CN116102689A - Concrete admixture sensitivity inhibitor, preparation method and application - Google Patents

Abstract

The invention relates to a concrete admixture sensitivity inhibitor, a preparation method and application thereof, wherein the concrete admixture sensitivity inhibitor comprises the following components: polyethylene glycol, polyethylene glycol monomethyl ether, acrylic acid, small molecule monoacid, polymerization inhibitor, catalyst, molecular regulator, initiator and reducing agent. The preparation method is that the polymers with wide molecular weight distribution are prepared by using the monomer collocation with different molecular weights through a special synthesis process, and the sensibility of the polycarboxylate superplasticizer is reduced by using the collocation of macromolecules and small molecules. The concrete admixture sensitivity inhibitor prepared by the invention can be directly compounded with the polycarboxylic acid water reducer or directly added when the concrete is sensitive. The prepared concrete admixture sensitivity inhibitor can reduce the sensitivity of various factors such as the mixing amount, the type, the water consumption, the temperature and the raw materials of the water reducer.

Description

Concrete admixture sensitivity inhibitor, preparation method and application

Technical Field

The invention belongs to the field of concrete additives, and particularly relates to a concrete additive sensitivity inhibitor, a preparation method and application thereof.

Background

In recent years, under the age background of the great tide of the construction of the infrastructure in China, the polycarboxylic acid additive becomes the water reducing agent with the widest application in the engineering building field by virtue of a series of advantages of lower mixing amount, excellent dispersion performance, functional designability, green environmental protection and the like. However, as the application range of the water reducer is wider and wider, the requirements of actual engineering on concrete are higher and higher, and the concrete raw materials are complex and changeable, the environment is different, the limitations of the technician are recognized, the use habituation and the like, so that a plurality of problems occur in the process of using the polycarboxylic acid water reducer, and the application effect of the polycarboxylic acid water reducer is directly influenced.

The problems of sensitivity of the polycarboxylate water reducer to concrete are more and more prominent due to complex varieties of concrete raw materials in various places nationwide, sand and stone water content fluctuation, temperature change, mixing amount fluctuation and other factors in the production process. Mainly shows that when the polycarboxylic acid water reducer is directly applied to concrete, the sensitivity problems of poor adaptability to cement and mineral admixture, unstable working performance of the concrete, easy segregation, larger slump loss and the like often occur, so that the requirements of a construction site cannot be met; in order to pursue cost performance, most of the polycarboxylic acid additives at present have higher water reducing rate, better slump retaining performance, excellent concrete rheological property and more sensitive mixing amount; in order to meet the requirement of long-distance transportation of concrete on slump retaining, a large amount of slump retaining agent is often added in the compounding process of the additive, so that the defect of concrete reaction hysteresis is easily caused, and popularization and use of the polycarboxylate water reducer are greatly restricted.

In order to reduce the sensitivity of concrete to the environment temperature, single water consumption, water reducing agent mixing amount, cement type and machine-made sand amount, researchers develop a plurality of low-sensitivity polycarboxylate water reducing agents.

CN109312032B discloses a fast low-temperature preparation method of low-dosage sensitive polycarboxylic acid, which comprises the steps of preparing a precursor by initiating free radical polymerization of unsaturated ester macromonomer and unsaturated monomer derivative through photoinitiator under irradiation, and then polymerizing the precursor, unsaturated ether macromonomer, unsaturated monomer derivative and the like through aqueous solution to obtain the product. CN106432628B discloses a low-sensitivity anti-mud ether ester copolymerization type polycarboxylate water reducer and a preparation method thereof, and the polycarboxylate water reducer is prepared by polymerizing 4-hydroxybutyl vinyl polyoxyethylene ether, methoxy polyethylene glycol methacrylate, unsaturated monocarboxylic acid, unsaturated carboxylic ester monomer, dibutyl itaconate and unsaturated ampholytic phosphate with molecular weight of 2000-5000. CN112707667B discloses a low-sensitivity water reducer and a preparation method thereof, comprising EPEG, unsaturated carboxylic acid small monomer, oxidant, reducer, molecular weight regulator and silane coupling agent modified layered calcium aluminum double metal hydroxide component, wherein CaAl-LDH nano-sheets with a large amount of positive charges are crosslinked with low-sensitivity polycarboxylic acid, so that the sensitivity of the polycarboxylic acid to the change of mud content is reduced. CN108559034 discloses an ether low-sensitivity polycarboxylate water reducer and a preparation method thereof, and branched chains are two-end two-stage polyether structures connected by ester groups, so that the sensitivity of products is obviously reduced.

Researchers almost concentrate on preparing a low-sensitivity polycarboxylate water reducer through modification or modification of a polycarboxylate water reducer molecular chain to solve the sensitivity problem of the polycarboxylate water reducer, but functional modification tends to have a certain negative effect or inhibition on the water-reducing and slump-retaining properties of the polycarboxylate.

