Concrete spraying system and concrete spraying method
By controlling the arrival order and conveyance conditions of liquid and powder rapid-setting agents, the concrete spraying system and method prevent solidification in piping, ensuring efficient concrete application and reducing downtime and costs.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- DENKA CO LTD
- Filing Date
- 2022-01-28
- Publication Date
- 2026-05-22
AI Technical Summary
In existing concrete spraying methods using both powdered and liquid rapid-setting agents, the materials tend to solidify within the piping, necessitating costly replacements and interrupting work efficiency.
A concrete spraying system and method that controls the order of arrival and conveyance of liquid and powder rapid-setting agents, ensuring the liquid agent arrives first and the powder agent arrives later, using specific pH and Blaine value conditions for the liquid agent and a controlled air flow and pressure for both agents to prevent solidification in the piping.
Prevents material solidification in the piping, maintaining work efficiency by ensuring effective mixing and application of concrete, thereby reducing downtime and costs.
Smart Images
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Abstract
Description
[Technical Field]
[0001] The present invention relates to, for example, tunnels for roads, railways, water conduits, etc., and concrete spraying systems and concrete spraying methods for spraying concrete onto exposed ground surfaces during tunnel excavation or underground cavity construction. [Background technology]
[0002] Concrete spraying is used to reinforce and stabilize exposed ground surfaces in tunnels for roads, railways, and water conduits, as well as in tunnel excavation and underground cavity construction. There are two main types of concrete spraying: dry spraying and wet spraying (see, for example, Patent Documents 1 and 2). Dry spraying involves adding water to a dry mix of concrete (without water) while it is being air-pressurized, and then supplying a quick-setting agent via air transport from a quick-setting agent supply facility to a branch pipe at the confluence to mix the concrete and quick-setting agent before spraying the concrete from a nozzle. Wet spraying involves preparing fresh concrete by pre-mixing cement, aggregate, and water, and then air-pressurizing the fresh concrete while simultaneously supplying a quick-setting agent via air transport from a quick-setting agent supply facility to a branch pipe at the confluence to mix the concrete and quick-setting agent before spraying the concrete from a nozzle. Currently, wet spraying is the mainstream method due to the reduced dust and rebound.
[0003] In wet spraying methods, there is a technique that uses both powdered and liquid rapid-setting agents as rapid-setting agents mixed into the concrete. However, in this technique, the materials can solidify within the piping that serves as the channel for mixing the powdered and liquid rapid-setting agents into the concrete. If the materials solidify within the piping, it not only necessitates replacing the piping, which increases costs, but also forces the concrete spraying work to be interrupted, resulting in a decrease in work efficiency. [Prior art documents] [Patent Documents]
[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 58-15056 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-189529 [Summary of the Invention] [Problems to be Solved by the Invention]
[0005] In view of the above problems, the present invention provides a concrete spraying system and a concrete spraying method capable of preventing the consolidation of materials in a pipe in a concrete spraying method in which a powder accelerating agent and a liquid accelerating agent are used in combination as accelerating agents and mixed with concrete. [Means for Solving the Problems]
[0006] As a result of intensive studies to solve the above problems, the present inventors have found that by controlling the order of arrival and conveyance of the liquid accelerating agent and the powder accelerating agent to the accelerating agent confluence part provided in the mixing part where the liquid accelerating agent and the powder accelerating agent are joined and mixed in the concrete, it is possible to prevent the consolidation of materials in the pipe, and have completed the present invention. That is, the present invention is as follows. [1] A liquid accelerating agent conveyance flow path for conveying a liquid accelerating agent having a pH of 1 to 4 containing aluminum sulfate as a main component, and a CaO / Al2O3 molar ratio of 1.7 to 3.0 and a Blaine value of 4,000 cm 2A concrete spraying system comprising: a powder rapid-setting agent transport channel for transporting a powder rapid-setting agent containing 30% or more by mass of calcium aluminate at a concentration of 1 / g or more; a concrete transport channel for transporting concrete; a rapid-setting agent confluence section provided in a part of the concrete transport channel for confluence of the liquid rapid-setting agent transported in the liquid rapid-setting agent transport channel and the powder rapid-setting agent transported in the powder rapid-setting agent transport channel, and a mixing section for mixing the liquid rapid-setting agent and the powder rapid-setting agent confluenced in the rapid-setting agent confluence section with the concrete; a spraying section provided downstream of the mixing section for spraying the concrete mixed with the liquid rapid-setting agent and the powder rapid-setting agent onto an object; and a control unit that controls the order in which the liquid rapid-setting agent and the powder rapid-setting agent reach the rapid-setting agent confluence section, so that the liquid rapid-setting agent arrives first and the powder rapid-setting agent arrives later. [2] The concrete spraying system according to [1], wherein the control unit controls the powdered fastener to reach the fastener confluence section at least two seconds after the liquid fastener has reached it. [3] The transport conditions for the liquid fastener being transported through the liquid fastener transport channel are such that the air flow rate is 2 to 4 m 3 A concrete spraying system as described in [1] or [2], wherein the air pressure is 0.2 to 0.7 MPa and the flow rate is / min. [4] The transport conditions for the powder rapid setting agent being transported through the powder rapid setting agent transport channel are such that the air flow rate is 2 to 5 m 3 A concrete spraying system as described in any of [1] to [3], wherein the flow rate is / min and the air pressure is 0.2 to 0.5 MPa. [5] A step of transporting a liquid rapid setting agent having a pH of 1 to 4 and mainly composed of aluminum sulfate through a liquid rapid setting agent transport channel, and a CaO / Al2O3 molar ratio of 1.7 to 3.0 and a Blaine value of 4,000 cm 2A step of conveying a powder quick-setting agent containing 30% by mass or more of calcium aluminate of / g or more in a powder quick-setting agent conveying flow path, a step of conveying concrete in a concrete conveying flow path, and a part of the concrete conveying flow path provided with a quick-setting material confluence part that merges the liquid quick-setting agent conveyed in the liquid quick-setting agent conveying flow path and the powder quick-setting agent conveyed in the powder quick-setting agent conveying flow path, and mixing the liquid quick-setting agent and the powder quick-setting agent merged at the quick-setting material confluence part with the concrete in a mixing part; a step of spraying the concrete in which the liquid quick-setting agent and the powder quick-setting agent are mixed onto an object at a spraying part provided on the downstream side of the mixing part; and a step of controlling, by a control part, the conveyance order of the liquid quick-setting agent and the powder quick-setting agent reaching the quick-setting material confluence part such that the liquid quick-setting agent comes first and the powder quick-setting agent comes later. A concrete spraying method including these steps. [6] The step of controlling by the control part is to control such that the powder quick-setting agent reaches 2 seconds or more after the liquid quick-setting agent reaches the quick-setting material confluence part. The concrete spraying method according to [5]. [7] In the step of conveying the liquid quick-setting agent conveying flow path, the conveying conditions of the liquid quick-setting agent are that the air flow rate is 2 - 4 m 3 / min, and the air pressure is 0.2 - 0.7 MPa. The concrete spraying method according to [5] or [6]. [8] In the step of conveying the powder quick-setting agent conveying flow path, the conveying conditions of the powder quick-setting agent are that the air flow rate is 2 - 5 m 3 / min, and the air pressure is 0.2 - 0.5 MPa. The concrete spraying method according to any one of [5] - [7].
