JPS6022153B2 - Concrete spraying construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the invention of a concrete spraying method, which aims at appropriate conveyance of concrete materials, and which achieves a water-cement ratio of 4.
・The objective is to obtain a method that enables smooth spraying of small concrete, reduces the amount of rebound and dust generation, and accurately forms shotcrete with excellent strength.

The spraying method is already known as one of the concrete construction methods.

In other words, while concrete construction like this generally requires forming a formwork and then filling and forming, this spraying method does not require such a formwork and can be applied to walls, slopes, etc. This eliminates the need for installing formwork and removing the formwork after it has hardened.Therefore, there is a large finish IJ that allows concrete work to be completed within a short time, and it can be used on surfaces such as tunnel walls and constructed slopes. It is being put into practical use in civil engineering work, etc. However, there are three types of concrete spraying methods that have been conventionally adopted: dry method, green method, and semi-wet method, and although each of these methods has merits, they also have disadvantages and drawbacks. . In other words, the wet method is a method in which a ready-mixed mixture of all the constituent materials of shotcrete is conveyed through a conduit such as a pipe or hose, and is sprayed by spraying from a nozzle, so that the cement, etc. can be well moistened. The strength of the shotcrete shotcrete produced by this method is also higher than that of the dry method, but the frictional resistance within the pressure-feeding pipeline is large, so it is necessary that the pipeline and mechanism for pressure-feeding each have sufficient pressure resistance. Therefore, it has to be large and strong, and even if the size and shape of the coarse aggregate are restricted and special consideration is given to the pipeline and pumping mechanism, the distance it can be conveyed is limited. The maximum strength is about 50 to 60 skin, which has the disadvantage that it is difficult to respond quickly enough to the actual situation at various construction sites.In addition, in terms of strength, which is the advantage mentioned above, there is no method that follows the water-cement ratio to obtain the optimum strength. Since the viscosity is at its highest, it is practically necessary to increase the water-cement ratio to ensure pressure-feeding properties, and it is difficult to obtain the ideal strength and it is difficult to achieve the desired benefits. Also, there are disadvantages such as a considerable amount of peeling off from the sprayed surface, and a limit to the thickness of the sprayed layer due to sagging and other factors. On the other hand, in the dry method, there is less frictional resistance in pipes, etc., and a relatively simple and compact mechanism and pipe line allow for a desired conveyance distance to be freely obtained, so for example, in a mine dug deep underground, the desired conveyance distance can be freely achieved. It can be pumped from a position sufficiently far away from the construction site, and in this sense it can be used freely depending on the site, but it generates a large amount of dust, and if it is inside a mine, the work must be interrupted for a short period of time. Failure to do so may result in the inability to confirm the intended construction status, significantly impairing the work environment, and the strength of the spraying method may not be as strong as the wet method because the cement, etc. does not come into sufficient contact with water. There is a definite disadvantage that it is only about half the size, and there are also significant disadvantages such as the amount of bounce. However, in the semi-wet construction method, which is considered to be an intermediate construction method between these methods, the water injection position in the dry construction method is shifted from the nozzle part and water is added in the middle of a conduit such as a pipe or hose, but this water level layer is Since a portion with high frictional resistance is formed at the end of the pumping system and a certain amount of quick-setting agent is mixed, the limit is about 5 to 6 points from the nozzle, and if the water level layer is made larger than this, the pipe or Paste, etc. will adhere to the inner surface of the hose and block the pipe, and even if you try to take full advantage of the advantage of increasing the pumping distance with the dry method, there will be a large resistance at the end of the pipe where the pressure has decreased. Since the dry method requires a high-performance pumping or piping mechanism that is unexpected in the dry method, it is not possible to achieve sufficient mixing of cement, etc. and water as in the wet method. In any of the above cases, in order to improve the adhesion of the raw kneaded material and reduce the amount of rebound and flaking, sudden streaks and instant setting of sodium citrate, calcium chloride, sodium aluminate, sodium carbonate, etc. are used. It has the disadvantage of requiring a large amount of agent. The present invention has been researched to eliminate the disadvantages and shortcomings of the conventional method as described above, and further aims to increase the desired strength by forming a shotcrete using ready-mixed concrete with a small water-cement ratio. It was designed after repeated consideration to be sufficiently large and to be able to be constructed with minimal splashing and dust generation. That is, the present inventors have investigated the rheological properties of this kind of raw kneaded material that does not harden after adding water, the actual flow characteristics of this kind of raw kneaded material, and the relationship between inert aggregates such as coarse aggregate and paste or mortar. He discovered many previously unknown facts regarding interfacial adhesion and the relationship between adsorption forces on solid surfaces, and based on these discoveries, he proposed new technical methods. Lidded Patent Application No. 157452 (Tokusekki Shokyu-8338) [Method for Measuring Fluidity of Plastic Fluid, Method for Adjusting Plastic Fluid, Method for Injecting the Plastic Fluid, and Apparatus Therefor], Patent Application No. 1983 No. 1147180, (Tokukan Sho 5
3-7185) [Method for measuring aggregate, method for determining amount of kneading water, and apparatus therefor] and patent application No. 12632-1983
Although the details of the above-mentioned relationships were elucidated in No. 3 (Tokukan Sho 54-60321) [Concrete manufacturing method and equipment], the present invention further develops these relationships. At the very least, the above-mentioned disadvantages and drawbacks of the conventional spraying method can be overcome. In other words, when a plastic fluid (Bingham type or non-Bingham type fluid) containing solid components such as cement paste, mortar, and concrete is deformed and flowed, there are yield values of several shear stresses, and their sizes are mixed. It varies depending on factors such as the amount of water, water-cement ratio, cement-sand ratio, coarse aggregate-sand ratio, and initial moisture content of the dispersant and sand.

