CN116119968A - Accelerating early strength agent for sprayed concrete and preparation method thereof - Google Patents
Accelerating early strength agent for sprayed concrete and preparation method thereof Download PDFInfo
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- CN116119968A CN116119968A CN202310393630.9A CN202310393630A CN116119968A CN 116119968 A CN116119968 A CN 116119968A CN 202310393630 A CN202310393630 A CN 202310393630A CN 116119968 A CN116119968 A CN 116119968A
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
- C04B40/0028—Aspects relating to the mixing step of the mortar preparation
- C04B40/0039—Premixtures of ingredients
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/10—Accelerators; Activators
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- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
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Abstract
The invention provides a coagulation accelerating early strength agent for sprayed concrete and a preparation method thereof, wherein the coagulation accelerating early strength agent for sprayed concrete comprises the following preparation raw materials in parts by weight: 90-130 parts of aluminum source, 70-110 parts of silicon source, 80-120 parts of dispersing agent, 10-30 parts of hybridization component and 10-40 parts of pH regulator. The accelerating early strength agent for sprayed concrete is prepared from the raw materials, so that the early strength of the sprayed concrete can be effectively improved, and the rebound rate is reduced.
Description
Technical Field
The invention relates to the field of concrete building materials, in particular to a coagulation accelerating early strength agent for sprayed concrete, and also relates to a preparation method of the coagulation accelerating early strength agent for sprayed concrete.
Background
In the present engineering construction of tunnels and the like, the support is often required to be carried out immediately after excavation, and the development of early strength of sprayed concrete has a decisive effect on the support. In addition, the development of early strength of the sprayed concrete has a direct effect on the excavation progress, so the early strength of the sprayed concrete is more important than the final strength. The biggest problem encountered in the construction of sprayed concrete in China is the problem of slow development of the early-age strength of the sprayed concrete, and the technical early-stage support of the excavated rock mass structures such as tunnels is affected. While various accelerator products used at present can meet the requirements of rapid hardening, the early-age strength (6 h and 12 h) is very low, the rapid supporting requirements of some projects can not be met, and the construction progress of tunnel construction is also influenced.
Currently, there are few studies on setting accelerator early strength agents and many are used for oil well cements and other cement-based materials (e.g., cement-based 3D printing materials, etc.). Patent CN113583642A discloses a modified nano silicon dioxide early-strength coagulant for oil well cement, a preparation method and application thereof, which comprises the following components: anhydrous sodium metasilicate, calcium nitrate tetrahydrate, 40% sodium hydroxide solution, 36% -37% formaldehyde aqueous solution, welan gum, nano titanium dioxide and softened water. CN112592091a discloses a set accelerator for 3D printed cementitious materials comprising a random copolymer polymerized from the following monomers: 60-70 parts by weight of unsaturated polyether, 15-25 parts by weight of unsaturated carboxylic acid or unsaturated carboxylate and 3-20 parts by weight of polar unsaturated monomer; further comprises: 10-20 parts of chitosan coated calcium fluoroaluminate. CN107555829a discloses a crystal nucleus type accelerating early strength agent for concrete and a preparation method thereof, wherein the agent is prepared from calcium nitrate, sodium silicate and 18# early strength type polycarboxylate water reducer, and the weight ratio of the components of the materials used for preparation is: 1.55 parts of calcium nitrate, 1.24 parts of sodium silicate and 1 part of 18# early-strength polycarboxylic acid.
Although the accelerating early strength agent prepared by the patents has a certain effect of improving early strength, the accelerating early strength agent is not suitable for sprayed concrete, rebound cannot be reduced, the property is very unstable, solidification and precipitation are easy to occur after long-term storage, and the using effect is influenced. Specific guidance is not given for the accelerating early strength agent for sprayed concrete, which improves the early strength of the sprayed concrete, reduces rebound and improves the construction environment.
Disclosure of Invention
The invention provides a coagulation accelerating early strength agent for sprayed concrete, which is used for improving the early strength of the sprayed concrete and reducing the rebound rate.
The accelerating and early strengthening agent for the sprayed concrete comprises the following preparation raw materials in parts by weight: 90-130 parts of aluminum source, 70-110 parts of silicon source, 80-120 parts of dispersing agent, 10-30 parts of hybridization component and 10-40 parts of pH regulator.
Further, the aluminum source comprises at least one of aluminum sulfate octadecanoate, aluminum nitrate nonahydrate and aluminum isopropoxide.
Further, the silicon source comprises at least one of sodium silicate nonahydrate, sodium metasilicate pentahydrate, sodium methyl silicate and a silane coupling agent.
Further, the hybridization component comprises at least one of magnesium sulfate heptahydrate, lithium sulfate, zirconium sulfate tetrahydrate and ferric sulfate nonahydrate.
Further, the pH regulator comprises at least one of monoethanolamine, diethanolamine, triethanolamine and triisopropanolamine.
Further, the preparation raw materials of the dispersing agent comprise the following components in parts by weight: 30-40 parts of pentaerythritol, 35-50 parts of methacrylic acid, 105-200 parts of unsaturated carboxylic acid and derivatives thereof, and 900-2000 parts of polyether macromonomer.