The CN110885389B of the applicant and the multifunctional concrete water-retaining agent CN202011643536.7 are prepared by a simple method, and indicate that the matching of macromolecules and micromolecules can improve the water retention of concrete and reduce the sensitivity of the water-reducing agent. In the previous application, the applicant has used a stationary reaction and one-pot feeding to control the molecular weight and molecular weight distribution, which, although it is possible to obtain a polymer having a very broad molecular weight distribution, does not allow precise control.

Disclosure of Invention

Aiming at the defects in the prior art, the inventor further designs and researches the concrete admixture sensitive inhibitor, the preparation method and the application.

A sensitive inhibitor for concrete additive is prepared from polyethylene glycol, polyethylene glycol monomethyl ether, acrylic acid, small-molecule monoacid, polymerization inhibitor, catalyst, molecular regulator, trigger and reducer. The molar ratio of polyethylene glycol, polyethylene glycol monomethyl ether, acrylic acid, small molecule monoacid, polymerization inhibitor, catalyst, molecular regulator, initiator and reducer is 0.12-0.3: 0.8-1.6: 2-6: 0.19-0.48: 0.001 to 0.004:0.5 to 1.4: 0.5-1.2: 0.1 to 0.5:0.1 to 0.4.

Preferably, the polyethylene glycol comprises PEG2000, PEG3000, PEG4000, PEG6000, PEG8000, PEG10000, in a molar ratio of PEG2000: PEG3000: PEG4000: PEG6000: PEG8000: PEG10000 = 1:1:1:1:1:1.

preferably, the polyethylene glycol monomethyl ether comprises MPEG200, MPEG350, MPEG400, MPEG500, MPEG750, MPEG1000, MPEG1200, MPEG1500, and the molar ratio of the polyethylene glycol monomethyl ether to the MPEG200 is: MPEG350: MPEG400: MPEG500: MPEG750: MPEG1000: MPEG1200: MPEG1500 = 1:1:1:1:1:1:1:1.

preferably, the small molecule monoacid comprises formic acid, acetic acid, propionic acid, benzoic acid and n-octanoic acid; the molar ratio of formic acid, acetic acid, propionic acid, benzoic acid, n-octanoic acid=1: 1:1:1:1.

preferably, the polymerization inhibitor is ZJ-705, and the catalyst is one of sulfamic acid, p-toluenesulfonic acid and strong acid cation exchange resin 732 type.

Preferably, the molecular regulator is one or more of mercaptoethanol, mercaptoacetic acid, dodecyl mercaptan, mercaptopropionic acid, mercaptopropanol, sodium formate and sodium hypophosphite; the initiator comprises one or more of ammonium persulfate, potassium persulfate, 30% hydrogen peroxide and 30% tertiary butyl hydrogen peroxide; the reducing agent comprises one or more of sodium metabisulfite, L-sodium ascorbate, sodium metabisulfite, E51 and ferrous sulfate.

The preparation method of the concrete admixture sensitivity inhibitor comprises the following steps:

s1, PEG2000, PEG3000, PEG4000, PEG6000, PEG8000 and PEG10000 are mixed according to the mole ratio of PEG2000: PEG3000: PEG4000: PEG6000: PEG8000: PEG10000 = 1:1:1:1:1:1, adding into a reaction kettle, starting stirring, sequentially adding a polymerization inhibitor and a catalyst, and then adding acrylic acid, wherein the mol ratio of the added PEG to the acrylic acid is 1: 1.1-1.6; and heating to 80-90 ℃ for reaction for 4-6h.

S2, dividing the product into 5 parts by weight, respectively reacting with micromolecular monoacids for 4-6 hours at the temperature of 80-90 ℃, and cooling to normal temperature, wherein the mole ratio of PEG to the micromolecular monoacids is 1:0.22 to 0.32.

S3, mixing MPEG200, MPEG350, MPEG400, MPEG500, MPEG750, MPEG1000, MPEG1200 and MPEG1500 according to the molar ratio of MPEG200: MPEG350: MPEG400: MPEG500: MPEG750: MPEG1000: MPEG1200: MPEG1500 = 1:1:1:1:1:1:1:1, adding into a reaction kettle, starting stirring, sequentially adding a polymerization inhibitor and a catalyst, and then adding acrylic acid, wherein the mol ratio of the added PEG to the acrylic acid is 1: 1.1-1.6; heating to 80-90 ℃ to react for 6-8h, and cooling to normal temperature;

s4, dissolving the rest acrylic acid and a reducing agent in deionized water to prepare a solution A;

s5, dissolving the initiator in deionized water to prepare a solution B;

