A 6C early-strengthening and viscosity-increasing functional polycarboxylate water reducer and its preparation method

Abstract

The present invention discloses a 6C early-strength and viscosity-increasing functional polycarboxylate water reducer and its preparation method, belonging to the technical field of building chemical materials. The 6C early-strength and viscosity-increasing functional polycarboxylate water reducer of the present invention comprises a base material, an additive and a neutralizing agent; wherein, the base material is made by dissolving a six-carbon macromonomer, polyethylene oxide, hydrogen peroxide and nano-titanium dioxide in water; the additive consists of two categories, A and B, wherein category A is an aqueous solution of mercaptopropionic acid, and category B is an aqueous solution of acrylic acid and hydroxyethyl methacrylate; the neutralizing agent is an aqueous solution of sodium hydroxide. The polycarboxylate water reducer prepared by the method of the present invention has multiple effects such as water reduction, early strength and viscosity increase, thereby reducing the rebound rate during the construction of shotcrete and having good application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of building chemical materials, and particularly relates to a 6C early-strength and viscosity-increasing functional polycarboxylate water reducer and a preparation method thereof. Background Art

[0002] In recent years, the construction speed of the Sichuan-Tibet Railway and urban subways has been rapid, and a large number of tunnels, tunnel linings and other projects need to be built. However, in the tunnel construction project, shotcrete is a key process in the initial support construction link. Although the wet spraying process can effectively ensure the quality of concrete, improve the tunnel construction quality and optimize the working environment, it is inevitable to have the rebound of concrete, reduce the strength of the support, cause waste of materials and increase the project cost.

[0003] At present, the means to solve the high rebound rate of shotcrete in the actual engineering construction process mainly include adjusting the concrete mix ratio, increasing the dosage of accelerator, increasing the working air pressure and using viscosity-increasing agents, etc. However, the adjustment of the concrete mix ratio requires a large amount of matching work in advance, increasing the workload in the actual project; increasing the dosage of the accelerator will affect the early strength of the concrete, and the incorporation of too much accelerator will increase the project cost; increasing the working air pressure will cause excessive pressure and result in the separation of the sprayed cement and sand, which is not conducive to the spraying on the top of the tunnel. The use of viscosity-increasing agents has an obvious effect on reducing the rebound rate, but when compounded with other admixtures, there will be problems such as poor compatibility and insufficient viscosity increase. Therefore, it has important scientific significance and broad application prospects to carry out research on early-strength and viscosity-increasing polycarboxylate water reducers and apply them to shotcrete to reduce the concrete rebound rate, reduce the construction cost and improve the support quality. Summary of the Invention

[0004] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a 6C early-strength and viscosity-increasing functional polycarboxylate water reducer and a preparation method thereof.

[0005] In order to achieve the above purpose, the present invention adopts the following technical scheme:

[0006] A 6C early-strength and viscosity-increasing functional polycarboxylate water reducer, comprising a base material, an additive and a neutralizing agent;

[0007] Wherein, the base material is made by dissolving a six-carbon macromonomer, polyethylene oxide, hydrogen peroxide and nano-titanium dioxide in water;

[0008] The additive consists of two categories, A and B. Among them, category A is an aqueous solution of mercaptopropionic acid, and category B is an aqueous solution of acrylic acid and hydroxyethyl methacrylate;

[0009] The neutralizing agent is an aqueous solution of sodium hydroxide.

[0010] On the basis of the above solution, the six-carbon macromonomer is ethylene glycol mono vinyl polyethylene glycol ether or 4-hydroxybutyl vinyl polyoxyethylene ether.

[0011] On the basis of the above solution, by mass, the additive A is made by dissolving 1.2 - 1.8 parts of mercaptopropionic acid in 18 - 25 parts of water, and the additive B is made by dissolving 6 - 10 parts of acrylic acid and 1.5 - 5 parts of hydroxyethyl methacrylate in 5 - 10 parts of water.

[0012] On the basis of the above solution, by mass, the neutralizer is made by dissolving 1 - 3 parts of sodium hydroxide in 7 - 15 parts of water.

[0013] On the basis of the above solution, by mass, the base material is made by dissolving 50 - 100 parts of six-carbon macromonomer, 0.01 - 0.05 parts of polyethylene oxide, 0.05 - 3.0 parts of nano-titanium dioxide and 0.5 - 1.8 parts of hydrogen peroxide in 80 - 150 parts of water.

