A concrete viscosity modifier, its preparation method and application

Abstract

The present application relates to the field of concrete, and discloses a preparation method of a concrete viscosity modifier, comprising the following steps: dissolving concentrated nitric acid aqueous solution in deionized water, adding multi-walled carbon nanotubes, heating and reacting to obtain carboxylated carbon nanotubes; dispersing the carboxylated carbon nanotubes in deionized water to obtain a carboxylated carbon nanotube water mixture; dispersing hydroxyethyl cellulose in deionized water to obtain a hydroxyethyl cellulose water mixture; adding the carboxylated carbon nanotube water mixture into the hydroxyethyl cellulose water mixture, and then adding p-toluenesulfonic acid, and reacting to obtain the concrete viscosity modifier. The present application also discloses a concrete and a preparation method thereof. The prepared concrete viscosity modifier can increase the viscosity of the concrete while taking into account the fluidity of the concrete, and increase the workability of the concrete.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of concrete, in particular to a concrete viscosity modifier, a preparation method and application thereof. BACKGROUND

[0002] With the rapid construction of economic highways, railways, hydropower stations, civil buildings and other projects, higher requirements are put forward for the performance of high-performance concrete. However, in the actual application process, due to the unstable composition of cement, poor adaptability of admixtures to cement, low content of powder and mud in sand and stone and other coarse and fine aggregates and other factors, the cohesiveness of concrete is poor, and phenomena such as segregation and bleeding are prone to occur.

[0003] In order to solve the problems of segregation, bleeding and poor workability of concrete, viscosity modifiers are often added in construction to increase the cohesiveness and water retention performance of concrete, avoid the phenomenon of "slurry and aggregate separation", improve the homogeneity of concrete slurry and improve the workability of concrete. However, most thickeners, such as cellulose, xanthan gum, sodium alginate, polyvinyl alcohol, polyacryl, EVA powder, sodium polyacrylate and the like, have incompatibility problems with polycarboxylic acid water reducing agent, and the air entraining effect of the above thickeners will also lead to low later strength of concrete.

[0004] Patent CN 113683341A discloses a concrete viscosity modifier and a preparation method thereof. The viscosity modifier comprises the following main components and weight fractions: branched starch 0.1-8 parts, butanediol 1-8 parts, dipropylene glycol dimethyl ether 1-12 parts, xanthan gum 10-40 parts, cyclic dextrin 10-20 parts, sodium polyacrylate 0.2-0.8 parts, carbamide 0.1-0.5 parts, sodium hydroxide 0.1-10 parts, and deionized water 900.7-977.5 parts. The concrete prepared by the present application has improved viscosity, but when the viscosity is too large, the fluidity of the concrete will decrease, and the viscosity and fluidity of the concrete cannot be better coordinated. SUMMARY

[0005] In order to solve the above technical problems, the present application provides a preparation method of a concrete viscosity modifier, which is prepared by the following steps:

[0006] Step (1) mixing concentrated nitric acid aqueous solution and deionized water, adding multi-walled carbon nanotubes, heating, and obtaining carboxylated carbon nanotubes by reaction;

[0007] Step (2) dispersing the carboxylated carbon nanotubes in deionized water to obtain a carboxylated carbon nanotube water mixture system; dispersing hydroxyethyl cellulose in deionized water to obtain a hydroxyethyl cellulose water mixture system;

[0008] Step (3) adds the carboxylated carbon nanotube water mixture into the hydroxyethyl cellulose water mixture, and then adds p-toluenesulfonic acid and heats to obtain the concrete viscosity modifier.

[0009] Preferably, the volume ratio of the concentrated nitric acid aqueous solution to the deionized water in step (1) is 3:1, the tube diameter of the multi-walled carbon nanotube is 100-150 nm, and the mass-volume ratio of the multi-walled carbon nanotube to the concentrated nitric acid aqueous solution is 0.01 g / mL.

