A mineral admixture adaptive polycarboxylic acid water reducing agent and a preparation method thereof

Abstract

The application discloses a mineral admixture adaptive polycarboxylic water reducing agent, which comprises unsaturated polyether macromonomer, unsaturated carboxylic acid monomer, acetylenic ester monomer, oxidizing agent, reducing agent and chain transfer agent; the molar ratio of the unsaturated polyether macromonomer, the unsaturated carboxylic acid monomer and the acetylenic ester monomer is 1:1-3:0.1-2; the amount of the oxidizing agent is 0.1%-1.5% of the total mass of the unsaturated polyether macromonomer; the amount of the reducing agent is 0.1%-2.0% of the total mass of the unsaturated polyether macromonomer; and the amount of the chain transfer agent is 0.1%-1.2% of the total mass of the unsaturated polyether macromonomer. The application further discloses a preparation method of the mineral admixture adaptive polycarboxylic water reducing agent. The mineral admixture adaptive polycarboxylic water reducing agent has the characteristics of reducing admixture and improving strength, and can effectively improve the poor workability, the unobvious strength improvement and the high admixture amount of low-grade silica fume concrete.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water reducing agent, and particularly relates to a mineral admixture adaptive polycarboxylic acid water reducing agent and a preparation method thereof. BACKGROUND

[0002] Silica ash is produced by a large amount of volatile SiO2 and Si gas in the smelting of ferrosilicon and industrial silicon (metallic silicon) in the submerged arc furnace, and the gas is rapidly oxidized and condensed after being discharged to form silica ash. It is a by-product of industrial smelting, and the whole process needs to be recycled by dust removal environmental protection equipment, and it is one of the industrial "three wastes".

[0003] When silica ash is added to concrete, it can fill the pores between cement particles and form a gel with the hydration products. In cement-based concrete, mortar, and castable refractory, the addition of a proper amount of silica ash can have the following effects: 1. significantly improve the compressive, anti-segregation, anti-permeability, corrosion resistance, impact resistance and wear resistance; 2. has the functions of water retention, prevention of segregation, bleeding, and greatly reduces the pumping resistance of concrete; 3. significantly prolongs the service life of concrete; 4. reduces the cost and improves the durability; 5. effectively prevents the occurrence of concrete alkali aggregate reaction; 6. improves the compactness of castable refractory, etc. Therefore, reasonable promotion and utilization of silica ash not only can protect and manage the environment, but also can improve the performance of concrete and save land and energy to a certain extent, which has important practical significance. However, at present, whether at home or abroad, the resource of silica ash is not sufficient, and the current production of silica ash in China far cannot meet the requirements, and the proportion of high-grade silica ash is small, most of which is medium and low-grade silica ash, and the low-grade silica ash has a large amount of loose porous structure, which is used as a raw material for concrete, and generally has high loss on ignition, increased water demand, and obvious concrete slump loss, etc. At the same time, it also has a serious negative impact on concrete admixtures. At present, there is a lack of relevant research on the development and use of medium and low-grade silica ash, and in actual production, this part of silica ash is often treated as industrial waste, such as the northwest ferroalloy plant in Gansu, which has a large amount of low-grade silica ash to be treated as "garbage" every year, which will not only cause resource waste but also cause environmental damage.

[0004] Through the synthesis technology of admixtures, a kind of low-grade silica ash adaptive admixture is developed, which is used to reduce the dosage of water reducing agent and improve the performance of concrete, which is the core technical problem of admixtures that needs to be solved urgently. SUMMARY

[0005] The present application aims to provide a mineral admixture adaptive polycarboxylic acid water reducing agent and a preparation method thereof, which solves the technical problems of high loss on ignition, increased water demand, and obvious concrete slump loss when low-grade silica ash is used as a raw material for concrete in the prior art.

[0006] To achieve the above object, one embodiment of the present application provides a mineral admixture adaptive polycarboxylic acid water reducer, which comprises unsaturated polyether macromonomer, unsaturated carboxylic acid monomer, acetylenic ester monomer, oxidizing agent, reducing agent and chain transfer agent.

[0007] The molar ratio of the unsaturated polyether macromonomer, the unsaturated carboxylic acid monomer and the acetylenic ester monomer is 1:1-3:0.1-2, the amount of the oxidizing agent is 0.1%-1.5% of the total mass of the unsaturated polyether macromonomer, the amount of the reducing agent is 0.1%-2.0% of the total mass of the unsaturated polyether macromonomer, and the amount of the chain transfer agent is 0.1%-1.2% of the total mass of the unsaturated polyether macromonomer.

[0008] In one preferred embodiment of the present application, the mineral admixture adaptive polycarboxylic acid water reducer further comprises a catalyst.