[0014] On the basis of the above solution, by mass,

[0015] The additive A is made by dissolving 1.5 parts of mercaptopropionic acid in 18 parts of water;

[0016] The additive B is made by dissolving 6.8 - 8 parts of acrylic acid and 2 - 3.2 parts of hydroxyethyl methacrylate in 8 parts of water;

[0017] The neutralizer is made by dissolving 2 parts of sodium hydroxide in 15 parts of water;

[0018] The base material is made by dissolving 90 parts of six-carbon macromonomer, 0.05 parts of polyethylene oxide, 1 part of hydrogen peroxide and 0.25 - 0.5 parts of nano-titanium dioxide in 80 parts of water.

[0019] The preparation method of the above 6C early-strength and viscosity-increasing functional polycarboxylate water reducer is as follows:

[0020] 1) Dissolve mercaptopropionic acid in water and stir to make solution A as an additive; dissolve acrylic acid and hydroxyethyl methacrylate in water and stir to make solution B as an additive;

[0021] 2) Dissolve sodium hydroxide in water to make the neutralizer;

[0022] 3) Dissolve the six-carbon macromonomer and polyethylene oxide in water. When the six-carbon macromonomer is dissolved and the temperature of the oil bath is 15 - 25 °C, add nano-titanium dioxide and hydrogen peroxide and stir for 5 min to make the base material;

[0023] 4) Slowly drop solutions A and B in the additive into the base material at a uniform speed. The dropping time is 1 h. After the dropping is completed, the solution temperature is 25 - 35 °C. Stir and keep warm for 2.5 h, and then cool and add the neutralizer to obtain the product.

[0024] On the basis of the above solution, in item 4), ultraviolet lamp irradiation is carried out while starting to drip, where the illumination distance is 0.8 - 1.5 m from the solution, and the illumination duration is 3 h.

[0025] Compared with the prior art, the present invention has the following beneficial technical effects:

[0026] Currently, the polyether macromonomers studied in synthesis mainly focus on methallyl polyoxyethylene ether (HPEG) and isopentenol polyoxyethylene ether (TPEG). Their low double-bond activity results in the need for relatively high temperatures (40 - 80 °C) and polymerization times during synthesis, consuming time and energy. However, the present invention uses a six-carbon macromonomer molecule, in which the unsaturated double bond in its structure is directly connected to an oxygen atom, forming a molecular structure of a group of C-O bonds, improving the reaction activity of the double bond in the macromonomer. The polymerization reaction can be carried out without heating, reducing energy consumption and conforming to the national policies of energy conservation and emission reduction.

[0027] The preparation process of the 6C early-strength and viscosity-increasing functional polycarboxylate water reducer of the present invention is a polymer free-radical polymerization reaction. The polymerization mechanism is that the molecular monomers containing vinyl bonds are polymerized into macromolecules. In the present invention, a redox system composed of hydrogen peroxide as an oxidant and nano-titanium dioxide as a reductant induces free radicals, and the nano-titanium dioxide needs to be catalyzed by ultraviolet light irradiation to generate its performance. The generated free radicals initiate the polymerization reaction of the six-carbon macromonomer, acrylic acid, and hydroxyethyl acrylate small monomers. The high-activity characteristics of the six-carbon macromonomer and the relatively low activation energy required under the redox system enable the polymerization reaction to occur at room temperature. Compared with the high-temperature heating process on the market, the present invention can be produced and synthesized under room temperature (15 - 25 °C) conditions, greatly reducing the production energy consumption.

[0028] The present invention fully utilizes the hydrogen bond affinity of the unshared electron pairs on the ether oxygen atoms in the ether macromonomer and the long chain of hydroxyethyl methacrylate to form a complex with polyethylene oxide, and grafts nano-titanium dioxide into the acrylic acid structure, playing the dual roles of supplementing crystal seeds to promote nucleation, increasing the interfacial contact area, and reducing water, realizing the multiple effects of water reduction, early strength, and viscosity increase of the polycarboxylate water reducer, thereby reducing the rebound rate during the construction of shotcrete.

[0029] Currently, those used on the market are all composed of two components, a water reducer and a viscosity-increasing agent, increasing the construction process and cost requirements, and the rebound rate of shotcrete fluctuates around 20%. However, the early-strength and viscosity-increasing polycarboxylate water reducer of the present invention simultaneously has the characteristics of water reduction, early strength, and viscosity increase, improving construction safety, reducing costs, and optimizing the construction process, effectively controlling the rebound rate of shotcrete, greatly reducing the loss of concrete, and reducing the construction cost. Detailed implementation mode

[0030] The terms used in the present invention, unless otherwise specified, generally have the meanings commonly understood by those of ordinary skill in the art.