[0010] Preferably, the reaction conditions of step (1) are as follows: heating to 120°C, reaction at a rotation speed of 3000-5000 r / min, and condensation reflux for 24 h to obtain the reaction product; the reaction product is first washed by centrifugation with ethanol for 3 times, and then washed by centrifugation with deionized water until the pH value of the liquid after centrifugation is 7, and the centrifugation product is obtained by removing the liquid after centrifugation, wherein the centrifugation condition of each time is as follows: centrifugation at a rotation speed of 3000-5000 r / min for 20-30 min; the centrifugation product is dried at 70°C for 48 h, and then ground to obtain the carboxylated carbon nanotube.

[0011] Preferably, step (2) disperses the carboxylated carbon nanotube with deionized water under the condition of a frequency of 50 KHz for 0.5-6 h to obtain the carboxylated carbon nanotube water mixture, wherein the mass fraction of the carboxylated carbon nanotube in the carboxylated carbon nanotube water mixture is 0.1%-3%; and disperses the hydroxyethyl cellulose with deionized water under the condition of a frequency of 50 KHz for 0.5-3 h to obtain the hydroxyethyl cellulose water mixture, wherein the mass fraction of the hydroxyethyl cellulose in the hydroxyethyl cellulose water mixture is 0.1%-1.5%.

[0012] Preferably, step (3) adds the carboxylated carbon nanotube water mixture into the hydroxyethyl cellulose water mixture, and then adds p-toluenesulfonic acid and heats to 105-120°C for 2-3 h to obtain the reaction liquid, wherein the volume ratio of the carboxylated carbon nanotube water mixture to the hydroxyethyl cellulose water mixture is 1:3-8, and the mass-volume ratio of the p-toluenesulfonic acid to the carboxylated carbon nanotube water mixture is 0.2-0.4 mg / mL; centrifuges the reaction liquid at a rotation speed of 4000 r / min for 30 min to obtain the centrifugation product, and then washes the centrifugation product with water, 5 wt% sodium bicarbonate aqueous solution and water in sequence, and dries to obtain the concrete viscosity modifier.

[0013] Compared with the prior art, the present application has the following beneficial effects:

[0014] (1) The concrete viscosity modifier of the present application has good compatibility with water reducing agent by the combination of carboxyl in carboxylated multi-walled carbon nanotubes and hydroxyl in hydroxyethyl cellulose, and at the same time, the molecular chain is increased and the molecular chains are intertwined with each other to form a network structure, preventing the migration of free water; the hydrophobic backbone in cellulose is combined with surrounding water molecules through hydrogen bonds, increasing the fluid volume of the polymer itself and reducing the space for free movement of particles, thereby increasing the viscosity of the system; on the other hand, due to the porous structure of carbon nanotubes, concrete particles will be adsorbed on the surface of the polymer, resulting in an increase in the diameter of the particles and an increase in the resistance to the migration of the polymer chain; in addition, the carboxyl groups in the carboxylated carbon nanotubes that are not combined with hydroxyl groups can also form hydrogen bonds with water; a variety of factors together ultimately enhance the viscosity of the concrete system.

[0015] (2) Most viscosity modifiers tend to greatly reduce the fluidity of the system while increasing the viscosity of the concrete, and how to better balance the viscosity and fluidity of the concrete is a big problem. In the present application, carbon nanotubes are introduced into the viscosity modifier, which has high strength and toughness, and is not prone to breakage under heavy stress. In addition, due to the tubular structure of carbon nanotubes, the small aspect ratio of carbon nanotubes can roll, which can enhance the viscosity of the concrete while minimizing the impact on its fluidity and increase the workability of the concrete. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a preparation schematic diagram of the concrete viscosity modifier of the present application.

[0017] Figure 2 is a comparison chart of the slump test of the concrete of the present application and the comparative example.

[0018] Figure 3 is a comparison chart of the spreadability test of the concrete of the present application and the comparative example.