[0009] In one preferred embodiment of the present application, part of the acetylenic ester monomer is used for olefin polymerization as an anchor point for acetylenic polymerization, and the other part is used for acetylene polymerization, and the proportion of the acetylenic ester monomer used for olefin polymerization is 70%-95%.

[0010] The amount of the catalyst is 0.1%-5% of the weight of the acetylenic ester monomer used for acetylene polymerization.

[0011] In one preferred embodiment of the present application, the acetylenic ester monomer is 4-ethynylphenyl propenoate.

[0012] In one preferred embodiment of the present application, the unsaturated polyether macromonomer is at least one of isopentenyl alcohol polyoxyethylene ether, isobutenyl alcohol polyoxyethylene ether and methyl allyl alcohol polyoxyethylene ether.

[0013] In one preferred embodiment of the present application, the unsaturated carboxylic acid monomer is at least one of acrylic acid, methacrylic acid and maleic anhydride.

[0014] In one preferred embodiment of the present application, the oxidizing agent is at least one of ammonium persulfate, sodium persulfate, potassium persulfate and hydrogen peroxide, the reducing agent is at least one of vitamin C, ferrous sulfate, sodium thiomethanesulfate, sodium sulfite, sodium bisulfite, sodium hypophosphite, sodium formaldehyde sulfoxylate and sodium hyposulfite, and the chain transfer agent is at least one of mercaptoacetic acid, mercaptoethanol, mercaptopropionic acid, aliphatic mercaptan, dodecyl mercaptan and sodium hydrogen phosphite.

[0015] In one preferred embodiment of the present application, the catalyst is an acetylenic polymerization catalyst, and the acetylenic polymerization catalyst is dirhodium dichloride.

[0016] Based on the mineral admixture adaptive polycarboxylic acid water reducer disclosed in the present application, the present application further discloses a preparation method of the mineral admixture adaptive polycarboxylic acid water reducer, which comprises the following steps:

[0017] Step (1): dissolving the unsaturated polyether macromonomer in water, then adding an oxidizing agent to obtain a reactant solution;

[0018] Step (2): under stirring at 10-60 DEG C, adding a mixed solution of the unsaturated carboxylic acid monomer and the alkyne ester monomer and a mixed solution of the reducing agent and the chain transfer agent into the obtained reactant solution respectively dropwise, and then keeping the reaction after the dropwise addition is completed to obtain the mineral admixture adaptive polycarboxylic acid water reducer.

[0019] In one of the preferred embodiments of the present application, in step (2), the dropwise addition time of the mixed solution of the unsaturated carboxylic acid monomer and the alkyne ester monomer is 30-180 min, the dropwise addition time of the mixed solution of the reducing agent and the chain transfer agent is 30-180 min, the temperature of the keeping reaction is 20-40 DEG C, and the reaction time is 0.5-2.5 h.

[0020] In summary, the present application has the following advantages:

[0021] 1. The present application introduces the hydrophobic long side chain by the unsaturated polyether macromonomer to provide steric hindrance and other steric repulsion, which determines the dispersion and dispersion retention performance of the water reducer; the strong polar anion group on the main chain is introduced by the unsaturated carboxylic acid monomer, which mainly plays the role of anchoring, solubilization, and providing electrostatic repulsion; the ester group containing the hydrolyzed carboxyl group is introduced by the alkyne ester monomer, on one hand, the hydrolysis of these groups in the alkaline environment of the cement paste continuously produces carboxyl groups in a long time, thereby improving the adsorption and dispersion capacity in the later period; on the other hand, the introduction of the alkyne ester monomer effectively improves the molecular structure of the polycarboxylic acid water reducer, and the subsequent polymerization of the polyacetylene monomer forms the polyacetylene chain, which can improve the rigidity of the molecular chain and exhibit the characteristics of improving the strength and reducing the dosage in the concrete, which is helpful to improve the workability of the concrete, and can also adjust the adsorption balance of the silica fume and the cement to the polycarboxylic acid water reducer; in addition, the benzene ring in the alkyne monomer can effectively weaken the influence of the loose and porous structure of the low-grade silica fume on the concrete, and exhibits good adaptability to the low-grade silica fume; moreover, the double bond in the alkyne ester monomer can participate in the free radical polymerization of the olefin, and the hydrolysis continues to produce unsaturated carboxylic acid, which plays the role of dispersion and slump retention. By using the strong polar anion group of the carboxyl group, the hydrolysis of the ester group, and the rigidity of the polyacetylene molecular chain, the mineral admixture adaptive polycarboxylic acid water reducer exhibits the characteristics of high water-reducing, high slump retention, and good workability, and can also improve the strength of the concrete.

