 can be used if necessary. Such a fine aggregate reduces the shrinkage that occurs when the water-hardened paste is cured, and prevents the occurrence of cracks in the cured product. In addition, it alleviates the heat generated by the hydration reaction of the water-hard component, suppresses the temperature rise of the water-hard paste, and prevents an excessive increase in fluidity and an extension of the setting time.

The content of the fine aggregate is preferably 10 to 30 parts by mass, more preferably 10 to 20 parts by mass, and even more preferably 10 to 18 parts by mass. If the content of the fine aggregate is less than this lower limit, the effect of adding the fine aggregate cannot be sufficiently obtained, and if it exceeds this upper limit, the fine aggregate is excessive compared to the water-hard component. As a result, crystal growth due to the hydration reaction of the water-hard component is inhibited, and a high-strength cured product cannot be obtained.

The anchor fixing capsule of the present invention is obtained by encapsulating the above hydraulic composition in a water-permeable tubular container. Anchor fixing capsules are used, for example, in post-construction anchor construction methods. A method of using the anchor fixing capsule will be described with reference to FIG. 1, which is a schematic partial cross-sectional view showing an example of a process of attaching a support column for fixing a rockfall protection net to stretched concrete by a post-construction anchor method.

FIG. 1A shows a step of forming a hole 13 in the upholstered concrete 11. The surface of the upholstered concrete 11 is inclined because it is formed by concrete upholstery on the slope 10. A core boring machine 20 is set on the surface 12 of the upholstered concrete 11, and a core drill 21 attached to the tip of the core boring machine 20 is rotated to form a cylindrical hole 13.

The drilling length M, which is the length of the drilling 13, is preferably at least 500 mm. As a result, even if the outside air temperature of the hole 13 is less than 5 ° C, the average temperature inside the hole 13 which is one of the ambient temperatures is stable in the range of 0 to 10 ° C, which is higher than the air temperature, and the anchor fixing capsule The hydraulic composition is condensed and cured in a desired time, and a high-strength cured product can be obtained. If the drilling length M is less than 500 mm when the air temperature is below freezing, the temperature inside the drilling 13 will also be below freezing, and the water absorbed in the hydraulic composition of the anchor fixing capsule will freeze, hindering the hydration reaction. As a result, condensation and hardening of the hydraulic composition do not proceed.

FIG. 1B shows a step of inserting the anchor fixing capsule 1 into the drilling hole 13. The water-permeable tubular container of the anchor fixing capsule 1 is preferably made of a non-woven sheet having good water permeability and easy crushability. Examples of such non-woven sheets include papers such as high-quality paper, medium-quality paper, kraft paper, Kent paper, imitation paper, crepe paper, Heatron paper, cone paper, and Japanese paper. As these raw materials, any one of wood pulp such as pulp made from coniferous tree and pulp made from broadleaf tree, non-wood pulp such as Mitsumata, Walla, Bagasse, Yoshi, Kenaf, and Kwa, and used paper pulp is used. It may be formed by mixing a plurality of them. Further, the paper may be a synthetic fiber paper such as rayon paper or acetate paper.

The non-woven sheet may contain a resin in addition to the paper. According to this, it is not easily destroyed during transportation / storage or construction, and the hydraulic composition as the content does not leak. Such resins include, for example, polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, and polytributylene terephthalate; polyamides such as nylon 6, nylon 66 and aramid. Resin: Polyacrylic resin containing acrylonitrile as a main component can be mentioned.

Put the water 31 in the tray 32. The water 31 is, for example, tap water. According to the anchor fixing capsule 1 having the hydraulic composition of the present invention, it is not necessary to heat the water 31 for the purpose of delaying the setting of the hydraulic composition and preventing the decrease in strength. Specifically, the temperature of water 31 as the ambient temperature is preferably 0 to 10 ° C, more preferably 0 to 5 ° C. The working temperature is preferably 10 ° C. at the highest, and more preferably 0 to 5 ° C. The anchor fixing capsule 1 is immersed in water 31 for 3 to 5 minutes, and the water 31 that has permeated through the water-permeable tubular container is absorbed by the hydraulic composition. As a result, the hydraulic composition is transformed into a hydraulic paste and exhibits fluidity. After taking out the anchor fixing capsule 1 from the water 31, it is inserted into the drilling hole 13.

