CN115368056A - Crystal nucleus enhanced liquid alkali-free accelerator and preparation method and application thereof - Google Patents
Crystal nucleus enhanced liquid alkali-free accelerator and preparation method and application thereof Download PDFInfo
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- CN115368056A CN115368056A CN202211009290.7A CN202211009290A CN115368056A CN 115368056 A CN115368056 A CN 115368056A CN 202211009290 A CN202211009290 A CN 202211009290A CN 115368056 A CN115368056 A CN 115368056A
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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
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F283/00—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G
- C08F283/06—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G on to polyethers, polyoxymethylenes or polyacetals
- C08F283/065—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G on to polyethers, polyoxymethylenes or polyacetals on to unsaturated polyethers, polyoxymethylenes or polyacetals
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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
- C04B2103/12—Set accelerators
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Abstract
The invention relates to the technical field of building materials, in particular to a crystal nucleus enhanced liquid alkali-free accelerator and a preparation method and application thereof. The crystal nucleus enhanced liquid alkali-free accelerator comprises the following raw materials in percentage by weight: 30 to 50 weight percent of aluminum sulfate, 5 to 10 weight percent of alcohol amine complex coagulation-promoting component, 0.5 to 5 weight percent of pH adjusting component, 1 to 3 weight percent of reinforcing component, 0.5 to 2 weight percent of anti-freezing component, 2 to 10 weight percent of crystal nucleus type nano calcium silicate hydrate early strength agent, 0.5 to 2 weight percent of thickening component and the balance of water. The crystal nucleus enhanced liquid alkali-free setting accelerator provided by the invention contains a crystal nucleus type nano calcium silicate hydrate early strength agent, and the early strength agent can greatly improve the early strength performance of the liquid alkali-free setting accelerator and has no adverse effect on the later strength.
Description
Technical Field
The invention relates to the technical field of building materials, in particular to a crystal nucleus enhanced liquid alkali-free accelerator and a preparation method and application thereof.
Background
With the development of wet-sprayed concrete technology, research on setting accelerators is increasing. The accelerator is an additive which can obviously shorten the setting time of concrete, enables the concrete to be quickly set and generates certain strength in a short time, and is widely applied to the construction of facilities such as submarine tunnels, coal mine anchoring supports, waterproof dams and the like. The addition of the accelerator can greatly reduce the rebound rate of concrete, reduce the construction cost and obviously improve the construction efficiency.
Liquid accelerators used in the early stage are all alkaline liquid accelerators which have strong alkalinity and can cause great damage to skin, respiratory tract and other parts of operators in the spraying process of concrete; meanwhile, the alkali content is high, so that the alkali-aggregate reaction in the concrete is easily caused, the later strength of the concrete is influenced, and the overall stability of the engineering is further influenced. In order to solve the problems, an alkali-free accelerator is developed, is generally weakly acidic, is more environment-friendly, safer and better in stability compared with an alkali-free accelerator, and can improve the early strength of concrete without influencing or even improving the later strength of the concrete.
However, with the increasing of the industrial standard, for example, the concrete with the alkali-free accelerator is required to have the compressive strength of more than or equal to 1Mpa in 6h and more than or equal to 10Mpa in the related standard of the alkali-free accelerator for the sprayed concrete for the tunnel, and the early strength performance of the existing alkali-free accelerator is difficult to reach the related requirement.
Disclosure of Invention
Therefore, the invention aims to overcome the defects that the alkali-free accelerator in the prior art has poor early strength performance and is difficult to meet the requirements of relevant industrial standards, and provides a crystal nucleus enhanced liquid alkali-free accelerator as well as a preparation method and application thereof.
Therefore, the invention provides a crystal nucleus enhanced liquid alkali-free accelerator which comprises the following raw materials in percentage by weight:
30 to 50 weight percent of aluminum sulfate, 5 to 10 weight percent of alcamines complexing coagulation-promoting component, 0.5 to 5 weight percent of pH adjusting component, 1 to 3 weight percent of reinforcing component, 0.5 to 2 weight percent of anti-freezing component, 2 to 10 weight percent of crystal nucleus type nano calcium silicate hydrate early strength agent, 0.5 to 2 weight percent of thickening component and the balance of water.
Optionally, the crystal nucleus type calcium silicate nano-hydrate early strength agent is taken as a reference, and the raw materials of the crystal nucleus type calcium silicate nano-hydrate early strength agent comprise 3-10 wt% of polycarboxylic acid dispersant, 10-15 wt% of soluble calcium salt, 5-9 wt% of soluble silicon salt and the balance of water.