The invention also provides a preparation method of the accelerating early strength agent for sprayed concrete, which comprises the following steps:
mixing deionized water and a dispersing agent, stirring and heating to 45-55 ℃, adding the hybridization component, and stirring until the hybridization component is completely dissolved to obtain a base solution; adding a pH regulator into the base solution, and regulating the pH of the base solution to 7-8; and (3) dropwise adding an aqueous solution of an aluminum source and an aqueous solution of a silicon source into the base solution, keeping the temperature and stirring after the dropwise adding is finished, and cooling to room temperature to obtain the coagulation accelerating early strength agent for sprayed concrete.
Further, the preparation method of the dispersing agent comprises the following steps:
mixing pentaerythritol and a polymerization inhibitor, heating to melt, adding methacrylic acid and a catalyst, continuously heating, introducing nitrogen for purging, and completing the reaction to obtain an esterified substance; preparing a first drop of the esterified substance, the unsaturated carboxylic acid and the derivative thereof and water, and preparing a second drop of the reducing agent, the chain transfer agent and the water; mixing polyether macromonomer with water, controlling the temperature to be 30-45 ℃, adding an initiator, stirring, dripping a first dripping material and a second dripping material, continuing stirring after the reaction is finished, and neutralizing the reactant to the pH value of 5-7.
Further, the polymerization inhibitor comprises at least one of hydroquinone and phenothiazine; and/or the initiator is at least one of hydrogen peroxide, ammonium persulfate and potassium persulfate; and/or the chain transfer agent is at least one of thioglycollic acid, mercaptopropionic acid and mercaptoethanol; and/or the reducing agent is at least one of vitamin C, sodium metabisulfite and sodium bisulphite.
Further, the unsaturated carboxylic acid and the derivative thereof comprise at least one of acrylic acid, maleic anhydride and itaconic acid; and/or the polyether macromonomer comprises at least one of isopentenyl alcohol polyoxyethylene ether and isobutenyl alcohol polyoxyethylene ether.
The accelerating early strength agent for sprayed concrete adopts an aluminum source, a silicon source, a dispersing agent, a hybridization component and a pH regulator to prepare nano-scale aluminosilicate, can be used as the accelerating early strength agent to excite cement hydration reaction, accelerates the biological generation of C-S-H gel and hydrated calcium sulfoaluminate, becomes a part of a cement concrete strength basic substance, and obviously improves the early strength of sprayed concrete. The dispersing agent is in a star-shaped structure, and the prepared nano aluminosilicate particles have small particle size (less than 100 nanometers), narrower particle size range and more uniform particles by matching with the hybridization component. The pH regulator can regulate the pH of the base solution in the preparation process to make the base solution alkalescent. The prepared accelerating early strength agent for sprayed concrete has good compatibility with an accelerating agent, the strength of mortar after 6 hours is improved to more than 3MPa, the later strength is not reduced, the rebound rate of sprayed concrete can be reduced to below 10%, and the construction site environment is greatly improved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention. In the drawings:
FIG. 1 is a graph showing the particle size measurement of aluminosilicate of the accelerating and early strength agent for shotcrete according to the present invention.
Detailed Description
It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other.
The experimental methods in the following examples are conventional methods unless otherwise specified. The test materials used in the examples described below, unless otherwise specified, were purchased from conventional biochemical reagent stores. In addition, unless specifically described otherwise, each term and process referred to in this embodiment is understood by those skilled in the art in light of the commonly recognized and conventional approaches in the art.
The accelerating and early strengthening agent for the sprayed concrete comprises the following preparation raw materials in parts by weight: 90-130 parts of aluminum source, 70-110 parts of silicon source, 80-120 parts of dispersing agent, 10-30 parts of hybridization component and 10-40 parts of pH regulator.
The accelerating early strength agent for sprayed concrete adopts aluminum source, silicon source, dispersing agent, hybridization component, pH regulator and a certain amount of water to prepare nano-scale aluminosilicate, can be used as the accelerating early strength agent to excite cement hydration reaction, accelerates the biological generation of C-S-H gel and hydrated calcium sulfoaluminate, becomes a part of cement concrete strength basic substance, and obviously improves the early strength of sprayed concrete (especially within 6 hours). Wherein the dispersing agent and the hybridization component can lead the particle size of the prepared nano aluminosilicate particles to be small (< 100 nanometers), the standard deviation of the particle size to be smaller, and the particles to be more uniform. The pH regulator can regulate the pH of the base solution in the preparation process to make the base solution alkalescent. The accelerating and early strength agent for sprayed concrete can be prepared by using water as a solvent of the raw materials, wherein the water is used for dissolving the raw materials, and the water can be 500-800 parts. The prepared accelerating early strength agent for sprayed concrete has good compatibility with an accelerating agent, after the product is used, the 6-hour strength of mortar is improved to be more than 3MPa, the later strength is not inverted, the rebound rate of sprayed concrete can be reduced to be less than 10%, and the construction site environment is greatly improved.
The aluminum source of the accelerating early strength agent for sprayed concrete can be inorganic aluminum salt, the inorganic aluminum salt preferably comprises aluminum sulfate octadecanoate and/or aluminum nitrate nonahydrate, and also can be organic aluminum alkoxide, preferably aluminum isopropoxide, and the aluminum-containing substance has strong reactivity and good compatibility with other components. The aluminum element can also accelerate the generation of ettringite and accelerate the hydration of cement, thereby enabling cement paste to be quickly coagulated and hardened.