[0031] The present invention will be described in further detail below in conjunction with specific embodiments and with reference to data. The following embodiments are only for illustrative purposes of the present invention and do not limit the scope of the present invention in any way.

[0032] A 6C early-strength and viscosity-increasing functional polycarboxylate water reducer, comprising a base material, an additive, and a neutralizing agent;

[0033] Among them, the base material is made by dissolving a six-carbon macromonomer, polyethylene oxide, hydrogen peroxide, and nano-titanium dioxide in water;

[0034] The six-carbon macromonomer is ethylene glycol mono vinyl polyethylene glycol ether or 4-hydroxybutyl vinyl polyoxyethylene ether, with a molecular weight of 2400-5000.

[0035] The additive consists of two categories, A and B. Among them, category A is an aqueous solution of mercaptopropionic acid, and category B is an aqueous solution of acrylic acid and hydroxyethyl methacrylate;

[0036] The neutralizing agent is an aqueous solution of sodium hydroxide.

[0037] By mass, category A of the additive is made by dissolving 1.2-1.8 parts of mercaptopropionic acid in 18-25 parts of water, and category B is made by dissolving 6-10 parts of acrylic acid and 1.5-5 parts of hydroxyethyl methacrylate in 5-10 parts of water.

[0038] By mass, the neutralizing agent is made by dissolving 1-3 parts of sodium hydroxide in 7-15 parts of water.

[0039] By mass, the base material is made by dissolving 50-100 parts of six-carbon macromonomer, 0.01-0.05 parts of polyethylene oxide, 0.05-3.0 parts of nano-titanium dioxide, and 0.5-1.8 parts of hydrogen peroxide in 80-150 parts of water.

[0040] The preparation method of the above 6C early-strength and viscosity-increasing polycarboxylate water reducer includes the following operations:

[0041] 1) Dissolve mercaptopropionic acid in water and stir to dissolve to make an additive solution of material A; dissolve acrylic acid and hydroxyethyl methacrylate in water and stir to dissolve to make an additive solution of material B;

[0042] 2) Dissolve sodium hydroxide in water to make a neutralizing agent;

[0043] 3) Dissolve the six-carbon macromonomer and polyethylene oxide in water. When the six-carbon macromonomer is dissolved and the temperature of the oil bath is 15-25 °C, add nano-titanium dioxide and hydrogen peroxide and stir for 5 minutes to make the base material;

[0044] 4) Slowly and evenly drop materials A and B in the base material. The dropping time is 1 h. After the dropping is completed, the solution temperature is 25 - 35°C, stir and keep warm for ripening for 2.5 h, and then cool and add neutralizer to make an early-strength and viscosity-increasing polycarboxylate water reducer.

[0045] In the above step 4), ultraviolet lamp irradiation is carried out while starting to drop. The distance between the light and the solution is 0.8 - 1.5 m, and the light irradiation time is 3 h.

[0046] The principle of preparing the 6C early-strength and viscosity-increasing functional polycarboxylate water reducer of the present invention:

[0047] Dissolve 6C polyether macromonomer and polyethylene oxide in an aqueous solution at 18°C, then introduce nano-titanium dioxide and irradiate it with ultraviolet light. The electrons on the valence band (VB) absorb energy and transition. The photo-generated electrons (e - ) are generated on the conduction band (CB). At the same time, corresponding oxidizing holes (h + ) are generated on the valence band, oxidize water molecules to generate hydroxyl radicals, and its reduction property reacts with hydrogen peroxide to generate free radicals by redox reaction. Use the free radicals to collide with monomers containing unsaturated double bonds. At this time, slowly drop the aqueous solution of mercaptopropionic acid in liquid A and the aqueous solutions of acrylic acid and hydroxyethyl methacrylate in liquid B, so that the monomers undergo chain polymerization growth, and then keep warm and continue the reaction, so that the hydroxyl groups formed by nano-titanium dioxide in the aqueous solution are grafted onto the carboxyl groups of acrylic acid. Finally, after cooling and neutralization, a 6C early-strength and viscosity-increasing polycarboxylate water reducer is obtained. Therefore, when the polycarboxylate water reducer synthesized by the present invention is incorporated into concrete, by using the viscosity-increasing property of polyethylene oxide, and at the same time using the large specific surface area and nucleation induction effect of nano-particles, the hydration process of cement is accelerated, and thus the early strength of concrete is improved. Generally, the polycarboxylate water reducer of the present invention can achieve multiple effects of water reduction, early strength and viscosity increase.

