Early-strength tackifier for high-titanium heavy slag-based sprayed concrete and preparation method of early-strength tackifier

Abstract

The invention discloses an early-strength tackifier for high-titanium heavy slag-based sprayed concrete and a preparation method of the early-strength tackifier, and relates to the technical field of tackifiers. The high-titanium heavy slag-based early-strength tackifier for the sprayed concrete is prepared from the following raw materials in parts by weight: 20 to 60 parts of high-titanium heavy slag, 15 to 40 parts of silica fume, 10 to 30 parts of cement, 6 to 10 parts of an exciting agent, 0.5 to 1 part of a modified retarder and 0.3 to 0.5 part of a modified dispersant. The prepared early-strength tackifier for the high-titanium heavy slag-based sprayed concrete has good compressive strength and rebound rate.

Description

Technical Field

[0001] The present invention relates to the technical field of tackifiers, and particularly relates to an early-strength tackifier for shotcrete based on high-titanium heavy slag and a preparation method thereof. Background Art

[0002] Due to the low external environmental temperature, low air pressure, dry and cold climate, dry and hot climate, large temperature difference between day and night, poor tunnel surrounding rock grade, and serious water seepage in alpine and high-altitude areas, the special environmental conditions put forward higher requirements for the early strength, initial and final setting times, etc. of the shotcrete required for tunnel construction. In a low-temperature and low-air-pressure environment, the hydration reaction rate of cement will be significantly reduced. Therefore, when preparing shotcrete in alpine and high-altitude areas, the setting time of the accelerator needs to be increased by more than one time compared with that in plain areas to meet the construction requirements.

[0003] Chinese invention patent with publication number CN119371136A discloses a concrete composite tackifier and a preparation method thereof. When preparing the concrete composite tackifier, the invention first polymerizes acrylic acid, methyl methacrylate, acrylamide, and vinyl diphenylphosphine to obtain a polyacrylic acid resin, reacts it with a modified porphyrin, and then sulfonates it to obtain a modified polyacrylic acid resin; secondly, pretreats silica fume with vinyltrimethoxysilane and reacts it with tetravinyltetramethylcyclotetrasiloxane and vinyl borate pinacol ester to obtain modified silica fume. Finally, the polyacrylic acid resin and the modified silica fume are mixed to obtain the concrete composite tackifier. The concrete composite tackifier prepared by the invention has good work performance and antibacterial properties, but has poor compressive strength and setting time performance. Therefore, it is of great practical significance to develop an early-strength tackifier that can not only improve the early strength but also reduce the rebound of shotcrete to ensure the normal construction of shotcrete in a special environment at an altitude of about 4000 meters. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide an early-strength tackifier for shotcrete based on high-titanium heavy slag and a preparation method thereof.

[0005] To achieve the above purpose, the present invention is realized through the following technical solutions:

[0006] An early-strength tackifier for shotcrete based on high-titanium heavy slag, comprising the following raw materials in parts by weight:

[0007] High-titanium heavy slag: 20 - 60 parts, silica fume: 15 - 40 parts, cement: 10 - 30 parts, activator: 6 - 10 parts, modified retarder: 0.5 - 1 part, modified dispersant: 0.3 - 0.5 part;

[0008] The modified retarder is prepared by the following method:

[0009] S1: N-(4-(2,5-dioxo-4-oxazolidinyl)butyl)-2,2,2-trifluoroacetamide reacts with sodium azide to form an azide compound;

[0010] S2: The azide compound reacts with the quaternary ammonium salt of N,N,N-trimethylpent-4-yn-1-amine under the action of cuprous bromide to form a quaternary ammonium salt compound;

[0011] S3: S-Sulfo-L-cysteine undergoes a cyclization reaction under the action of triphosgene and α-pinene to obtain a sulfonic acid group compound;

[0012] S4: The quaternary ammonium salt compound, the sulfonic acid group compound, and 2,5-dioxo-4-oxazolinepropionic acid react under the action of n-hexylamine to form a modified retarder.

[0013] In the step S1, the molar ratio of N-(4-(2,5-dioxo-4-oxazolidinyl)butyl)-2,2,2-trifluoroacetamide to sodium azide in the feed is 1:(4 - 6).

[0014] In the step S2, the molar ratio of the azide compound to the quaternary ammonium salt of N,N,N-trimethylpent-4-yn-1-amine in the feed is 1:(3 - 5).

[0015] In the step S3, the molar ratio of S-sulfo-L-cysteine, triphosgene, and α-pinene in the feed is 1:(0.4 - 1):(0.8 - 2).

[0016] In the step S4, the molar ratio of the quaternary ammonium salt compound, the sulfonic acid group compound, and 2,5-dioxo-4-oxazolinepropionic acid in the feed is 1:(1 - 2):(1 - 2).