However, the slump test conventionally used to measure the fluidity of concrete is a test measurement of this qualitative quantity, but depending on the qualitative measurement value, the plastic fluid as described above The actual situation cannot necessarily be elucidated, and relative quantitative measurements should be used. Furthermore, in such a plastic fluid, the action of water between particles is not completely eliminated, but there is an adsorption force on the surface of solid particles including cement particles, that is, the amount of adsorbed water on the surface of solid particles is extremely large. If the particles become smaller, adjacent particles will share adsorbed water with each other, and the force will become considerably large. Furthermore, in the case of adding water to cement and kneading it, in the conventional technology, hydration and setting proceed immediately after adding water; Therefore, by determining the mixing time within these limits and then performing the secondary kneading, it is possible to advantageously improve the adhesion strength (i.e. concrete strength) and fluidity of the coarse aggregate. However, regarding the scale shear stress yield value as described above, when dehydrating the raw kneaded material (plastic fluid) as described above (for example, pressurized dehydration using furnace paper), the scale shear stress yield value increases in proportion to the amount of dehydration. Although the value increases, this type of dehydration method does not require the use of furnace paper, and it is possible to obtain the same dehydration results even if the raw kneaded material is dried or contains a small amount of water, or even if materials are added. This makes it possible to obtain a bonding relationship based on a large adsorption force that utilizes adsorbed water sharing.

For example, in the case of the conventional dry method, it is accepted that the strength of concrete decreases, even though the mixing time is zero.
Further, by employing some form of the above-mentioned mixing time and secondary cross-contact, the strength of shotcrete can be improved to a certain extent. In the present invention, which is based on the above-mentioned technical background, water is added to hydraulic powder such as cement or gypsum and sufficiently kneaded to sufficiently increase the specific surface area of the powder, and the water-cement ratio is appropriately adjusted. The selected paste or mortar is pressure-fed through a pipe, and it is preferable to allow the necessary mixing time after this water-mixing.

However, this pressure feeding can generally be carried out at a pressure ΔP determined by the following equation '1''. △P
=Nosanichi≧t(F.

10＾U〆) L+ph...(1) However, Lmax is the maximum distance that can be injected, Lm similar = U hand T - Ko Li Ding, and L:
It is B4.

Also, the speed U'' for injecting L (伽) at P (Yu/Ji) with constant rate injection is given by the following 0 formula.

Una=△Pノ4xLFO^go+△p2go214X2^2
- (Shige LFO entering △p2) 2XL^2...m) However, △P=P-ph Furthermore, with constant velocity flow, the maximum speed Uf that can make L (arc) flow
max is determined by the following m formula.

X...(m) U ma Desired.

In addition, in equations (1) to (W) as described above, Fo(
evening/earth): Relative periodic shear stress yield value ^ (evening/sec/sakaki/hada): relative flow viscosity coefficient Una (c
m/sec): superficial velocity p (night/lump): unit volume weight of plastic fluid L (arc): aggregate layer length S: aggregate porosity X (ground/sec): filling per unit time degree T (sec)
: Maximum injectable time, which is based on the technical method of Hakamabuta No. 157452/1986 mentioned above.

Furthermore, in the present invention, in addition to the above-mentioned pumping of hydraulic powder using a fluidity due to moisture, gravel or sand (for paste), aggregate such as gravel, and cement as necessary. Even if powdered materials such as those containing water contain water, they are pumped under dry conditions in which the water does not contribute to the flow effect. The distance and amount of aggregate that is transported is determined by the wind pressure, air volume, and pipe diameter, and since it is carried out under dry conditions, the length can be several hundred meters or more than 1,000 kites. It is sufficient even in cases.
Furthermore, the separately pumped materials are combined to form a sprayed layer during the spraying process, but it is not necessary to use the pressure-feeding process after adding water to the hydraulic powder as described above, or the pressure-feeding process described above. A raw kneaded product of the hydraulic powder is obtained by taking an appropriate kneading time and adding the aggregate pumped under dry conditions to find the appropriate fluidity. It is possible to form a sprayed layer that increases the shear stress yield value by achieving a dehydration effect on
Various performances such as physical properties, workability, management, economic efficiency, and range of use of the green kneaded material are greatly improved, and advantageous construction can be carried out by solving the conflicting physical phenomena of fluidity and adhesion at once.

To explain the present invention in more detail, a green kneaded material prepared by using Bortland cement and adding an alkylaryl sulfonic acid dispersant in an amount of 3% of the weight of the cement is prepared using Tsubakinu Akira as described above. 51-157452
According to the method of the above issue, glass balls with a diameter of 8 ribs were filled over a length of 20 arcs as a resistor, and the raw dough was kneaded for 1 hour and then kneaded for a second time.The results were as follows: As shown in the table, if the water-cement ratio is less than 28%, fluidity measurement is impossible, if it is more than 31%, breathing will occur, and if it is more than 32%, separation will occur between water and cement particles. It was something to do.