[0022] 2、The mineral admixture adaptive polycarboxylate superplasticizer of the present application utilizes its characteristics of reducing admixture and improving strength to effectively improve the poor workability, unobvious strength improvement and high admixture content of low-grade silica fume concrete, and utilizes its improvement on the performance of low-grade silica fume concrete to solve the problem of large amount of low-grade silica fume waste treatment in the northwest region every year, and at the same time, the waste is used as a raw material to reduce the cost of concrete, achieving a win-win effect.

[0023] 3、The ratio between the unsaturated polyether macromonomer, the unsaturated carboxylic acid monomer and the alkyne ester monomer of the present application has a great influence on the performance of the superplasticizer. If the molar ratio of the unsaturated carboxylic acid monomer to the polyether macromonomer (hereinafter referred to as acid ether ratio) is too low, the water reducing rate is low; if the acid ether ratio is too high, the water reducing rate may be large, and in actual application, bleeding problems may occur, and at the same time, due to the high acid ether ratio, the adsorption balance of cement and silica fume on the polycarboxylate superplasticizer is affected, resulting in a significant reduction in water reducing rate. If the molar ratio of the unsaturated carboxylic acid monomer to the alkyne ester monomer (hereinafter referred to as acid ester ratio) is too high, on the one hand, the number of carboxyl groups generated by hydrolysis of ester groups is small, and the slump retention performance is poor, on the other hand, the reduction of polyacetylene chain leads to small molecular chain rigidity, and the strength improvement effect is reduced; if the acid ester ratio is too low, the number of carboxyl groups in the system is small, and the water reducing rate may be reduced. Therefore, the acid ether ratio, the acid ester ratio, the amount of the initiation system and the amount of the bond transfer agent of the present application will all affect the water reducing rate and slump retention performance of the superplasticizer, and at the same time, will also affect the characteristics of the superplasticizer in improving the mechanical properties and working performance of concrete.

[0024] 4、The present application can achieve high water reducing and high slump retention performance characteristics under the condition of a specific molar ratio of unsaturated polyether macromonomer, unsaturated carboxylic acid monomer and alkyne ester monomer, weaken the negative influence of low-grade silica fume on the performance of admixtures and concrete, and at the same time, can improve the mechanical properties and working performance of concrete. Specifically, by fixing the proportion of unsaturated polyether macromonomer, adjusting the amount of unsaturated carboxylic acid monomer, the initial adsorption capacity of polycarboxylate superplasticizer can be adjusted, so as to change the water reducing rate of polycarboxylate superplasticizer; by adjusting the amount of alkyne ester monomer used for free radical polymerization, the late adsorption capacity of polycarboxylate superplasticizer can be adjusted, so as to change the slump retention performance of polycarboxylate superplasticizer; by adjusting the amount of alkyne ester monomer used for coordination polymerization, the influence of polycarboxylate superplasticizer on the rigidity of concrete can be adjusted.

[0025] 5、The present application introduces alkyne groups and unsaturated carboxylic acid monomers in the molecular structure by free radical polymerization, adjusts the ratio between the components, synthesizes polycarboxylate superplasticizer, and then introduces polyacetylene molecular fragments in the molecular structure by coordination polymerization, synthesizes mineral admixture adaptive polycarboxylate superplasticizer with rigid structure and for low-grade silica fume loose and porous structure, and the specific reaction process is as follows:

[0026]

[0027]

[0028] 6、The polycarboxylic acid water reducing agent has rigid structure and hydrolysis groups, can effectively improve the strength of concrete, and can improve the slump retention of concrete and weaken the negative influence of low-grade silica ash on the polycarboxylic acid water reducing agent and concrete. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a chemical structural formula of 4-ethynyl phenyl acrylate in one embodiment of the present application. DETAILED DESCRIPTION

[0030] The application discloses a mineral admixture adaptive polycarboxylic acid water reducing agent.

[0031] The molar ratio of the unsaturated polyether macromonomer, the unsaturated carboxylic acid monomer and the alkyne ester monomer is 1:1-3:0.1-2, the amount of the oxidizing agent is 0.1%-1.5% of the total mass of the unsaturated polyether macromonomer, the amount of the reducing agent is 0.1%-2.0% of the total mass of the unsaturated polyether macromonomer, and the amount of the chain transfer agent is 0.1%-1.2% of the total mass of the unsaturated polyether macromonomer.

[0032] The alkyne ester monomer is used for olefin polymerization as an anchor point of alkyne polymerization, and is used for alkyne polymerization, and the proportion of the alkyne ester monomer used for olefin polymerization is 70%-95%, and the amount of the catalyst is 0.1%-5% of the weight of the alkyne ester monomer used for alkyne polymerization.