[0048] Example 1

[0049] A 6C early-strength and viscosity-increasing functional polycarboxylate water reducer contains the following components in parts by mass:

[0050] 19.5 parts of additive A, 18 parts of additive B, 17 parts of neutralizer, and 171.3 parts of base material;

[0051] Among them,

[0052] The additive A is an aqueous solution of mercaptopropionic acid, which is made by dissolving 1.5 parts of mercaptopropionic acid in 18 parts of water;

[0053] The additive B is an aqueous solution of acrylic acid and hydroxyethyl methacrylate, which is made by dissolving 8 parts of acrylic acid and 2 parts of hydroxyethyl methacrylate in 8 parts of water;

[0054] The neutralizing agent is an aqueous solution of sodium hydroxide, which is prepared by dissolving 2 parts of sodium hydroxide in 15 parts of water;

[0055] The base material is prepared by dissolving 90 parts of 4-hydroxybutyl vinyl polyoxyethylene ether, 0.05 part of polyethylene oxide, 1 part of hydrogen peroxide and 0.25 part of nano-titanium dioxide in 80 parts of water.

[0056] The preparation method of the above 6C early-strength and viscosity-increasing functional polycarboxylate water reducer is as follows:

[0057] (1) Dissolve 1.5 parts of mercaptopropionic acid in 18 parts of water and stir evenly to prepare Class A additive;

[0058] (2) Dissolve 8 parts of acrylic acid and 2 parts of hydroxyethyl methacrylate in 8 parts of water and stir evenly to prepare Class B additive;

[0059] (3) Dissolve 2 parts of sodium hydroxide in 15 parts of water to prepare a neutralizing agent;

[0060] (4) Dissolve 90 parts of 4-hydroxybutyl vinyl polyoxyethylene ether and 0.05 part of polyethylene oxide in 80 parts of water. When the 4-hydroxybutyl vinyl polyoxyethylene ether is completely dissolved and the temperature in the oil bath is 15 - 25 °C, add 0.25 part of nano-titanium dioxide and 1 part of hydrogen peroxide and stir for 5 minutes to prepare the base material;

[0061] (5) Slowly and evenly drip Additives A and B in the additive into the base material through a peristaltic pump. The dropping time is 1 h. After the dropping is completed, the solution temperature is 25 - 35 °C. Stir and keep warm for 2.5 h, and then cool and add the neutralizing agent to prepare the 6C early-strength and viscosity-increasing functional polycarboxylate water reducer.

[0062] In the step (5), ultraviolet lamp irradiation is carried out while starting to drip. The illumination distance is 1 m from the solution, and the illumination time is 3 h.

[0063] Example 2

[0064] A 6C early-strength and viscosity-increasing functional polycarboxylate water reducer contains the following components in parts by mass:

[0065] Additive A 19.5 parts, Additive B 18 parts, Neutralizing agent 17 parts, Base material 171.55 parts;

[0066] Among them,

[0067] The Additive A is an aqueous solution of mercaptopropionic acid, which is prepared by dissolving 1.5 parts of mercaptopropionic acid in 18 parts of water;

[0068] The Additive B is an aqueous solution of acrylic acid and hydroxyethyl methacrylate, which is prepared by dissolving 6.8 parts of acrylic acid and 3.2 parts of hydroxyethyl methacrylate in 8 parts of water.

[0069] The neutralizing agent is an aqueous solution of sodium hydroxide, which is prepared by dissolving 2 parts of sodium hydroxide in 15 parts of water;

[0070] The base material is prepared by dissolving 90 parts of 4-hydroxybutyl vinyl polyoxyethylene ether, 0.05 part of polyethylene oxide, 1 part of hydrogen peroxide and 0.5 part of nano-titanium dioxide in 80 parts of water.