Advantages of the Invention
[0007] According to the present invention, in a concrete spraying method in which a powder quick-setting material and a liquid quick-setting material are used in combination as a quick-setting agent and mixed with concrete, a concrete spraying system and a concrete spraying method capable of preventing solidification of materials in a pipe can be provided.
Brief Description of the Drawings
[0008] [Figure 1] This is a schematic diagram showing a concrete spraying system according to an embodiment of the present invention. [Modes for carrying out the invention]
[0009] The present invention will be described in detail below. In this invention, parts and percentages are expressed on a mass basis unless otherwise specified.
[0010] [Concrete spraying system] As shown in Figure 1, a concrete spraying system according to an embodiment of the present invention comprises a liquid quick-setting agent transport channel 1, a powder quick-setting agent transport channel 2, a concrete transport channel 3, a mixing section 4, a spraying section 5, and a control section 6.
[0011] In a concrete spraying system according to an embodiment of the present invention, the concrete transport channel 3 is a channel for transporting concrete. The concrete transported by the concrete transport channel 3 is prepared by pre-mixing cement, aggregate, and water. The pre-prepared concrete is transported to the spraying construction site by an agitator truck 30 and supplied to the concrete pump 31. The concrete pump 31 pumps the supplied concrete through the concrete transport channel 3, through the mixing section 4, and to the spraying section 5. For the concrete transport channel 3, a pressure-resistant metal mesh hose (pressure-resistant hose) or metal piping can be used. Typically, a pressure-resistant hose is used, and it is preferable to use metal pipes before and after it. The diameter of the pressure-resistant hose is usually 2.5 to 3.5 inches, considering the ability to pump concrete and the ease of handling the pressure-resistant hose.
[0012] The cement used in this invention is not particularly limited and can include various types of Portland cement such as ordinary, rapid-hardening, ultra-rapid-hardening, moderate-heat, and low-heat cements, filler cements made by mixing these Portland cements with blast furnace slag, fly ash, and limestone powder, and environmentally friendly cements (eco-cements) manufactured using municipal solid waste incineration ash and sewage sludge incineration ash as raw materials. These can also be used after being powdered. The ratio of the mixture to the cement in the mixed cement is not particularly limited, and it is also possible to use mixtures in proportion to the admixtures that are assumed by JIS standards. The cement may also contain, if necessary, commercially available cement admixtures such as water-reducing agents, air-entraining agents, polymer emulsions, thickeners, shrinkage-reducing agents, rust inhibitors, antifreeze agents, clay minerals, and silica fume, to the extent that they do not impair its performance.
[0013] The aggregate used in this invention is preferably one that has a low water absorption rate and high aggregate strength. As for aggregates, there are no particular limitations as long as they can be used in sprayed concrete; fine aggregates and coarse aggregates can be used. Suitable fine aggregates include river sand, mountain sand, sea sand, lime sand, and silica sand, while suitable coarse aggregates include river gravel, mountain gravel, and lime gravel. Crushed sand and crushed stone can also be used. The ratio of fine aggregate to coarse aggregate can be expressed as the ratio of the volume of fine aggregate (s) to the volume of aggregate (a), where s / a is preferably 60-70% by volume.
[0014] The concrete spraying system according to an embodiment of the present invention includes a liquid accelerator unit 10 that stores and pumps a liquid accelerator. The liquid accelerator unit 10 is connected to a control unit 6 and controls the supply of the liquid accelerator under the control of the control unit 6. The liquid accelerator unit 10 includes a liquid accelerator tank 11 that stores the liquid accelerator, and a liquid accelerator feeder 12 that is connected to a compressor 50 and pumps the liquid accelerator by compressed air. The liquid accelerator unit 10 pumps the liquid accelerator stored in the liquid accelerator tank 11 through a liquid accelerator conveyance passage 1 to a liquid accelerator inlet 41 and a quick-setting material confluence section 43 of a mixing section 4 by the compressor 50 and the liquid accelerator feeder 12. As the liquid accelerator conveyance passage 1, any pressure-resistant hose such as a pressure-resistant hose with a thread or a hose with a metal mesh, or a metal pipe with excellent pressure resistance can be used. Usually, a pressure-resistant hose is used, and it is preferable to use metal pipes before and after it. The diameter of the pressure-resistant hose is usually 0.5 to 1.5 inches from the aspects of the pumpability of the liquid accelerator and the workability such as handling of the pressure-resistant hose.