Optionally, the grain size of the crystal nucleus type calcium silicate hydrate early strength agent is 180-250 nm;
optionally, in the crystal nucleus type calcium silicate nano-hydrate early strength agent, the molar ratio of calcium element to silicon element is (1-2) to 1;
optionally, the soluble calcium salt is selected from at least one of calcium nitrate, calcium nitrite, and calcium formate;
optionally, the soluble silicon salt is selected from at least one of sodium silicate, sodium metasilicate, and sodium fluorosilicate.
Optionally, the preparation process of the crystal nucleus type calcium silicate nano-hydrate early strength agent comprises the following steps:
(a) Taking part of the polycarboxylic acid dispersant, adding water for dilution, and adjusting the pH value to 12-14 to obtain dispersant aqueous solution; (b) Mixing the rest polycarboxylic acid dispersant with a silicon salt aqueous solution to obtain a dispersant-silicon salt mixed aqueous solution; (c) And (2) dripping a calcium salt aqueous solution and the dispersant-silicon salt mixed aqueous solution into the dispersant aqueous solution simultaneously within 8-24 h under the stirring condition of 30-80 ℃, and cooling to room temperature.
Optionally, the weight of the part of the polycarboxylic acid dispersant in the operation (a) accounts for 70-95% of the total weight of the polycarboxylic acid dispersant;
optionally, in the operation (a), adjusting the pH value by using an alkali liquor, wherein the alkali liquor is a sodium hydroxide aqueous solution, and the mass fraction of sodium hydroxide is 1-35%;
optionally, the mass fraction of the polycarboxylic acid dispersant in the dispersant aqueous solution is 1-10%, the mass fraction of the soluble silicate in the silicate aqueous solution is 20-40%, and the mass fraction of the soluble calcium salt in the calcium salt aqueous solution is 40-70%.
Optionally, the polycarboxylic acid dispersant comprises the following raw materials in parts by weight:
1000-1600 parts of polyether macromonomer, 30-60 parts of unsaturated organic acid, 1000-1500 parts of water, 4-6 parts of molecular weight regulator, 1-2 parts of reducing agent, 5-15 parts of oxidant, 5-27 parts of cationic monomer and 20-55 parts of complexing monomer.
Optionally, the polycarboxylic acid dispersant comprises the following raw materials in parts by weight:
1200-1600 parts of polyether macromonomer, 35-50 parts of unsaturated organic acid, 1200-1500 parts of water, 4.5-6 parts of molecular weight regulator, 1-2 parts of reducing agent, 7-14 parts of oxidant, 8-25 parts of cationic monomer and 25-50 parts of complexing monomer.
Optionally, the complexing monomer is an unsaturated monomer containing a nitrogen atom and/or an oxygen atom, and the complexing monomer can complex with calcium ions and silicon ions;
optionally, the complexing monomer is selected from at least one of 3- [ [2- (methacryloyloxy) ethyl ] dimethylammonium ] propionate, 2- (methacryloyloxy) ethyl-2- (trimethylamino) ethyl phosphate, N-dimethyl-N-2-propenyl-2-propen-1-aminium chloride, and N, N' -bis (vinylsulfonylacetyl) ethylenediamine.
Optionally, the polyether macromonomer is selected from at least one of 4-hydroxybutyl vinyl ether, ethylene glycol monovinyl polyethylene glycol ether, prenyl polyoxyethylene ether and methallyl alcohol polyoxyethylene ether;
the unsaturated organic acid is selected from acrylic acid and/or methacrylic acid;
the molecular weight regulator is selected from at least one of mercaptopropionic acid, thioglycolic acid and mercaptoethanol;
the reducing agent is at least one selected from vitamin C, ferrous sulfate and sodium formaldehyde sulfoxylate;
the oxidant is at least one of hydrogen peroxide, ammonium persulfate and potassium persulfate;
the cationic monomer is selected from methacryloyloxyethyl trimethyl ammonium chloride and/or dimethylaminoethyl acrylate chloromethane salt.