The length L and the diameter D from the tip end to the base end of the anchor fixing capsule 1 are selected to be smaller than the drilling length M and the drilling diameter, respectively. For example, the length L is preferably 200 to 450 mm, more preferably 300 to 400 mm, further preferably 380 to 390 mm, and even more preferably 380 to 385 mm. The diameter D at this time is preferably 20 to 40 mm, more preferably 26 to 34 mm, and even more preferably 28 to 32 mm, respectively. When the length L is within this range, the anchor fixing capsule 1 can be easily stored and transported, and good handleability is provided, and the water-permeable tubular container is damaged due to bending during handling by hand. Can be prevented. By changing the value of the diameter D, the time required to complete the water absorption of the hydraulic composition, that is, the immersion time in water 31 can be changed. When the diameter D is within the above range, the immersion time can be as short as 3 to 5 minutes, and even if the anchor fixing capsule 1 is immersed beyond this time, it does not absorb water in excess of the required amount. Construction management is simple and construction efficiency can be improved.

For example, the anchor fixing capsule 1 inserted into the hole 13 having a hole length M of 650 mm and a hole diameter of 40 mm has a length L of 380 mm and a diameter D of 30 mm, and the immersion time thereof is at least. 3 minutes. In this case, since the drilling length M is longer than the length L of the anchor fixing capsule 1, a plurality of, for example, two anchor fixing capsules 1 are inserted into the drilling 13.

FIG. 1C shows an anchor bolt driving process. The anchor bolt 40 has a base end having a plane substantially perpendicular to the central axis thereof, and a sharply pointed tip so as to easily penetrate the water-permeable tubular container of the anchor fixing capsule 1. A male screw is provided on the surface of the base end portion. A nut for fixing the support of the rockfall protection net is screwed into this base end. The total length of the anchor bolt 40 is larger than the drilling length M of the drilling 13 so that the anchor bolt fixing length specified in the standard is satisfied and the base end portion having the male screw protrudes from the opening of the drilling 13. It's a little long.

An operator who performs the driving work of the anchor bolt 40 grasps the base end portion of the anchor bolt 40 with his / her hand 50 and inserts it into the drilled hole 13, and pierces the anchor bolt 40 into the anchor fixing capsule 1. The sharp tip of the anchor bolt 40 pierces and crushes the water-permeable tubular container, and the water-hard paste flows into the drilled hole 13. Since the water-permeable tubular container is an easily crushable non-woven sheet, it can be crushed immediately by piercing the anchor bolt 40 with a slight external force such as the force of a hand or arm without using a driving device. The operator once pulls out the anchor bolt 40 from the drilled hole 13 and inserts it again. By repeating this, the operator surely crushes the permeable tubular capsule. If necessary, the operator further inserts the anchor fixing capsule 1 immersed in water 31 into the drilling hole 32, and then inserts and removes the anchor bolt 40 again. The operator repeats these steps until the hydraulic paste overflows from the opening of the drilling 32.

Since the water-hard paste has high fluidity, the anchor bolt 40 can be manually inserted and removed, and the space between the inner wall surface of the drilled hole 13 and the anchor bolt 40 is filled without a gap. Further, the anchor bolt 40 does not require large equipment that is difficult to be stably supported on a slope, and is not accompanied by noise.

The water-hard paste reaches the onset of condensation 5 to 75 minutes after the completion of absorption of the water 31 at the above temperature and the end of condensation 7 to 95 minutes later, and then cures. The operator performs the driving process within the setting time from the start of condensation to the end of condensation. The operator can know that the water-hardened paste is approaching the end of condensation by sensing an increase in the insertion resistance of the anchor bolt 40. The operator supports the anchor bolt 40 in the drilling hole 13 with the hand 50 so as to have a predetermined angle. Since the water-hardened paste that has reached the end of condensation starts to harden, the anchor bolt 40 is fixed in the drilled hole 13 while maintaining a predetermined angle without requiring the support of an operator. Curing proceeds even at low temperatures such as an outside air temperature of 0 to 5 ° C. Therefore, according to the anchor fixing apuser 1, it is possible to eliminate the need for curing accompanied by heat retention even in a cold region. The operator removes the water-hard paste overflowing from the drilling hole 13 as needed.

The upholstered concrete 11 that has undergone the steps shown in FIGS. 1 (a) to 1 (c) is shown in FIG. 1 (d). A cured body obtained by curing the hydraulic paste closes the opening of the drilled hole 13, and is densely filled between the inner wall surface of the drilled hole 13 and the anchor bolt 40. The anchor bolt 40 is fixed to the upholstered concrete 11, and the nut 41 is screwed to the base end portion thereof to fix the support column 14.