s6, dissolving 1/3 of the product of S1 and 1/3 of the product of S2 in deionized water at normal temperature to prepare a solution C; 1/3 of solution A and 1/3 of solution B are respectively dripped into the stirred solution C, wherein the dripping time of the solution A is 45min, and the dripping time of the solution B is 60min; after the completion, 1/3 of the product of S1 and 1/3 of the product of S2 are added into the solution C, 1/3 of the solution A and 1/3 of the solution B are respectively dripped into the stirred solution C, the dripping time of the solution A is 45min, and the dripping time of the solution B is 60min; then, continuously supplementing 1/3 of the product of S1 and 1/3 of the product of S2 into the solution C, heating to 60-70 ℃, respectively dropwise adding 1/3 of the solution A and 1/3 of the solution B into the stirred solution C, wherein the dropwise adding time of the solution A is 60min, and the dropwise adding time of the solution B is 90min; and (5) continuing to keep the temperature and stir for 1h after the dripping is finished, thus obtaining the concrete admixture sensitive inhibitor with the solid content of 35-38%.

Wherein the mass concentration of the solution A is 10-15%, and the mass concentration of the solution B is 8-10%.

The concrete admixture sensitive inhibitor prepared by the invention can be directly compounded with a polycarboxylic acid water reducer, and the dosage is 10-20 kg/ton (1.6% mixing amount); or directly adding 1 cubic concrete with 0.5-1kg when the concrete is sensitive.

The mechanism of the invention: in the previous researches, the inventor obtains a polymer with very wide molecular weight distribution by using a standing reaction and one-time feeding mode, and the polymer can be isolated without grabbing ground and has good softness under the condition of increasing 20% -50% of reference doping amount, and can still meet the pumping requirement. Based on such theory and facts, the invention aims to design a polymer with wide molecular weight distribution so as to reduce the sensitivity of concrete to the ambient temperature, single water consumption, water reducer doping amount, cement type and machine-made sand consumption.

The standing reaction and the one-time feeding can increase the molecular weight dispersion degree, but the whole reaction is greatly influenced by temperature, reaction environment size, standing time, stirring nodes and raw material quality fluctuation, the whole reaction condition needs repeated fumbling and verification, and the performance stability of the reaction is at risk.

According to the method, the polymers with wide molecular weight distribution are prepared by using the monomer collocations with different molecular weights through a special synthesis process, and the sensitivity of the polycarboxylate water reducer is reduced by using the collocation of macromolecules and small molecules.

The invention uses polyethylene glycol monomethyl ether (MPEG) with molecular weight of 200-1500 and acrylic acid to esterify to form molecules with active double bonds which are uniformly or quantitatively distributed in different molecular weight ranges (100-500, 500-1000, 1000-2000, etc.); polyethylene glycol (PEG) with the molecular weight of 2000-10000 and acrylic acid are utilized to form active double bond molecules which are uniformly or quantitatively distributed in different molecular weight ranges (2000-3000, 3000-4000, 4000-5000, 5000-6000, 6000-8000, 8000-10000 and the like), and meanwhile, acid with different molecular weights is utilized to carry out end-capped esterification (formic acid, acetic acid, propionic acid, benzoic acid and n-octanoic acid) at the other side, so that the hydrophilic performance of monomers and the differentiation of the molecular weights are improved.

In the preparation method S5, the bottom material is added dropwise by 3 times, and the mode of adding the chain transfer agent once causes the polymer of the whole system to also form the difference of molecular weight. The chain transfer agent is added into the bottom material at one time, the chain transfer agent in the earlier stage is excessive, the molecular weight distribution formed by polymerization is uniform, and the molecular weight is small (500-5000); by the middle stage, the chain transfer agent is gradually consumed, and the molecular weight of the polymer is increased (5000-20000); the chain transfer agent is almost consumed in the later period, the chain length of the polymer molecules is increased more rapidly, and a small part of the polymers with small molecular weight can be activated to participate in polymerization, so that the polymers with uneven chain lengths of polymer side chains and a certain amount of distribution of the molecular weight of the main chain in different molecular weight ranges are formed.

The dispersion effect of the polycarboxylate water reducer mainly utilizes the steric hindrance effect and the electrostatic repulsion effect to achieve the effect of dispersing cement particles, and the existence of regular molecular weight distribution and large molecular weight ensures the excellent performance of the polycarboxylate water reducer, but the root of the advantage is the adsorption of the polycarboxylate water reducer molecular chain to cement, and once the external environment is changed (the environment temperature, the water consumption, the water reducer doping amount, the cement and admixture types and sand rate), the adsorption of the polycarboxylate molecular chain is changed, and once the polycarboxylate molecular chain cannot be rapidly adapted to the change, the sensitivity is shown.