[0019] Figure 4 is a comparison chart of the compressive strength test of the concrete of the present application and the comparative example. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0021] Example 1

[0022] The embodiment discloses a preparation method of concrete, and comprises the following steps:

[0023] (1) mixing concentrated nitric acid aqueous solution and deionized water according to a volume ratio of 3:1, adding multi-walled carbon nanotubes with a pipe diameter of 100 nm, heating to 120 DEG C, reacting at a rotating speed of 3000 r / min, and condensing backflow for 24 h to obtain a reaction product, wherein the mass-volume ratio of the multi-walled carbon nanotubes to the concentrated nitric acid aqueous solution is 0.01 g / mL; centrifuging and washing the reaction product with ethanol for 3 times, and then centrifuging and washing with deionized water until the pH value of the liquid after centrifugation is 7, removing the liquid after centrifugation to obtain a centrifuged product, wherein the centrifugation condition is that centrifuging at a rotating speed of 3000 r / min for 20 min; drying the centrifuged product at 70 DEG C for 48 h, grinding, and obtaining carboxylated carbon nanotubes.

[0024] (2) ultrasonically dispersing the carboxylated carbon nanotubes and deionized water under the condition of a frequency of 50 KHz for 0.5 h to obtain a carboxylated carbon nanotube water mixture, wherein the mass fraction of the carboxylated carbon nanotubes in the carboxylated carbon nanotube water mixture is 0.1%; ultrasonically dispersing hydroxyethyl cellulose and deionized water under the condition of a frequency of 50 KHz for 0.5 h to obtain a hydroxyethyl cellulose water mixture, wherein the mass fraction of the hydroxyethyl cellulose in the hydroxyethyl cellulose water mixture is 0.1%.

[0025] (3) adding the carboxylated carbon nanotube water mixture into the hydroxyethyl cellulose water mixture, adding p-toluenesulfonic acid, heating to 105 DEG C, and reacting for 2 h to obtain a reaction liquid, wherein the volume ratio of the carboxylated carbon nanotube water mixture to the hydroxyethyl cellulose water mixture is 1:3, and the mass-volume ratio of the p-toluenesulfonic acid to the carboxylated carbon nanotube water mixture is 0.2 mg / mL; centrifuging the reaction liquid at a rotating speed of 4000 r / min for 30 min to obtain a centrifuged product, washing the centrifuged product with water, 5wt% sodium bicarbonate aqueous solution and water in sequence, and drying to obtain a concrete viscosity modifier.

[0026] (4) mixing cement, fly ash, mineral powder, sand, stone, water, the concrete viscosity modifier and water reducing agent according to a mass ratio of 250:60:40:830:1035:160:2:0.5 to prepare concrete.

[0027] Embodiment 2

[0028] The embodiment discloses a preparation method of concrete, and comprises the following steps:

[0029] (1) mixing concentrated nitric acid aqueous solution and deionized water according to a volume ratio of 3:1, adding multi-walled carbon nanotubes with a pipe diameter of 150 nm, heating to 120°C, reacting at a rotation speed of 5000 r / min, and condensing reflux for 24 h to obtain a reaction product, wherein the mass-volume ratio of the multi-walled carbon nanotubes to the concentrated nitric acid aqueous solution is 0.01 g / mL; centrifuging and washing the reaction product with ethanol for 3 times, and then centrifuging and washing with deionized water until the pH value of the liquid after centrifugation is 7, removing the liquid after centrifugation to obtain a centrifuged product, wherein the centrifugation condition of each time is: centrifuging at a rotation speed of 5000 r / min for 30 min; drying the centrifuged product at 70°C for 48 h, grinding, and obtaining carboxylated carbon nanotubes.

[0030] (2) ultrasonically dispersing the carboxylated carbon nanotubes with deionized water under the condition of a frequency of 50 KHz for 6 h to obtain a carboxylated carbon nanotube water mixture, wherein the mass fraction of the carboxylated carbon nanotubes in the carboxylated carbon nanotube water mixture is 3%; ultrasonically dispersing hydroxyethyl cellulose with deionized water under the condition of a frequency of 50 KHz for 3 h to obtain a hydroxyethyl cellulose water mixture, wherein the mass fraction of the hydroxyethyl cellulose in the hydroxyethyl cellulose water mixture is 1.5%.