An example in which the hydraulic composition of the present invention and an anchor fixing capsule using the same are applied, and a comparative example to which the present invention is not applied are shown below.

(Example)
Raw materials such as early-strength Portland cement, alumina cement, quick-setting agent (mixture of dihydrate gypsum and semi-hydrated gypsum), fine aggregate (silica sand No. 6), strength enhancer (baked kaolin, manufactured by BASF Japan Co., Ltd., product) Table 1 shows the name: Metamax), the fluidizing agent (polycarboxylic acid ether, manufactured by Lion Specialty Chemicals Co., Ltd., product name: Leopac (registered trademark)), and the coagulation modifier (trisodium citrate). Each of them was weighed and put into a mixer and stirred to prepare a water-hard composition. The fluidizing agent was 3.7 parts by mass and the coagulation adjusting agent was 0.4 parts by mass with respect to 100 parts by mass of the total of the water-hardening component and the strength enhancer.

(Comparison example)
A comparative hydraulic composition consisting of early-strength Portland cement was prepared.

Anchors of Examples and Comparative Examples in which 450 g of this hydraulic composition is sealed in a water-permeable tubular container made of a non-woven sheet made of paper and polyethylene at a basis weight of 40 g / m ² and having a length of 380 mm and a diameter of 30 mm. A fixed capsule was obtained.

(Water absorption test)
After measuring the mass, 14 of the anchor fixing capsules of the examples were immersed in water at 0 ° C. and 7 capsules at 10 ° C. For each water temperature, the mass was measured after immersion for 1 minute. The water absorption rate was determined from the ratio of the mass before immersion to the mass after immersion. The water absorption rate was determined in the same manner for the anchor fixing capsules in which the immersion time was 2, 3, 4, 5, 8, and 10 minutes. The results are shown in FIG.

FIG. 2 is a graph showing the correlation between the immersion time in water and the water absorption rate in the water absorption test of the example. The horizontal axis is the immersion time (minutes), and the vertical axis is the water absorption rate (mass%). As shown in the figure, the anchor fixing capsule of the example reached a water absorption rate of about 30% by mass in a immersion time of 3 minutes regardless of the water temperature, and the water absorption rate did not increase even if the immersion time was extended thereafter.

(Condensation test)
The anchor fixing capsules of Examples and Comparative Examples were left in a constant temperature bath kept at 0 ° C. until the respective hydraulic compositions reached 0 ° C. Then, it was immersed in tap water at 0 ° C. for 3 minutes to make a water-hard composition into a water-hard paste, and the water-permeable tubular container was broken and taken out. In a constant temperature bath kept at 0 ° C., the starting time at which the water-hard paste started to condense and the ending time at which the coagulation ended from the time it was taken out from the water-permeable tubular container were measured. The number of samples in the examples and comparative examples was set to n = 3, respectively. The results are shown in Table 2.

As shown in Table 2, the anchor-fixing apuseru of the example did not cause a condensation delay despite the conditions that the air temperature, the water temperature, and the hydraulic composition were all 0 ° C. On the other hand, the anchor fixing capsule of the comparative example was significantly slower in both the start time and the end time than the example, and was inferior in workability.

(Compression test)
The same operation as in the coagulation test was carried out to obtain water-hardened pastes of Examples and Comparative Examples. Using this, a cured product specimen was prepared in accordance with JIS A1108 (2006) and subjected to a compression strength test, and the compression strength (N / mm ² ) of curing 1, 3, 7, and 28 days was performed. Was measured. All curing temperatures were set to 0 ° C. The number of samples in the examples and comparative examples was set to n = 3, respectively. The results are shown in Table 3.

The cured product using the hydraulic composition of the example showed a compressive strength far exceeding 24 N / mm ^2, which is sufficient as an initial strength after only one day of curing in an environment of 0 ° C. On the other hand, the cured product using the hydraulic composition of Comparative Example did not satisfy 24 N / mm ² even after curing on 28 days.

(Liquidity test)
The same operation as in the coagulation test was carried out to obtain water-hardened pastes of Examples and Comparative Examples. Each of the water-hardened pastes was taken out from a constant temperature bath kept at 0 ° C. and immediately subjected to a J14 funnel test specified in JIS CE-F 541-2013 and a flow test specified in JIS R5201 (2015). Table 4 shows the results of the J14 funnel test in which the number of samples of Examples and Comparative Examples was n = 3, and Table 5 shows the results of the flow test in which both samples were set to n = 4, respectively.