According to Table 1, that is, the results described above, when water is added to cement, the interparticle voids are generally filled with water bound to the particle surfaces, and therefore the mixing torque is at its maximum. The state of change from the capillary castle shown in the figure to the slurry castle shown in Fig. 2, in which the amount of water increases and becomes unrestricted to the particle surface (therefore, the mixing torque rapidly decreases again), is clarified, i.e. In the capillary region, the number shear stress is at its maximum and the mixing torque is at its peak as described above, and it is generally difficult to form a flowing fluid, but once it enters the slurry region, fluidity is clearly shown and it becomes free. If a liquid level is to be formed and a cement paste without breathing or separation phenomena is desired, the W/C of the slurry is in the range of about 28 to 30%, which is a minimized range.

Moreover, when considering the above-mentioned relative periodic stress yield value within such a range, 6.293/0.273=
23.051, which is a huge difference of 2 dollars, and the relative flow viscosity coefficient is also 1.82 needles, and the relative occlusion coefficient is 47. There is a difference in sealing.

In this way, even if the slurry is the same but within a narrow range of W/C, slight differences in W/C will greatly change the fluidity. When it is applied, it immediately sag and becomes thinner than a few inches thick, making it almost impossible to form a desirable shotcrete. The idea is to make a slurry of this level or higher, use a pork silk agent and a quickening agent, and try to thicken this layer by time lag, which increases the number of man-hours and requires a long time, and at the same time, it is difficult to obtain a preferable sprayed layer. I can do it. In the present invention, a slurry with good fluidity is formed in the conveyance process, and just before spraying, powder and granules under dry conditions from another conveyance system are added to the slurry from the pipe to the spraying surface. During the process, they are combined to form a blown part in a capillary state, and for aggregate conveyance, fluid frictional resistance is replaced by powdered frictional resistance, and in the blown layer, a layer of water between solid particles is formed. This reduces the amount of adsorbed water and increases the adsorption force due to shared adsorption of water.

That is, for example, a paste with a good fluidity W/C of about 30% is pumped through a pipe such as a hose, and aggregate is pumped through another pipe, which is combined at the nozzle and then sprayed to form concrete. For example, if the amount of cement in this concrete sprayed layer is about 15%, the W/C of the sprayed layer will be reduced to 26%, or below the level of the capillary. As the amount of water in the area is increased, the adsorption power as the above-mentioned covalently adsorbed water is naturally exerted greatly, and even if no hydration reaction is expected in this sprayed cement, the effect is sufficiently obtained and the shear stress and adhesion force are reduced. Both will be greatly improved. Therefore, it is also possible to layer at least a portion of such cement powder with an inert material such as silica powder having a similar specific surface area. Also, considering the case where surface-dry sand with a small specific surface area of the inert material is pumped through one pipe, and the paste is pumped through the other pipe and combined, the maximum sand-paste ratio is such that the sand voids are completely filled. It is the sum of the amount of paste to be filled and the amount of paste that coats the surface of the sand very thinly, and although it varies depending on the particle size of the sand, it is approximately a little over 30%, and the sand absorbs water from the paste. The W/C of the paste becomes small because the water, cement, and sand absorb water, and the relationship between water, cement, and sand becomes a complete capillary castle, and the adsorbed water is very thin even between the cement particles rather than solid between the sand particles. This becomes a covalent phenomenon and the two are combined by their adsorption force, resulting in a large shearing stress and adhesion force.

In addition, in the case of mortar in which sand is mixed with cement paste as described above, the water-cement ratio, cement-sand ratio,
Even if the blending conditions of the cement dispersant ratio are all the same, the injection characteristics, flow value, breathing rate, etc. change due to changes in the moisture content of the initial sand, as described by Sendo [Samurai Sho 51- No. 14718 (Unexamined Japanese Patent Publication No. 53-7
1859)].

That is, as an experimental example, the water content was changed from standard sand with zero voids in the particles (from rope dry sand made of silica sand to water content -6 to obtain various types of hydrated sand ranging up to 40%
5. In a vacuum mixer of 5 g on the same day, water was mixed to the water ratio shown in Table 2 below, and cement was added and mixed. The results of measuring the fluidity and physical properties of a secondary paste prepared by adding the above-mentioned allylsulfonic acid-based dispersant along with the remaining water to achieve the water-to-cement ratio of 40% are shown in Table 2 below. be. The fluidity was measured using the same method as for the paste filled with two glass bulbs. Table 2: Table 2 shows the case where the cement-sand ratio is 1:1, but if the cement-sand ratio is, for example, 1:2, the amount of cement is the same but the amount of sand is doubled. Therefore, it is numerically clear that similar results can be obtained by reducing the moisture content to one-half of the value in Table 2. It is clear that even in this case, the same results as in Table 2 can be obtained by setting the water content of the sand to 1/3 to 1/6 of the values in Table 2.

In other words, the physical properties of the resulting mortar such as fluidity, breathing rate, and separation rate vary greatly depending on the water content of the sand used, and in particular, the relative periodic shear stress yield value (Fo
) is large, and this value is considered to be an arch action against the passage of the fluid, and is therefore estimated to be determined by the particle size. , condition (e.g. 10% or less)
When cement powder is charged and kneaded into sand with a higher water content than when cement powder is packed into sand in a bag, the attached cement layer becomes thicker and the diameter increases, resulting in a larger Fo value. However, when the concentration exceeds a certain value, such as 30% or more, the Hishiri cement immediately becomes a slurry, and a water layer intervenes between the sand and cement paste layer, causing the grain ridges of the sand grains. It is recognized that the increasing effect decreases, and the Fo value decreases on the contrary. Moreover, what should be noted in this case is that in the case of the above experiment, after mixing,
This indicates that the cement paste, which has been adhered to the sand and has been increased in size, does not peel off even after undergoing the harsh treatment of secondary mixing, and the Fo value increases as described above. This indicates that the paste has a considerably high adhesion strength, and the cement powder initially absorbs water and adheres to the surface of the sand, and then the adsorption as described above due to the water-to-cement ratio occurs. I can understand that the shared phenomenon is precisely desired. In the present invention, the above-mentioned technical relationship is actively and accurately utilized, and during spraying construction, the distance between the grain-increasing sands is increased by the spraying pressure on the spraying surface. The remaining fluid paste is brought close to the distance where the adsorption force is generated, and the remaining fluid paste is sprayed with separately pumped sand, lees aggregate, powder, etc. to adsorb the slurry water contained in the paste, and the nuclear fluid paste is also drawn into the capillary. , and loses its fluidity to form a stabilized sprayed layer.