The concrete admixture sensitive inhibitor prepared by the invention can make up the defects of molecular weight distribution of the polycarboxylate water reducer. The small molecular weight polymer in the concrete admixture sensitive inhibitor has small molecular weight and high degree of freedom, and can be quickly adsorbed on the surface of cement particles in the early stage of cement dispersion; the polymer with large molecular weight has large steric hindrance and stronger dispersion effect due to large molecular weight; the matching of the macromolecules and the small molecules forms continuous adsorption, and polymers with different molecular weights can coordinate the adsorption effect of the materials and the environment mutation to form a stable and continuous release state, so that the sensitivity of the water reducer is reduced.

The beneficial effects of the invention are as follows:

the prepared concrete admixture sensitivity inhibitor can reduce the sensitivity of various factors such as the mixing amount, the type, the water consumption, the temperature and the raw materials of the water reducer.

Examples of the embodiments

The technical scheme of the invention is further described and explained through the following specific examples.

Example 1

0.005mol PEG2000,0.005mol PEG3000,0.005mol PEG4000,0.005mol PEG6000,0.005mol PEG8000,0.005mol PEG10000 is put into a reaction kettle, stirring is started, 0.0001mol of ZJ-705 and 0.07mol of sulfamic acid are sequentially put into the reaction kettle, then 0.033mol of acrylic acid is put into the reaction kettle, the temperature is raised to 80 ℃ for 6 hours, 5 parts of the reaction kettle are divided into 5 parts by weight, and the reaction kettle is continuously reacted with 0.0066mol of formic acid, 0.0066mol of acetic acid, 0.0066mol of propionic acid, 0.0066mol of benzoic acid and 0.0066mol of n-octanoic acid for 6 hours under the environment of 80 ℃, and the reaction kettle is cooled to normal temperature.

0.02mol MPEG200,0.02mol MPEG350,0.02mol MPEG400,0.02mol MPEG500,0.02mol MPEG750,0.02mol MPEG1000,0.02mol MPEG1200,0.02mol MPEG1500 is put into a reaction kettle, stirring is started, 0.0002 ZJ-705 and 0.054mol of sulfamic acid are sequentially put into the reaction kettle, then 0.176mol of acrylic acid is put into the reaction kettle, the temperature is raised to 90 ℃ for reaction for 6 hours, and the reaction kettle is cooled to normal temperature.

Dissolving 0.2mol of acrylic acid and 0.01mol of hanging white block in 90g of deionized water to prepare a solution A;

dissolving 0.03mol of ammonium persulfate in 62g of deionized water to prepare a solution B;

at normal temperature, 1/3 mass of the product of S1, 1/3 mass of the product of S2, and 0.1mol of mercaptoethanol were dissolved in 477g of deionized water to prepare a C solution. 1/3 of the solution A and 1/3 of the solution B are respectively added into the stirred solution C in a dropwise manner for 45min and 60min. After the completion, 1/3 of the product of S1 and 1/3 of the product of S2 are added into the solution C, 1/3 of the solution A and 1/3 of the solution B are respectively added into the stirred solution C in a dropwise manner, the dropwise addition time of the solution A is 45min, and the dropwise addition time of the solution B is 60min. Then, continuously supplementing 1/3 of the product of S1 and 1/3 of the product of S2 into the solution C, heating to 60 ℃, respectively dropwise adding 1/3 of the solution A and 1/3 of the solution B into the stirred solution C, wherein the dropwise adding time of the solution A is 60min, and the dropwise adding time of the solution B is 90min. And (5) continuing to keep the temperature and stir for 1h after the dripping is finished, thus obtaining the concrete admixture sensitive inhibitor.

Example 2

0.005mol PEG2000,0.005mol PEG3000,0.005mol PEG4000,0.005mol PEG6000,0.005mol PEG8000,0.005mol PEG10000 is put into a reaction kettle, stirring is started, 0.0002mol of ZJ-705 and 0.04mol of p-toluenesulfonic acid are sequentially put into the reaction kettle, then 0.048mol of acrylic acid is put into the reaction kettle, the temperature is raised to 90 ℃ for reaction for 6 hours, 5 parts of the reaction kettle are divided into 5 parts by weight, and the reaction kettle is continuously reacted with 0.007mol of formic acid, 0.007mol of acetic acid, 0.007mol of propionic acid, 0.007mol of benzoic acid and 0.007mol of n-octanoic acid for 6 hours under the environment of 90 ℃ respectively, and the reaction kettle is cooled to normal temperature.

0.02mol MPEG200,0.02mol MPEG350,0.02mol MPEG400,0.02mol MPEG500,0.02mol MPEG750,0.02mol MPEG1000,0.02mol MPEG1200,0.02mol MPEG1500 is put into a reaction kettle, stirring is started, 0.0002 ZJ-705 and 0.056mol of sulfamic acid are sequentially put into the reaction kettle, then 0.25mol of acrylic acid is put into the reaction kettle, the temperature is raised to 80 ℃ for reaction for 8 hours, and the reaction kettle is cooled to normal temperature.