[0015] The conveyance conditions of the liquid accelerator conveyed through the liquid accelerator conveyance passage 1 are preferably such that the air flow rate is 2 to 4 m 3 / min, more preferably 2.2 to 3.8 m 3 / min, and even more preferably 2.4 to 3.6 m 3 / min. Also, the conveyance conditions of the liquid accelerator conveyed through the liquid accelerator conveyance passage 1 are preferably such that the air pressure is 0.2 to 0.7 MPa, more preferably 0.25 to 0.65 MPa, and even more preferably 0.3 to 0.6 MPa. By setting the air flow rate and air pressure within the above ranges as the conveyance conditions of the liquid accelerator conveyed through the liquid accelerator conveyance passage 1, it becomes easy to control the supply of the liquid accelerator to the quick-setting material confluence section 43 provided in the mixing section 4.
[0016] The liquid rapid-setting agent transported in the liquid rapid-setting agent transport channel 1 has a pH of 1 to 4. If the pH of the liquid rapid-setting agent is less than 1, it is unsuitable in terms of corrosion and handling of the liquid rapid-setting agent transport channel 1 and other components that transport the liquid rapid-setting agent. Furthermore, if the pH of the liquid rapid-setting agent exceeds 4, when mixed with the powdered rapid-setting agent, the mixing with the concrete will be poor, resulting in a decrease in strength development. From the above viewpoint, the liquid rapid-setting agent preferably has a pH of 1.2 to 3.8, more preferably 1.4 to 3.6, and even more preferably 1.6 to 3.4. Furthermore, in order to prepare a liquid rapid setting agent exhibiting a pH within the above range, an acid component such as sulfuric acid may be added as appropriate.
[0017] The liquid rapid setting agent can be an aluminum sulfate solution containing aluminum sulfate as its main component. For example, water can be used as the solvent for the aluminum sulfate solution. In this specification, "main component" refers to the component present in the highest concentration. The amount of aluminum sulfate, the main component of the liquid quick-setting agent, is preferably 20% by mass or more, more preferably 23% by mass or more, more preferably 25% by mass or more, and even more preferably 26% by mass or more, on an anhydrous basis of aluminum sulfate.
[0018] The concentration of aluminum sulfate in the liquid quick-setting agent is preferably 20-35%, more preferably 23-30%, and even more preferably 25-28%. When the concentration of aluminum sulfate is within the above range, the viscosity of the liquid quick-setting agent is not excessively high, resulting in good pumpability and excellent quick-setting properties.
[0019] Liquid quick-setting agents may contain components other than the main component, aluminum sulfate. Other components that can be included include, for example, inorganic acids such as sulfuric acid, phosphoric acid, boric acid, and hydrofluoric acid, and their salts (sodium, potassium, lithium, calcium, magnesium, aluminum), as well as organic acids such as monocarboxylic acids, dicarboxylic acids, polycarboxylic acids, oxycarboxylic acids, and amino acids, and solutions of these salts (sodium, potassium, lithium) diluted in water. Among these, the combined use of dicarboxylic acids, oxycarboxylic acids, and their salts is preferred in terms of solubility in water and ease of handling. The amount of components other than aluminum sulfate, which is the main component of the liquid rapid setting agent, is preferably 10% by mass or less, more preferably 7.5% by mass or less, preferably 5% by mass or less, and even more preferably 3% by mass or less.
[0020] The amount of liquid quick-setting agent used is preferably 2 to 14 parts, more preferably 3 to 12 parts, and even more preferably 4 to 10 parts per 100 parts of cement. If the amount of liquid quick-setting agent used is above the lower limit, excellent rapid setting properties are obtained, and if the amount of liquid quick-setting agent used is below the upper limit, good long-term strength development is obtained.
[0021] Liquid quick-setting agents can have their setting properties improved by heating them to a temperature range of 20-60°C and mixing them with concrete. However, when using acidic components such as sulfuric acid in the liquid quick-setting agent, the viscosity of the liquid itself increases, so it is even more preferable to use them in the temperature range of 5-40°C.
[0022] The solid content concentration of the liquid quick-setting agent is preferably 21-45%, more preferably 23-40%, and even more preferably 25-35%. When the solid content concentration of the liquid quick-setting agent is within the above range, the viscosity of the liquid quick-setting agent is not excessively high, resulting in good pumpability and excellent quick-setting properties.
[0023] An embodiment of the present invention provides a concrete spraying system equipped with a powder rapid-setting agent supply machine 20 for storing and pumping powder rapid-setting agent. The powder rapid-setting agent supply machine 20 is connected to a control unit 6, and the supply of the powder rapid-setting agent is controlled by the control unit 6. The powder rapid-setting agent supply machine 20 includes a powder rapid-setting agent tank 21 for storing the powder rapid-setting agent, and an air dryer 22 connected to a compressor 50 for supplying dry compressed air to the powder rapid-setting agent tank 21 and pumping the powder rapid-setting agent. The powder rapid-setting agent supply machine 20 pumps the powder rapid-setting agent stored in the powder rapid-setting agent tank 21 through the powder rapid-setting agent transport channel 2 to the powder rapid-setting agent inlet 42 and the rapid-setting agent confluence section 43 of the mixing section 4 using the compressor 50 and the air dryer 22. For the powder rapid-setting agent conveying channel 2, a pressure-resistant metal mesh hose (pressure-resistant hose) or metal piping can be used. Typically, a pressure-resistant hose is used, and it is preferable to use metal pipes before and after it. The diameter of the pressure-resistant hose is usually 0.5 to 1.5 inches, considering the ability to pump the powder rapid-setting agent and the ease of handling the pressure-resistant hose.