[0033] The alkyne ester monomer is 4-ethynyl phenyl acrylate, and a structural formula thereof is as shown in the figure. Figure 1 The unsaturated polyether macromonomer is at least one of iso-pentenyl alcohol polyoxyethylene ether, iso-butenyl alcohol polyoxyethylene ether and methyl allyl alcohol polyoxyethylene ether, the unsaturated carboxylic acid monomer is at least one of acrylic acid, methacrylic acid and maleic anhydride, the oxidizing agent is at least one of ammonium persulfate, sodium persulfate, potassium persulfate and hydrogen peroxide, the reducing agent is at least one of vitamin C, ferrous sulfate, sodium thiomethanesulfate, sodium sulfite, sodium bisulfite, sodium hypophosphite, sodium formaldehyde sulfoxylate and sodium dithionite, the chain transfer agent is at least one of mercaptoacetic acid, mercaptoethanol, mercaptopropionic acid, aliphatic mercaptan, dodecyl mercaptan and sodium hydrogen phosphite, and the catalyst is an alkyne polymerization catalyst, and the alkyne polymerization catalyst is dirhodium dichloride.

[0034] A preparation method of the mineral admixture adaptive polycarboxylic acid water reducing agent comprises the following steps:

[0035] Step (1): in a glass reactor equipped with a thermometer, a mechanical stirrer, unsaturated polyether macromonomer and water were sequentially added and stirred at low temperature, then an oxidizing agent was added to obtain a reactant solution;

[0036] Step (2): unsaturated carboxylic acid monomer and part of alkyne ester monomer used for alkyne polymerization as anchor point of alkynyl polymerization were dissolved in water, stirred and uniformly dispersed to obtain solution A; a reducing agent and a chain transfer agent were dissolved in water, stirred and dissolved to obtain solution B;

[0037] Step (3): under the condition of stirring at 10-60℃, solution A and solution B were added dropwise into the reactant solution in step (1), solution A was added dropwise for 30-180 min, solution B was added dropwise for 30-180 min, after the addition was completed, the solution was incubated at 20-40℃ for 0.5-2.5 h to obtain solution C;

[0038] Step (4): under the condition of stirring at 10-60℃, another part of alkyne ester monomer used for alkyne polymerization and a catalyst were added into solution C, and incubated for 3 h to obtain a mineral admixture adaptive polycarboxylic acid water reducer.

[0039] Example 1

[0040] A mineral admixture adaptive polycarboxylic acid water reducer, comprising unsaturated polyether macromonomer isopentenyl alcohol polyoxyethylene ether 222.5 g, unsaturated carboxylic acid monomer acrylic acid 16.7 g, alkyne ester monomer 4-ethynylphenyl acrylate 15.59 g, oxidizing agent hydrogen peroxide 0.92 g, reducing agent vitamin C 0.30 g, chain transfer agent mercaptoethanol 0.54 g, and catalyst rhodium dichloride 16 mg;

[0041] The molar ratio of the unsaturated polyether macromonomer, the unsaturated carboxylic acid monomer, and the alkyne ester monomer is 1:2.5:1,

[0042] A mineral admixture adaptive polycarboxylic acid water reducer, comprising the following steps:

[0043] Step (1): in a glass reactor equipped with a thermometer, a mechanical stirrer, 222.5 g of isopentenyl alcohol polyoxyethylene ether and 190 g of deionized water were sequentially added and stirred at low temperature for 30 min, then 0.92 g of hydrogen peroxide was added to obtain a reactant solution;

[0044] Step (2): 16.7 g of acrylic acid and 12.76 g of 4-ethynylphenyl acrylate were stirred and uniformly dispersed in 27.4 g of deionized water to obtain solution A, wherein 12.76 g of 4-ethynylphenyl acrylate was dissolved in 3 ml of N,N-dimethylformamide; 0.54 g of mercaptoethanol, 0.30 g of vitamin C, and 40 g of water were stirred and dissolved to obtain solution B;

[0045] Step (3): Under the condition of stirring at 30℃, A solution and B solution were added dropwise into the reactant solution in step (1) respectively, A solution was added dropwise for 90 min, B solution was added dropwise for 120 min, and after the dropwise addition was completed, the solution was kept at 40℃ for 1 h to obtain solution C;

[0046] Step (4): Under the condition of stirring at 30℃, 3.19 g of 4-ethynylphenyl acrylate and 16 mg of dichlorobisrhodium were added into solution C, and the solution was kept for 3 h to obtain a mineral admixture adaptive polycarboxylate superplasticizer, wherein 3.19 g of 4-ethynylphenyl acrylate was dissolved in 0.5 ml of N,N-dimethylformamide.

[0047] Example 2

[0048] A mineral admixture adaptive polycarboxylate superplasticizer comprises unsaturated polyether macromonomer methyl allyl alcohol polyoxyethylene ether 222.5 g, unsaturated carboxylic acid monomer methyl methacrylate 17.22 g, acetylenic ester monomer 4-ethynylphenyl acrylate 12.76 g, oxidizing agent hydrogen peroxide 0.75 g, reducing agent vitamin C 0.30 g, chain transfer agent mercaptoethanol 0.54 g, and catalyst dichlorobisrhodium 13 mg.