The silicon element can accelerate the generation of C-S-H gel, shortens the induction period of tricalcium silicate, accelerates the further hydration of tricalcium silicate, and ensures that cement is quickly coagulated and hardened. The silicon source preferably comprises at least one of sodium silicate nonahydrate, sodium metasilicate pentahydrate, sodium methyl silicate and silane coupling agent.
Because nanoscale aluminosilicate produced by an aluminum source and a silicon source is unstable in character, nanoparticles are easy to agglomerate to form a precipitate, and the dispersing agent prepared from the following raw materials can be preferably adopted: 30-40 parts of pentaerythritol, 35-50 parts of methacrylic acid, 105-200 parts of unsaturated carboxylic acid and derivatives thereof, and 900-2000 parts of polyether macromonomer. The preparation process of the dispersing agent comprises that pentaerythritol and methacrylic acid are polymerized with polyether macromonomer, unsaturated carboxylic acid and derivatives thereof after being subjected to esterification, so that the molecular structure of the dispersing agent is star-shaped, the steric hindrance effect is stronger, nano particles can be effectively dispersed when the accelerating and early strength agent is prepared, the particle size of the nano particles is smaller, the effect of nano crystal nucleus is more obvious, and the early strength improvement performance is better.
The hybrid component belongs to inorganic salt, positive and negative ions are ionized in water, and the random movement of the positive and negative ions can rapidly disperse nano-scale aluminosilicate to prevent the agglomeration of nano-scale aluminosilicate particles. The dispersant and the hybridization component together provide a base solution with very good dispersion performance, so that the particle size of the prepared nano aluminosilicate particles is small (< 100 nanometers), the standard deviation of the particle size is smaller, the particles are more uniform, the nano aluminosilicate particles can be kept stable in a nano-scale form in the process of generating the aluminosilicate, and the particle size detection of the nano aluminosilicate is shown in figure 1. The hybridization component of the present invention preferably adopts at least one of magnesium sulfate heptahydrate, lithium sulfate, zirconium sulfate tetrahydrate and ferric sulfate nonahydrate. The sulfate ions generated by hydrolysis of the hybridization components react with calcium ions generated by hydration of cement to generate fine secondary gypsum when the accelerating early strength agent for sprayed concrete is mixed with the concrete, the reactivity of the secondary gypsum is higher than that of the original gypsum in the cement, the reaction process of tricalcium aluminate in the cement is accelerated, needle-shaped ettringite crystals are easier to generate, the sulfate radicals and calcium hydroxide in a liquid phase can directly and rapidly react to generate ettringite, the ettringite expands in volume and mutually staggers to form a compact reticular structure, and the porous seams are filled, so that the slurry is compact, the strength development is facilitated, and the cement concrete is rapidly coagulated.
The pH regulator can regulate the pH of the base solution in the preparation process, so that the base solution can be in a slightly alkaline state, and ion precipitation is effectively prevented. The pH regulator preferably comprises at least one of monoethanolamine, diethanolamine, triethanolamine and triisopropanolamine, wherein N atoms in the alcohol amine have a pair of lone pair electrons, which can complex metal ions in the accelerating and early strength agent for the sprayed concrete, so that the shape of the accelerating and early strength agent for the sprayed concrete can be kept stable for a long time. When the calcium aluminate and the tetra-calcium ferroaluminate are mixed into cement, complex ions which are easy to dissolve in water can be generated with calcium ions, iron ions and the like of the cement, so that the solubility of the surface of cement particles is improved, the formation of an impermeable layer on the surface of tricalcium aluminate in the early stage of hydration is prevented, the dissolution of tricalcium aluminate and tetra-calcium ferroaluminate is promoted, and the reaction of the tricalcium aluminate and the gypsum is accelerated to generate calcium sulfoaluminate. Meanwhile, the reaction also reduces the concentration of calcium ions and aluminum ions in the liquid phase, and further promotes the hydration of tricalcium silicate, thereby promoting the early strength of concrete to be increased, greatly improving the diffusion rate of hydration products and obviously shortening the cement setting time. The alcohol amine pH regulator has the advantages of stabilizing the shape of the accelerating early strength agent and improving the early strength of concrete.
The accelerating early strength agent for sprayed concrete and the alkali-free liquid accelerator have good compatibility, can be used in combination, can meet the requirements of rapid hardening of sprayed concrete, and simultaneously meet the technical requirements of rapid early strength development and greatly improved supporting effect of sprayed concrete, improve the quality of wet sprayed concrete and prevent the problem of quality stability of sprayed concrete in severe environments.
The invention also provides a preparation method of the accelerating early strength agent for sprayed concrete, which specifically comprises the following steps:
adding deionized water and a dispersing agent into a reaction kettle, stirring and heating to 45-55 ℃, adding the hybridization component, and stirring until the hybridization component is completely dissolved to obtain a base solution. Adding pH regulator to regulate pH of the base solution to 7-8. Weighing an aluminum source, dissolving the aluminum source with a certain amount of deionized water to prepare a solution A, and weighing a silicon source, dissolving the silicon source with a certain amount of deionized water to prepare a solution B. And simultaneously, dropwise adding the solution A and the solution B into the base solution at the same speed for 3-4 hours, and after the dropwise adding is finished, preserving heat and stirring for 1-2 hours, and cooling to room temperature to obtain the coagulation accelerating early strength agent for sprayed concrete.