[0024] The transport conditions for the powder rapid setting agent being transported through the powder rapid setting agent transport channel 2 are an air flow rate of 2-5 m³. 3 It is preferably / min, and 2.2 to 4.5m 3 It is more preferable that it be / min, and 2.4~4m 3 It is even more preferable that the flow rate is / min. Furthermore, the transport conditions for the powder rapid binder transported through the powder rapid binder transport channel 2 are preferably such that the air pressure is 0.2 to 0.5 MPa, more preferably 0.25 to 0.45 MPa, and even more preferably 0.3 to 0.4 MPa. By having the air flow rate and air pressure within the above ranges as transport conditions for the powder rapid binder transported through the powder rapid binder transport channel 2, it becomes easier to control the supply of the powder rapid binder to the rapid binder confluence section 43 provided in the mixing section 4.
[0025] The calcium aluminate incorporated into the powdered rapid-setting agent is a rapid-setting component that causes concrete to set in the initial stages. Calcium aluminate is a calcium aluminate obtained by mixing raw materials containing calcia, alumina, silica, etc., and then heat-treating them by firing in a kiln or melting in an electric furnace. It is mainly composed of CaO and Al2O3, and contains 1 to 4 parts SiO2 in terms of oxide. In addition, compounds in which part of the CaO and / or Al2O3 of the calcium aluminate is substituted with alkali metal oxides, alkaline earth metal oxides, titanium oxide, iron oxide, alkali metal halogen compounds, alkaline earth metal halogen compounds, alkali metal sulfates, and alkaline earth metal sulfates, or substances in which small amounts of these are solid-dissolved in a substance mainly composed of CaO and Al2O3, can also be used. In terms of mineral form, it may be either crystalline or amorphous. Among these, amorphous calcium aluminate is preferred in terms of reaction activity and pumpability, C 12 A more preferable option is an amorphous calcium aluminate obtained by rapidly cooling a heat-treated product containing silicon dioxide in composition A7. The amount of SiO2 contained in the calcium aluminate is preferably 1 to 4 parts in terms of oxide, and more preferably 2 to 4 parts, per 100 parts of calcium aluminate. Having 1 part or more allows for good setting characteristics, while having 4 parts or less allows for sufficient initial strength.
[0026] The molar ratio of CaO / Al2O3 in calcium aluminate is in the range of 1.7 to 3.0. If the CaO / Al2O3 molar ratio is less than 1.7 or greater than 3.0, it becomes difficult to shorten the curing time and improve the initial strength development. From the viewpoint of further shortening the curing time and improving the initial strength development, the molar ratio is preferably in the range of 2.0 to 2.9, more preferably in the range of 2.1 to 2.8, and even more preferably in the range of 2.2 to 2.7. As long as the molar ratio is within the above range, it can be used regardless of the form, such as crystalline or amorphous, and even if the molar ratio is mixed within the range.
[0027] The Blaine specific surface area (hereinafter referred to as the Blaine value) of calcium aluminate is 4,000 cm². 2 The value is 4,000 cm² or more.2 If the value is less than / g, the rapid setting and initial strength development of the sprayed concrete will decrease. From the perspective of improving the rapid setting and initial strength development of sprayed concrete, the Blaine value should be 4,000 cm 2 It is preferable that the amount be 4,500 cm² or more. 2 It is more preferable that the amount be 5,000 cm² or more. 2 It is even more preferable that the value be 1 / g or higher. The Blaine value is set at 9,000 cm from the viewpoint of suppressing the possibility of excessive viscosity in the concrete and impairing its pumpability. 2 It is preferable that the value be less than or equal to / g.
[0028] The amount of calcium aluminate blended into the powdered rapid-setting agent is 30% or more. If the amount of calcium aluminate is less than 30%, the rapid-setting properties and initial strength development of the sprayed concrete will decrease. From the viewpoint of improving the rapid-setting properties and initial strength development of the sprayed concrete, the amount of calcium aluminate is preferably 35% or more, more preferably 40% or more, and even more preferably 45% or more. From the viewpoint of appropriately exhibiting the rapid-setting properties and initial strength development of the sprayed concrete, the amount of calcium aluminate is preferably 70% or less.
[0029] In the concrete spraying system according to an embodiment of the present invention, a mixing section 4 provided in a part of the concrete transport channel 3 mixes the liquid rapid-setting agent transported in the liquid rapid-setting agent transport channel 1 and the powder rapid-setting agent transported in the powder rapid-setting agent transport channel 2 with the concrete. The mixing unit 4 has a rapid-setting agent confluence section 43 where piping such as a liquid rapid-setting agent inlet 41 and a powder rapid-setting agent inlet 42 is installed. The liquid rapid-setting agent and the powder rapid-setting agent are combined in the rapid-setting agent confluence section 43 and mixed with concrete that has been separately pumped to produce sprayed concrete. Any existing equipment can be used as the mixing unit 4, for example, tilt mixers, omni mixers, Henschel mixers, V-type mixers, and Nauta mixers can be used.
[0030] In a concrete spraying system according to an embodiment of the present invention, the control unit 6 is connected to the liquid quick-setting agent unit 10, the powder quick-setting agent supply unit 20, and the compressor 50, and controls the order in which the liquid quick-setting agent and the powder quick-setting agent arrive at the quick-setting agent confluence section 43, so that the liquid quick-setting agent arrives first and the powder quick-setting agent arrives second. By performing the above control, the control unit 6 can suppress solidification in the quick-setting agent confluence section 43 and piping where the powder quick-setting agent and the liquid quick-setting agent are combined, as well as in the mixing section 4 where the powder quick-setting agent and the liquid quick-setting agent are mixed with concrete.
[0031] From the viewpoint of effectively suppressing material solidification in the mixing section 4, the rapid-setting agent confluence section 43, and piping, the control unit 6 preferably controls the powder rapid-setting agent to arrive at the rapid-setting agent confluence section 43 at least 2 seconds after the liquid rapid-setting agent arrives, more preferably at least 5 seconds later, and even more preferably at least 10 seconds later. To prevent the supply of excess liquid rapid-setting agent, the control unit 6 preferably controls the powder rapid-setting agent to arrive at the rapid-setting agent confluence section 43 at least 20 seconds before the liquid rapid-setting agent arrives.