In the specific implementation of the present invention, the amount of sand and kasukotsumura added at the spray nozzle section is controlled. A container such as a box is installed, and the amount added can be adjusted according to the construction situation on the target wall surface. For example, at the start of spraying, the conveyance of coarse aggregate is stopped,
After forming a first layer of paste and mortar only, coarse aggregate and sand are gradually added and poured into the first layer.Also, when the target wall surface is sufficiently saturated with groundwater, etc. On the contrary, only air-blown aggregate with cement added is sprayed to form the first layer, and then mortar or paste is gradually added and poured into this first layer. A special stripping method can be implemented to reduce the amount of rebound and peeling. In addition, in order to appropriately obtain the effect of increasing the particle size as described above, for example, as shown in Table 2 above, cement is mixed in advance with sand with an appropriate water content, then dry kneaded, and then the mixture is mixed. It is preferable to make mortar by adding water and kneading it afterwards.If you first add the entire amount of water required for mortar preparation to the sand and then add cement, the water content of the sand is 40% or more. It is the same as when cement is mixed, and the desired effect of increasing grain size cannot be obtained. In addition to this mortar, in the case of paste as well, after preparing the raw kneaded material, leave it as is for the time period mentioned above to improve the relative fluidity, and then knead it for a second time and then pressurize and spray it. is preferable, which is the above-mentioned interruption, and this secondary kneading can be replaced by a flow process in the pressure feed pipe without particularly using a mixer. Generally, the aggregate may be added at the nozzle part, or in some cases, it may be in the pressure-feeding pipe immediately before the nozzle or on the construction wall surface. Further, the mortar or paste may be pumped by air pressure or by a pump machine, and the aggregate may be pumped by air, and metal fibers, glass wool or other fibrous materials may be added to the aggregate. I can do it. In addition, powdered substances such as fly ash, Suiren powder, pozzolan, water glass, colloidal silica, polymeric plastic material, calcium chloride,
One or more additives such as alum, sodium aluminate, sodium carbonate, and sodium hydroxide may be blended.

In carrying out the invention, it is of course effective to use a quick-stripping agent in order to obtain a stable sprayed layer. Divide it into both sides of the village and add it to each side separately.

In addition, appropriately heated materials are used as the raw kneaded material, aggregate, and air for pumping, and refractory materials are used as the aggregate, and raw materials such as alumina cement and silica sol are used in sol form. Used in colloidal form. When adding a raw kneaded material to a pneumatically fed powder or granular mixture, it is necessary to add the raw kneaded material in an evenly dispersed state, so that the raw mixed material is added gradually. The diameter is narrowed and discharged, or the material is discharged and added through a discharge port material having a vertical diameter. That is, by narrowing the diameter at the addition position in this way, the discharged kneaded material can be discharged at an appropriate high speed due to higher pressure conditions against the flow of the pneumatically fed powder/granular mixture, which is preferable for dispersion. Additive coalescence can be obtained. The length of the discharge port should be at least 10 times the diameter of the pipe for pressurizing the raw kneaded material.
% or more, and of course, forming an extremely contracted discharge section would increase the pressure and make it difficult to feed the raw kneaded material, but in general, the pipe diameter for pressurizing the raw kneaded material is For example, in the case of the example described later, in the raw kneaded material pressure-feeding conduit with an inner diameter of 50.8mm, the diameter of the stripe at the discharge port is 38.8mm. 1 skin,
Tests were carried out under narrow conditions such as 31.8 skin, 1 proboscis, 12.7 ribs, and 9.5 side, but in all of these cases, the raw kneaded product exhibited fluidity characteristics as shown in those examples. In all cases, it was possible to obtain addition in a substantially preferable dispersed state. Specific embodiments of the present invention will be described below. Example 1 Relative initial shearing stress yield of a paste (raw kneaded material) prepared by mixing 1 part of Voltland cement with 0.35 part of water and 0.01 part of admixture against 2-sided J marbles The value Fo is 0.2 (evening/earth), and △Fo is 0.00
The paste was pumped at a rate of 30 seconds per minute using a screw-type pressure pump, and the paste was dried separately at approximately 2.5 seconds per minute. River sand having a particle size of less than a foot was added at a position 3 mm before the nozzle of the Honemura pumping line, which was pumped by an aggregate blower at a rate of about 30 m/min.

The paste was sent through a pipe with an inner diameter of 5.0mm (2 inches), and the river sand was also sent through a pipe with an inner diameter of 5.08mm, but the river sand pumping line addition section of the paste pumping pipeline had a diameter of about 10mm. The inner diameter is narrowed down to 2.54 mm (1 inch) in the range of
I Spray the added material into the sand pressure pipeline with a nozzle,
It was sprayed onto a nearly vertical wall. The sprayed coating formed on the sprayed construction surface can be applied to a thickness of about 7 skins with almost no sagging, and the results of measuring the compressive strength of this construction layer 3 days after spraying are as follows. 2
51.3k9/su and 395.2 after 7 days
k9/clump, and after 28 days it was 515.6k9/land, and according to the results of analyzing the ratio of cement to sand in the construction area, the ratio of sand to 1 part of cement was 1.9 bases.