0.3mol of acrylic acid, 0.015mol of L-sodium ascorbate and 0.005 ferrous sulfate are dissolved in 144g of deionized water to prepare solution A;

dissolving 0.02mol of potassium persulfate in 53g of deionized water to prepare a solution B;

1/3 mass of the S1 product, 1/3 mass of the S2 product, 0.05mol of thioglycolic acid, and 0.05mol of mercaptopropanol were dissolved in 442g of deionized water at room temperature to prepare a C solution. 1/3 of the solution A and 1/3 of the solution B are respectively added into the stirred solution C in a dropwise manner for 45min and 60min. After the completion, 1/3 of the product of S1 and 1/3 of the product of S2 are added into the solution C, 1/3 of the solution A and 1/3 of the solution B are respectively added into the stirred solution C in a dropwise manner, the dropwise addition time of the solution A is 45min, and the dropwise addition time of the solution B is 60min. Then, continuously supplementing 1/3 of the product of S1 and 1/3 of the product of S2 into the solution C, heating to 60 ℃, respectively dropwise adding 1/3 of the solution A and 1/3 of the solution B into the stirred solution C, wherein the dropwise adding time of the solution A is 60min, and the dropwise adding time of the solution B is 90min. And (5) continuing to keep the temperature and stir for 1h after the dripping is finished, thus obtaining the concrete admixture sensitive inhibitor.

Example 3

0.005mol PEG2000,0.005mol PEG3000,0.005mol PEG4000,0.005mol PEG6000,0.005mol PEG8000,0.005mol PEG10000 is put into a reaction kettle, stirring is started, 0.0003mol of ZJ-705 and 0.04mol of p-toluenesulfonic acid are sequentially put into the reaction kettle, then 0.036mol of acrylic acid is put into the reaction kettle, the temperature is raised to 90 ℃ for reaction for 6 hours, 5 parts of the reaction kettle are divided into 5 parts by weight, and the reaction kettle is continuously reacted with 0.0096mol of formic acid, 0.0096mol of acetic acid, 0.0096mol of propionic acid, 0.0096mol of benzoic acid and 0.0096mol of n-octanoic acid for 6 hours at the temperature of 90 ℃ respectively, and the reaction kettle is cooled to normal temperature.

0.01mol MPEG200,0.01mol MPEG350,0.01mol MPEG400,0.01mol MPEG500,0.01mol MPEG750,0.01mol MPEG1000,0.01mol MPEG1200,0.01mol MPEG1500 is put into a reaction kettle, stirring is started, 0.0001 ZJ-705 and 0.1mol of strong acid cation exchange resin 732 type are sequentially put into the reaction kettle, then 0.01mol of acrylic acid is put into the reaction kettle, the temperature is raised to 90 ℃ for reaction for 8 hours, the reaction kettle is cooled to normal temperature, and the catalyst is filtered.

0.4mol of acrylic acid and 0.04mol of sodium metabisulfite are dissolved in 196g of deionized water to prepare solution A;

dissolving 0.05mol of hydrogen peroxide (30%) in 65g of deionized water to prepare a solution B;

at normal temperature, 1/3 mass of the S1 product, 1/3 mass of the S2 product, and 0.05mol of dodecyl mercaptan were dissolved in 275g of deionized water to prepare a C solution. 1/3 of the solution A and 1/3 of the solution B are respectively added into the stirred solution C in a dropwise manner for 45min and 60min. After the completion, 1/3 of the product of S1 and 1/3 of the product of S2 are added into the solution C, 1/3 of the solution A and 1/3 of the solution B are respectively added into the stirred solution C in a dropwise manner, the dropwise addition time of the solution A is 45min, and the dropwise addition time of the solution B is 60min. Then, continuously supplementing 1/3 of the product of S1 and 1/3 of the product of S2 into the solution C, heating to 60 ℃, respectively dropwise adding 1/3 of the solution A and 1/3 of the solution B into the stirred solution C, wherein the dropwise adding time of the solution A is 60min, and the dropwise adding time of the solution B is 90min. And (5) continuing to keep the temperature and stir for 1h after the dripping is finished, thus obtaining the concrete admixture sensitive inhibitor.