[0031] (3) adding the carboxylated carbon nanotube water mixture into the hydroxyethyl cellulose water mixture, adding p-toluenesulfonic acid, heating to 120°C, and reacting for 3 h to obtain a reaction liquid, wherein the volume ratio of the carboxylated carbon nanotube water mixture to the hydroxyethyl cellulose water mixture is 1:8, and the mass-volume ratio of the p-toluenesulfonic acid to the carboxylated carbon nanotube water mixture is 0.4 mg / mL; centrifuging the reaction liquid at a rotation speed of 4000 r / min for 30 min to obtain a centrifuged product, washing the centrifuged product with water, 5 wt% sodium bicarbonate aqueous solution and water in sequence, and drying to obtain a concrete viscosity modifier.

[0032] (4) mixing cement, fly ash, mineral powder, sand, stone, water, the concrete viscosity modifier and water reducing agent according to a mass ratio of 250:60:40:830:1035:160:10:2.5 to prepare concrete.

[0033] Example 3

[0034] The embodiment discloses a preparation method of concrete, which is prepared by the following steps:

[0035] (1) mixing concentrated nitric acid aqueous solution and deionized water according to a volume ratio of 3:1, adding multi-walled carbon nanotubes with a tube diameter of 120 nm, heating to 120℃, reacting at a rotation speed of 4000 r / min, and condensing reflux for 24 h to obtain a reaction product, wherein the mass-volume ratio of the multi-walled carbon nanotubes to the concentrated nitric acid aqueous solution is 0.01 g / mL; centrifuging and washing the reaction product with ethanol for 3 times, and then centrifuging and washing with deionized water until the pH value of the liquid after centrifugation is 7, removing the liquid after centrifugation to obtain a centrifuged product, wherein the centrifugation condition of each time is centrifuging at a rotation speed of 4000 r / min for 20 min; drying the centrifuged product at 70℃ for 48 h, grinding, and obtaining carboxylated carbon nanotubes.

[0036] (2) ultrasonically dispersing the carboxylated carbon nanotubes with deionized water under a frequency of 50 KHz for 5 h to obtain a carboxylated carbon nanotube water mixture, wherein the mass fraction of the carboxylated carbon nanotubes in the carboxylated carbon nanotube water mixture is 1.5%; ultrasonically dispersing hydroxyethyl cellulose with deionized water under a frequency of 50 KHz for 1.5 h to obtain a hydroxyethyl cellulose water mixture, wherein the mass fraction of the hydroxyethyl cellulose in the hydroxyethyl cellulose water mixture is 1%.

[0037] (3) adding the carboxylated carbon nanotube water mixture into the hydroxyethyl cellulose water mixture, adding p-toluenesulfonic acid, heating to 115℃, and reacting for 2.5 h to obtain a reaction liquid, wherein the volume ratio of the carboxylated carbon nanotube water mixture to the hydroxyethyl cellulose water mixture is 1:5, and the mass-volume ratio of the p-toluenesulfonic acid to the carboxylated carbon nanotube water mixture is 0.3 mg / mL; centrifuging the reaction liquid at a rotation speed of 4000 r / min for 30 min to obtain a centrifuged product, washing the centrifuged product with water, 5 wt% sodium bicarbonate aqueous solution and water in sequence, and drying to obtain a concrete viscosity modifier.

[0038] (4) mixing cement, fly ash, mineral powder, sand, stone, water, the concrete viscosity modifier and water reducing agent according to a mass ratio of 250:60:40:830:1035:160:6:1.5 to prepare concrete.

[0039] Example 4

[0040] The embodiment discloses a preparation method of concrete, which is prepared by the following steps:

[0041] (1) mixing concentrated nitric acid aqueous solution and deionized water according to a volume ratio of 3:1, adding multi-walled carbon nanotubes with a tube diameter of 110 nm, heating to 120°C, reacting at a rotation speed of 3500 r / min, and condensing reflux for 24 h to obtain a reaction product, wherein the mass-volume ratio of the multi-walled carbon nanotubes to the concentrated nitric acid aqueous solution is 0.01 g / mL; centrifuging and washing the reaction product with ethanol for 3 times, and then centrifuging and washing with deionized water until the pH value of the liquid after centrifugation is 7, removing the liquid after centrifugation to obtain a centrifuged product, wherein the centrifugation condition of each time is: centrifuging at a rotation speed of 3500 r / min for 25 min; drying the centrifuged product at 70°C for 48 h, grinding, and obtaining carboxylated carbon nanotubes.