Example 2 The same paste as in Example 1 above was sent under the same conditions, and this paste was mixed with river sand (air-dried) of 2.5 ribs or less and crushed stone of 10 to 15 fences in approximately the same weight ratio. The mixture was pumped at a rate of 30 per minute, mixed and combined at a position 3 feet from the nozzle tip in the same manner as in Example 1, and sprayed onto a vertical wall surface to be sprayed.

The maximum shear stress at this time is 118 tano, and the thickness is 1
It is possible to form a preferable sprayed layer with almost no sagging even on walls of the size of pine trees, and the compressive strength after 3 days of spraying is 347 kg/, and after 7 days it is 484
．． 3k9/m, and 653k9/m after 28 days.
We were able to show our enemies and form an effective concrete layer.

Example 3 Approximately 40q of paste was prepared by mixing 0.35 parts of water to 1 part of cement in the same manner as in Examples 1 and 2.
The mixture was allowed to stand for 1 hour under the temperature condition of 0.000 m, then charged into the mixer again, and 0.01 part of an admixture was added thereto, followed by starch for 3 minutes.

This paste was pumped in the same manner as in Example 2, and in the same way, river sand (air-dried) of 2.5 or less and 10 to 15
Mixed willow crushed stone in the same weight ratio at 30 so/min.
The mixture was pumped at a speed of 1, and was similarly sprayed onto the spraying surface, which was a vertical wall surface.

In this case, as in the case of Example 2, a sprayed layer with a thickness of about 15 skins can be properly applied with almost no sagging, and the compressive strength after 3 days of spraying is 468 x 9 / ground, After 7 days, it was 628.6k9/m, and after 28 days, it was 672x9/m, and an effective concrete layer could be formed.

Example 4 Mortar mixed with 1 part of Voltland cement and 1 part of sand, 0.37 part of water and 0.008 part of admixture has a relative initial breaking stress yield value Fo for glass beads with a diameter of 2mm.
is 0.19 evening/earth, △Fo is 0.0003 evening/arc 4, ^
1.6 evening. It was confirmed that the mortar had a sec/ga 4 and had good fluidity, and the mortar was heated for 30 min/min.
A pressure pump was used to feed the inside of the pipe with an inner diameter of 20 inches (50.8 inch) at a speed of The mortar was added and mixed to the same machine at a position three skins from the nozzle tip and sprayed onto a vertical wall surface.

The distance from the supply source of mortar and river sand to the construction wall surface is approximately 150 m, and this pumping distance is 2 inches (50 mm) in inner diameter.
In the case of this example using a pipe of 7 sails)
It can be carried out smoothly and by spraying with a pumping pressure of about K9/1, and the mortar is applied to the river sand pumping line by squeezing it to 11/cape size (31.8 skin) in the same way as in Examples 1 and 2. In this example, a uniform mixed state was formed as in each of the previous examples, and the thickness was 1.
It was possible to form a sprayed layer of 5 arcs with almost no sagging. The initial maximum shear stress of the sprayed layer is 93 k/m, and the compressive strength after 3 days of construction is 288 k9/m, 430 kg/m after 7 days, and 543 kg/m after 28 days.
So it was hot.

Separately, mortar mixed with 1 part of Bortland cement, 1.5 parts of sand, 0.4 part of water, and 0.01 part of admixture has a relative initial number of glass beads with a diameter of 2 m. The shear stress yield value Fo is 4 tano, △Fo is 0.05 sec/sec/4, and on the other hand, 1 part of river sand with the same particle size as above and 10% surface water is used. On the other hand, prepare a mixture of 0.5 parts of Boltland cement and sprinkle it on the surface of the sand, and pump it in the same way as above, and add it to the mortar lk9 at a position 3 rivers before the tip of the slide. On the other hand, pneumatic sand was mixed at a ratio of 2k9 parts and sprayed onto a vertical wall surface in the same manner.

That is, in this case, compared to the above, Fo value, △F
It is a mortar with high o and ^ values and relatively poor fluidity, and the amount of pneumatic aggregate added to this mortar is also large, and the composition of the sprayed layer is 1 part of cement. Although the sand was 1.77 parts, the W/C was 0.28, and the admixture was about 0.004 parts, spraying could be carried out in almost the same way.

However, the initial maximum shear stress of this sprayed layer is 185k9/mm, the compressive strength after 3 days is 295k9/mm, after 7 days it is 450k9/mm, and after 28 days it is 621mm.
It was k9/th.

Example 5 1 part cement, 1 part sand, 0.36 part water, 0.01 admixture
The Fo value of the mortar mixed and adjusted in the proportion of 0.4
3 evening/earth, △Fo is 0.01 tanomono 4, ^ value is 1.3
30 seconds/m of this mortar
It was pumped in.

In addition, a mixture of air-dried river sand on the 5th side and crushed stone on the 5th to 15th sides in approximately the same weight ratio was mixed with 0.4 to 1 part of the mortar.
The mixture was added under pressure using compressed air at a ratio of 2 parts, and sprayed onto a substantially vertical spray surface through a nozzle.