[0017] The modified dispersant is prepared by the following method:

[0018] A1: Triethylene glycol - acetic acid and acrylic acid react under the action of p-toluenesulfonic acid to form an acrylate;

[0019] A2: The acrylate and sodium methallylsulfonate react under the action of ammonium persulfate to form a copolymer;

[0020] A3: The copolymer and propylene oxide react under the condition of sodium hydroxide to form a modified dispersant.

[0021] In the step A1, the molar ratio of triethylene glycol - acetic acid to acrylic acid in the feed is 5:1.

[0022] In the step A2, the molar ratio of the acrylate to sodium methallylsulfonate in the feed is 1:1.5; in the step A3, the mass ratio of the copolymer to propylene oxide in the feed is 1:5.

[0023] The activator is one of sodium sulfate, calcium sulfate, and potassium sulfate.

[0024] A preparation method of an early-strength viscosity-increasing agent for high-titanium heavy slag-based shotcrete, comprising the following steps:

[0025] (1) Weigh by weight: 20 - 60 parts of high-titanium heavy slag, 15 - 40 parts of silica fume, 10 - 30 parts of cement, 6 - 10 parts of activator, 0.5 - 1 part of modified retarder, and 0.3 - 0.5 part of modified dispersant;

[0026] (2) Crush, dry, and ultrafinely grind the high-titanium heavy slag to obtain high-titanium heavy slag micropowder; mix the high-titanium heavy slag micropowder with silica fume at high speed to obtain ultrafine mixed micropowder;

[0027] (3) Stir and mix the ultrafine mixed micropowder with cement, activator, modified retarder, and modified dispersant evenly to obtain an early-strength viscosity-increasing agent for high-titanium heavy slag-based shotcrete.

[0028] Due to the above technical solutions, the beneficial effects of the present invention include:

[0029] The quaternary ammonium salt group of the modified retarder prepared in the present invention has good water solubility and dispersibility, which helps to improve the dispersibility of cement particles, thereby enhancing the compactness of the cement paste and increasing the compressive strength. The hydrophilic groups (such as sulfonic acid groups) in the modified retarder can delay the cement hydration reaction and reduce the release of early hydration heat, thereby reducing the rebound rate. The polyethylene glycol segment introduced in the modified dispersant prepared in the present invention has good hydrophilicity and dispersibility, which helps to improve the dispersibility of cement particles, thereby enhancing the compactness of the cement paste and increasing the compressive strength. Specific embodiments

[0030] The following is further described in conjunction with embodiments, but the present invention is not limited to these embodiments.

[0031] Example 1 Preparation of modified retarder:

[0032] S1: Add 300 ml of DMF, 0.1 mol of N-(4-(2,5-dioxo-4-oxazolidinyl)butyl)-2,2,2-trifluoroacetamide, and 0.4 mol of sodium azide to the reactor, stir and mix evenly, heat up to 50 °C, react for 50 h, then cool to room temperature, filter, perform vacuum distillation at 60 °C for 2 h, then add 100 ml of DCM and stir to dissolve, filter again, add 100 ml of methanol, stir for 10 min, precipitate, centrifuge, and dry in vacuum at 70 °C for 4 h to obtain an azide compound; the reaction equation is shown as follows:

[0033]

[0034] S2: Under airtight conditions, add 500 ml of DMF, 0.1 mol of azide compound and 0.3 mol of N,N,N-trimethylpent-4-yn-1-amine quaternary ammonium salt to the reactor, stir and mix evenly, then add 0.1 mol of cuprous bromide and 0.1 mol of N,N,N′,N″,N″-pentamethyldiethylenetriamine, react at room temperature for 24 h, then expose to air for 1 h to quench the reaction, dialyze in a 2 wt% EDTA DMF solution (MwCO = 8 KDa) for 24 h, then dialyze in deionized water (MwCO = 8 KDa) for 24 h, and freeze-dry at -20 °C for 5 h to obtain the quaternary ammonium salt compound; the reaction equation is shown as follows:

[0035]

[0036] The 1H NMR data are as follows:

[0037] 1 H NMR(500MHz,Chloroform-d)δ8.52(t,J=0.8Hz,3H),8.27(s,1H),5.71(d,J=7.3Hz,1H),4.22(dt,J=7.3,5.2Hz,1H),3.38(t,J=9.0Hz,6H),3.29(s,27H),3.21(tdd,J=4.5,3.3,0.6Hz,2H),2.94(td,J=8.3,0.9Hz,6H),2.20(tt,J=9.0,8.3Hz,6H),1.70–1.53(m,6H).