[0032] In an embodiment of the present invention, the concrete spraying system sprays concrete mixed with a liquid quick-setting agent and a powdered quick-setting agent onto an object using a spraying unit 5 provided downstream of the mixing unit 4. For the spraying section 5, a continuously tapering section or one with a straight pipe attached to straighten the concrete flow after tapering can be used. The spraying section 5 can be made of metal or ceramic, and a nozzle with a rubber piping inner surface lined with ceramics or metal, or with chips of these materials embedded inside, can also be used. The spraying pressure from the spraying unit 5 is not particularly limited, and the discharge volume of sprayed concrete is typically 1.5 to 20 m³. 3 The rate is / hr, and the amount of blown air is not particularly limited.
[0033] According to the concrete spraying system of the embodiment of the present invention, in a concrete spraying method in which a powdered rapid-setting agent and a liquid rapid-setting agent are used in combination and mixed with concrete as rapid-setting agents, the order in which the liquid rapid-setting agent and the powdered rapid-setting agent arrive at the rapid-setting agent confluence section provided in the mixing section for mixing the liquid rapid-setting agent and the powdered rapid-setting agent with the concrete can be controlled, thereby preventing the material from solidifying inside the pipe.
[0034] [Concrete spraying method] By using the concrete spraying system according to the embodiment of the present invention, it is possible to prevent the material from solidifying inside the pipes in a concrete spraying method in which a powdered rapid-setting agent and a liquid rapid-setting agent are mixed in combination with the concrete as rapid-setting agents. The concrete spraying method in this embodiment includes the following steps (1) to (6). (1) A process of transporting a liquid fastener having a pH of 1 to 4, mainly composed of aluminum sulfate, through a liquid fastener transport channel. (2) The molar ratio of CaO / Al2O3 is 1.7 to 3.0, and the Blaine value is 4,000 cm². 2 A process of conveying a powdered rapid setting agent containing 30% or more calcium aluminate (at a concentration of 1g or more) through a powdered rapid setting agent conveying channel. (3) Process of transporting concrete through a concrete transport channel (4) A process in which a concrete conveying channel is provided in part of the concrete conveying channel and has a rapid-setting material confluence section that combines the liquid rapid-setting material conveyed in the liquid rapid-setting material conveying channel and the powder rapid-setting material conveyed in the powder rapid-setting material conveying channel, and the liquid rapid-setting material and powder rapid-setting material that have been combined in the rapid-setting material confluence section are mixed with concrete in a mixing section. (5) A process in which concrete mixed with liquid quick-setting agent and powder quick-setting agent is sprayed onto the target object using a spraying section located downstream of the mixing section. (6) A process in which the conveyance of liquid and powder fasteners to the fastener confluence is controlled by the control unit so that the liquid fastener arrives first and the powder fastener arrives second.
[0035] In a concrete spraying method according to an embodiment of the present invention, the transport conditions for the liquid quick-setting agent transported through the liquid quick-setting agent transport channel 1 in step (1) are such that the air flow rate is 2 to 4 m3 It is preferably / min, and 2.2 to 3.8 m 3 It is more preferable that it be / min, and 2.4~3.6m 3 It is even more preferable that the flow rate is / min. Furthermore, the transport conditions for the liquid fastener transported through the liquid fastener transport channel 1 are preferably such that the air pressure is 0.2 to 0.7 MPa, more preferably 0.25 to 0.65 MPa, and even more preferably 0.3 to 0.6 MPa. By having the air flow rate and air pressure within the above ranges as transport conditions for the liquid fastener transported through the liquid fastener transport channel 1, it becomes easier to control the supply of the liquid fastener to the fastener confluence section 43 provided in the mixing section 4.
[0036] In the concrete spraying method according to an embodiment of the present invention, the transport conditions for the powdered rapid binder transported through the powdered rapid binder transport channel 2 in step (2) are such that the air flow rate is 2 to 5 m 3 It is preferably / min, and 2.2 to 4.7m 3 It is more preferable that it be / min, and 2.4~4.5m 3 It is even more preferable that the flow rate is / min. Furthermore, the transport conditions for the powder rapid binder transported through the powder rapid binder transport channel 2 are preferably such that the air pressure is 0.2 to 0.5 MPa, more preferably 0.25 to 0.45 MPa, and even more preferably 0.3 to 0.4 MPa. By having the air flow rate and air pressure within the above ranges as transport conditions for the powder rapid binder transported through the powder rapid binder transport channel 2, it becomes easier to control the supply of the powder rapid binder to the rapid binder confluence section 43 provided in the mixing section 4.
[0037] In the concrete spraying method according to an embodiment of the present invention, the control unit 6 in step (6) preferably controls the powdered rapid-setting agent to arrive at the rapid-setting agent confluence 43 at least 2 seconds after the liquid rapid-setting agent arrives, more preferably at least 5 seconds after, and even more preferably at least 10 seconds after, from the viewpoint of effectively suppressing solidification in the mixing unit 4, the rapid-setting agent confluence 43, and the piping. In order to prevent the supply of excess liquid rapid-setting agent, the control unit 6 preferably controls the powdered rapid-setting agent to arrive at the rapid-setting agent confluence 43 at least 20 seconds before the liquid rapid-setting agent arrives.
[0038] According to the concrete spraying method according to an embodiment of the present invention, in a concrete spraying method in which a powdered rapid-setting agent and a liquid rapid-setting agent are used in combination and mixed with concrete as rapid-setting agents, the order in which the liquid rapid-setting agent and the powdered rapid-setting agent arrive at the rapid-setting agent confluence section provided in the mixing section for mixing the liquid rapid-setting agent and the powdered rapid-setting agent with the concrete can be controlled, thereby preventing the material from solidifying inside the pipe. [Examples]
[0039] The present invention will be described in more detail below based on experimental examples, but the present invention is not limited to these examples.