Wherein the dispersant may be prepared preferably by the following method:
esterification reaction: adding 30-40 parts of pentaerythritol and 0.1-0.3 part of polymerization inhibitor into a reaction bottle, heating to 70-90 ℃ to melt, adding 35-50 parts of methacrylic acid, adding 1-3 parts of sodium p-toluenesulfonate as a catalyst, heating to 110-125 ℃, introducing nitrogen for purging, and reacting for 4-6 hours to obtain an esterified product.
Copolymerization reaction: weighing 65-90 parts of esterified substance, adding 105-200 parts of unsaturated carboxylic acid and its derivative and water to prepare a first dripping material. Preparing a second drop of the reducing agent with the concentration of 0.5-4% by using 0.3-1 part of the reducing agent, 0.5-2.5 parts of the chain transfer agent and water. 900-2000 parts of polyether macromonomer and 600-1200 parts of water are added into a reaction bottle, stirring is started, the reaction temperature is kept at 30-45 ℃, 1-3 parts of initiator is added after the reaction is completely dissolved, stirring is carried out for 5-10min, a first dripping material and a second dripping material are simultaneously dripped, the dripping speed of the first dripping material is controlled to be within 1.5-2.5 h, and the dripping speed of the second dripping material is controlled to be within 2-3 h. After the reaction is finished, stirring continuously for 0.5-1.5-h, and neutralizing the reactant with liquid alkali until the pH value is 5-7.
The liquid alkali may be at least one of sodium hydroxide, sodium carbonate and potassium hydroxide. The polymerization inhibitor preferably includes at least one of hydroquinone and phenothiazine; the initiator is at least one of hydrogen peroxide, ammonium persulfate and potassium persulfate; the chain transfer agent is at least one of thioglycollic acid, mercaptopropionic acid and mercaptoethanol; the reducing agent is at least one of vitamin C, sodium metabisulfite and sodium bisulphite. The unsaturated carboxylic acid and its derivative include at least one of acrylic acid, maleic anhydride, itaconic acid; the polyether macromonomer comprises at least one of isopentenyl alcohol polyoxyethylene ether and isobutenyl alcohol polyoxyethylene ether, and the molecular weight is preferably 2400-5000.
Specific embodiments of the present invention are described in detail below.
Example 1
The specific preparation method of the dispersing agent comprises the following steps:
(1) Esterification reaction: 30 parts of pentaerythritol and 0.1 part of hydroquinone are added into a reaction bottle, the temperature is raised to 70 ℃ to heat the mixture until the mixture is melted, 35 parts of methacrylic acid is added, 1 part of sodium p-toluenesulfonate is added as a catalyst, the temperature is raised to 110 ℃, nitrogen is introduced for purging, and the mixture is reacted for 4 hours to obtain an esterified substance. (2) copolymerization: 65 parts of the esterified material was weighed, 105 parts of acrylic acid and 30 parts of water were added to prepare a first drop feed. 0.33 parts of vitamin C, 0.8 parts of mercaptopropionic acid and 225 parts of water were formulated as a second drop feed at a concentration of 0.5%. 900 parts of isopentenol polyoxyethylene ether with molecular weight of 2400 and 600 parts of water are added into a reaction bottle, stirring is started, the reaction temperature is kept at 30 ℃, after complete dissolution, 1 part of hydrogen peroxide is added, stirring is carried out for 5min, a first dripping material and a second dripping material are simultaneously dripped, the dripping speed of the first dripping material is controlled to be within 1.5 h, and the dripping speed of the second dripping material is controlled to be within 2 h. After the reaction was completed, stirring was continued for 0.5. 0.5 h, and then the reaction was neutralized with a liquid base to a pH of 5.5.
The preparation method of the accelerating early strength agent for sprayed concrete comprises the following steps:
380 parts of deionized water and 100 parts of dispersing agent are added into a reaction kettle, stirred and heated to 45 ℃, 50 parts of magnesium sulfate heptahydrate are added, and stirred until the magnesium sulfate heptahydrate is completely dissolved, thus obtaining base solution. Monoethanolamine was added to adjust the pH of the base solution to 7. 100 parts of aluminum sulfate octadecanoate is weighed and dissolved by 100 parts of deionized water to prepare a solution A, 108 parts of sodium silicate nonahydrate is weighed and dissolved by 192 parts of deionized water to prepare a solution B. Simultaneously, dropwise adding the solution A and the solution B into the base solution at the same speed, setting the dropwise adding speed to ensure that the solution A and the solution B are dropwise added at the same time for 3 hours, preserving heat and stirring for 1 hour after the dropwise adding is finished, and cooling to room temperature to obtain the accelerating early strength agent.