Optionally, the preparation process of the polycarboxylic acid dispersant comprises the following steps:
(1) Taking partially unsaturated organic acid, cationic monomer and complexing monomer, and uniformly mixing to prepare a first solution; (2) Taking part of water and a molecular weight regulator, and uniformly mixing to prepare a second solution; (3) Taking part of water and a reducing agent, and uniformly mixing to prepare a third solution; (4) Taking the rest water, the polyether macromonomer, the oxidant and the rest unsaturated organic acid, and uniformly mixing to prepare a fourth solution; (5) And dropwise adding the first solution, the second solution and the third solution into the fourth solution, and carrying out heat preservation reaction.
Optionally, the weight of the partially unsaturated organic acid in operation (1) accounts for 50-75% of the total weight of the unsaturated organic acid, and the weight of the remaining unsaturated organic acid in operation (4) accounts for 25-50% of the total weight of the unsaturated organic acid. The unsaturated organic acid is added into the fourth solution, and the dosage of the unsaturated organic acid is controlled, so that the fourth solution has a proper pH value, a proper reaction condition is provided for the reaction of the operation (5), the reaction efficiency and the reaction degree are improved, and the quality of the polycarboxylic acid dispersant product is further improved.
Optionally, in the operation (5), the dropping time of the first solution is 60 to 90min; the dripping time of the second solution is 90-120 min; the dropping time of the third solution is 90-120 min; the dropping time of the first solution is less than that of the second solution, and the dropping time of the second solution is less than that of the third solution. The molecular weight of the reaction product is controlled by controlling the dropping time of each solution, and the polycarboxylic acid dispersant product with proper molecular weight is prepared.
Optionally, in the operation (5), the conditions of the incubation reaction include: the reaction temperature is 13-20 ℃, and the reaction time is 0.5-1.5 h.
Optionally, the alkanolamine complexing coagulation-promoting component is selected from at least one of diethanolamine, triethanolamine and triisopropanolamine;
the pH adjusting component is selected from magnesium oxide and/or magnesium hydroxide;
the reinforcing component is selected from at least one of sodium sulfate, magnesium sulfate, lithium carbonate and basic silica sol;
the antifreeze component is glycerol;
the thickening component is selected from at least one of hydrated magnesium silicate, cellulose, guar gum and polyacrylamide.
The invention also provides a method for preparing the crystal nucleus enhanced liquid alkali-free accelerator, which comprises the following operations: s1, weighing a thickening component according to a ratio, adding the thickening component into water, and stirring for 25-40 min at 2000-4000 rpm by using a high-speed dispersion machine to obtain a thickening agent solution; s2, sequentially adding aluminum sulfate, a pH adjusting component, a reinforcing component, an anti-freezing component and a crystal nucleus type nano calcium silicate hydrate early strength agent into the thickening agent solution, mechanically stirring at 40-70 ℃ for 45-60 min, adding an alcamine complexing coagulation-promoting component, and continuously stirring until the solution is uniform and granular-free.
The invention also provides application of the crystal nucleus enhanced liquid alkali-free accelerator in wet sprayed concrete.
The technical scheme of the invention has the following advantages:
1. the crystal nucleus enhanced liquid alkali-free accelerator provided by the invention contains a crystal nucleus type nano calcium silicate hydrate early strength agent, and the early strength agent can greatly improve the early strength performance of the liquid alkali-free accelerator and has no adverse effect on the later strength.
2. The crystal nucleus enhanced liquid alkali-free accelerator provided by the invention contains the crystal nucleus type nano calcium silicate hydrate early strength agent which is a composite product of calcium silicate hydrate and polycarboxylic acid dispersant, has small and uniform particle size and stronger early strength performance, can obviously improve the early strength of concrete under the condition of smaller using amount, has smaller influence on the later strength of the concrete, and ensures that the later strength of the concrete is stable; in addition, the polycarboxylic acid dispersant also plays a role in dispersion stability, and can ensure that the alkali-free accelerator product is stable and does not delaminate.
3. The crystal nucleus enhanced liquid alkali-free accelerator provided by the invention contains a crystal nucleus type nano calcium silicate hydrate early strength agent, the crystal nucleus type nano calcium silicate hydrate early strength agent contains a polycarboxylic acid dispersing agent, and the raw material of the polycarboxylic acid dispersing agent contains a complexing monomer, so that the adsorption mode and adsorption sites of the polycarboxylic acid dispersing agent are increased, the polycarboxylic acid dispersing agent has stronger complexing adsorption effect, and thus, the polycarboxylic acid dispersing agent has stronger dispersing performance. Specifically, the polycarboxylic acid dispersing agent can act on the surface of the raw materials of the early strength agent, so that the steric hindrance between the raw materials of the early strength agent is increased, the reaction rate between the raw materials of the early strength agent is reduced, and the phenomenon that the particle size of the particles of the early strength agent is too large due to the too high reaction rate is avoided, so that the nanoscale early strength agent is prepared; meanwhile, the polycarboxylic acid dispersing agent can also act on the surfaces of the early strength agent particles, so that the contact probability among the early strength agent particles is effectively reduced, the agglomeration phenomenon among the early strength agent particles is effectively reduced, and the early strength agent particles can maintain smaller particle size. Therefore, the polycarboxylic acid dispersant can obviously reduce the particle size of the early strength agent particles, thereby improving the early strength performance of the early strength agent.