[0040] <Materials used> • Liquid quick-setting agent A: Reagent-grade aluminum sulfate is dissolved in pure water, adjusted to a concentration of 27%, pH 2.0 • Powdered rapid setting agent A: Blaine value 5,000 cm² 2 / g, Calcium aluminate 45%, Calcium sulfate 40%, Slaked lime 15% • Calcium aluminate: A heat-treated material with a CaO / Al2O3 molar ratio equivalent to 2.5 was rapidly cooled, resulting in a vitrification rate of 90% and a Blaine value of 5,900 cm². 2 Contains 3 parts SiO2 per gram (in oxide terms). • Ordinary cement: Commercially available product, Brain value 3,200 cm 2 / g, density 3.15 • Fine aggregate: Sand from the Himekawa River system in Itoigawa City, Niigata Prefecture, maximum size 5mm or less, density 2.62 • Coarse aggregate: Itoigawa No. 6 crushed stone from Niigata Prefecture, maximum size 15 mm, density 2.67 • Water: Tap water • Water-reducing agents: Commercially available, high-performance water-reducing agents
[0041] [Experimental Example 1] Concrete prepared according to the concrete mix conditions listed in Table 1 was discharged using a concrete pump "MKW-25SMT (manufactured by Syntec)" at a pump discharge condition of 12 m³. 3 The liquid quick-setting agent is quantitatively transported at a rate of / hr to the quick-setting agent mixing section, and from one end, liquid quick-setting agent A is quantitatively supplied at a weight ratio of 6% to the cement, with compressed air conditions set to a flow rate of 2.5 m³ before the liquid quick-setting agent confluence. 3 The liquid is adjusted to a flow rate of 0.4 MPa at a pressure of 0.4 MPa, and continuously transported through the liquid quick-setting agent channel. Powdered quick-setting agent A is quantified at a mass ratio of 6% relative to the cement, and the compressed air conditions are such that the flow rate before the confluence of the powdered quick-setting agent is 4.0 m³. 3 The powder rapid setting agent was continuously transported through the channel at a rate of 1 / hr and a pressure of 0.35 MPa. The liquid and powder were combined just before the concrete confluence, then mixed and combined with the concrete to adjust the rapid setting concrete. The solidified material and mixability were then evaluated when sprayed from the spraying section. Furthermore, the transport procedures shown in Table 2 control the transport of liquid and powdered rapid setting agents.
[0042] [Table 1]
[0043] <Rating> • Consolidation evaluation: While transporting concrete in a fixed quantity, the liquid and powdered rapid-setting agents specified for the mixing section are continuously transported in a fixed quantity for 10 minutes. After 10 minutes, the amount of solidified material in the liquid and powdered rapid-setting agent inlets, which serve as the confluence points in the mixing section, is measured. • Mixability Evaluation: Sprayed concrete was applied to a 1m x 1m x 20cm thick wooden frame, and the Proctor penetration resistance value was measured 10 times after 10 minutes. The average value and standard deviation of the measured Proctor penetration resistance values were then calculated. A smaller standard deviation value indicates improved mixability.
[0044] [Table 2]
[0045] Table 2 shows that changing the transport procedure for liquid and powder rapid setting agents results in differences in the amount of solidified material and the standard deviation of the Proctor penetration resistance. When powder was transported simultaneously with the liquid, and when liquid was transported after the powder, the amount of solidified material increased, and the standard deviation also increased, indicating poorer mixing. This is thought to be due to the increased amount of solidified material narrowing the pipe, leading to uneven addition to the concrete. Furthermore, delaying the powder transport time after liquid transport resulted in a decrease in the amount of solidified material and a lower standard deviation. However, no further improvement was observed when the delay after liquid transport was 20 seconds or more.
[0046] [Experimental Example 2] Similar to Example 1, concrete prepared according to the concrete mix conditions listed in Table 1 was discharged using a concrete pump "MKW-25SMT (manufactured by Syntec Co., Ltd.)" at a pump discharge condition of 12 m³. 3 The liquid quick-setting agent is quantitatively transported at a rate of / hr to the quick-setting agent mixing section. From one end, the types of liquid quick-setting agents shown in Table 3 are quantitatively added at a weight ratio of 6% to the cement, and the compressed air conditions are such that the flow rate before the liquid quick-setting agent confluence is 2.5 m³. 3 The liquid is adjusted to a flow rate of 0.4 MPa at a rate of / min, and continuously transported through the liquid quick-setting agent channel. Powdered quick-setting agent A is quantified at a weight ratio of 6% relative to the cement, and the compressed air conditions are set to a flow rate of 4.0 m³ before the confluence of the powdered quick-setting agents. 3 The powder rapid setting agent was continuously transported through the channel at a rate of 1 / hr and a pressure of 0.35 MPa. The liquid and powder were combined just before the concrete confluence, then mixed and combined with the concrete to adjust the rapid setting concrete. The solidified material and mixability were then evaluated when sprayed from the spraying section. Furthermore, the transport procedures shown in Table 2, No. 1-4, were used to control the transport of liquid and powdered rapid setting agents.
[0047] <Materials used> • Liquid quick-setting agent A: Dissolve sulfuric acid and aluminum oxide in pure water to a pH of 0.8 and adjust the concentration to 27%. • Liquid quick-setting agent (U): Dissolve sulfuric acid and aluminum oxide in pure water to a pH of 1.0 and adjust the concentration to 27%. • Liquid quick-setting agent E: Dissolve sulfuric acid and aluminum oxide in pure water to a pH of 4.0 and adjust the concentration to 27%. • Liquid quick-setting agent O: Dissolve sulfuric acid and aluminum oxide in pure water to a pH of 5.0 and adjust the concentration to 27%.
[0048] [Table 3]
[0049] As shown in Table 3, a pH of less than 1.0 for the liquid rapid setting agent is undesirable for this purpose because, although the amount of solidified material is small, the average value of the Proctor penetration resistance is low. Furthermore, when the pH of the liquid rapid setting agent exceeds 4.0, the average value of the Proctor penetration resistance is high, but there is a tendency for the standard deviation to increase. Therefore, a pH of 1.0 to 4.0 is preferable for the liquid rapid setting agent.