Example 2
The specific preparation method of the dispersing agent comprises the following steps:
(1) Esterification reaction: 35 parts of pentaerythritol, 0.1 part of hydroquinone and 0.1 part of phenothiazine are added into a reaction bottle, the temperature is raised to 80 ℃ to heat the mixture until the mixture is melted, 40 parts of methacrylic acid is added, 1.5 parts of sodium p-toluenesulfonate is added as a catalyst, the temperature is raised to 120 ℃, nitrogen is introduced to purge the mixture, and the mixture is reacted for 5 hours to obtain an esterified product. (2) copolymerization: 70 parts of the esterified material was weighed, and 200 parts of maleic anhydride and 30 parts of water were added to prepare a first drop feed. 0.6 part of vitamin C, 1.0 part of thioglycollic acid and 80 parts of water are prepared as a second drop of feed with a concentration of 2%. 1200 parts of isobutylenol polyoxyethylene ether (molecular weight 3000) and 800 parts of water are added into a reaction bottle, stirring is started, the reaction temperature is kept at 40 ℃, after the reaction is completely dissolved, 1.5 parts of ammonium persulfate is added, stirring is carried out for 10min, a first drop of material and a second drop of material are simultaneously dripped, the first drop of material dripping is controlled to be completed within 2h, and the second drop of material dripping is controlled to be completed within 2.5 h. After the reaction was completed, stirring was continued for 1h, and then the reaction was neutralized with a liquid base to pH 6.
The preparation method of the accelerating early strength agent for sprayed concrete comprises the following steps:
410 parts of deionized water and 80 parts of dispersing agent are added into a reaction kettle, stirred and heated to 50 ℃,10 parts of lithium sulfate is added, and the mixture is stirred until the mixture is completely dissolved, thus obtaining base solution. Diethanolamine was added to adjust the pH of the base solution to 7.5. 90 parts of aluminum nitrate nonahydrate is weighed and dissolved by 110 parts of deionized water to prepare a solution A, 76 parts of sodium methyl silicate is weighed and dissolved by 224 parts of deionized water to prepare a solution B. Simultaneously, dropwise adding the solution A and the solution B into the base solution at the same speed, setting the dropwise adding speed to be 3.5 hours and simultaneously completing dropwise adding, preserving heat and stirring for 1 hour after the dropwise adding is finished, and cooling to room temperature to obtain the accelerating early strength agent.
Example 3
The specific preparation method of the dispersing agent comprises the following steps:
(1) Esterification reaction: 40 parts of pentaerythritol and 0.3 part of phenothiazine are added into a reaction bottle, the temperature is raised to 90 ℃ to heat the mixture until the mixture is molten, 50 parts of methacrylic acid is added, 3 parts of sodium paratoluenesulfonate is added as a catalyst, the temperature is raised to 125 ℃, nitrogen is introduced to purge the mixture, and the mixture is reacted for 6 hours to obtain an esterified substance.
(2) Copolymerization reaction: 90 parts of the esterified material was weighed, and 200 parts of itaconic acid and 30 parts of water were added to prepare a first drop feed. 1 part of white suspended cake, 2.5 parts of mercaptoethanol and 87 parts of water were prepared as a second drop charge with a concentration of 4%. 2000 parts of isopentenol polyoxyethylene ether (molecular weight 5000) and 1200 parts of water are added into a reaction bottle, stirring is started, the reaction temperature is kept at 45 ℃,3 parts of potassium persulfate is added after the reaction is completely dissolved, stirring is carried out for 10min, a first dripping material and a second dripping material are simultaneously dripped, the dripping speed of the first dripping material is controlled to be within 2.5h, and the dripping speed of the second dripping material is controlled to be within 3 h. After the reaction was completed, stirring was continued for 1.5. 1.5 h, and then the reaction was neutralized with a liquid base to pH 6.8.
The preparation method of the accelerating early strength agent for sprayed concrete comprises the following steps:
390 parts of deionized water and 90 parts of dispersing agent are added into a reaction kettle, stirred and heated to 50 ℃, 20 parts of zirconium sulfate tetrahydrate are added, and stirred until the zirconium sulfate tetrahydrate is completely dissolved, thus obtaining base solution. Triethanolamine was added to adjust the pH of the base solution to 8. 90 parts of aluminum isopropoxide is weighed and dissolved by 110 parts of deionized water to prepare a solution A, and 100 parts of sodium metasilicate pentahydrate is weighed and dissolved by 200 parts of deionized water to prepare a solution B. Simultaneously, dropwise adding the solution A and the solution B into the base solution at the same speed, setting the dropwise adding speed to ensure that the solution A and the solution B are dropwise added at the same time for 3 hours, preserving heat and stirring for 2 hours after the dropwise adding is finished, and cooling to room temperature to obtain the accelerating early strength agent.