In addition, the raw materials of the polycarboxylic acid dispersant also contain a cationic monomer, so that the polycarboxylic acid dispersant has certain early strength performance, the polycarboxylic acid dispersant can synergize the early strength performance of the early strength agent, and after the early strength agent is used for an alkali-free accelerator, the early strength of concrete can be remarkably improved, and no adverse effect is caused on the later strength of the concrete.
Therefore, the polycarboxylic acid dispersant can improve the early strength performance of the early strength agent from the aspects of particle size reduction and synergistic interaction, and moreover, the use amount of the early strength agent can be reduced by improving the early strength performance of the early strength agent, so that the influence of the early strength agent on the later strength of the concrete is reduced, and the later strength of the concrete is stable.
4. The invention provides a crystal nucleus enhanced liquid alkali-free accelerator, wherein a crystal nucleus type nano calcium silicate hydrate early strength agent is an early strength agent subjected to directional optimization, and specifically, based on the characteristics of the raw material of the early strength agent, an unsaturated complexing monomer containing a nitrogen atom and an oxygen atom is pertinently introduced into a polycarboxylic acid dispersing agent, so that adsorption groups of the polycarboxylic acid dispersing agent, the raw material (calcium salt and silicon salt) of the early strength agent and the early strength agent are introduced, the adsorption effect of the polycarboxylic acid dispersing agent, the raw material of the early strength agent and the early strength agent is obviously improved, and the dispersion effect of the polycarboxylic acid dispersing agent on the raw material of the early strength agent and the early strength agent is further enhanced. The complexing monomer absorbs calcium and silicon ions in the raw material of the early strength agent through N and O atoms based on the complexing action, and the reaction rate is reduced by utilizing the steric hindrance effect of a polyether side chain to reduce the contact probability of calcium salt and silicon salt, so that the aim of small and controllable particle size of the early strength agent is fulfilled; the early strength agent particles are likely to be agglomerated by contact collision, and the agglomeration of the early strength agent and/or the accelerating agent is reduced by using the steric hindrance effect of the polycarboxylic acid dispersing agent according to the same principle, so that the early strength agent and/or the accelerating agent is uniform in product, stable in storage, free from precipitation and layering.
Detailed Description
The following examples are provided to further understand the present invention, not to limit the scope of the present invention, but to provide the best mode, not to limit the content and the protection scope of the present invention, and any product similar or similar to the present invention, which is obtained by combining the present invention with other prior art features, falls within the protection scope of the present invention.
The examples do not show the specific experimental steps or conditions, and can be performed according to the conventional experimental steps described in the literature in the field. The reagents or instruments used are not indicated by manufacturers, and are all conventional reagent products which can be obtained commercially.
Preparation example 1
The preparation example provides a polycarboxylic acid dispersant, which is prepared by the following method:
(1) Uniformly mixing 30g of unsaturated organic acid (acrylic acid), 20g of cationic monomer (methacryloyloxyethyl trimethyl ammonium chloride) and 45g of complexing monomer (3- [ [2- (methacryloyloxyethyl ] dimethyl ammonium ] propionate) to prepare a first solution;
(2) Taking 50g of water and 5g of a molecular weight regulator (mercaptopropionic acid), and uniformly mixing to prepare a second solution;
(3) Taking 50g of water and 1.5g of reducing agent (vitamin C), and uniformly mixing to obtain a third solution;
(4) 1300g of water and 1400g of polyether macromonomer (4-hydroxybutyl vinyl ether) are uniformly mixed until the mixture is completely dissolved, 13g of oxidant (hydrogen peroxide) and 15g of unsaturated organic acid (acrylic acid) are added, and the mixture is uniformly mixed to prepare a fourth solution;
(5) Sequentially dropwise adding the first solution, the second solution and the third solution into the fourth solution, and after dropwise adding is finished, carrying out heat preservation reaction at 15 ℃ for 1h to obtain a polycarboxylic acid dispersant; wherein the dropping time of the first solution is 75min, the dropping time of the second solution is 100min, and the dropping time of the third solution is 110min.