[0038] S3: Under nitrogen protection, add 1000 ml of tetrahydrofuran, 1 mol of S-sulfo-L-cysteine and 0.8 mol of α-pinene to the reactor, stir and mix evenly, then slowly dropwise add 500 ml of a tetrahydrofuran solution of triphosgene (0.4 mol of triphosgene dissolved in 500 ml of tetrahydrofuran), the dropping takes 20 min, heat up to 50 °C and react for 5 h, then cool to room temperature, rotary evaporate at 50 °C for 2 h, then add 300 ml of cold n-hexane to precipitate, filter, and vacuum dry at 70 °C for 2 h to obtain the sulfonic acid group compound; the reaction equation is shown as follows:

[0039]

[0040] The 1H NMR data are as follows:

[0041] 11H NMR (500 MHz, Chloroform-d) δ 8.73 (s, 1H), 5.52 (d, J = 6.8 Hz, 1H), 4.59 (dt, J = 6.8, 5.0 Hz, 1H), 3.44 (ddd, J = 125.9, 14.8, 5.0 Hz, 2H).

[0042] S4: Add 500 ml of acetic acid, 0.1 mol of quaternary ammonium salt compound, 0.1 mol of sulfonic acid group compound, and 0.1 mol of 2,5-dioxo-4-oxazolinepropionic acid into the reactor, then add 0.1 mol of n-hexylamine, stir evenly, heat up to 40 °C, after reacting for 18 h, add 200 ml of ether, precipitate out, filter, and dry in vacuum at 70 °C for 2 h to obtain the modified retarder; the reaction equation is shown as follows:

[0043]

[0044] Preparation of the modified retarder in Example 2:

[0045] S1: Add 300 ml of DMF, 0.1 mol of N-(4-(2,5-dioxo-4-oxazolidinyl)butyl)-2,2,2-trifluoroacetamide, and 0.5 mol of sodium azide into the reactor, stir evenly, heat up to 60 °C, after reacting for 48 h, cool to room temperature, filter, distill under reduced pressure at 60 °C for 2 h, then add 100 ml of DCM and stir to dissolve, filter again, add 100 ml of methanol, stir for 10 min, precipitate out, centrifuge, and dry in vacuum at 70 °C for 4 h to obtain the azide compound;

[0046] S2: Under closed conditions, add 500 ml of DMF, 0.1 mol of azide compound and 0.4 mol of N,N,N-trimethylpent-4-yn-1-amine quaternary ammonium salt into the reactor, stir evenly, then add 0.1 mol of copper(I) bromide and 0.1 mol of N,N,N′,N″,N″-pentamethyldiethylenetriamine, react at room temperature for 24 h, then expose to air for 1 h to quench the reaction, dialyze in a 2 wt% EDTA DMF solution (MwCO = 8 KDa) for 24 h, then dialyze in deionized water (MwCO = 8 KDa) for 24 h, and freeze-dry at -20 °C for 5 h to obtain the quaternary ammonium salt compound;

[0047] S3: Under nitrogen protection, add 1000 ml of tetrahydrofuran, 1 mol of S-sulfo-L-cysteine, and 1.5 mol of α-pinene into the reactor, stir to mix evenly, and then slowly dropwise add a 500 ml tetrahydrofuran solution of triphosgene (0.6 mol of triphosgene dissolved in 500 ml of tetrahydrofuran). The dropping takes 20 min. After heating to 55 °C and reacting for 4.5 h, cool to room temperature, rotary evaporate at 50 °C for 2 h, then add 300 ml of cold n-hexane to precipitate, filter, and vacuum dry at 70 °C for 2 h to obtain the sulfonic acid group compound;

[0048] S4: Add 500 ml of acetic acid, 0.1 mol of quaternary ammonium salt compound, 0.15 mol of sulfonic acid group compound, and 0.15 mol of 2,5-dioxo-4-oxazolidinepropionic acid into the reactor, then add 0.1 mol of n-hexylamine, stir to mix evenly, heat to 40 °C, and after reacting for 16 h, add 200 ml of ether to precipitate, filter, and vacuum dry at 70 °C for 2 h to obtain the modified retarder.

[0049] Preparation of the modified retarder in Example 3:

[0050] S1: Add 300 ml of DMF, 0.1 mol of N-(4-(2,5-dioxo-4-oxazolidinyl)butyl)-2,2,2-trifluoroacetamide, and 0.6 mol of sodium azide into the reactor, stir to mix evenly, heat to 70 °C, and after reacting for 46 h, cool to room temperature, filter, distill under reduced pressure at 60 °C for 2 h, then add 100 ml of DCM and stir to dissolve, filter again, add 100 ml of methanol, stir for 10 min, precipitate, centrifuge, and vacuum dry at 70 °C for 4 h to obtain the azide compound;