Example 4
The specific preparation method of the dispersing agent comprises the following steps:
(1) Esterification reaction: 38 parts of pentaerythritol and 0.15 part of hydroquinone are added into a reaction bottle, the temperature is raised to 80 ℃ to heat the mixture until the mixture is melted, 45 parts of methacrylic acid is added, 2 parts of sodium p-toluenesulfonate is added as a catalyst, the temperature is raised to 125 ℃, nitrogen is introduced for purging, and the mixture is reacted for 5 hours to obtain an esterified substance. (2) copolymerization: 70 parts of the esterified substance was weighed, and 100 parts of acrylic acid and 40 parts of water were added to prepare a first drop feed. 0.8 part of sodium bisulphite, 1.5 parts of mercaptopropionic acid and 115 parts of water were prepared as a second drop charge at a concentration of 2%. 1200 parts of isopentenol polyoxyethylene ether (molecular weight 2400) and 800 parts of water are added into a reaction bottle, stirring is started, the reaction temperature is kept at 30 ℃, after the reaction is completely dissolved, 2 parts of hydrogen peroxide are added, stirring is carried out for 5min, a first dripping material and a second dripping material are simultaneously dripped, the dripping speed of the first dripping material is controlled to be within 2.5h, and the dripping speed of the second dripping material is controlled to be within 3 h. After the reaction was completed, stirring was continued for 0.5. 0.5 h, and then the reaction was neutralized with a liquid base to pH 6.
The preparation method of the accelerating early strength agent for sprayed concrete comprises the following steps:
350 parts of deionized water and 120 parts of dispersing agent are added into a reaction kettle, stirred and heated to 55 ℃, 30 parts of ferric sulfate is added, and stirred until the mixture is completely dissolved, thus obtaining base solution. Triisopropanolamine was added to adjust the pH of the base to 7.5. 100 parts of aluminum isopropoxide is weighed and dissolved by 110 parts of deionized water to prepare a solution A, and 110 parts of silane coupling agent is weighed and dissolved by 190 parts of deionized water to prepare a solution B. Simultaneously, dropwise adding the solution A and the solution B into the base solution at the same speed, setting the dropwise adding speed to ensure that the solution A and the solution B are dropwise added at the same time for 4 hours, preserving heat and stirring for 1.5 hours after the dropwise adding is finished, and cooling to room temperature to obtain the accelerating early strength agent.
Example 5
The specific preparation method of the dispersing agent comprises the following steps:
(1) Esterification reaction: 40 parts of pentaerythritol and 0.25 part of phenothiazine are added into a reaction bottle, the temperature is raised to 80 ℃ to heat the mixture until the mixture is melted, 50 parts of methacrylic acid is added, 2 parts of sodium paratoluenesulfonate is added as a catalyst, the temperature is raised to 120 ℃, nitrogen is introduced to purge the mixture, and the mixture is reacted for 5 hours to obtain an esterified substance. (2) copolymerization: 80 parts of the esterified material was weighed, and 180 parts of itaconic acid and 20 parts of water were added to prepare a first drop feed. 0.3 part of vitamin C, 0.5 part of mercaptopropionic acid and 80 parts of water were formulated as a second drop feed at a concentration of 1%. 1500 parts of isobutylenol polyoxyethylene ether (molecular weight 3000) and 750 parts of water are added into a reaction bottle, stirring is started, the reaction temperature is kept at 45 ℃,1 part of hydrogen peroxide is added after the reaction is completely dissolved, stirring is carried out for 10min, a first dripping material and a second dripping material are simultaneously dripped, the dripping speed of the first dripping material is controlled to be completed within 2h, and the dripping speed of the second dripping material is controlled to be completed within 2.5 h. After the reaction was completed, stirring was continued for 1h, and then the reaction was neutralized with a liquid base to pH 6.
The preparation method of the accelerating early strength agent for sprayed concrete comprises the following steps:
370 parts of deionized water and 90 parts of dispersing agent are added into a reaction kettle, stirred and heated to 50 ℃, 40 parts of magnesium sulfate heptahydrate are added, and stirred until the magnesium sulfate heptahydrate is completely dissolved, thus obtaining base solution. Triethanolamine was added to adjust the pH of the base solution to 7. 125 parts of aluminum nitrate nonahydrate is weighed and dissolved by 125 parts of deionized water to prepare a solution A, 80 parts of silane coupling agent is weighed and dissolved by 170 parts of deionized water to prepare a solution B. Simultaneously, dropwise adding the solution A and the solution B into the base solution at the same speed, setting the dropwise adding speed to be 3.5 hours and simultaneously completing dropwise adding, preserving heat and stirring for 2 hours after the dropwise adding is finished, and cooling to room temperature to obtain the accelerating early strength agent.
Example 6
The specific preparation method of the dispersing agent comprises the following steps:
(1) Esterification reaction: 30 parts of pentaerythritol, 0.1 part of hydroquinone and 0.1 part of phenothiazine are added into a reaction bottle, the temperature is raised to 80 ℃ to heat the mixture until the mixture is melted, 50 parts of methacrylic acid is added, 1.5 parts of sodium p-toluenesulfonate is added as a catalyst, the temperature is raised to 125 ℃, nitrogen is introduced to purge the mixture, and the mixture is reacted for 6 hours to obtain an esterified product. (2) copolymerization: 70 parts of the esterified substance was weighed, and 110 parts of acrylic acid and 20 parts of water were added to prepare a first drop feed. 0.5 part of white suspended block, 0.5 part of thioglycollic acid and 100 parts of water are prepared into a second drop of feed, and the concentration is 1%. 1800 parts of isopentenol polyoxyethylene ether (molecular weight 2400) and 900 parts of water are added into a reaction bottle, stirring is started, the reaction temperature is kept at 40 ℃, after the reaction is completely dissolved, 1.5 parts of ammonium persulfate is added, stirring is carried out for 10min, a first dripping material and a second dripping material are simultaneously dripped, the dripping of the first dripping material is controlled to be completed within 2.5h, and the dripping of the second dripping material is controlled to be completed within 3 h. After the reaction was completed, stirring was continued for 1 hour, and then the reaction was neutralized with a liquid alkali to a pH of 6.5.