The polycarboxylic acid dispersant prepared in the embodiment comprises the following raw materials in parts by weight: 1400 parts of polyether macromonomer (4-hydroxybutyl vinyl ether), 45 parts of unsaturated organic acid (acrylic acid), 1400 parts of water, 5 parts of molecular weight regulator (mercaptopropionic acid), 1.5 parts of reducing agent (vitamin C), 13 parts of oxidizing agent (hydrogen peroxide), 20 parts of cationic monomer (methacryloyloxyethyl trimethyl ammonium chloride) and 45 parts of complexing monomer (3- [ [2- (methacryloyloxy) ethyl ] dimethyl ammonium ] propionate).
Preparation example 2
A polycarboxylic acid dispersant was prepared according to the method of preparation example 1, except that the amount of the raw materials was adjusted such that the polycarboxylic acid dispersant prepared in this preparation example includes the following raw materials in parts by weight: 1200 parts of polyether macromonomer (4-hydroxybutyl vinyl ether), 50 parts of unsaturated organic acid (acrylic acid), 1200 parts of water, 6 parts of molecular weight regulator (mercaptopropionic acid), 1 part of reducing agent (vitamin C), 14 parts of oxidizing agent (hydrogen peroxide), 8 parts of cationic monomer (methacryloyloxyethyl trimethyl ammonium chloride) and 50 parts of complexing monomer (3- [ [2- (methacryloyloxy) ethyl ] dimethyl ammonium ] propionate).
Preparation example 3
A polycarboxylic acid dispersant was prepared according to the method of preparation example 1, except that the amount of the raw materials was adjusted so that the polycarboxylic acid dispersant prepared in this preparation example includes the following raw materials in parts by weight: 1600 parts of polyether macromonomer (4-hydroxybutyl vinyl ether), 35 parts of unsaturated organic acid (acrylic acid), 1500 parts of water, 4.5 parts of molecular weight regulator (mercaptopropionic acid), 2 parts of reducing agent (vitamin C), 7 parts of oxidizing agent (hydrogen peroxide), 25 parts of cationic monomer (methacryloyloxyethyl trimethyl ammonium chloride) and 25 parts of complexing monomer (3- [ [2- (methacryloyloxy) ethyl ] dimethyl ammonium ] propionate).
Preparation example 4
A polycarboxylic acid dispersant was prepared according to the method of preparation example 1, except that the amount of the raw materials was adjusted such that the polycarboxylic acid dispersant prepared in this preparation example includes the following raw materials in parts by weight: 1000 parts of polyether macromonomer (4-hydroxybutyl vinyl ether), 60 parts of unsaturated organic acid (acrylic acid), 1000 parts of water, 6 parts of molecular weight regulator (mercaptopropionic acid), 1 part of reducing agent (vitamin C), 15 parts of oxidizing agent (hydrogen peroxide), 5 parts of cationic monomer (methacryloyloxyethyl trimethyl ammonium chloride) and 55 parts of complexing monomer (3- [ [2- (methacryloyloxy) ethyl ] dimethyl ammonium ] propionate).
Preparation example 5
A polycarboxylic acid dispersant was prepared according to the method of preparation example 1, except that the amount of the raw materials was adjusted so that the polycarboxylic acid dispersant prepared in this preparation example includes the following raw materials in parts by weight: 1600 parts of polyether macromonomer (4-hydroxybutyl vinyl ether), 30 parts of unsaturated organic acid (acrylic acid), 1500 parts of water, 4 parts of molecular weight regulator (mercaptopropionic acid), 2 parts of reducing agent (vitamin C), 5 parts of oxidizing agent (hydrogen peroxide), 27 parts of cationic monomer (methacryloyloxyethyl trimethyl ammonium chloride) and 20 parts of complexing monomer (3- [ [2- (methacryloyloxy) ethyl ] dimethyl ammonium ] propionate).
Preparation example 6
A polycarboxylic acid dispersant was prepared by following the procedure of preparation example 1, except that the polyether macromonomer used in this preparation example was ethylene glycol monovinyl polyglycol ether, the unsaturated organic acid was methacrylic acid, the molecular weight modifier was thioglycolic acid, the reducing agent was ferrous sulfate, the oxidizing agent was ammonium persulfate, the cationic monomer was dimethylaminoethyl acrylate chloromethane salt, and the complexing monomer was 2- (methacryloyloxy) ethyl-2- (trimethylamino) ethyl phosphate.