In addition, in this spraying construction, only the mortar is used at the initial stage of spraying, that is, after the ground layer is covered with mortar, the aggregate is gradually added to form the above-mentioned ratio relationship. We aimed to improve adhesion and reduce the amount of rebound.

The results of the analysis of the composition of the formed blown attachments are roughly as follows.
1 part cement, 1.5 parts sand, 0.5 parts lees aggregate, 0.3 parts water
6 parts, and the compressive strength of this after 3 days is 21
5X9/enemy, 7 days later 428XQ/, 28 days later 52
It was 6k9/ground. In addition, 1 part cement, 1.2 parts sand, and 0.0 parts water. Isobe, the Fo value of the mortar adjusted with the proportion of 0.01 part of admixture is 5 y/s, and △Fo is 0.04.
5 Tano enemy 4, ^ value is false evening / sec / 4, and the surface water is 10%, 1 part of sand is pre-sprinkled with 0.5 part of cement and attached. A mixture of 1.5 parts of the same crushed stone (approximately the same weight ratio) was added by compressed air at a ratio of 1.5 k9 of pneumatic bone mortar to 1 k9 of the mortar, and construction was carried out in the same manner. In other words, the composition of this sprayed layer is 1 part cement to 1.5 parts sand.
6 parts, crushed stone 1.1 parts, water 0.192 parts, admixture 0.0
Although the amount of sand and crushed stone was considerably increased at about 0.4 parts, almost favorable spraying work could be achieved.

The initial maximum sea bream shear stress in the sprayed layer thus formed is 1
50k9/ground, compressive strength after 3 days is 283k9/
land, 453k9/land after 7 days, 595k9/land after 28 days
It was a pleasure.

Example 6 The same mortar as in Example 5 was pumped in the same manner and added to the pumped aggregate mixed with 30% air-dried JII sand (5 kites) and 70% gravel of 5 to 15 ribs. Spraying was carried out in exactly the same manner as in Example 5.

The results of compositional analysis of the sprayed layer formed are roughly cement 1.
1.36 parts of sand, 0.74 parts of gravel, and 0.36 parts of water per part, and its maximum shear stress is 138 parts per day, making it suitable for spraying even on arched ceiling surfaces. It is possible, and the compressive strength after 3 days of construction is 228k9/ground, and after 7 days is 4
36X9/c rudder, 28 days later it was 8k9/c.

Example 7 In preparing the same mortar as in Examples 5 and 6, approximately 40
The kneading machine was left as it was for 1 hour at zero temperature, and then charged into the kneading machine again, 0.01 part of the admixture was added, and secondary kneading was carried out using the same machine as in Example 4 described above. It is.

This mortar was added to aggregate having exactly the same composition and pumping conditions as in Example 6, and spraying was carried out in the same manner.

The results of compositional analysis of the sprayed layer thus formed are approximately 1 part cement, 1.36 parts sand, and 0.0 parts gravel.
74 parts and 0.36 parts of water are the same as in Example 6, but the compressive strength after 3 days of spraying was 418k.
After 7 days, the compressive strength was 523k9/ground, which is considerably higher than that of Example 6, and after 28 days, the compressive strength was 5.
It was 73k9/.

Example 8 1 part of cement was added to 3.8 parts of JII sand adjusted to have a surface water of 8.5%, mixed in advance, and the cement was mixed with JII sand.
II Prepare as a sprinkled on sand particles, and add 5
The gravel on the ~15th side was added to an amount equivalent to 82% on the outside and forced to flow with compressed air, and mortar adjusted exactly the same as in Examples 4 and 5 was mixed with such air-forced aggregate. I sprayed it.

The blending ratio of air-forced aggregate and mortar is 12:1,
The compositional analysis result of the sprayed layer formed is that the ratio is approximately 1:1 of cement, 1.63 of sand, 0.99 of gravel, and 0.34 of water, and the maximum initial breaking stress of the sprayed layer thus formed is is 235 m/m, and the compressive strength after 3 days of spraying is 35 m/m.
2k9/earth, 5 spots k9/earth after 7 days, 62 after 28th
It was 5k9/ground. Example 9 1 part of cement, 1 part of sand, 0.36 parts of water, 0.01 part of admixture, Fo was 0.43 mm/ground, △Fo was 0
．． The slump value of the slurry-like mixture prepared by mixing 1 part of gravel with a diameter of 5 to 15 ribs to the mortar of 1.3 min/sec/pressure 4 was 23. However, even when gravel was mixed in as described above, it still behaved as a slurry-like mixture.

To this, 1 part of cement was added to 38 parts of 2.5 parts of sand with surface water adjusted to 7% as aggregate, and sprinkled on the surface of the river sand particles, and the surface was left to dry. 4 parts of 5 to 15 side gravel is added to the aggregate and blown with high pressure air. It was installed.

That is, the mixing ratio of the slurry-like green kneaded material and the air blown aggregate is approximately 1:1.2, and an analysis of the composition of the formed shotcrete reveals that it is approximately 1:1 cement to 1:1 sand. &
The ratio of gravel was 1.9 and water was 0.33, and although it was almost the same as Example 8 except for the addition of mortar gravel, the concrete had a lot of gravel.

The maximum shearing force of the shotcrete thus formed was 350 m/m, and the compressive strength after 3 days of spraying was 347 m/m.
k9/enemy, 489 after 7 days k9/ji, 595 after 28 days
It was k9/ground. Example 10 Fo value of mortar prepared by mixing 1 part of cement, 1 part of sand, 0.36 part of water, and 0.01 part of admixture is 0.43 m/m, △Fo is 0
．． The input value was 1.3 sec/sec/4, and the mortar was mixed with 2% glass fiber by volume to obtain a thriller-like hawk bran product JISR520.
The spreading flow value with 1 was 245 (ribs).