[0071] The preparation method of the above 6C early-strength and viscosity-increasing functional polycarboxylate water reducer is as follows:

[0072] (1) Dissolve 1.5 parts of mercaptopropionic acid in 18 parts of water and stir evenly to prepare additive A;

[0073] (2) Dissolve 6.8 parts of acrylic acid and 3.2 parts of hydroxyethyl methacrylate in 8 parts of water and stir evenly to prepare additive B;

[0074] (3) Dissolve 2 parts of sodium hydroxide in 15 parts of water to prepare a neutralizing agent;

[0075] (4) Dissolve 90 parts of 4-hydroxybutyl vinyl polyoxyethylene ether and 0.05 part of polyethylene oxide in 80 parts of water. When the 4-hydroxybutyl vinyl polyoxyethylene ether is completely dissolved and the temperature in the oil bath is 15 - 25 °C, add 0.5 part of nano-titanium dioxide and 1 part of hydrogen peroxide and stir for 5 minutes to prepare the base material;

[0076] (5) Slowly and evenly drip additive A and B in the additive into the base material through a peristaltic pump. The dropping time is 1 h. After the dropping is completed, the solution temperature is 25 - 35 °C. Stir and keep warm for 2.5 h, and then cool and add the neutralizing agent to prepare the 6C early-strength and viscosity-increasing functional polycarboxylate water reducer.

[0077] In the step (5), ultraviolet lamp irradiation is carried out while starting to drip. The distance between the light source and the solution is 1 m, and the irradiation time is 3 h.

[0078] Example 3

[0079] A 6C early-strength and viscosity-increasing functional polycarboxylate water reducer, comprising the following components in parts by mass:

[0080] Additive A 19.5 parts, additive B 18 parts, neutralizing agent 17 parts, base material 171.4 parts;

[0081] Among them,

[0082] The additive A is an aqueous solution of mercaptopropionic acid, which is prepared by dissolving 1.5 parts of mercaptopropionic acid in 18 parts of water;

[0083] The additive B is an aqueous solution of acrylic acid and hydroxyethyl methacrylate, which is prepared by dissolving 7.6 parts of acrylic acid and 2.4 parts of hydroxyethyl methacrylate in 8 parts of water;

[0084] The neutralizing agent is an aqueous solution of sodium hydroxide, which is prepared by dissolving 2 parts of sodium hydroxide in 15 parts of water;

[0085] The base material is prepared by dissolving 90 parts of 4-hydroxybutyl vinyl polyoxyethylene ether, 0.05 part of polyethylene oxide, 1 part of hydrogen peroxide and 0.35 part of nano-titanium dioxide in 80 parts of water.

[0086] The preparation method of the above 6C early-strength and viscosity-increasing functional polycarboxylate water reducer is as follows:

[0087] (1) Dissolve 1.5 parts of mercaptopropionic acid in 18 parts of water and stir evenly to prepare additive A;

[0088] (2) Dissolve 7.6 parts of acrylic acid and 2.4 parts of hydroxyethyl methacrylate in 8 parts of water and stir evenly to prepare additive B;

[0089] (3) Dissolve 2 parts of sodium hydroxide in 15 parts of water to prepare a neutralizing agent;

[0090] (4) Dissolve 90 parts of 4-hydroxybutyl vinyl polyoxyethylene ether and 0.05 part of polyethylene oxide in 80 parts of water. When the 4-hydroxybutyl vinyl polyoxyethylene ether is completely dissolved and the temperature in the oil bath is 15-25 °C, add 0.35 part of nano-titanium dioxide and 1 part of hydrogen peroxide and stir for 5 minutes to prepare the base material;

[0091] (5) Slowly and evenly drip additive A and additive B in the additive into the base material through a peristaltic pump. The dropping time is 1 h. After the dropping is completed, the solution temperature is 25-35 °C, stir and keep warm for 2.5 h, and then cool and add the neutralizing agent to prepare the 6C early-strength and viscosity-increasing functional polycarboxylate water reducer.

[0092] In the step (5), ultraviolet lamp irradiation is carried out while starting to drip. The illumination distance is 1 m from the solution, and the illumination time is 3 h.

[0093] Example 4

[0094] A 6C early-strength and viscosity-increasing functional polycarboxylate water reducer contains the following components in parts by mass:

[0095] Additive A 19.7 parts, additive B 18 parts, neutralizing agent 17 parts, base material 171.05 parts;

[0096] Among them,

[0097] The additive A is an aqueous solution of mercaptopropionic acid and L-ascorbic acid, which is prepared by dissolving 1.5 parts of mercaptopropionic acid and 0.2 part of L-ascorbic acid in 18 parts of water;

[0098] The additive B is an aqueous solution of acrylic acid and hydroxyethyl methacrylate, which is prepared by dissolving 7.6 parts of acrylic acid and 2.4 parts of hydroxyethyl methacrylate in 8 parts of water;

[0099] The neutralizing agent is an aqueous solution of sodium hydroxide, which is prepared by dissolving 2 parts of sodium hydroxide in 15 parts of water;

[0100] The base material is prepared by dissolving 90 parts of 4-hydroxybutyl vinyl polyoxyethylene ether, 0.05 part of polyethylene oxide, and 1 part of hydrogen peroxide in 80 parts of water.