[0042] (2) ultrasonically dispersing the carboxylated carbon nanotubes with deionized water under a frequency of 50 KHz for 4 h to obtain a carboxylated carbon nanotube water mixture, wherein the mass fraction of the carboxylated carbon nanotubes in the carboxylated carbon nanotube water mixture is 1%; ultrasonically dispersing hydroxyethyl cellulose with deionized water under a frequency of 50 KHz for 1 h to obtain a hydroxyethyl cellulose water mixture, wherein the mass fraction of the hydroxyethyl cellulose in the hydroxyethyl cellulose water mixture is 0.5%.

[0043] (3) adding the carboxylated carbon nanotube water mixture into the hydroxyethyl cellulose water mixture, adding p-toluenesulfonic acid, heating to 110°C, and reacting for 2.2 h to obtain a reaction liquid, wherein the volume ratio of the carboxylated carbon nanotube water mixture to the hydroxyethyl cellulose water mixture is 1:4, and the mass-volume ratio of the p-toluenesulfonic acid to the carboxylated carbon nanotube water mixture is 0.25 mg / mL; centrifuging the reaction liquid at a rotation speed of 4000 r / min for 30 min to obtain a centrifuged product, washing the centrifuged product with water, 5 wt% sodium bicarbonate aqueous solution and water in sequence, and drying to obtain a concrete viscosity modifier.

[0044] (4) mixing cement, fly ash, mineral powder, sand, stone, water, the concrete viscosity modifier and water reducing agent according to a mass ratio of 250:60:40:830:1035:160:4:1 to prepare concrete.

[0045] Example 5

[0046] The embodiment discloses a preparation method of concrete, which is prepared by the following steps:

[0047] (1) mixing concentrated nitric acid aqueous solution and deionized water according to a volume ratio of 3:1, then adding multi-walled carbon nanotubes with a tube diameter of 130 nm, heating to 120°C, reacting at a rotation speed of 4500 r / min, and condensing reflux for 24 h to obtain a reaction product, wherein the mass-volume ratio of the multi-walled carbon nanotubes to the concentrated nitric acid aqueous solution is 0.01 g / mL; centrifugally washing the reaction product with ethanol for 3 times, then centrifugally washing with deionized water until the pH value of the liquid after centrifugation is 7, removing the liquid after centrifugation to obtain a centrifugation product, wherein the centrifugation condition of each time is centrifugation at a rotation speed of 4500 r / min for 20 min; drying the centrifugation product at 70°C for 48 h, grinding, and obtaining carboxylated carbon nanotubes.

[0048] (2) ultrasonically dispersing the carboxylated carbon nanotubes with deionized water under a frequency of 50 KHz for 5.5 h to obtain a carboxylated carbon nanotube water mixture, wherein the mass fraction of the carboxylated carbon nanotubes in the carboxylated carbon nanotube water mixture is 2.5%; ultrasonically dispersing hydroxyethyl cellulose with deionized water under a frequency of 50 KHz for 2.5 h to obtain a hydroxyethyl cellulose water mixture, wherein the mass fraction of the hydroxyethyl cellulose in the hydroxyethyl cellulose water mixture is 1.2%.

[0049] (3) adding the carboxylated carbon nanotube water mixture into the hydroxyethyl cellulose water mixture, then adding p-toluenesulfonic acid, heating to 118°C, and reacting for 2.8 h to obtain a reaction liquid, wherein the volume ratio of the carboxylated carbon nanotube water mixture to the hydroxyethyl cellulose water mixture is 1:7, and the mass-volume ratio of the p-toluenesulfonic acid to the carboxylated carbon nanotube water mixture is 0.35 mg / mL; centrifuging the reaction liquid at a rotation speed of 4000 r / min for 30 min to obtain a centrifugation product, washing the centrifugation product with water, 5 wt% sodium bicarbonate aqueous solution, and water in sequence, and drying to obtain a concrete viscosity modifier.

[0050] (4) mixing cement, fly ash, mineral powder, sand, stone, water, the concrete viscosity modifier, and water reducing agent according to a mass ratio of 250:60:40:830:1035:160:8:2 to prepare concrete.