To this, 1 part of river sand with a moisture content of 8% and 0.26 parts of cement were added and sprinkled on the surface of the river sand particles, and this was then pumped with high pressure air. Spraying was carried out by adding a contaminant.

The mixing ratio of the air-forced aggregate and the slurry-like raw kneaded material is approximately 1:
5, and the composition of the sprayed layer was 1 part cement, 1.2 ml sand, 0.05 ml fiber, 0.35 ml water, and the volume ratio of the fiber was 1.9%.

However, the maximum breaking amount of this sprayed layer was 175k9/m, and no sagging was observed even though no fastening agent was used. However, the compressive strength of this material at 3 days old is 2 spots k9/ground, and the total bending strength is k9/, so at 7 days old, the compressive strength is 3 kg/ground, and the bending strength is 97 k.
At 28 days old, the compressive strength was 537k9/dimensions, and the bending strength was 125k9/dm, showing high compressive and bending strengths. Example 11 1 part cement, 1 part sand, 0. Shibe, Fo of mortar mixed at a ratio of 0.01 part of admixture is 0.2 m/m, △
F〇 is 0.001 evening/earth 4, entry is 0.8 evening/sec/
It was a mortar with good fluidity.

On the other hand, as an aggregate, 2.5 parts of sand with surface water adjusted to 10% is mixed at a ratio of 3.3 parts to 1 part of cement, dry kneaded, and the sand grains are sprinkled with cement. Furthermore, prepare a material by mixing and kneading 0.30 x 15 side steel fibers at a ratio of 0.66 parts, and mix this aggregate with 10k9
The mortar was added to the mortar at a rate of 30 tons/min and sprayed onto the vertical construction surface. The maximum forced stress of the sprayed layer is 355 mm, and its composition is 1 part of cement, 1.6 parts of sand, and 0.6 parts of steel fiber. Moribe, 0.35 parts of water, 0.007 parts of admixture, the compressive strength after 7 days of spraying was 5k9/base, the strength after 28 days was 498k9/base, and the bending strength was After 7 days, it was 75k9/ground, and after 28 days, it was 113 [9/ground].

Example 12 To the same mortar as in Example 11, synthetic fiber was added in place of the steel fiber as aggregate at a rate of 0.0% per part of the sand.
The test was carried out under the same conditions as in Example 9 except that the amount was changed to 5 parts (more than 0.18 parts to 1 part of cement).

The compressive strength of the obtained sprayed layer after 7 days is nanny kg/
The bending strength was 476k9/ground after 28 days, and the bending strength was 66k9/ground after 7 days and 108k9/ground after 28 days.

Example 13 In preparing the same mortar as in Examples 11 and 12, the mixture was first kneaded with something other than the admixture, and then mottled ~ 4
The pieces of 1 were left as they were for 1 hour at a temperature of 1 pm, and then 0.01 part of an admixture was added and kneaded for a second time.

The conditions for adjusting and the composition of the aggregate to which the mortar was added were exactly the same as those described in Example 11, and the mortar was added in the same manner to the mortar and sprayed.

It goes without saying that the compositional relationship in the sprayed layer is the same as that described in Example 11, but the compressive strength of the sprayed layer thus obtained after 7 days was 437k9/m, which is lower than that in Example 11. Considerably high, bending strength is 101k
9/2 was also commercially available, and after 28 days, the compressive strength was 507k9/ground and the bending strength was 118k9/ground.

Example 14 As aggregates added to the same mortar as in Example 11, 1 part of cement, 3 parts of sand of 2.5 skin or less, 3 parts of gravel on the 5th to 15th sides, and 0.2 ribs ◇ × 15 ribs were added. Using 0.8 parts of steel fibers, the surface water of sand was adjusted to 10%, and the above cement was mixed and sprinkled, and then the gravel and steel fibers were added and mixed. All spraying was carried out under the same conditions as in Example 11, except that the mixing ratio of aggregate and mortar was 1.2:1.

The composition of the obtained sprayed layer was 1 part of cement, 1.5 parts of sand, 0.8 parts of gravel, 0.34 parts of water, and 0.22 parts of steel fiber.
The shear stress at Gidai-nada is about 800 k9/ground, and the rebound rate when sprayed is 4.8%, and the compressive strength of this product is 205 k9/2 after 3 days and 413 k9/2 after 7 days.
The bending strength was 505k9/m after 8 days, 69k9/m after 7 days, and 125k9/m after 28 days.

Example 15 Alumina cement was mixed in the same ratio with refractory material powder obtained by crushing anorsite-based clay spikes and acidic refractory material, and 0.4 parts of water was added. The fluidity of the mixture was as follows. 0
．． 7 evenings/lump, entry is 6.2 evenings/sec/skin 4, △F
o was 0.004 / 4 and was a raw twill material with favorable fluidity.

On the other hand, the above-mentioned green kneaded material is used for the granular refractory aggregate, which is made by blending graphite and magnesia with some dolomite and crushing it after firing to give a grain size of 10 to 2. A mixture containing the same amount of added refractory material powder was prepared.

However, after preparing the raw kneaded material as described above, it is left as it is for about 3 hours, then kneaded again, and then pumped using a pump at a rate of 30 mm/min using the fluidity of the added water. Similarly, to the flow of coarse aggregate that is being pumped with high-pressure air at a rate of 30 m/min, it is dispersed and added at a position 3 kites before the spray nozzle, and is combined to form a cylindrical steel shell. The inner surface was sprayed as a fireproof coating.