Example 4

0.002mol PEG2000,0.002mol PEG3000,0.002mol PEG4000,0.002mol PEG6000,0.002mol PEG8000,0.002mol PEG10000 is put into a reaction kettle, stirring is started, 0.0001mol of ZJ-705 and 0.015mol of p-toluenesulfonic acid are sequentially put into the reaction kettle, then 0.015mol of acrylic acid is put into the reaction kettle, the temperature is raised to 90 ℃ for reaction for 8 hours, 5 parts of the reaction kettle are divided into 5 parts by weight, and the reaction kettle is continuously reacted with 0.0038mol of formic acid, 0.0038mol of acetic acid, 0.0038mol of propionic acid, 0.0038mol of benzoic acid and 0.0038mol of n-octanoic acid for 8 hours under the environment of 90 ℃, and the reaction kettle is cooled to normal temperature.

0.01mol MPEG200,0.01mol MPEG350,0.01mol MPEG400,0.01mol MPEG500,0.01mol MPEG750,0.01mol MPEG1000,0.01mol MPEG1200,0.01mol MPEG1500 is put into a reaction kettle, stirring is started, 0.0001 ZJ-705 and 0.035mol of sulfamic acid are sequentially put into the reaction kettle, then 0.088mol of acrylic acid is put into the reaction kettle, the temperature is raised to 90 ℃ for reaction for 8 hours, the reaction kettle is cooled to normal temperature, and the catalyst is filtered.

A solution A was prepared by dissolving 0.1mol of acrylic acid and 0.02mol of E51 in 96g of deionized water;

dissolving 0.01mol of tert-butyl hydroperoxide (30%) in 27g of deionized water to prepare a solution B;

at normal temperature, 1/3 mass of the product of S1, 1/3 mass of the product of S2, and 0.12mol of sodium hypophosphite were dissolved in 182g of deionized water to prepare a C solution. 1/3 of the solution A and 1/3 of the solution B are respectively added into the stirred solution C in a dropwise manner for 45min and 60min. After the completion, 1/3 of the product of S1 and 1/3 of the product of S2 are added into the solution C, 1/3 of the solution A and 1/3 of the solution B are respectively added into the stirred solution C in a dropwise manner, the dropwise addition time of the solution A is 45min, and the dropwise addition time of the solution B is 60min. Then, continuously supplementing 1/3 of the product of S1 and 1/3 of the product of S2 into the solution C, heating to 60 ℃, respectively dropwise adding 1/3 of the solution A and 1/3 of the solution B into the stirred solution C, wherein the dropwise adding time of the solution A is 60min, and the dropwise adding time of the solution B is 90min. And (5) continuing to keep the temperature and stir for 1h after the dripping is finished, thus obtaining the concrete admixture sensitive inhibitor.

The sensitivity of the concrete admixture sensitivity inhibitor to various factors including the water reducing agent doping amount, water consumption, temperature and raw materials is tested. The specific test method is as follows:

TABLE 1 concrete mix ratio

(1) Evaluation of sensitivity to blending amount

The concrete mixing ratio is kept unchanged, and the sensitivity is evaluated by adjusting the mixing amount of the additive. For comparison performance, 3 different types of polycarboxylate water reducers were used for verification, which were JS-1, JS-2 and JS-3, respectively.

TABLE 2 concrete expansion at different doping levels

As can be seen from the data of Table 2, the doping amount of the external JS-1, JS-2 and JS-3 water reducers is 1.8%, and the expansion degree of the external JS-1, JS-2 and JS-3 water reducers exceeds 620mm; when the mixing amount is 2.0%, the expansion degree is more than 670, and serious bleeding segregation occurs. 15 kg of the water reducer of the embodiment 1 to the embodiment 4 are compounded in the JS-1 water reducer, and it can be obviously seen that the water reducer is unsaturated (the expansion degree is lower than 580 mm) when the mixing amount is low, the embodiment 1 to the embodiment 4 has the function of assisting water reduction, and the dispersion of cement is promoted; the use of examples 1-4 can increase the mixing amount width of the water reducer at high mixing amount, and the concrete expansion degree is not greatly changed under the condition of increasing the mixing amount by 4 (1.8% -2.2%), so that the sensitivity of the mixing amount change of the water reducer is reduced.

(2) Evaluation of Water consumption sensitivity

The admixture mixing amount is kept to be 1.6 percent, the concrete mixing ratio is kept unchanged, the water consumption of the concrete mixing ratio is adjusted, and the unit water consumption is increased by 15 kg. And calculating the difference value of the concrete expansion degree under the two water consumption amounts, wherein the smaller difference value is the less sensitive to the water consumption amount.

TABLE 3 expansion and differential values in concrete with different water usage

As can be seen from Table 3, the difference of concrete expansion degree is not large and the sensitivity difference is not large under the condition that the unit water consumption is increased by the outsourcing JS-1, JS-2 and JS-3 water reducers; 15 kg of the examples 1-4 are compounded in the JS-1 water reducer, and it can be obviously seen that the expansion degree difference of the examples 1-4 is lower than that of the JS-1, JS-2 and JS-3 water reducers.