[0049] The molar ratio of the unsaturated polyether macromonomer, the unsaturated carboxylic acid monomer, and the acetylenic ester monomer is 1:2.7:1.

[0050] A preparation method of a mineral admixture adaptive polycarboxylate superplasticizer comprises the following steps:

[0051] Step (1): A glass reactor equipped with a thermometer and a mechanical stirrer was used, and 222.5 g of methyl allyl alcohol polyoxyethylene ether and 190 g of deionized water were sequentially added, and then stirred at low temperature for 20 min, and then 0.75 g of hydrogen peroxide was added to obtain a reactant solution;

[0052] Step (2): 17.22 g of methyl methacrylate and 10.21 g of 4-ethynylphenyl acrylate and 20 g of deionized water were stirred and dispersed uniformly to obtain A solution, wherein 10.21 g of 4-ethynylphenyl acrylate was dissolved in 3 ml of N,N-dimethylformamide; 0.54 g of mercaptoethanol, 0.30 g of vitamin C, and 40 g of water were stirred and dissolved to obtain B solution;

[0053] Step (3): Under the condition of stirring at 18℃, A solution and B solution were added dropwise into the reactant solution in step (1) respectively, A solution was added dropwise for 40 min, B solution was added dropwise for 55 min, and after the dropwise addition was completed, the solution was kept at 40℃ for 0.5 h to obtain solution C;

[0054] Step (4): 2.55g of 4-ethynylphenyl acrylate and 13mg of dichlorobis rhodium were added to solution C under stirring at 30℃ for 3h to obtain the mineral admixture adaptable polycarboxylate superplasticizer, wherein 2.55g of 4-ethynylphenyl acrylate was dissolved in 0.5ml of N,N-dimethylformamide.

[0055] Example 3

[0056] A mineral admixture adaptable polycarboxylate superplasticizer, comprising unsaturated polyether macromonomer isoamylenol polyoxyethylene ether 222.5g, unsaturated carboxylic acid monomer maleic anhydride 15.45g, acetylenic ester monomer 4-ethynylphenyl acrylate 23.92g, oxidizing agent hydrogen peroxide 0.92g, reducing agent vitamin C 0.30g, chain transfer agent mercaptopropionic acid 0.54g, and catalyst dichlorobis rhodium 12mg.

[0057] The molar ratio of the unsaturated polyether macromonomer, the unsaturated carboxylic acid monomer, and the acetylenic ester monomer is 1:1.7:1.5.

[0058] A preparation method of a mineral admixture adaptable polycarboxylate superplasticizer, comprising the following steps:

[0059] Step (1): A glass reactor equipped with a thermometer and a mechanical stirrer was used to sequentially add 222.5g of isoamylenol polyoxyethylene ether and 190g of deionized water, and then 0.92g of hydrogen peroxide was added under low-temperature stirring for 20min to obtain a reactant solution;

[0060] Step (2): 15.45g of maleic anhydride and 21.53g of 4-ethynylphenyl acrylate were uniformly dispersed in 20g of deionized water to obtain solution A, wherein 21.53g of 4-ethynylphenyl acrylate was dissolved in 3ml of N,N-dimethylformamide; 0.54g of mercaptoethanol, 0.30g of vitamin C, and 40g of water were stirred and dissolved to obtain solution B;

[0061] Step (3): Solution A and solution B were added dropwise to the reactant solution in step (1) under stirring at 25℃, solution A was added dropwise for 90min, and solution B was added dropwise for 120min; after the dropwise addition was completed, the solution was incubated at 40℃ for 1h to obtain solution C;

[0062] Step (4): 2.55g of 4-ethynylphenyl acrylate and 13mg of dichlorobis rhodium were added to solution C under stirring at 30℃ for 3h to obtain the mineral admixture adaptable polycarboxylate superplasticizer, wherein 2.55g of 4-ethynylphenyl acrylate was dissolved in 0.5ml of N,N-dimethylformamide.

[0063] Example 4

[0064] A mineral admixture adaptive polycarboxylic acid water reducing agent, comprising unsaturated polyether macromonomer isoamylenol polyoxyethylene ether 222.5g, unsaturated carboxylic acid monomer 23.6g, acetylenic ester monomer 4-ethynylphenyl acrylate 19.14g, oxidizing agent hydrogen peroxide 0.92g, reducing agent vitamin C 0.30g, chain transfer agent mercaptoethanol 0.54g and catalyst rhodium dichloride 19mg;

[0065] Wherein, the unsaturated carboxylic acid monomer is a mixture of acrylic acid and maleic anhydride, and the addition amount of acrylic acid is 12g, and the addition amount of maleic anhydride is 11.6g; the molar ratio of unsaturated polyether macromonomer, unsaturated carboxylic acid monomer and acetylenic ester monomer is 1:2:1.2.