[0051] Comparative Example 1

[0052] The present comparative example discloses a preparation method of concrete.

[0053] Mixing cement, fly ash, mineral powder, sand, stone, water, carbon nanotubes, hydroxyethyl cellulose, and water reducing agent according to a mass ratio of 250:60:40:830:1035:160:3:3:1.5 to prepare concrete.

[0054] Comparative Example 2

[0055] The comparative example discloses a preparation method of concrete.

[0056] The cement, fly ash, mineral powder, sand, stone, water, hydroxyethyl cellulose and water reducing agent are mixed according to the mass ratio of 250:60:40:830:1035:160:6:1.5 to prepare the concrete.

[0057] Comparative example 3

[0058] The comparative example discloses a preparation method of concrete, which is prepared by the following steps:

[0059] (1) The concentrated nitric acid aqueous solution and deionized water are mixed according to the volume ratio of 3:1, and then the multi-walled carbon nanotubes with a pipe diameter of 110 nm are added, heated to 120 DEG C, reacted at a rotating speed of 4000 r / min, and condensed backflow for 24 h to obtain a reaction product, wherein the mass-volume ratio of the multi-walled carbon nanotubes to the concentrated nitric acid aqueous solution is 0.01 g / mL; the reaction product is first washed by centrifugation with ethanol for 3 times, and then washed by centrifugation with deionized water until the pH value of the liquid after centrifugation is 7, and the liquid after centrifugation is removed to obtain a centrifugation product, wherein the centrifugation condition of each time is that the centrifugation is carried out at a rotating speed of 4000 r / min for 20 min; the centrifugation product is dried at 70 DEG C for 48 h, ground, and then carboxylated carbon nanotubes are obtained.

[0060] (2) The cement, fly ash, mineral powder, sand, stone, water, carboxylated carbon nanotubes and water reducing agent are mixed according to the mass ratio of 250:60:40:830:1035:160:6:1.5 to prepare the concrete.

[0061] The mass fraction of nitric acid in the concentrated nitric acid aqueous solution in each embodiment and the comparative example of the application is 68%.

[0062] Blank group

[0063] The blank group discloses a preparation method of concrete:

[0064] The cement, fly ash, mineral powder, sand, stone and water are mixed according to the mass ratio of 250:60:40:830:1035:160 to prepare the concrete.

[0065] The cement in all the embodiments and the comparative example is Ousheng P.O 52.5 cement, the water reducing agent is CP1801X polycarboxylic acid water reducing agent, the fly ash is grade II (GB 1596-91), the mineral powder is S95 grade, and the fineness modulus of the sand is 2.8; the particle size of the stone is 5-20 mm.

[0066] Test table 1: slump and spread test: the test is carried out according to GB / T 50080-2016 'Standard Test Methods for Properties of Fresh Ordinary Concrete'.

[0067] Table 1

[0068]

[0069] From the test results of Table 1, it can be seen that the slump of the concrete of the embodiment of the present application is greatly improved compared with the blank group and the comparative examples, and the addition of the concrete viscosity modifier has good slump retention; the spread of the concrete in the embodiment is not much different from that of the blank group, indicating that the addition of the concrete viscosity modifier of the present application has little effect on the fluidity of the concrete. Among them, the blank group does not add the concrete viscosity modifier and the water reducing agent, the carbon nanotubes in Comparative Example 1 are not modified by carboxylation, Comparative Example 2 does not add carbon nanotubes, and Comparative Example 3 does not add hydroxyethyl cellulose.

[0070] Test two

[0071] Table 2: Compressive strength, refer to GB / T50081-2002 "Standard for test methods of mechanical properties of ordinary concrete"

[0072] Table 2

[0073]

[0074] From the test results of Table 2, it can be seen that the addition of the concrete viscosity modifier has no adverse effect on the strength of the concrete, and can even increase the strength of the concrete.