(3) Evaluation of sensitivity to raw materials

The mixing ratio of the admixture is kept unchanged by 1.6%, factors such as cement, sand and the like are replaced, the non-replaced raw materials and the expansion degree corresponding to the replaced raw materials are tested according to a testing method for evaluating the mixing sensitivity, and the absolute value of the difference between the expansion degree when the raw materials are replaced and the expansion degree when the raw materials are not replaced is calculated according to the raw material sensitivity = the expansion degree value when the raw materials are replaced-the expansion degree value when the raw materials are not replaced, wherein the smaller the value is, the less sensitive to the raw materials is indicated.

TABLE 4 spread and differential in different types of sand

As can be seen from Table 4, the initial expansion degree of the purchased JS-1 water reducer to the concrete using different types of sand is different, and the expansion degree of the concrete using the river sand is smaller than that of the concrete using the machine-made sand, because the proportion and difference of the river sand and the poor adaptability of the JS-1 water reducer to the river sand lead to the poor water-retaining and slurry-extracting performance of the river sand, so that the condition of small expansion degree and bleeding occurs; 15 kg of the examples 1-4 are compounded in the JS-1 water reducer, and it can be obviously seen that the expansion degree difference is smaller than that of the JS-1 water reducer alone, and the expansion degree of concrete using river sand is larger than that of concrete using machine-made sand, probably because the sensitivity inhibitor of the concrete admixture prepared by the invention improves the water retention performance of the concrete through the molecular weight adjustment, the grading adjustment and the system uniformity.

(4) Evaluation of the amount of Compound

Table 5 additive formulations

As can be seen from the data in Table 5, the concrete admixture sensitivity inhibitor prepared by the invention can be directly compounded with the polycarboxylic acid water reducer, and the dosage is 10-20 kg/ton (1.6% mixing amount). When the dosage of the example 1 is 5kg, the doping amount is increased from 1.6% to 1.8%, and the expansion degree is increased by 50mm; when the dosage of the embodiment 1 is 10-20kg, the dosage is increased from 1.6% to 1.8%, the expansion degree is increased by about 10mm, and the concrete loss with time is not affected; when the dosage of the concrete admixture prepared by the method is 25kg, the dosage is increased from 1.6% to 1.8%, and the expansion degree is reduced by 40mm, which proves that the concrete admixture prepared by the method has adverse effects on the performance of the polycarboxylate water reducer after the dosage of the sensitive inhibitor is too high.

(5) Directly adding dosage

TABLE 6 direct addition level

As can be seen from the data in Table 6, 1 cubic concrete was added with 0.5-1kg directly when the concrete was sensitive. The dosage is too low, the sensitive inhibition effect is not obvious, and the excessive dosage can produce side effects and have adverse effects on the performance of the polycarboxylate water reducer.

Claims (10)

1. A concrete admixture sensitivity inhibitor, characterized by comprising: polyethylene glycol, polyethylene glycol monomethyl ether, acrylic acid, small molecule monoacid, polymerization inhibitor, catalyst, molecular regulator, initiator and reducing agent.

2. The concrete admixture sensitivity inhibitor according to claim 1, wherein: the molar ratio of polyethylene glycol, polyethylene glycol monomethyl ether, acrylic acid, small molecule monoacid, polymerization inhibitor, catalyst, molecular regulator, initiator and reducer is 0.12-0.3: 0.8-1.6: 2-6: 0.19-0.48: 0.001 to 0.004:0.5 to 1.4: 0.5-1.2: 0.1 to 0.5:0.1 to 0.4.

3. The concrete admixture sensitivity inhibitor according to claim 1, wherein said polyethylene glycol comprises: polyethylene glycol having an average molecular weight of 2000, polyethylene glycol having an average molecular weight of 3000, polyethylene glycol having an average molecular weight of 4000, polyethylene glycol having an average molecular weight of 6000, polyethylene glycol having an average molecular weight of 8000, polyethylene glycol having an average molecular weight of 10000; the molar ratio of PEG2000: PEG3000: PEG4000: PEG6000: PEG8000: PEG10000 is 1:1:1:1:1:1.

4. the concrete admixture sensitivity inhibitor according to claim 1, wherein said polyethylene glycol monomethyl ether comprises: polyethylene glycol monomethyl ether having an average molecular weight of 200, polyethylene glycol monomethyl ether having an average molecular weight of 350, polyethylene glycol monomethyl ether having an average molecular weight of 400, polyethylene glycol monomethyl ether having an average molecular weight of 500, polyethylene glycol monomethyl ether having an average molecular weight of 750, polyethylene glycol monomethyl ether having an average molecular weight of 1000, polyethylene glycol monomethyl ether having an average molecular weight of 1200, polyethylene glycol monomethyl ether having an average molecular weight of 1500; the molar ratio of MPEG200: MPEG350: MPEG400: MPEG500: MPEG750: MPEG1000: MPEG1200: MPEG1500 is 1:1:1:1:1:1:1:1.