[0066] A preparation method of a mineral admixture adaptive polycarboxylic acid water reducing agent, comprising the following steps:

[0067] Step (1): a glass reactor equipped with a thermometer and a mechanical stirrer was used, 222.5g of isoamylenol polyoxyethylene ether and 190g of deionized water were sequentially added, low-temperature stirring was carried out for 20min, then 0.92g of hydrogen peroxide was added, and a reactant solution was obtained;

[0068] Step (2): 12g of acrylic acid, 11.6g of maleic anhydride and 15.31g of 4-ethynylphenyl acrylate and 20g of deionized water were uniformly dispersed by stirring to obtain an A solution, wherein 15.31g of 4-ethynylphenyl acrylate was dissolved in 3ml of N,N-dimethylformamide; 0.54g of mercaptoethanol, 0.30g of vitamin C and 40g of water were stirred and dissolved to obtain a B solution;

[0069] Step (3): under the condition of stirring at 25℃, the A solution and the B solution were added dropwise into the reactant solution in step (1), the A solution was added dropwise for 90min, the B solution was added dropwise for 120min, after the dropwise addition was completed, the solution was kept at 40℃ for 0.8h, and a solution C was obtained;

[0070] Step (4): under the condition of stirring at 30℃, 3.83g of 4-ethynylphenyl acrylate and 19mg of rhodium dichloride were added into the solution C, and the solution was kept for 3h, and a mineral admixture adaptive polycarboxylic acid water reducing agent was obtained, wherein 3.83g of 4-ethynylphenyl acrylate was dissolved in 0.5ml of N,N-dimethylformamide.

[0071] Comparative Example 1

[0072] A mineral admixture adaptive polycarboxylic acid water reducing agent, comprising unsaturated polyether macromonomer isoamylenol polyoxyethylene ether 222.5g, unsaturated carboxylic acid monomer acrylic acid 16.69g, functional ester monomer hydroxyethyl acrylate 21.51g, oxidizing agent hydrogen peroxide 0.92g, reducing agent vitamin C 0.30g and chain transfer agent mercaptoethanol 0.54g;

[0073] wherein the molar ratio of the unsaturated polyether macromonomer, the unsaturated carboxylic acid monomer, and the functional ester monomer is 1:2.5:2.

[0074] A preparation method of a mineral admixture adaptive polycarboxylic acid water reducer includes the following steps:

[0075] Step (1): In a glass reactor equipped with a thermometer and a mechanical stirrer, 222.5 g of isoamyl alcohol polyoxyethylene ether and 190 g of deionized water were sequentially added, stirred at low temperature for 20 min, and then 0.92 g of hydrogen peroxide was added to obtain a reactant solution;

[0076] Step (2): 16.69 g of acrylic acid, 21.51 g of hydroxyethyl acrylate, and 20 g of deionized water were stirred and dispersed uniformly to obtain an A solution; 0.54 g of mercaptoethanol, 0.30 g of vitamin C, and 40 g of water were stirred and dissolved to obtain a B solution;

[0077] Step (3): Under stirring at 25°C, the A solution and the B solution were added dropwise to the reactant solution in step (1), the A solution was added dropwise for 90 min, and the B solution was added dropwise for 120 min; after the dropwise addition was completed, the reaction was carried out at 40°C for 1 h to obtain a mineral admixture adaptive polycarboxylic acid water reducer.

[0078] Comparative Example 2

[0079] A mineral admixture adaptive polycarboxylic acid water reducer includes 222.5 g of unsaturated polyether macromonomer isoamyl alcohol polyoxyethylene ether, 15.95 g of unsaturated carboxylic acid monomer methacrylic acid, 18.09 g of functional ester monomer hydroxypropyl acrylate, 0.92 g of oxidizing agent hydrogen peroxide, 0.30 g of reducing agent vitamin C, and 0.54 g of chain transfer agent mercaptoethanol.

[0080] wherein the molar ratio of the unsaturated polyether macromonomer, the unsaturated carboxylic acid monomer, and the functional ester monomer is 1:2:1.5.