Comparative preparation example 1
A dispersant was prepared according to the method of preparation example 1, except that no complexing monomer was added during the preparation of the dispersant of this comparative preparation example.
Preparation examples 7 to 12
By using the polycarboxylic acid dispersants prepared in preparation examples 1 to 6 in sequence, a crystal nucleus type calcium silicate nano-hydrate early strength agent was prepared as follows:
(a) Taking 54g of polycarboxylic acid dispersant, adding 647g of water for dilution, and adjusting the pH to 12-14 by using a 10% by mass sodium hydroxide aqueous solution to obtain an 8% by mass dispersant aqueous solution;
(b) Mixing 6g of polycarboxylic acid dispersant with 150g of silicon salt (sodium metasilicate) aqueous solution with the mass fraction of 40% to obtain dispersant-silicon salt mixed aqueous solution;
(c) And (3) dripping 143g of 70 mass percent calcium salt (calcium nitrate) aqueous solution and the dispersant-silicon salt mixed aqueous solution obtained in the operation (b) into the dispersant aqueous solution obtained in the operation (a) simultaneously within 10 hours under the stirring condition of 50 ℃, and cooling to room temperature after finishing dripping to obtain the crystal nucleus type calcium silicate nano-hydrate early strength agent.
Comparative preparation example 2
An early strength agent was prepared in accordance with the procedure of preparation example 7, except that the dispersant prepared in comparative preparation example 1 used in this comparative preparation example was used in place of the polycarboxylic acid dispersant in preparation example 7.
Examples 1 to 3
The crystal nucleus type calcium silicate nano hydrate early strength agent prepared in preparation examples 7-9 is sequentially utilized to prepare a crystal nucleus enhanced liquid alkali-free accelerator according to the following method:
s1, weighing 5g of thickening component (hydrated magnesium silicate) and adding the thickening component into 455g of water, and stirring for 30min at 3000rpm of a high-speed dispersion machine to obtain a thickening agent solution;
s2, sequentially adding 300g of aluminum sulfate, 5g of pH adjusting component (magnesium oxide), 30g of reinforcing component (sodium sulfate), 5g of anti-freezing component (glycerol) and 100g of crystal nucleus type nano calcium silicate hydrate early strength agent into the thickener solution obtained in the operation S1, mechanically stirring for 45min at 70 ℃, adding 100g of alcamines complexing coagulation-promoting component (diethanolamine), continuously stirring until the solution is uniform and granular, stopping heating, and cooling to room temperature to obtain the crystal nucleus type reinforced liquid alkali-free accelerator.
Examples 4 to 6
The crystal nucleus type calcium silicate nano-hydrate early strength agent prepared in preparation examples 10-12 is used in sequence to prepare a crystal nucleus enhanced liquid alkali-free accelerator according to the following method:
s1, weighing 20g of thickening component (polyacrylamide) and adding into 330g of water, and stirring for 30min at 3000rpm of a high-speed dispersion machine to obtain a thickening agent solution;
s2, sequentially adding 500g of aluminum sulfate, 50g of pH adjusting component (magnesium hydroxide), 10g of reinforcing component (magnesium sulfate), 20g of anti-freezing component (glycerol) and 20g of crystal nucleus type nano calcium silicate hydrate early strength agent into the thickener solution obtained in the operation S1, mechanically stirring for 60min at 40 ℃, adding 50g of alcohol amine complex coagulation promoting component (triethanolamine), continuously stirring until the solution is uniform and granular, stopping heating, and cooling to room temperature to obtain the crystal nucleus type reinforced liquid alkali-free accelerator.
Comparative example 1
A liquid alkali-free setting accelerator was prepared in the same manner as in example 1, except that the early strength agent prepared in comparative preparation example 2 was used in this comparative example instead of the crystal nucleus type calcium silicate trihydrate early strength agent in example 1.
Comparative example 2
A liquid alkali-free setting accelerator was prepared by following the procedure of example 1 except that the core type nano calcium silicate hydrate early strength agent was not used in this comparative example.
Experimental example 1
The average particle diameters of the respective early strength agent particles prepared in preparation examples 7 to 12 and comparative preparation example 2 were measured by a nano-particle size analyzer, and the measurement results are shown in table 1.