[0051] S2: Under airtight conditions, add 500 ml of DMF, 0.1 mol of azide compound and 0.5 mol of N,N,N-trimethylpent-4-yn-1-amine quaternary ammonium salt into the reactor, stir to mix evenly, then add 0.1 mol of copper(I) bromide and 0.1 mol of N,N,N′,N″,N″-pentamethyldiethylenetriamine, react at room temperature for 24 h, then expose to air for 1 h to quench the reaction, dialyze in a 2 wt% DMF solution of EDTA (MwCO = 8 KDa) for 24 h, then dialyze in deionized water (MwCO = 8 KDa) for 24 h, and freeze-dry at -20 °C for 5 h to obtain the quaternary ammonium salt compound;

[0052] S3: Under nitrogen protection, add 1000 ml of tetrahydrofuran, 1 mol of S-sulfo-L-cysteine, and 2 mol of α-pinene into the reactor, stir to mix evenly, then slowly dropwise add a tetrahydrofuran solution of 500 ml of triphosgene (1 mol of triphosgene is dissolved in 500 ml of tetrahydrofuran). The dropping takes 20 min. After heating to 60 °C and reacting for 4 h, cool to room temperature, rotary evaporate at 50 °C for 2 h, then add 300 ml of cold n-hexane to precipitate, filter, and vacuum dry at 70 °C for 2 h to obtain the sulfonic acid group compound;

[0053] S4: Add 500 ml of acetic acid, 0.1 mol of quaternary ammonium salt compound, 0.2 mol of sulfonic acid group compound, and 0.2 mol of 2,5-dioxo-4-oxazolinepropionic acid into the reactor, then add 0.1 mol of n-hexylamine, stir to mix evenly, heat to 45 °C, after reacting for 15 h, add 200 ml of ether to precipitate, filter, and vacuum dry at 70 °C for 2 h to obtain the modified retarder.

[0054] Example 4 Preparation of modified dispersant:

[0055] A1: Under nitrogen protection, add 200 ml of toluene, 0.5 mol of triethylene glycol-acetic acid, 0.02 mol of p-toluenesulfonic acid, and 5 g of hydroquinone into the reactor, stir to mix evenly, heat to 90 °C, after reacting for 5 h (removing the generated water with a water separator during the reaction), add 0.1 mol of acrylic acid, continue to react for 4 h, cool to room temperature, then add a 5 wt% NaHCO3 solution to neutralize the pH value to neutral, carry out vacuum distillation at 70 °C for 1.5 h, wash the product with deionized water 3 times (using 50 ml of deionized water each time), and vacuum dry at 50 °C for 8 h to obtain the acrylate; The hydroxyl groups and carboxylic acids between different molecules of triethylene glycol-acetic acid undergo self-esterification reaction, and then the hydroxyl groups in the esterification product continue to react with the carboxylic acids in acrylic acid to obtain the acrylate.

[0056] A2: Under nitrogen protection, add 200 ml of deionized water, 0.1 mol of acrylate, and 0.15 mol of sodium methallylsulfonate into the reactor, stir to mix evenly, heat to 60 °C, slowly dropwise add an aqueous solution of ammonium persulfate (5 g of ammonium persulfate is dissolved in 15 ml of deionized water). The dropping takes 20 min. After reacting for 4 h, cool to room temperature, dialyze in deionized water (MwCO = 8 KDa) for 48 h, and freeze-dry at -20 °C for 10 h to obtain the copolymer; The double bonds in the acrylate and the double bonds in sodium methallylsulfonate undergo free radical polymerization reaction to form the copolymer.

[0057] A3: Add 300 ml of anhydrous ethanol, 20 g of copolymer, and 5 g of sodium hydroxide to the reactor, stir to mix evenly, heat up to 60 °C, react for 30 min, then dropwise add 100 g of propylene oxide (pre-cooled to 0 °C) over 1 h. After reacting for 4 h, carry out reduced-pressure distillation at 60 °C for 4 h and vacuum dry at 70 °C for 3 h to obtain the modified dispersant; the carboxyl groups contained in the copolymer react with the epoxy groups in the propylene oxide to form the modified dispersant.

[0058] Example 5 Preparation of early-strength and viscosity-increasing agent for high-titanium heavy slag-based shotcrete:

[0059] (1) Weigh: high-titanium heavy slag: 200 g, silica fume: 150 g, cement: 100 g, activator (sodium sulfate): 60 g, modified retarder (prepared in Example 1): 5 g, modified dispersant (prepared in Example 4): 3 g;

[0060] (2) Add the high-titanium heavy slag to a jaw crusher for crushing for 20 min, dry it at 100 °C for 40 min using a rotary dryer, then add it to a vertical roller mill for grinding, and pass through a 10-mesh sieve to obtain high-titanium heavy slag micropowder; mix the high-titanium heavy slag micropowder and silica fume at high speed and stir at 1500 rpm for 4.5 min to obtain ultrafine mixed micropowder;

[0061] (3) Stir and mix the ultrafine mixed micropowder, cement, activator, modified retarder, and modified dispersant evenly at a rotation speed of 5000 r / min for 3 min to obtain the early-strength and viscosity-increasing agent for high-titanium heavy slag-based shotcrete.