[0075] Although embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method of preparing a concrete viscosity modifier, characterized by, Prepared by comprising the following steps: Step (1) mixing concentrated nitric acid aqueous solution with deionized water, adding multi-walled carbon nanotubes, heating, and reacting to obtain carboxylated carbon nanotubes; Step (2) dispersing the carboxylated carbon nanotubes in deionized water to obtain a carboxylated carbon nanotube water mixture; dispersing hydroxyethyl cellulose in deionized water to obtain a hydroxyethyl cellulose water mixture; Step (3) adding the carboxylated carbon nanotube water mixture to the hydroxyethyl cellulose water mixture, then adding p-toluenesulfonic acid, and heating to obtain a concrete viscosity modifier.

2. The method for preparing a concrete viscosity modifier according to claim 1, characterized in that, In the step (1), the volume ratio of the concentrated nitric acid aqueous solution to the deionized water is 3:1, the tube diameter of the multi-walled carbon nanotubes is 100-150 nm, and the mass-volume ratio of the multi-walled carbon nanotubes to the concentrated nitric acid aqueous solution is 0.01 g / mL.

3. The method of claim 1, wherein the concrete viscosity modifier is prepared by the steps of: The reaction conditions of the step (1) are as follows: heating to 120℃, reacting at a rotation speed of 3000-5000 r / min, and condensing reflux for 24 h to obtain a reaction product; centrifugally washing the reaction product with ethanol for 3 times, then centrifugally washing with deionized water until the pH value of the liquid after centrifugation is 7, removing the liquid after centrifugation to obtain a centrifugation product, wherein the centrifugation condition of each time is as follows: centrifuging at a rotation speed of 3000-5000 r / min for 20-30 min; drying the centrifugation product at 70℃ for 48 h, grinding, and obtaining the carboxylated carbon nanotubes.

4. The method of claim 1, wherein the concrete viscosity modifier is prepared by the steps of: In the step (2), the carboxylated carbon nanotubes are ultrasonically dispersed in the deionized water for 0.5-6 h at a frequency of 50 KHz to obtain the carboxylated carbon nanotube water mixture, wherein the mass fraction of the carboxylated carbon nanotubes in the carboxylated carbon nanotube water mixture is 0.1%-3%; and the hydroxyethyl cellulose is ultrasonically dispersed in the deionized water for 0.5-3 h at a frequency of 50 KHz to obtain the hydroxyethyl cellulose water mixture, wherein the mass fraction of the hydroxyethyl cellulose in the hydroxyethyl cellulose water mixture is 0.1%-1.5%.

5. The method of claim 1, wherein the concrete viscosity modifier is prepared by the steps of: In the step (3), the carboxylated carbon nanotube water mixture is added to the hydroxyethyl cellulose water mixture, then p-toluenesulfonic acid is added, heated to 105-120℃, and reacted for 2-3 h to obtain a reaction liquid, wherein the volume ratio of the carboxylated carbon nanotube water mixture to the hydroxyethyl cellulose water mixture is 1:3-8, and the mass-volume ratio of the p-toluenesulfonic acid to the carboxylated carbon nanotube water mixture is 0.2-0.4 mg / mL; the reaction liquid is centrifuged at a rotation speed of 4000 r / min for 30 min to obtain a centrifugation product, which is washed with water, 5 wt% sodium bicarbonate aqueous solution, and water in sequence, dried, and obtained as the concrete viscosity modifier.

6. A concrete viscosity modifier prepared by the preparation method of any one of claims 1-5.

7. Use of the concrete viscosity modifier prepared according to claim 6 for the production of concrete, characterized in that The concrete is prepared by the following method: mixing cement, fly ash, mineral powder, sand, stone, water, a concrete viscosity modifier, and a water reducing agent to obtain the concrete.

8. Use according to claim 7, characterized in that, The mass ratio among the cement, fly ash, mineral powder, sand, stone, water, concrete viscosity modifier, water reducing agent is 250:60:40:830:1035:160:2-10:0.5-2.

5.

9. Concrete prepared based on the concrete viscosity modifier according to claim 6, characterized in that Prepared from the following raw materials: cement, fly ash, mineral powder, sand, stone, water, concrete viscosity modifier, water reducing agent.

10. The concrete according to claim 9, characterized in that The mass ratio among the cement, fly ash, mineral powder, sand, stone, water, concrete viscosity modifier, water reducing agent is 250:60:40:830:1035:160:2-10:0.5-2.5.

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