TABLE 1 average particle diameter of respective particles of early strength agents
| Early strength agent | Average particle diameter |
| Preparation example 7 | 180nm |
| Preparation example 8 | 195nm |
| Preparation example 9 | 200nm |
| Preparation example 10 | 230nm |
| Preparation example 11 | 245nm |
| Preparation example 12 | 250nm |
| Comparative preparation example 2 | 430nm |
Experimental example 2
Using the liquid alkali-free setting accelerators prepared in examples 1 to 6 and comparative examples 1 to 2, mortar test pieces were prepared according to the method described in GB/T35159, and the 6-hour compressive strength, 1-day compressive strength and 28-day compressive strength ratio were measured, and the measurement results are shown in Table 2.
TABLE 2 determination results of compressive strength and compressive strength ratio of each test piece
Experimental example 3
The stability of the liquid alkali-free accelerators prepared in examples 1 to 6 and comparative examples 1 to 2 was measured according to the method described in GB/T35159, and the volume of the supernatant of each liquid alkali-free accelerator after standing for 28 days was recorded as shown in Table 3.
TABLE 3 volume measurement of supernatant after leaving each liquid alkali-free setting accelerator for 28 days
| Liquid alkali-free accelerator | Volume of supernatant, mL, after standing for 28 days |
| Example 1 | 0 |
| Example 2 | 1 |
| Example 3 | 1 |
| Example 4 | 3 |
| Example 5 | 3 |
| Example 6 | 4 |
| Comparative example 1 | 5 |
| Comparative example 2 | 15 |
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. This need not be, nor should it be exhaustive of all embodiments. And obvious variations or modifications derived therefrom are intended to be within the scope of the invention.
Claims (10)
1. The nuclear-enhanced liquid alkali-free accelerator is characterized by comprising the following raw materials in percentage by weight:
30 to 50 weight percent of aluminum sulfate, 5 to 10 weight percent of alcohol amine complex coagulation-promoting component, 0.5 to 5 weight percent of pH adjusting component, 1 to 3 weight percent of reinforcing component, 0.5 to 2 weight percent of anti-freezing component, 2 to 10 weight percent of crystal nucleus type nano calcium silicate hydrate early strength agent, 0.5 to 2 weight percent of thickening component and the balance of water.
2. A crystal nucleus-enhanced liquid alkali-free accelerator as claimed in claim 1, wherein the crystal nucleus-enhanced calcium silicate monohydrate early strength agent is prepared from 3-10 wt% of polycarboxylic acid dispersant, 10-15 wt% of soluble calcium salt, 5-9 wt% of soluble silicon salt and the balance of water.
3. A crystal nucleus-enhanced liquid alkali-free accelerator according to claim 2, wherein the particle size of the crystal nucleus type nano calcium silicate hydrate early strength agent is 180-250 nm;
optionally, in the crystal nucleus type calcium silicate nano-hydrate early strength agent, the molar ratio of calcium element to silicon element is (1-2) to 1;
optionally, the soluble calcium salt is selected from at least one of calcium nitrate, calcium nitrite, and calcium formate;
optionally, the soluble silicon salt is selected from at least one of sodium silicate, sodium metasilicate, and sodium fluorosilicate.
4. A crystal nucleus-enhanced liquid alkali-free accelerator as claimed in claim 2, wherein the polycarboxylic acid dispersant comprises the following raw materials in parts by weight:
1000-1600 parts of polyether macromonomer, 30-60 parts of unsaturated organic acid, 1000-1500 parts of water, 4-6 parts of molecular weight regulator, 1-2 parts of reducing agent, 5-15 parts of oxidizing agent, 5-27 parts of cationic monomer and 20-55 parts of complexing monomer.
5. A crystal nucleus-enhanced liquid alkali-free accelerator as claimed in claim 4, wherein the polycarboxylic acid dispersant comprises the following raw materials in parts by weight:
1200-1600 parts of polyether macromonomer, 35-50 parts of unsaturated organic acid, 1200-1500 parts of water, 4.5-6 parts of molecular weight regulator, 1-2 parts of reducing agent, 7-14 parts of oxidant, 8-25 parts of cationic monomer and 25-50 parts of complexing monomer.