[0062] Example 6 Preparation of early-strength and viscosity-increasing agent for high-titanium heavy slag-based shotcrete:

[0063] (1) Weigh: high-titanium heavy slag: 400 g, silica fume: 250 g, cement: 200 g, activator (calcium sulfate): 80 g, modified retarder (prepared in Example 2): 8 g, modified dispersant (prepared in Example 4): 4 g;

[0064] (2) Add the high-titanium heavy slag to a jaw crusher for crushing for 20 min, dry it at 100 °C for 40 min using a rotary dryer, then add it to a vertical roller mill for grinding, and pass through a 10-mesh sieve to obtain high-titanium heavy slag micropowder; mix the high-titanium heavy slag micropowder and silica fume at high speed and stir at 1500 rpm for 4.5 min to obtain ultrafine mixed micropowder;

[0065] (3) Stir and mix the ultrafine mixed micropowder, cement, activator, modified retarder, and modified dispersant evenly at a rotation speed of 5000 r / min for 3 min to obtain the early-strength and viscosity-increasing agent for high-titanium heavy slag-based shotcrete.

[0066] Example 7 Preparation of Early Strength and Viscosity Increasing Agent for High Titanium Heavy Slag Based Shotcrete:

[0067] (1) Weigh: High titanium heavy slag: 600 g, silica fume: 400 g, cement: 300 g, activator (potassium sulfate): 100 g, modified retarder (prepared in Example 3): 10 g, modified dispersant (prepared in Example 4): 5 g;

[0068] (2) Add the high titanium heavy slag to a jaw crusher and crush it for 20 min, dry it at 100 °C for 40 min using a rotary dryer, then add it to a vertical roller mill for grinding, and pass through a 10-mesh sieve to obtain high titanium heavy slag micro-powder; Mix the high titanium heavy slag micro-powder and silica fume at high speed and stir at 1500 rpm for 4.5 min to obtain ultra-fine mixed micro-powder;

[0069] (3) Stir and mix the ultra-fine mixed micro-powder, cement, activator, modified retarder, and modified dispersant evenly at a rotation speed of 5000 r / min for 3 min to obtain an early strength and viscosity increasing agent for high titanium heavy slag based shotcrete.

[0070] Comparative Example 1

[0071] The raw material composition and process of the early strength and viscosity increasing agent for high titanium heavy slag based shotcrete are basically the same as those in Example 6, except that the modified retarder is replaced with an equal weight of a modified retarder prepared by the following method:

[0072] The preparation method of the modified retarder is basically the same as that in Example 2, except that N-(4-(2,5-dioxo-4-oxazolidinyl)butyl)-2,2,2-trifluoroacetamide in step S1 is replaced with an equal weight of 4-(4-chlorobenzyl)oxazolidine-2,5-dione.

[0073] Comparative Example 2

[0074] The raw material composition and process of the early strength and viscosity increasing agent for high titanium heavy slag based shotcrete are basically the same as those in Example 6, except that the modified retarder is replaced with an equal weight of a modified retarder prepared by the following method:

[0075] S1: Add 300 ml of DMF, 0.1 mol of N-(4-(2,5-dioxo-4-oxazolidinyl)butyl)-2,2,2-trifluoroacetamide, and 0.5 mol of sodium azide to a reactor, stir and mix evenly, heat up to 60 °C, react for 48 h, then cool to room temperature, filter, distill under reduced pressure at 60 °C for 2 h, then add 100 ml of DCM, stir to dissolve, filter again, add 100 ml of methanol, stir for 10 min, precipitate, centrifuge, and dry in vacuum at 70 °C for 4 h to obtain an azide compound;

[0076] S2: Under airtight conditions, add 500 ml of DMF, 0.1 mol of azide compound and 0.4 mol of N,N,N-trimethylpent-4-yn-1-amine quaternary ammonium salt to the reactor, stir and mix evenly, then add 0.1 mol of cuprous bromide and 0.1 mol of N,N,N′,N″,N″-pentamethyldiethylenetriamine, react at room temperature for 24 h, then expose to air for 1 h to quench the reaction, dialyze in a DMF solution of 2 wt% EDTA (MwCO = 8 KDa) for 24 h, and then dialyze in deionized water (MwCO = 8 KDa) for 24 h, and freeze-dry at -20 °C for 5 h to obtain the quaternary ammonium salt compound;

[0077] S3: Add 500 ml of acetic acid, 0.1 mol of quaternary ammonium salt compound, 0.15 mol of 2,5-oxazolidinedione, and 0.15 mol of 2,5-dioxo-4-oxazolinepropionic acid to the reactor, then add 0.1 mol of n-hexylamine, stir and mix evenly, heat up to 40 °C, after reacting for 16 h, add 200 ml of ether, precipitate, filter, and vacuum dry at 70 °C for 2 h to obtain the modified retarder.