[0081] A preparation method of a mineral admixture adaptive polycarboxylic acid water reducer includes the following steps:

[0082] Step (1): In a glass reactor equipped with a thermometer and a mechanical stirrer, 222.5 g of isoamyl alcohol polyoxyethylene ether and 190 g of deionized water were sequentially added, stirred at low temperature for 20 min, and then 0.92 g of hydrogen peroxide was added to obtain a reactant solution;

[0083] Step (2): 15.95 g of methacrylic acid, 18.09 g of hydroxypropyl acrylate, and 20 g of deionized water were stirred and dispersed uniformly to obtain an A solution; 0.54 g of mercaptoethanol, 0.30 g of vitamin C, and 40 g of water were stirred and dissolved to obtain a B solution;

[0084] Step (3): under stirring at 25°C, the solution of the reactants in step (1) was added dropwise with solution A and solution B respectively, solution A was added dropwise for 90 min, solution B was added dropwise for 120 min, after the dropwise addition was completed, the reaction was kept at 40°C for 1 h, to obtain the mineral admixture-adapted polycarboxylate superplasticizer.

[0085] Comparative Example 3

[0086] The existing comprehensive polycarboxylate superplasticizer is model 3A02.

[0087] Test detection

[0088] The superplasticizers in the examples and comparative examples of the present application were subjected to cement paste fluidity test and concrete test, the cement paste fluidity was tested according to GB / T 8077-2000 "Concrete Admixture Homogeneity Test Method". The cement used was Esheng cement, the specific properties of low-grade silica fume were shown in Table 1, the water-cement ratio was 0.29, and the silica fume replaced 5% of the cement. The concrete performance was tested according to GB 8076-2008 "Concrete Admixture", the slump and the spread were measured, the machine-made sand in the concrete had a fineness modulus of 2.8, the gravel was continuously graded gravel with a particle size of 5-25 mm, the low-grade silica fume replaced 5% of the cement, and the polycarboxylate superplasticizer had a dosage of 1.6-2.6 wt%. The results of the cement paste fluidity test, the results of the concrete performance, and the results of the concrete strength of the superplasticizers were shown in Table 2, Table 3, and Table 4 respectively.

[0089] Table 1: Specific properties of low-grade silica fume

[0090]

[0091] Table 2: Cement paste fluidity data

[0092]

[0093]

[0094] Table 3: Concrete performance data C30

[0095]

[0096] Table 4: Concrete strength data C30

[0097]

[0098]

[0099] From the net paste performance test results in Table 2, the concrete test results in Table 3, and the concrete strength test results in Table 4, it can be seen that the water reducing agent performance in Examples 1-4 is better than that of the water reducing agents in Comparative Examples 1-3, the mineral admixture-adaptable polycarboxylic acid water reducing agent provided by the application has high initial water reducing rate, good slump retention performance, and good workability, and meanwhile, the mineral admixture-adaptable polycarboxylic acid water reducing agent provided by the application can improve the strength of concrete compared with Comparative Examples 1-3.

[0100] The experimental results of Example 2 and Comparative Example 3 with and without low-grade silica fume are compared. In the case of similar fluidity, the amount of low-grade silica fume in Example 2 is increased, but the amount of increase is relatively small compared with Comparative Example 3, indicating that the water reducing agent exhibits better low-grade silica fume adaptability in the case of using 4-ethynylphenyl acrylate, proving that 4-ethynylphenyl acrylate can reduce the amount of admixture in low-grade silica fume concrete. Meanwhile, the comparison of the strength shows that low-grade silica fume has little effect on the early strength of concrete, but has a relatively obvious improvement at 7d and 28d, and the admixture using 4-ethynylphenyl acrylate also has a certain improvement on the strength of concrete.

[0101] The water reducing agent in Comparative Example 1 is compared with the water reducing agent in Example 1. The low-grade silica fume adaptability and concrete strength of the hydroxyethyl acrylate used in Comparative Example 1 are far worse than those of 4-ethynylphenyl acrylate in the application, proving that 4-ethynylphenyl acrylate in the application has a great influence on the performance of the water reducing agent.

[0102] The water reducing agent in Comparative Example 2 is compared with the water reducing agent in Example 2. After adjusting the ratio between the unsaturated polyether macromonomer and the unsaturated carboxylic acid and ester monomer, the cement paste fluidity and the workability of concrete are far worse than those in the example when low-grade silica fume is added, proving that the ratio between the three also greatly affects the use effect.

[0103] The water reducing agent in Comparative Example 3 is compared with the water reducing agent in Example 2. In the case of adding low-grade silica fume, the cement paste fluidity and the workability of concrete are far worse than those in Example 2.

[0104] Taking example of the embodiment 2 and the comparative example 3, the water reducing agent is changed in the amount of mixing, and it can be seen from the performance results that the embodiment 2 is better in adaptability to the low-grade silica fume, the performance of the concrete mixed with the low-grade silica fume is better than others under the same amount of mixing, the state of the concrete is better with the reduced amount of mixing, and the loss over time is small; the concrete is not segregated with the increased amount of mixing, and the paddle is rich; in the comparative example 3, the initial state is general with the reduced amount of mixing, and the loss over time is fast; the concrete is segregated with the increased amount of mixing, which shows that the amount of mixing of the water reducing agent in the embodiment 2 is better in adaptability to the concrete mixed with the low-grade silica fume, and the influence of the water reducing agent on the performance of the concrete is not sensitive, while the influence of the water reducing agent on the performance of the concrete in the comparative example 3 is sensitive, which shows that the sensitivity of the amount of mixing in the embodiment 2 is better than that in the comparative example 3.