The preparation method of the accelerating early strength agent for sprayed concrete comprises the following steps:
370 parts of deionized water and 100 parts of dispersing agent are added into a reaction kettle, stirred and heated to 55 ℃, 30 parts of zirconium sulfate tetrahydrate are added, and stirred until the zirconium sulfate tetrahydrate is completely dissolved, thus obtaining base solution. Diethanolamine was added to adjust the pH of the base solution to 7.5. 120 parts of aluminum sulfate is weighed and dissolved by 120 parts of deionized water to prepare a solution A, 80 parts of sodium metasilicate is weighed and dissolved by 180 parts of deionized water to prepare a solution B. Simultaneously, dropwise adding the solution A and the solution B into the base solution at the same speed, setting the dropwise adding speed to ensure that the solution A and the solution B are dropwise added at the same time for 3 hours, preserving heat and stirring for 1 hour after the dropwise adding is finished, and cooling to room temperature to obtain the accelerating early strength agent.
Comparative example 1
The comparative example uses the calcium aluminosilicate hydrate nanocrystal core early strength agent of CN 111470794A.
Comparative example 2
This comparative example is substantially the same as example 1 except that the hybridization component ferric sulfate is not added.
Comparative example 3
This comparative example is substantially the same as example 1 except that the pH adjuster monoethanolamine is not added.
The cement paste setting time and the cement paste compressive strength were tested according to the requirements of GB/T35159-2017 quick setting admixture for shotcrete, the mixing amount was 3% of the cement consumption.
Determination of setting time of cement paste: 400g of reference cement and 140g of water.
And (3) measuring the compressive strength of the cement mortar: 900g of standard cement, 1350g of standard sand and 450g of water.
The water comprises water in the accelerator, and the water consumption should be deducted from the water in the accelerator and the accelerator. The test results are shown in table 1:
TABLE 1 setting time and compressive Strength test results of accelerator and set accelerator
The experimental results in Table 1 show that the accelerating early strength agent prepared by the invention has a certain accelerating effect, obviously improves the 6-hour strength of mortar, is more than 3MPa, and has no collapse of the later strength.
Example 1 compared with comparative example 1 shows that the accelerating effect and early compressive strength of the accelerating early strength agent prepared by the invention are obviously better than those of the accelerating early strength agent prepared by other methods.
Example 1 compared to comparative example 2 shows that no addition of the hybrid component has no significant effect on the setting time, but a reduction in early compressive strength.
Compared with comparative example 3, example 1 shows that the coagulation time is prolonged without adding a pH regulator, and the early compressive strength is not obviously affected.
The examples were tested for rebound according to the method mentioned in appendix G of JGJ/T372-2016 technical Specification for shotcrete applications. The test results are shown in Table 2.
TABLE 2 test results of rebound Rate of the accelerator of the invention
As can be seen from Table 2, the accelerating early strength agent prepared by the invention can reduce the rebound rate of sprayed concrete to below 10%, and can greatly improve the construction site environment.
Example 1 compared with comparative example 1 shows that the rebound rate of the accelerating early strength agent prepared by the invention is higher than that of the accelerating early strength agent prepared by other methods.
Example 1 compared to comparative example 2 shows that without addition of the hybrid component, lower early strength results in higher rebound.
Example 1 compared to comparative example 3 shows that without the addition of a pH adjustor, a longer setting time results in a higher rebound rate.
According to the test method of the stability of the coagulant in the Q/CR 807-2020 standard, the coagulant early strength agent for sprayed concrete of each example is placed at different temperatures and stored for a certain time, if the volume of supernatant (or bottom sediment) in 100mL of liquid accelerator is less than or equal to 5mL, the stability is qualified in the storage period, otherwise, the stability is not qualified. At the same time, when the test viscosity was measured for 3 months, the test results are shown in table 3, with "v" indicating that the stability was acceptable and "×" indicating that the stability was unacceptable.
Table 3 stability and viscosity test
Example 1 compared with comparative example 1 shows that the coagulation accelerator obtained by the invention has better stability than other methods.
Comparison of example 1 with comparative example 2 shows that no addition of the hybrid component has no significant effect on stability.
Compared with comparative example 3, example 1 shows that the pH regulator is not added, which is unfavorable for complexation of aluminum ions, and results in easy crystallization and poor stability.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the scope of the technical concept of the present invention, and all the simple modifications belong to the protection scope of the present invention.
In addition, the specific features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various possible combinations are not described further.
Claims (10)
1. A coagulation accelerating early strength agent for sprayed concrete is characterized in that: the preparation raw materials of the accelerating early strength agent for sprayed concrete comprise the following components in parts by weight: 90-130 parts of aluminum source, 70-110 parts of silicon source, 80-120 parts of dispersing agent, 10-30 parts of hybridization component and 10-40 parts of pH regulator.