[0078] Comparative Example 3

[0079] The raw material composition and process of the early strength and viscosity increasing agent for high-titanium heavy slag-based shotcrete are basically the same as those in Example 6, the difference is that the modified retarder is replaced with an equal weight of the modified retarder prepared by the following method:

[0080] (1) Weigh 60 g of sodium vinylbenzenesulfonate, 12 g of itaconic acid, 19 g of acrylic acid, 7 g of N,N-dimethylacrylamide and 2 g of N-(N-propylacrylamide)-N,N-dimethyloctadecylammonium bromide.

[0081] (2) Add the monomers sodium vinylbenzenesulfonate, itaconic acid, acrylic acid and N,N-dimethylacrylamide to Container 1, then add 196 g of deionized water, stir and dissolve at room temperature to obtain Solution 1; add N-(N-propylacrylamide)-N,N-dimethyloctadecylammonium bromide and 17 g of deionized water to Container 2, stir and dissolve at room temperature to obtain Solution 2;

[0082] (3) Mix Solution 1 and Solution 2 to obtain Solution 3, adjust the pH of the solution to 7 with an aqueous sodium hydroxide solution; add the initiator azodiisobutyramidine hydrochloride, react at 80 °C with stirring for 6 h, and cool to room temperature to obtain a water-soluble amphoteric hydrophobic polymer retarder; the addition amount of azodiisobutyramidine hydrochloride is 0.6% of the total mass of the monomers.

[0083] Comparative Example 4

[0084] The raw material composition and process of the early-strength viscosity-increasing agent for high-titanium heavy slag-based shotcrete are basically the same as those in Example 6, except that the modified dispersant is replaced with an equal weight of the modified dispersant prepared by the following method:

[0085] The preparation method of the modified dispersant is basically the same as that in Example 4, except that the triethylene glycol-acetic acid in Step S1 is replaced with an equal weight of 2-hydroxypropionic acid.

[0086] Comparative Example 5

[0087] The raw material composition and process of the early-strength viscosity-increasing agent for high-titanium heavy slag-based shotcrete are basically the same as those in Example 6, except that the modified dispersant is replaced with an equal weight of the copolymer prepared in Step A2 of Example 4.

[0088] Comparative Example 6

[0089] A concrete composite viscosity-increasing agent prepared with the raw material composition and process of Example 2 of the Chinese invention patent with the publication number CN119371136A.

[0090] The preparation steps of N,N,N-trimethylpent-4-yn-1-amine quaternary ammonium salt are as follows:

[0091] Dissolve 10.0 g of N,N-dimethylpent-4-yn-1-amine in 100 mL of acetonitrile, stir to dissolve, slowly add 31.0 g of methyl iodide dropwise, add dropwise for 20 min, heat to reflux and react for 24 hours, then cool to room temperature, rotary evaporate at 70 °C for 3 h, then add 50 mL of cold ether, stir to precipitate a white solid, filter by suction and wash with ether 3 times (20 mL each time), and vacuum dry at 40 °C for 12 h to obtain N,N,N-trimethylpent-4-yn-1-amine quaternary ammonium salt.

[0092] Application Example: Apply the early-strength viscosity-increasing agent for high-titanium heavy slag-based shotcrete prepared in the examples and comparative examples to concrete, and the concrete mix ratio is shown in Table 1.

[0093] Table 1 Concrete Mix Ratio Table (kg / m 3 )

[0094] Cement Sand Crushed stone Water Water reducing agent Early strength and viscosity increasing agent Accelerator 433 807 807 168 8.65 76 40.72

[0095] The materials used in the examples and comparative examples of this application are as follows: The cement is p.042.5 cement, purchased from Lijiang Ancient City Southwest Cement Co., Ltd.; The main components (by weight ratio) of high-titanium heavy slag include: 7.67% MgO, 16.7% Al2O3, 24.88% SiO2, 27% CaO, 21.74% TiO2, 0.34% Fe2O3, purchased from Panzhihua Huanye Metallurgical Slag Development Co., Ltd.; The gravel particle size is 5-10 mm; The water reducer is The polycarboxylate superplasticizer of type was purchased from Jiangsu Sobute New Materials Co., Ltd.; the accelerating admixture was Liquid accelerating admixture (alkali-free type), Jiangsu Sobute New Materials Co., Ltd.; the sand used was the manufactured sand (medium sand) produced by Heni Township Sand and Gravel Quarry.