[0101] The preparation method of the above 6C early-strength and viscosity-increasing functional polycarboxylate water reducer is as follows:

[0102] (1) Dissolve 1.5 parts of mercaptopropionic acid and 0.2 part of L-ascorbic acid in 18 parts of water and stir evenly to prepare additive A;

[0103] (2) Dissolve 7.6 parts of acrylic acid and 2.4 parts of hydroxyethyl methacrylate in 8 parts of water and stir evenly to prepare additive B;

[0104] (3) Dissolve 2 parts of sodium hydroxide in 15 parts of water to prepare a neutralizing agent;

[0105] (4) Dissolve 90 parts of 4-hydroxybutyl vinyl polyoxyethylene ether and 0.05 part of polyethylene oxide in 80 parts of water. When the 4-hydroxybutyl vinyl polyoxyethylene ether is completely dissolved and the temperature in the oil bath is 15-25 °C, add 1 part of hydrogen peroxide and stir for 5 minutes to prepare the base material;

[0106] (5) Slowly drip additive A and B into the base material through a peristaltic pump. The dripping time is 1 h. After the dripping is completed, the solution temperature is 25-35 °C. Stir and keep warm for 2.5 h, and then cool and add the neutralizing agent to prepare the 6C early-strength and viscosity-increasing functional polycarboxylate water reducer.

[0107] In the step (5), ultraviolet lamp irradiation is carried out while starting to drip. The light distance is 1 m from the solution, and the light irradiation time is 3 h.

[0108] Example 5

[0109] A 6C early-strength and viscosity-increasing functional polycarboxylate water reducer contains the following components in parts by mass:

[0110] 19.5 parts of additive A, 18 parts of additive B, 17 parts of neutralizing agent, and 171.35 parts of base material;

[0111] Among them,

[0112] The additive A is an aqueous solution of mercaptopropionic acid, which is prepared by dissolving 1.5 parts of mercaptopropionic acid in 18 parts of water;

[0113] The additive B is an aqueous solution of acrylic acid and hydroxyethyl methacrylate, which is prepared by dissolving 7.6 parts of acrylic acid and 2.4 parts of hydroxyethyl methacrylate in 8 parts of water;

[0114] The neutralizing agent is an aqueous solution of sodium hydroxide, which is prepared by dissolving 2 parts of sodium hydroxide in 15 parts of water;

[0115] The base material is prepared by dissolving 90 parts of 4-hydroxybutyl vinyl polyoxyethylene ether, 1 part of hydrogen peroxide and 0.35 part of nano titanium dioxide in 80 parts of water.

[0116] The preparation method of the above 6C early-strength and viscosity-increasing functional polycarboxylate water reducer is as follows:

[0117] (1) Dissolve 1.5 parts of mercaptopropionic acid in 18 parts of water and stir evenly to prepare additive A;

[0118] (2) Dissolve 7.6 parts of acrylic acid and 2.4 parts of hydroxyethyl methacrylate in 8 parts of water and stir evenly to prepare additive B;

[0119] (3) Dissolve 2 parts of sodium hydroxide in 15 parts of water to prepare a neutralizing agent;

[0120] (4) Dissolve 90 parts of 4-hydroxybutyl vinyl polyoxyethylene ether in 80 parts of water. When the 4-hydroxybutyl vinyl polyoxyethylene ether is completely dissolved and the temperature in the oil bath is 15 - 25 °C, add 0.35 part of nano titanium dioxide and 1 part of hydrogen peroxide and stir for 5 minutes to prepare the base material;

[0121] (5) Use a peristaltic pump to uniformly drip additive A and B into the base material. The dripping time is 1 h. After the dripping is completed, the solution temperature is 25 - 35 °C, stir and keep warm for 2.5 h, and then cool and add the neutralizing agent to prepare the 6C early-strength and viscosity-increasing functional polycarboxylate water reducer.

[0122] In the step (5), ultraviolet lamp irradiation is carried out while starting to drip, wherein the light distance is 1 m from the solution, and the light irradiation time is 3 h.

[0123] Performance test of different 6C early-strength and viscosity-increasing functional polycarboxylate water reducers

[0124] 1. Net paste viscosity and mortar properties

[0125] Detect the net paste viscosity and mortar properties of the water reducers prepared in Examples 1 - 5, and use a commercially available polycarboxylate water reducer as a comparative example.