2. The accelerating early strength agent for sprayed concrete according to claim 1, wherein: the aluminum source comprises at least one of aluminum sulfate octadecanoate, aluminum nitrate nonahydrate and aluminum isopropoxide.
3. The accelerating early strength agent for sprayed concrete according to claim 1, wherein: the silicon source comprises at least one of sodium silicate nonahydrate, sodium metasilicate pentahydrate, sodium methyl silicate and a silane coupling agent.
4. The accelerating early strength agent for sprayed concrete according to claim 1, wherein: the hybridization component comprises at least one of magnesium sulfate heptahydrate, lithium sulfate, zirconium sulfate tetrahydrate and ferric sulfate nonahydrate.
5. The accelerating early strength agent for sprayed concrete according to claim 1, wherein: the pH regulator comprises at least one of monoethanolamine, diethanolamine, triethanolamine and triisopropanolamine.
6. The accelerating early strength agent for shotcrete according to any one of claims 1 to 5, wherein: the dispersing agent is prepared from the following raw materials in parts by weight: 30-40 parts of pentaerythritol, 35-50 parts of methacrylic acid, 105-200 parts of unsaturated carboxylic acid and derivatives thereof, and 900-2000 parts of polyether macromonomer.
7. A preparation method of a coagulation accelerating early strength agent for sprayed concrete is characterized by comprising the following steps: the method comprises the following steps:
mixing deionized water and a dispersing agent, stirring and heating to 45-55 ℃, adding the hybridization component, and stirring until the hybridization component is completely dissolved to obtain a base solution;
adding a pH regulator into the base solution, and regulating the pH of the base solution to 7-8;
and (3) dropwise adding an aqueous solution of an aluminum source and an aqueous solution of a silicon source into the base solution, keeping the temperature and stirring after the dropwise adding is finished, and cooling to room temperature to obtain the coagulation accelerating early strength agent for sprayed concrete.
8. The method for preparing a set accelerator for sprayed concrete according to claim 7, wherein the method for preparing the dispersing agent comprises the steps of:
mixing pentaerythritol and a polymerization inhibitor, heating to melt, adding methacrylic acid and a catalyst, continuously heating to 110-125 ℃, introducing nitrogen for purging, and completing the reaction to obtain an esterified substance; preparing a first drop of the esterified substance, the unsaturated carboxylic acid and the derivative thereof and water, and preparing a second drop of the reducing agent, the chain transfer agent and the water;
mixing polyether macromonomer with water, controlling the temperature to be 30-45 ℃, adding an initiator, stirring, dripping a first dripping material and a second dripping material, continuing stirring after the reaction is finished, and neutralizing the reactant to the pH value of 5-7.
9. The method for preparing the accelerating early strength agent for sprayed concrete according to claim 8, wherein the method comprises the following steps: the polymerization inhibitor comprises at least one of hydroquinone and phenothiazine;
and/or the initiator is at least one of hydrogen peroxide, ammonium persulfate and potassium persulfate;
and/or the chain transfer agent is at least one of thioglycollic acid, mercaptopropionic acid and mercaptoethanol;
and/or the reducing agent is at least one of vitamin C, sodium metabisulfite and sodium bisulphite.
10. The method for preparing the accelerating early strength agent for sprayed concrete according to claim 8 or 9, characterized in that: the unsaturated carboxylic acid and the derivative thereof comprise at least one of acrylic acid, maleic anhydride and itaconic acid; and/or the polyether macromonomer comprises at least one of isopentenyl alcohol polyoxyethylene ether and isobutenyl alcohol polyoxyethylene ether.
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| CN107840593A (en) * | 2017-11-17 | 2018-03-27 | 武汉理工大学 | A kind of gunite concrete early-strength alkali-free liquid setting accelerator and preparation method thereof |
| CN109231871A (en) * | 2018-09-19 | 2019-01-18 | 攀枝花市吉源科技有限责任公司 | A kind of low-mix quantity high performance alkali-free chlorine-free liquid accelerator and preparation method thereof |
| CN115745455A (en) * | 2022-10-21 | 2023-03-07 | 贵州天威建材科技有限责任公司 | Water reducing agent for sprayed concrete, preparation method and application |
| CN115893895A (en) * | 2023-01-09 | 2023-04-04 | 石家庄市长安育才建材有限公司 | Coagulation accelerating early strength agent, preparation method thereof and concrete composition |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107840593A (en) * | 2017-11-17 | 2018-03-27 | 武汉理工大学 | A kind of gunite concrete early-strength alkali-free liquid setting accelerator and preparation method thereof |
| CN109231871A (en) * | 2018-09-19 | 2019-01-18 | 攀枝花市吉源科技有限责任公司 | A kind of low-mix quantity high performance alkali-free chlorine-free liquid accelerator and preparation method thereof |
| CN115745455A (en) * | 2022-10-21 | 2023-03-07 | 贵州天威建材科技有限责任公司 | Water reducing agent for sprayed concrete, preparation method and application |
| CN115893895A (en) * | 2023-01-09 | 2023-04-04 | 石家庄市长安育才建材有限公司 | Coagulation accelerating early strength agent, preparation method thereof and concrete composition |
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