[0050] [Experimental Example 3] Similar to Example 1, concrete prepared according to the concrete mix conditions listed in Table 1 was discharged using a concrete pump "MKW-25SMT (manufactured by Syntec Co., Ltd.)" at a pump discharge condition of 12 m³. 3 The liquid quick-setting agent is quantitatively transported at a rate of / hr to the quick-setting agent mixing section, and from one end, liquid quick-setting agent A is quantitatively supplied at a weight ratio of 6% to the cement, with compressed air conditions set to a flow rate of 2.5 m³ before the liquid quick-setting agent confluence. 3 The liquid was adjusted to a pressure of 0.4 MPa at a rate of / min, and continuously transported through the liquid quick-setting agent channel. Powdered quick-setting agent A containing calcium aluminate in the CaO / Al2O3 molar ratio shown in Table 4 was quantified at a weight ratio of 6% relative to the cement, and the compressed air conditions were set to a flow rate of 4.0 m³ before the powdered quick-setting agent confluence. 3 The powder rapid setting agent was continuously transported through the channel at a rate of 1 / hr and a pressure of 0.35 MPa. The liquid and powder were combined just before the concrete confluence, then mixed and combined with the concrete to adjust the rapid setting concrete. The solidified material and mixability were then evaluated when sprayed from the spraying section. Furthermore, the transport procedures shown in Table 2, No. 1-4, were used to control the transport of liquid and powdered rapid setting agents.
[0051] <Materials used> • Calcium aluminate: A heat-treated material corresponding to the CaO / Al2O3 molar ratio shown in Table 4 was rapidly cooled, resulting in a Blaine value of 5,900 cm². 2 Contains 3 parts SiO2 per gram (in oxide terms).
[0052] [Table 4]
[0053] As shown in Table 4, the evaluation of calcium aluminate based on its CaO / Al2O3 molar ratio revealed that when the CaO / Al2O3 molar ratio of calcium aluminate was less than 1.7, there was no caking and the standard deviation was small, but the average value of the Proctor penetration resistance was low overall, which is undesirable. Furthermore, when the CaO / Al2O3 molar ratio of calcium aluminate exceeded 3.0, the amount of caking increased, the standard deviation was high, and the results were inconsistent. Therefore, a CaO / Al2O3 molar ratio of calcium aluminate between 1.7 and 3.0 is preferable.
[0054] [Experimental Example 4] Similar to Example 1, concrete prepared according to the concrete mix conditions listed in Table 1 was discharged using a concrete pump "MKW-25SMT (manufactured by Syntec Co., Ltd.)" at a pump discharge condition of 12 m³. 3 The liquid quick-setting agent is quantitatively transported at a rate of / hr to the quick-setting agent mixing section, and from one end, liquid quick-setting agent A is quantitatively supplied at a weight ratio of 6% to the cement, with compressed air conditions set to a flow rate of 2.5 m³ before the liquid quick-setting agent confluence. 3 The liquid was adjusted to a flow rate of 0.4 MPa at a rate of / min, and continuously transported through the liquid quick-setting agent channel. The powder quick-setting agent A containing calcium aluminate, as shown in Table 5, was quantified at a weight ratio of 6% relative to the cement, and the compressed air conditions were set to a flow rate of 4.0 m³ before the confluence of the powder quick-setting agents. 3 The powder rapid setting agent was continuously transported through the channel at a rate of 1 / hr and a pressure of 0.35 MPa. The liquid and powder were combined just before the concrete confluence, then mixed and combined with the concrete to adjust the rapid setting concrete. The solidified material and mixability were then evaluated when sprayed from the spraying section. Furthermore, the transport procedures shown in Table 2, No. 1-4, were used to control the transport of liquid and powdered rapid setting agents.
[0055] <Materials used> • Calcium aluminate: A heat-treated material with a CaO / Al2O3 molar ratio equivalent to 2.5 was rapidly cooled, and the Blaine value was adjusted to match the values shown in Table 5. It contains 3 parts SiO2 in oxide terms.
[0056] [Table 5]
[0057] From the results in Table 5, the Braine value of calcium aluminate was 4,000 cm². 2 When the value was less than / g, although there was no solidified material, the average value of the Proctor penetration resistance decreased. For this reason, a Braine value of 4,000 or higher is preferable for calcium aluminate.
[0058] [Experimental Example 5] Similar to Example 1, concrete prepared according to the concrete mix conditions listed in Table 1 was discharged using a concrete pump "MKW-25SMT (manufactured by Syntec Co., Ltd.)" at a pump discharge condition of 12 m³. 3 The liquid quick-setting agent is quantitatively transported at a rate of / hr to the quick-setting agent mixing section, and from one end, liquid quick-setting agent A is quantitatively supplied at a weight ratio of 6% to the cement, with compressed air conditions set to a flow rate of 2.5 m³ before the liquid quick-setting agent confluence. 3 The liquid is adjusted to a flow rate of 0.4 MPa at a rate of / min, and continuously transported through the liquid quick-setting agent channel. The types of powder quick-setting agents shown in Table 5 are quantified at a weight ratio of 6% relative to the cement, and the compressed air conditions are set to a flow rate of 4.0 m³ before the confluence of the powder quick-setting agents. 3 The powder rapid setting agent was continuously transported through the channel at a rate of 1 / hr and a pressure of 0.35 MPa. The liquid and powder were combined just before the concrete confluence, then mixed and combined with the concrete to adjust the rapid setting concrete. The solidified material and mixability were then evaluated when sprayed from the spraying section. Furthermore, the transport procedures shown in Table 2, No. 1-4, were used to control the transport of liquid and powdered rapid setting agents.