[0126] Among them, the polycarboxylate water reducers in Examples 1-3 changed the dosages of acrylic acid, hydroxyethyl methacrylate, and nano-titanium dioxide. The variable of the polycarboxylate water reducer in Example 4 was replacing nano-titanium dioxide with L-ascorbic acid, and the variable of the polycarboxylate water reducer in Example 5 was polyethylene oxide.

[0127] The cement paste viscosity test was carried out with reference to TJ / GW112-2013 "Test Method for Cement Paste Viscosity Ratio": The water-cement ratio W / C was 0.40, the solid content of the water reducer was 0.20% of the cement dosage, and the cement used was P·O 42.5 ordinary Portland cement.

[0128] The formula for detecting the mortar performance is as follows: 450.0 g of cement, 1350.0 g of standard sand, and the solid content of the water reducer is 0.25% of the cement dosage.

[0129] The measurement results are shown in Table 1.

[0130] Table 1 Performance Test of Different 6C Early Strength and Viscosity-increasing Functional Polycarboxylate Water Reducers

[0131]

[0132]

[0133] Note: The commercially available water reducer is a high-performance early strength type polycarboxylate water reducer

[0134] As can be seen from Table 1, compared with the commercially available water reducer, for the samples prepared from the examples of this application, the net paste viscosity values of the samples prepared with the water reducers prepared in Examples 1-3 and Example 5 of the present invention were significantly improved; while the viscosity of Example 4 was comparable to that of the commercially available water reducer because the reducing agent used in Example 4 was L-ascorbic acid. This shows that using nano-titanium dioxide as a reducing agent can increase the viscosity of the cement paste, but the test results of the mortar water reduction rate show that excessive increase in viscosity will reduce the mortar water reduction rate, but the increase in viscosity will significantly improve the 1d mortar strength performance; the comprehensive test results show that the polycarboxylate water reducer prepared by the present invention has good viscosity-increasing and early strength effects.

[0135] 2. Concrete Performance Test

[0136] The concrete performance of the water reducers prepared in Examples 1-5 was detected, and a commercially available polycarboxylate water reducer was used as a comparative example. The commercially available water reducer is a high-performance early strength type polycarboxylate water reducer. Among them, the polycarboxylate water reducer mother liquor was diluted to a solid content of 16%, and the concrete test was carried out according to the same solid content of the water reducer of 0.25% of the cement dosage. The concrete mix ratio is shown in Table 2, and the test results are shown in Table 3.

[0137] Table 2 Concrete Mix Ratio

[0138] Cement (Yumen) Sand Fine aggregate Water 450 848 848 171

[0139] Table 3 Concrete test results

[0140]

[0141]

[0142] As can be seen from Table 3, the concrete reverse lift outflow time of the samples prepared in Examples 1-3 and Example 5 of the present application is significantly slower than that of the commercially available water reducing agent. For the polycarboxylic acid water reducing agent prepared with L-ascorbic acid as the reducing agent in Example 4, it has good fluidity, a large water reducing rate, resulting in low viscosity of the concrete, bleeding phenomenon, poor wrapping property, and low strength. The test results show that the water reducing agent of the present invention has a good viscosity increasing effect, and the 1-day compressive strength of the concrete is higher than that of the commercially available water reducing agent, showing a good early strength effect. However, due to the excessive increase in viscosity, the initial slump and slump retention effect of the concrete will decrease, and the comprehensive performance is best in Example 1.

[0143] 3. Performance tests of setting acceleration performance and shotcrete rebound rate

[0144] The setting acceleration performance of the water reducing agent prepared in Example 1 was tested. The accelerating agent used complied with GB / T 35159-2017 "Accelerating agent for shotcrete" and TB10424-2018 "Acceptance standard for railway concrete engineering construction". The test results are shown in Table 4.

[0145] Table 4 Setting acceleration performance test results

[0146]

[0147] Note: 1. The dosage of the accelerating agent is 6-9%;

[0148] 2. Ordinary Portland cement with a strength grade not lower than 42.5 and within the shelf life should be used;

[0149] 3. Add strictly according to the mixing ratio dosage. Adaptability tests should be carried out when changing the cement.