5. the concrete admixture sensitivity inhibitor according to claim 1, wherein said small molecule monoacid comprises: formic acid, acetic acid, propionic acid, benzoic acid and n-octanoic acid, wherein the molar ratio is as follows: formic acid: acetic acid: propionic acid: benzoic acid: n-octanoic acid is 1:1:1:1:1.

6. the concrete admixture sensitivity inhibitor according to claim 1, wherein: the polymerization inhibitor is as follows: the catalyst is one of sulfamic acid, p-toluenesulfonic acid and strong acid cation exchange resin 732 type; the molecular regulator is as follows: one or more of mercaptoethanol, mercaptoacetic acid, dodecyl mercaptan, mercaptopropionic acid, mercaptopropanol, sodium formate and sodium hypophosphite; the initiator comprises: one or more of ammonium persulfate, potassium persulfate, 30% hydrogen peroxide and 30% tertiary butyl hydroperoxide; the reducing agent comprises: one or more of sodium ascorbate, sodium metabisulfite, E51 and ferrous sulfate.

7. The preparation method of the concrete admixture sensitivity inhibitor is characterized by comprising the following steps of:

s1, PEG2000, PEG3000, PEG4000, PEG6000, PEG8000 and PEG10000 are mixed according to the mole ratio of PEG2000: PEG3000: PEG4000: PEG6000: PEG8000: PEG10000 = 1:1:1:1:1:1, adding into a reaction kettle, starting stirring, sequentially adding a polymerization inhibitor and a catalyst, and then adding acrylic acid, wherein the mol ratio of the added PEG to the acrylic acid is 1: 1.1-1.6; heating to 80-90 ℃ to react for 4-6h;

s2, dividing the product into 5 parts by weight, respectively reacting with micromolecular monoacids for 4-6 hours at the temperature of 80-90 ℃, and cooling to normal temperature, wherein the mole ratio of PEG to the micromolecular monoacids is 1: 0.22-0.32;

s3, mixing MPEG200, MPEG350, MPEG400, MPEG500, MPEG750, MPEG1000, MPEG1200 and MPEG1500 according to the molar ratio of MPEG200: MPEG350: MPEG400: MPEG500: MPEG750: MPEG1000: MPEG1200: MPEG1500 = 1:1:1:1:1:1:1:1, adding into a reaction kettle, starting stirring, sequentially adding a polymerization inhibitor and a catalyst, and then adding acrylic acid, wherein the mol ratio of the added PEG to the acrylic acid is 1: 1.1-1.6; heating to 80-90 ℃ to react for 6-8h, and cooling to normal temperature;

s4, dissolving the rest acrylic acid and a reducing agent in deionized water to prepare a solution A;

s5, dissolving the initiator in deionized water to prepare a solution B;

s6, dissolving 1/3 of the product of S1 and 1/3 of the product of S2 in deionized water at normal temperature to prepare a solution C; 1/3 of solution A and 1/3 of solution B are respectively dripped into the stirred solution C, wherein the dripping time of the solution A is 45min, and the dripping time of the solution B is 60min; after the completion, 1/3 of the product of S1 and 1/3 of the product of S2 are added into the solution C, 1/3 of the solution A and 1/3 of the solution B are respectively dripped into the stirred solution C, the dripping time of the solution A is 45min, and the dripping time of the solution B is 60min; then, continuously supplementing 1/3 of the product of S1 and 1/3 of the product of S2 into the solution C, heating to 60-70 ℃, respectively dropwise adding 1/3 of the solution A and 1/3 of the solution B into the stirred solution C, wherein the dropwise adding time of the solution A is 60min, and the dropwise adding time of the solution B is 90min; and (5) continuing to keep the temperature and stir for 1h after the dripping is finished, thus obtaining the concrete admixture sensitive inhibitor with the solid content of 35-38%.

8. The method for preparing the concrete admixture sensitivity inhibitor according to claim 7, wherein: the mass concentration of the solution A is 10-15%, and the mass concentration of the solution B is 8-10%.

9. An application of a concrete admixture sensitivity inhibitor is characterized in that: the concrete admixture sensitive inhibitor prepared by the invention is directly compounded with the polycarboxylic acid water reducer, and the dosage is 1.6 percent, and the mixing amount is 10-20 kg/ton.

10. An application of a concrete admixture sensitivity inhibitor is characterized in that: when the concrete is sensitive, the sensitive inhibitor of the concrete admixture prepared by the invention is directly added, and 0.5-1kg of 1 cubic concrete is added.