[0059] <Materials used> • Powdered rapid setting agent A: Blaine value 5,000 cm² 2 / g, Calcium aluminate 45%, Calcium sulfate 40%, Slaked lime 15% • Powdered rapid setting agent B: Blaine value 5,000 cm 2 / g, Calcium aluminate 29%, Calcium sulfate 40%, Slaked lime 31% • Powdered rapid setting agent C: Blaine value 5,000 cm 2 / g, Calcium aluminate 30%, Calcium sulfate 40%, Slaked lime 30% • Powdered rapid setting agent D: Blaine value 5,000 cm 2 / g, 60% calcium aluminate, 40% calcium sulfate • Powdered rapid setting agent E: Blaine value 5,000 cm 2 / g, 100% calcium aluminate • Powdered rapid setting agent F: Blaine value 5,000 cm² 2 / g, 70% calcium aluminate, 30% slaked lime • Calcium aluminate: A heat-treated material with a CaO / Al2O3 molar ratio equivalent to 2.5 was rapidly cooled, resulting in a vitrification rate of 90% and a Blaine value of 5,900 cm². 2 Contains 3 parts SiO2 per gram (in oxide terms).
[0060] [Table 6]
[0061] As shown in Table 6, when the calcium aluminate content in the powder rapid setting agent is less than 30%, the amount of solidified material decreases, and although the variation is small, the average value of the Proctor penetration resistance is low, which is undesirable. Therefore, it is preferable that the calcium aluminate content in the powder rapid setting agent be 30% or more. [Explanation of symbols]
[0062] 1…Liquid quick-setting agent transport channel 2…Powder rapid setting agent conveying channel 3…Concrete transport channel 4…Mixing section 5...Sprayed area 6…Control Unit 10…Liquid quick-setting agent unit 11…Liquid quick-setting agent tank 12…Liquid quick-setting agent dispenser 20... Powder quick-setting agent dispenser 21... Powder rapid setting agent tank 22... Air dryer 30... Agitator vehicle 31... Concrete pump 41... Liquid quick-setting agent inlet 42...Inlet for powder rapid setting agent 43…Quick setting material confluence section 50... Compressor
Claims
1. A liquid quick-setting agent transport channel for transporting a liquid quick-setting agent having a pH of 1 to 4 and mainly composed of aluminum sulfate, CaO / Al ２ O ３ The molar ratio is 1.7 to 3.0, and the Blaine value is 4,000 cm⁻¹. ２ A powder rapid setting agent transport channel for transporting a powder rapid setting agent containing 30% or more by mass of calcium aluminate, which is 1g or more, A concrete transport channel for transporting concrete, A part of the concrete transport channel is provided, and has a rapid-setting material confluence section that combines the liquid rapid-setting material transported in the liquid rapid-setting material transport channel and the powder rapid-setting material transported in the powder rapid-setting material transport channel, and a mixing section that mixes the liquid rapid-setting material and the powder rapid-setting material combined in the rapid-setting material confluence section with the concrete, A spraying section is provided downstream of the mixing section and sprays the concrete, which is a mixture of the liquid quick-setting agent and the powdered quick-setting agent, onto an object. The system includes a control unit that controls the order in which the liquid fastener and the powder fastener reach the aforementioned fastener confluence, such that the liquid fastener arrives first and the powder fastener arrives second. The control unit controls the powdered rapid-setting agent to reach the rapid-setting agent confluence point at least two seconds after the liquid rapid-setting agent reaches it, in a concrete spraying system.
2. The transport conditions for the liquid fastener being transported through the aforementioned liquid fastener transport channel are such that the air flow rate is 2 to 4 m³. ３ The concrete spraying system according to claim 1, wherein the pressure is / min and the air pressure is 0.2 to 0.7 MPa.
3. The transport conditions for the powder rapid setting agent being transported through the aforementioned powder rapid setting agent transport channel are such that the air flow rate is 2 to 5 m ３ The concrete spraying system according to claim 1 or 2, wherein the air pressure is 0.2 to 0.5 MPa and the current is / min.
4. A process of transporting a liquid rapid-setting agent having a pH of 1 to 4, mainly composed of aluminum sulfate, through a liquid rapid-setting agent transport channel, CaO / Al ２ O ３ The molar ratio is 1.7 to 3.0, and the Blaine value is 4,000 cm⁻¹. ２ A process of conveying a powder rapid setting agent containing 30% or more by mass of calcium aluminate, which is 1 / g or more, through a powder rapid setting agent conveying channel, The process of transporting concrete through a concrete transport channel, The concrete transport channel is provided in part of the concrete transport channel and has a rapid-setting material confluence section that combines the liquid rapid-setting material transported in the liquid rapid-setting material transport channel and the powder rapid-setting material transported in the powder rapid-setting material transport channel, and the liquid rapid-setting material and the powder rapid-setting material that have been combined in the rapid-setting material confluence section are mixed with the concrete in a mixing section, A spraying section is provided downstream of the mixing section and sprays the concrete, which is a mixture of the liquid quick-setting agent and the powder quick-setting agent, onto the target object. The process includes controlling the order in which the liquid fastener and the powder fastener reach the aforementioned fastener confluence section, such that the liquid fastener arrives first and the powder fastener arrives second, using a control unit. The concrete spraying method is characterized in that the control unit controls the process so that the powdered rapid-setting agent reaches the rapid-setting agent confluence point at least two seconds after the liquid rapid-setting agent reaches it.
5. In the step of conveying the liquid quick-setting agent conveyance flow path, the conveyance conditions of the liquid quick-setting agent are such that the air flow rate is 2 to 4 m ３ / min and the air pressure is 0.2 to 0.7 MPa. The concrete spraying method according to claim 4.
6. In the process of transporting the powder rapid-setting agent through the aforementioned transport channel, the transport conditions for the powder rapid-setting agent are such that the air flow rate is 2 to 5 m ３ The concrete spraying method according to claim 4 or 5, wherein the air pressure is 0.2 to 0.5 MPa and the current is / min.