The thickness of the applied sprayed layer was approximately 18 cm thick, and a stable layer adhesion with almost no sagging was obtained during the entire process of spraying. The results of analysis of the composition of 1 part of cement (alumina cement) were 1.7 parts of refractory powder, 0.9 parts of granular cross-sectional coarse aggregate, and water was 1 part of cement (alumina cement). The compressive strength at the time of 2 hours after the completion of spraying was 262 k9/m.

Example 16 The same green kneaded material as in Example 15 was used, and the same refractory coarse aggregate was used, but this refractory coarse aggregate had water adhering to its surface added to about 8% by weight. After spraying, the refractory material powder adjusted to less than 1 side was sprinkled, and all other operations were carried out in accordance with Example 15. As a result, the compressive strength after 2 feeding hours after spraying was 284 kg/.

According to the present invention as explained above, when carrying out this type of concrete spraying construction, paste or mortar and lees aggregate such as gravel or pongee aggregate such as sand are separately pumped through pipes. This makes it possible to pump paste or mortar in a slurry state that maintains favorable fluidity, and also enables the above-mentioned coarse aggregate and pongee aggregate to be pumped in smooth pipes under dry conditions. This makes it possible to carry out pressure feeding over considerable distances using relatively simple equipment and pressure conditions, and by combining and spraying this on the construction surface, the shear stress yield value can be reduced. It enables the formation of a sprayed layer in a sufficiently raised capillary area, and achieves efficient spraying with little rebound or flaking, and is effective against powdery materials such as cement. As mentioned above, since the paste or mortar is pumped and sprayed as a sufficiently hydrated paste or mortar, there is almost no dust generation during the whole pumping or spraying process, and the work can be done in a favorable working environment. In addition, since the water-to-cement ratio is small and the interparticle distance is favorable so that adsorption force can be expressed as described above, a sprayed layer with excellent strength can be obtained, and its thickness can be increased to a sufficient level. This invention is industrially very effective because it can be made larger in size, and advantageous spraying construction that is not required by conventional wet, dry, or semi-wet methods can be carried out smoothly.

[Brief explanation of the drawing]

The drawings are for explaining the technical relationship in the present invention; Fig. 1 is an explanatory diagram showing the capillary state in a collar style,
The figure is an explanatory diagram similar to FIG. 1 in a slurry state. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. A paste made by adding water to a hydraulic substance such as cement or gypsum, or a slurry-like green kneaded material such as a mortar in which sand or similar fine-grained material is mixed with the paste, and gravel. Coarse aggregate such as sand, fine aggregate such as sand, or a granular mixture of one or more powdered materials are pumped through separate pipes, and these separately pumped materials are A concrete spraying construction method characterized by combining and spraying. 2. A paste made by adding water to a hydraulic substance such as cement or gypsum, or a slurry-like mixture such as mortar mixed with sand or similar fine-grained material, and a coarse aggregate such as gravel or A fine aggregate such as sand or a granular mixture of one or more types of powder is moistened to an appropriate level and then sprinkled with powder of a hydraulic substance such as cement. A method for spraying concrete, which is characterized in that concrete is pumped through a pipe, and these separately pumped materials are combined and sprayed. 3 A paste made by adding water to a hydraulic substance such as cement or gypsum, or a slurry-like mixture such as mortar mixed with sand or similar fine-grained material, and a coarse aggregate such as gravel or A granular mixture of one or more fine aggregates such as sand or powder materials, and one or more of fibrous materials such as metallic fiber materials, synthetic fiber materials, asbestos, rock wire, and high slag cotton. A method for spraying concrete, characterized in that a mixture of two or more types is pumped through separate pipes, and these separately pumped materials are combined and sprayed. 4. A green kneaded material prepared as a slurry is fluidized and pumped using the fluidity of its liquid content, and this is mixed with the pneumatically pumped powder/granule mixture and sprayed to achieve a water content approximately like that of a capillary. A concrete spraying construction method according to any one of claims 1 to 3, which forms a sprayed layer having the following properties. 4. The concrete spraying method according to any one of claims 1 to 4, which uses mortar prepared by mixing sand and cement in advance and then adding water. 6. Claims 1 to 5 in which a green kneaded material such as paste or mortar is once prepared, then kneaded for a required period of time, and then kneaded for a second time in the pressure-feeding pipeline or just before the pressure-feeding.
Concrete spraying construction method described in any of paragraphs. 7. The concrete spraying method according to any one of claims 1 to 6, wherein the raw kneaded material is combined in the vicinity of a nozzle and then sprayed. 8 Claims 1 to 7 in which a fire-resistant layer is formed using alumina cement as a raw kneaded material and one or both of fire-resistant coarse aggregate and fine aggregate as a powdery mixture. The concrete spraying method described in any of the above. 9 Add fly ash to the slurry-like mixture, water slag powder,
Claims that include one or more of powdered substances such as pozzolan or additives such as water glass, colloidal silica, polymeric plastic materials, calcium chloride, sodium aluminate, sodium carbonate, and sodium hydroxide. The concrete spraying method according to any one of paragraphs 1 to 8. 10 Claims 1 to 9, in which the raw kneaded product is added in a dispersed manner to the pumping flow path of the powder and granule mixture by narrowing the diameter of the pressure pipe at the point where it is added to the pneumatically fed powder and granule mixture. Concrete spraying construction method described in any of paragraphs.