6. A crystal nucleus-enhanced liquid alkali-free accelerator according to claim 4, wherein the complexing monomer is an unsaturated monomer containing a nitrogen atom and/or an oxygen atom, and the complexing monomer is capable of complexing with calcium ions and silicon ions;
optionally, the complexing monomer is selected from at least one of 3- [ [2- (methacryloyloxy) ethyl ] dimethylammonium ] propionate, 2- (methacryloyloxy) ethyl-2- (trimethylamino) ethyl phosphate, N-dimethyl-N-2-propenyl-2-propen-1-aminium chloride, and N, N' -bis (vinylsulfonylacetyl) ethylenediamine.
7. A nuclear-enhanced liquid alkali-free accelerator according to claim 6, wherein the polyether macromonomer is at least one selected from the group consisting of 4-hydroxybutyl vinyl ether, ethylene glycol monovinyl polyglycol ether, isopentenol polyoxyethylene ether, and methallyl alcohol polyoxyethylene ether;
the unsaturated organic acid is selected from acrylic acid and/or methacrylic acid;
the molecular weight regulator is selected from at least one of mercaptopropionic acid, thioglycolic acid and mercaptoethanol;
the reducing agent is selected from at least one of vitamin C, ferrous sulfate and sodium formaldehyde sulfoxylate;
the oxidant is at least one of hydrogen peroxide, ammonium persulfate and potassium persulfate;
the cationic monomer is selected from methacryloyloxyethyl trimethyl ammonium chloride and/or dimethylaminoethyl acrylate chloromethane salt.
8. A crystal nucleus-enhanced liquid alkali-free accelerator according to any one of claims 1 to 7, wherein the alkanolamine-based complex accelerating component is at least one selected from diethanolamine, triethanolamine and triisopropanolamine;
the pH adjusting component is selected from magnesium oxide and/or magnesium hydroxide;
the reinforcing component is selected from at least one of sodium sulfate, magnesium sulfate, lithium carbonate and basic silica sol;
the anti-freeze component is glycerol;
the thickening component is selected from at least one of hydrated magnesium silicate, cellulose, guar gum and polyacrylamide.
9. A method for preparing a crystal nucleus-enhanced liquid alkali-free accelerator as claimed in any one of claims 1 to 8, which comprises the following operations:
s1, weighing a thickening component according to a ratio, adding the thickening component into water, and stirring for 25-40 min at 2000-4000 rpm by using a high-speed dispersion machine to obtain a thickening agent solution;
s2, sequentially adding aluminum sulfate, a pH adjusting component, a reinforcing component, an anti-freezing component and a crystal nucleus type nano calcium silicate hydrate early strength agent into the thickening agent solution in sequence, mechanically stirring at 40-70 ℃ for 45-60 min, adding an alcamine complexing coagulation-promoting component, and continuously stirring until the solution is uniform and granular-free.
10. Use of a crystal nucleus-enhanced liquid alkali-free accelerator as defined in any one of claims 1 to 8 in wet shotcrete.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116553855A (en) * | 2023-04-12 | 2023-08-08 | 自贡市星星化学建材有限公司 | Preparation process of alkali-free accelerator |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114014991A (en) * | 2021-10-29 | 2022-02-08 | 四川华西绿舍建材有限公司 | Calcium silicate hydrate crystal nucleus early-strength polycarboxylate superplasticizer and preparation method thereof |
| CN114409306A (en) * | 2022-01-06 | 2022-04-29 | 山西佳维新材料股份有限公司 | Fluoride-free high-early-strength liquid alkali-free setting accelerator and preparation method and application thereof |
| CN114656191A (en) * | 2022-04-28 | 2022-06-24 | 江苏博拓新型建筑材料股份有限公司 | Method for preparing crystal nucleus early-strength polycarboxylate superplasticizer with long-term dispersibility |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114014991A (en) * | 2021-10-29 | 2022-02-08 | 四川华西绿舍建材有限公司 | Calcium silicate hydrate crystal nucleus early-strength polycarboxylate superplasticizer and preparation method thereof |
| CN114409306A (en) * | 2022-01-06 | 2022-04-29 | 山西佳维新材料股份有限公司 | Fluoride-free high-early-strength liquid alkali-free setting accelerator and preparation method and application thereof |
| CN114656191A (en) * | 2022-04-28 | 2022-06-24 | 江苏博拓新型建筑材料股份有限公司 | Method for preparing crystal nucleus early-strength polycarboxylate superplasticizer with long-term dispersibility |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116553855A (en) * | 2023-04-12 | 2023-08-08 | 自贡市星星化学建材有限公司 | Preparation process of alkali-free accelerator |
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