[0096] The early-strength and viscosity-increasing admixture for high-titanium heavy slag-based shotcrete in the examples and comparative examples was applied to concrete, and the performance tests of the concrete were carried out. The results are shown in Table 2.

[0097] The compressive strength was carried out according to the test method in Appendix C of JGJ / T 372-2016 "Technical Specification for Application of Shotcrete"; the rebound rate was carried out according to the method in Appendix G of JGJ / T 372-2016 "Technical Specification for Application of Shotcrete"; the setting time was carried out according to the method of GB / T 35159-2017 "Accelerating Admixture for Shotcrete". The blank group was the concrete without adding the early-strength and viscosity-increasing admixture.

[0098] Table 2 Concrete Performance Indexes

[0099]

[0100] It can be seen from Table 1 that the early-strength and viscosity-increasing admixture for high-titanium heavy slag-based shotcrete prepared in Examples 5-7 of this application has excellent compressive strength, rebound rate and setting time.

[0101] The modified retarder prepared by the present invention introduces a sulfonic acid group. The sulfonic acid group has strong hydrophilicity and can be adsorbed on the surface of cement particles, improving the particle dispersibility and reducing the water-cement ratio. At the same time, the sulfonic group can chelate with Ca 2+ , delaying the hydration reaction rate of cement minerals, avoiding structural defects and enhancing the late strength. The carboxylic acid group in the introduced 2,5-dioxo-4-oxazolinepropionic acid can form a stable complex with Ca 2+ in the cement hydration products, thereby enhancing the matrix toughness. The quaternary ammonium salt compound has a positive charge center. In the high-titanium heavy slag-based shotcrete system, these positive charges can have an electrostatic interaction with the negatively charged particles in the concrete, promoting the aggregation and close packing of the particles, reducing the porosity, increasing the density of the concrete and enhancing its compressive capacity.

[0102] The modified dispersant prepared by the present invention introduces sodium methallylsulfonate units to provide a high density of sulfonic acid group negative charges, which disperse high-titanium heavy slag particles and cement particles through electrostatic repulsion, preventing their aggregation caused by van der Waals forces. The uniformly dispersed particle system is conducive to the uniform development of the hydration process, can promote the formation of dense calcium silicate hydrate (C-S-H) gel, reduce the porosity, and thus improve the compressive strength. The ether oxygen bond (-O-) introduced by triethylene glycol - acetic acid forms hydrogen bonds with water molecules, which can form a hydration film on the particle surface and inhibit particle aggregation. The hydroxyl groups introduced by the ring-opening reaction of propylene oxide can be anchored on the surface of slag or cement particles to form a stable adsorption layer, reducing interface defects. At the same time, the hydroxyl groups may participate in the chelation of calcium ions, regulate the hydration kinetics, and optimize the structural arrangement of the C-S-H gel.

[0103] The reason for the poor performance of Comparative Example 1 is that 4-(4-chlorobenzyl)oxazolidine-2,5-dione contains only one chlorine atom, and only one triazole ring is formed in Step S2. The triazole ring can delay the hydration of C3S and ensure the normal development of the later strength of the cement. The reduction of the triazole ring structure will lead to the imbalance of the hydration reaction stage and ultimately reduce the 28-day compressive strength of the concrete.

[0104] The reason for the poor performance of Comparative Example 2 is that the sulfonic acid group is a strongly water-soluble anionic group, which efficiently disperses cement particles through electrostatic repulsion. When the sulfonic acid group is lacking, only the cationic dispersion of the quaternary ammonium salt is relied on, and the charge neutralization is incomplete, and the particles are prone to agglomeration, resulting in uneven hydration and a decrease in compressive strength.

[0105] The reason for the poor performance of Comparative Example 3 is that in the modified retarder prepared in this application, oxazoline propionic acid and sulfonic acid group regulate the hydration kinetics by chelating calcium ions and delay the early hydration of tricalcium silicate. Although the carboxylic acid groups of itaconic acid and acrylic acid in Comparative Example 3 can partially chelate Ca 2+ ,but lack the rigid chelating structure of the oxazoline ring, and have a weak binding ability to Ca 2+ , resulting in unstable early strength development.

[0106] The modified dispersant prepared in Comparative Example 5 lacks hydroxyl groups (-OH). The hydroxyl groups can combine with the polar groups on the surface of cement particles through hydrogen bonds or chemical adsorption to form a stable adsorption layer, enhancing the interfacial binding force between the dispersant and the particles. After the lack, the dispersant molecules only rely on the electrostatic adsorption of the sulfonic acid group, and the adsorption layer is easily damaged by dynamic stress. After the particles are desorbed, they re-agglomerate, resulting in a decrease in dispersibility.