[0105] The above only describes the preferred embodiments of the present application and should not be used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

[0106] Although the specific embodiments of the present application are described in detail with reference to the accompanying drawings, it should not be understood as limiting the protection scope of the present patent. Various modifications and changes made by those skilled in the art within the scope described in the claims are still within the protection scope of the present patent.

Claims

1. A mineral admixture adaptable polycarboxylate superplasticizer, characterized in that: The preparation raw materials include unsaturated polyether macromonomer, unsaturated carboxylic acid monomer, acetylenic ester monomer, oxidizing agent, reducing agent and chain transfer agent; The molar ratio of the unsaturated polyether macromonomer, the unsaturated carboxylic acid monomer and the acetylenic ester monomer is 1:1-3:0.1-2, the amount of the oxidizing agent is 0.1%-1.5% of the total mass of the unsaturated polyether macromonomer, the amount of the reducing agent is 0.1%-2.0% of the total mass of the unsaturated polyether macromonomer, and the amount of the chain transfer agent is 0.1%-1.2% of the total mass of the unsaturated polyether macromonomer; The preparation raw materials of the mineral admixture adaptable polycarboxylate superplasticizer further include acetylenic polymerization catalyst; The acetylenic ester monomer is partially used for olefin polymerization as an anchor point of acetylenic polymerization, and partially used for acetylene polymerization, and the acetylenic ester monomer used for olefin polymerization accounts for 70%-95%, the unsaturated polyether macromonomer, the unsaturated carboxylic acid monomer and part of the acetylenic ester monomer are polymerized by free radical polymerization, the acetylenic group is introduced into the molecular structure, and the other part of the acetylenic ester monomer is introduced into the molecular structure by coordination polymerization; The amount of the acetylenic polymerization catalyst is 0.1%-5% of the weight of the acetylenic ester monomer used for acetylene polymerization. The acetylenic ester monomer is 4-ethynylphenyl acrylate.

2. The mineral admixture adaptable polycarboxylate superplasticizer according to claim 1, characterized in that: The unsaturated polyether macromonomer is at least one of isoprenyl alcohol polyoxyethylene ether and isobutenyl alcohol polyoxyethylene ether.

3. The mineral admixture adaptable polycarboxylate superplasticizer according to claim 1, characterized in that: The unsaturated carboxylic acid monomer is at least one of acrylic acid, methacrylic acid and maleic anhydride.

4. The mineral admixture-adaptable polycarboxylate water-reducing agent according to claim 1, characterized in that: The oxidizing agent is at least one of ammonium persulfate, sodium persulfate, potassium persulfate and hydrogen peroxide, the reducing agent is at least one of vitamin C, ferrous sulfate, sodium sulfite, sodium bisulfite, sodium hypophosphite, formaldehyde sodium sulfite and sodium hyposulfite, and the chain transfer agent is at least one of mercaptoacetic acid, mercaptoethanol, mercaptopropionic acid and aliphatic mercaptan.

5. The mineral admixture adaptable polycarboxylate superplasticizer according to claim 1, characterized in that: The acetylenic polymerization catalyst is dirhodium dichloride.

6. A method for producing a mineral admixture-adapted polycarboxylate superplasticizer for producing the mineral admixture-adapted polycarboxylate superplasticizer according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: Step (1): unsaturated polyether macromonomer and water are sequentially added into a glass reactor provided with a thermometer and a mechanical stirrer, and stirred at low temperature, and then an oxidizing agent is added to obtain a reactant solution; Step (2): unsaturated carboxylic acid monomer and part of acetylenic ester monomer used for olefin polymerization as an anchor point of acetylenic polymerization are dissolved in water, and stirred and dispersed uniformly to obtain solution A; a reducing agent and a chain transfer agent are dissolved in water, and stirred and dissolved to obtain solution B; Step (3): under the condition of stirring at 10-60℃, solution A and solution B are respectively added dropwise into the reactant solution in step (1), solution A is added dropwise for 30-180 min, solution B is added dropwise for 30-180 min, and after the dropwise addition is completed, the solution is reacted at 20-40℃ for 0.5-2.5 h to obtain solution C; Step (4): under the condition of stirring at 10-60℃, another part of acetylenic ester monomer used for acetylene polymerization and a catalyst are added into solution C, and the solution is kept for 3 h to obtain a mineral admixture adaptable polycarboxylate superplasticizer.

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