[0150] The performance test of the shotcrete rebound rate of Example 1 and the commercially available water reducing agent was carried out. The commercially available water reducing agent is a high-performance early-strength polycarboxylic acid water reducing agent. The mix ratio is shown in Table 5 below, and the test results are shown in Table 6 below:

[0151] Table 5 Concrete mix ratio

[0152] Cement (Yumen) Sand Fine aggregate Water 480 848 848 173

[0153] Table 6 Rebound rate record table

[0154] Water reducing agent Number of tests Average compressive strength at 1d (MPa) Average rebound rate (%) Commercially available water reducing agent 3 15.6 20～25 Water reducing agent of Example 1 3 21.8 5～10

[0155] In the above tests of shotcrete, compared with commercially available water reducers, the water reducer of Example 1 has the following obvious characteristics:

[0156] 1) The early strength is improved. The strength at 24 hours can reach over 20 MPa, and the effect is far better than that of shotcrete with commercially available water reducers, which can meet the requirements of most initial supports and early strength of tunnels (and the initial setting time and final setting time are 3 minutes and 5 minutes respectively, with a fast setting speed).

[0157] 2) The rebound rate is low. After multiple test detections, the rebound rate of the shotcrete with the water reducer of Example 1 is lower, all around 5 - 10%, and the effect is remarkable.

[0158] 3) The bonding force is strong. The bonding effect of the concrete sprayed with the water reducer of Example 1 with the steel bar skeleton and the rock formation is good, while the bonding of the commercially available polycarboxylate water reducer to the steel bar skeleton is poor.

[0159] 4) The thickness of a single shot is increased. The thickness of the shotcrete on the rock wall with the water reducer of Example 1 is more plump than that with commercially available water reducers.

[0160] 5) It can significantly reduce dust pollution and protect the physical health of construction workers.

[0161] The above are only the preferred embodiments of the present invention, and it is not intended to limit the present invention in other forms. Any person skilled in the art may use the disclosed technical content to make changes or modifications into equivalent embodiments with equivalent changes. However, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution content of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A 6C early-strengthening and viscosity-increasing functional polycarboxylate water reducer, characterized in that, It includes a base material, an additive, and a neutralizing agent; Among them, the base material is made by dissolving a six-carbon macromonomer, polyethylene oxide, hydrogen peroxide, and nano-titanium dioxide in water; The additive consists of two categories, A and B. Among them, category A is an aqueous solution of mercaptopropionic acid, and category B is an aqueous solution of acrylic acid and hydroxyethyl methacrylate; The neutralizing agent is an aqueous solution of sodium hydroxide; The six-carbon macromonomer is ethylene glycol mono vinyl polyethylene glycol ether or 4-hydroxybutyl vinyl polyoxyethylene ether; By mass fraction, The additive A is made by dissolving 1.5 parts of mercaptopropionic acid in 18 parts of water; The additive B is made by dissolving 8 parts of acrylic acid and 2 parts of hydroxyethyl methacrylate in 8 parts of water; The neutralizing agent is made by dissolving 2 parts of sodium hydroxide in 15 parts of water; The base material is made by dissolving 90 parts of the six-carbon macromonomer, 0.05 part of polyethylene oxide, 1 part of hydrogen peroxide, and 0.25 - 0.5 part of nano-titanium dioxide in 80 parts of water; The hydrogen peroxide and nano-titanium dioxide generate free radicals under ultraviolet light irradiation, thereby initiating the polymerization reaction of the six-carbon macromonomer, acrylic acid, and hydroxyethyl acrylate monomers.

2. The preparation method of the 6C early-strengthening and viscosity-increasing functional polycarboxylate water reducer according to claim 1, characterized in that, The steps are as follows: 1) Dissolve mercaptopropionic acid in water and stir to dissolve to make an additive solution of material A; dissolve acrylic acid and hydroxyethyl methacrylate in water and stir to dissolve to make an additive solution of material B; 2) Dissolve sodium hydroxide in water to make a neutralizing agent; 3) Dissolve the six-carbon macromonomer and polyethylene oxide in water. When the six-carbon macromonomer is dissolved and the temperature of the oil bath is 15 - 25 °C, add nano-titanium dioxide and hydrogen peroxide and stir for 5 min to make the base material; 4) Slowly and evenly drip materials A and B in the additive into the base material. The dripping time is 1 h. After the dripping is completed, the solution temperature is 25 - 35 °C. Stir and keep warm for 2.5 h, and then cool and add the neutralizing agent to obtain the product.

3. The preparation method of the 6C early-strength and viscosity-increasing functional polycarboxylate water reducer according to claim 2, characterized in that, In step 4), ultraviolet lamp irradiation is carried out while starting to drip. The distance between the light source and the solution is 0.8 - 1.5 m, and the irradiation time is 3 h.

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