As shown in Tables 4 and 5, the hydraulic paste using the hydraulic composition of Examples showed lower flow value and higher flow test value than those of Comparative Example. From this, it was found that the hydraulic paste obtained from the hydraulic composition of Examples was excellent in fluidity in a low temperature environment of 0 ° C.

(Tensile test)
In winter in Hokkaido, a core boring machine was used to form a hole with a hole length of 650 mm and a hole diameter of 40 mm. The anchor fixing capsules of the examples were left under a temperature of -2 ° C. until the respective hydraulic compositions reached 0 ° C. Then, it was immersed in tap water at 0 ° C. for 3 minutes. When the temperature of tap water was recorded every 30 seconds, all the values were within 1σ at an average of 0 ° C. Anchor fixing capsules were inserted into the holes while maintaining the air temperature at -2 ° C. Anchor bolts (D22 reinforcing bar, length 800 mm) were manually inserted and removed from the holes, and the hydraulic paste was allowed to flow into the holes. Insertion of the anchor fixing capsule and insertion / removal of the anchor bolt were repeated until the hydraulic paste overflowed from the hole, and the anchor bolt was fixed to the bedrock. After curing for one day at an air temperature of -2 ° C, a tensile test of anchor bolts was performed. The anchor fixing capsule of the comparative example was also subjected to a tensile test in the same manner as in the example. The results of Examples and Comparative Examples are shown in FIG.

FIG. 3A is a graph showing the correlation between the displacement of the anchor bolt and the tensile load in the tensile test of the example. The horizontal axis is the displacement (mm) of the anchor bolt, and the vertical axis is the tensile load (kN). As shown in the figure, the anchor bolts fixed by the anchor fixing capsule of the example did not come off from the bedrock even when the withdrawal load of 75 kN was reached. From this, it was found that the anchor fixing capsule of the example can impart a high fixing force to the anchor bolt.

FIG. 3B is a graph showing the correlation between the displacement of the anchor bolt and the tensile load in the tensile test of the comparative example. The horizontal axis and the vertical axis are the same as the graph shown in FIG. As shown in FIG. 3B, the anchor bolt fixed by the anchor fixing capsule of the comparative example showed a peak of the withdrawal load at 13.7 kN, but the withdrawal load decreased thereafter. When the bedrock was visually observed, it was confirmed that the interface between the anchor bolt and the hardened body obtained by hardening the hydraulic paste was broken and the anchor bolt was removed from the bedrock.

The hydraulic composition of the present invention and the anchor fixing capsule encapsulating it are used for reinforcing existing concrete skeletons and ground in low temperature environments such as winter and cold regions, and for attaching workpieces to them. It is used for the post-construction anchor construction method.

1 is an anchor fixing capsule, 10 is a slope, 11 is a stretched concrete, 12 is a surface, 13 is a hole, 14 is a support, 20 is a core boring machine, 21 is a core drill, 31 is water, 32 is a tray, and 40 is an anchor. Bolt, 41 is a nut, 50 is a hand, D is a diameter, L is a length, and M is a drilling length.

Claims (5)

A hydraulic composition for cold regions that cures at a working temperature of up to 10 ° C. and / or an ambient temperature upon contact with water, and a hydraulic component containing Portland cement, alumina cement, and a quick-setting admixture. a strength enhancing agent composed mainly of kaolin, and Nde including a fluidizing agent, and a condensation modifier,
With respect to 50 parts by mass of the alumina cement, 20 to 40 parts by mass of the Portland cement, 10 to 30 parts by mass of the quick-setting agent, 1 to 10 parts by mass of the kaolin, and 0.1 to 1 parts by mass of the coagulation adjuster. A water-hardening composition characterized by having 0.1 to 1 part by mass of the fluidizing agent . The hydraulic composition according to claim 1, wherein the kaolin is calcined kaolin. The fast-setting agent contains gypsum, the coagulation modifier is at least one selected from oxycarboxylic acid, lignin sulfonic acid, citric acid, and salts thereof, and the fluidizing agent is polycarboxylic acid ether, alkyl. The water-hard composition according to claim 1 or 2 , wherein it is at least one selected from allyl sulfonic acid, melamine sulfonic acid, and salts thereof. An anchor fixing capsule, wherein the hydraulic composition according to any one of claims 1 to 3 is enclosed in a water-permeable tubular container. The anchor fixing capsule according to claim 4 , wherein the anchor fixing capsule has a length of 200 to 450 mm and a diameter of 20 to 40 mm.

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