[0107] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. However, for those of ordinary skill in the art, without departing from the scope of the technical solution of the present invention, any minor changes, modifications, and equivalent variations made using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of protection of the technical solution of the present invention.

Claims

1. An early strength and viscosity increasing agent for high-titanium heavy slag-based shotcrete, characterized in that, Comprising raw materials in the following parts by weight: High-titanium heavy slag: 20 - 60 parts, silica fume: 15 - 40 parts, cement: 10 - 30 parts, activator: 6 - 10 parts, modified retarder: 0.5 - 1 part, modified dispersant: 0.3 - 0.5 part; The modified retarder is prepared by the following method: S1: N-(4-(2,5-dioxo-4-oxazolidinyl)butyl)-2,2,2-trifluoroacetamide reacts with sodium azide to form an azide compound; S2: The azide compound reacts with N,N,N-trimethylpent-4-yn-1-amine quaternary ammonium salt under the action of copper(I) bromide to form a quaternary ammonium salt compound; S3: S-sulfo-L-cysteine undergoes a cyclization reaction under the action of triphosgene and α-pinene to obtain a sulfonic acid group compound; S4: The quaternary ammonium salt compound, the sulfonic acid group compound, and 2,5-dioxo-4-oxazolinepropionic acid react under the action of n-hexylamine to form a modified retarder.

2. The early strength and viscosity increasing agent for high-titanium heavy slag-based shotcrete according to claim 1, characterized in that In step S1, the feeding molar ratio of N-(4-(2,5-dioxo-4-oxazolidinyl)butyl)-2,2,2-trifluoroacetamide to sodium azide is 1:(4 - 6).

3. The early strength and viscosity increasing agent for high-titanium heavy slag-based shotcrete according to claim 1, characterized in that, In step S2, the feeding molar ratio of the azide compound to N,N,N-trimethylpent-4-yn-1-amine quaternary ammonium salt is 1:(3 - 5).

4. The early strength and viscosity increasing agent for high-titanium heavy slag-based shotcrete according to claim 1, characterized in that In step S3, the feeding molar ratio of S-sulfo-L-cysteine, triphosgene, and α-pinene is 1:(0.4 - 1):(0.8 - 2).

5. The early strength and viscosity increasing agent for high-titanium heavy slag-based shotcrete according to claim 1, characterized in that, In step S4, the feeding molar ratio of the quaternary ammonium salt compound, the sulfonic acid group compound, and 2,5-dioxo-4-oxazolinepropionic acid is 1:(1 - 2):(1 - 2).

6. The early strength and viscosity increasing agent for high-titanium heavy slag-based shotcrete according to claim 1, characterized in that, The modified dispersant is prepared by the following method: A1: Triethylene glycol - acetic acid and acrylic acid react under the action of p-toluenesulfonic acid to form an acrylate; A2: The acrylate and sodium methallylsulfonate react under the action of ammonium persulfate to form a copolymer; A3: The copolymer and propylene oxide react under the condition of sodium hydroxide to form a modified dispersant.

7. The early strength and viscosity increasing agent for high-titanium heavy slag-based shotcrete according to claim 6, characterized in that, In step A1, the feeding molar ratio of triethylene glycol - acetic acid to acrylic acid is 5:

1.

8. The early strength and viscosity increasing agent for high-titanium heavy slag-based shotcrete according to claim 6, characterized in that, In step A2, the feeding molar ratio of the acrylate to sodium methallylsulfonate is 1:1.5; in step A3, the feeding mass ratio of the copolymer to propylene oxide is 1:

5.

9. The early strength and viscosity increasing agent for high-titanium heavy slag-based shotcrete according to claim 1, characterized in that, The activator is one of sodium sulfate, calcium sulfate, and potassium sulfate.

10. A preparation method of an early strength and viscosity increasing agent for high-titanium heavy slag-based shotcrete according to any one of claims 1-9, characterized in that, Including the following steps: (1) Weigh by parts by weight: high-titanium heavy slag: 20 - 60 parts, silica fume: 15 - 40 parts, cement: 10 - 30 parts, activator: 6 - 10 parts, modified retarder: 0.5 - 1 part, modified dispersant: 0.3 - 0.5 part; (2) Crush, dry, and ultrafinely grind the high-titanium heavy slag to obtain high-titanium heavy slag micropowder; mix the high-titanium heavy slag micropowder with silica fume at high speed to obtain an ultrafine mixed micropowder; (3) Stir and mix the ultrafine mixed micropowder with cement, activator, modified retarder, and modified dispersant evenly to obtain an early-strength and viscosity-increasing agent for high-titanium heavy slag-based shotcrete.

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