A composite drag-reducing and viscosity-reducing concrete for high-lift pumping and its preparation method

Abstract

The present invention discloses a composite drag reduction and viscosity reduction concrete for high-lift pumping and a preparation method thereof, relating to the technical field of concrete. The viscosity reduction concrete comprises the following raw materials in parts by weight: cement: 100-120 parts, manufactured sand: 50-70 parts, silica fume: 15-25 parts, deionized water: 30-50 parts, defoamer: 2-5 parts, modified polycarboxylate water reducer: 5-10 parts; in the present invention, intermediate 1 is prepared by reacting 9-amino-1-nonanol with methyl dec-9-enoate, then intermediate 2 is prepared by reacting intermediate 1 with citric acid, after that intermediate 3 is prepared by reacting intermediate 2 with acryloyl chloride, and finally a modified polycarboxylate water reducer is prepared by free radical polymerization of acrylic acid, intermediate 3 and sodium methallylsulfonate. The viscosity reduction concrete prepared by the present invention has good compressive strength, water reduction rate and net paste fluidity.

Description

Technical Field

[0001] The invention relates to the technical field of concrete, and in particular to a composite drag-reducing and viscosity-reducing concrete for high-lift pumping and a preparation method thereof. Background Art

[0002] As the most widely used building material in civil engineering today, concrete is made of cement as a gelling material, sand and stone as aggregates, and water mixed. Concrete not only has the advantages of abundant raw materials and low cost, but also has good plasticity, high strength and long durability, which is why it is used as the main building material. In recent years, with the rapid development of highways, high-speed railways, bridges, tunnels and urbanization construction, people's requirements for various properties of concrete are also constantly increasing. At present, adding admixtures to concrete has become the main measure to improve the performance of concrete. As the main admixture of concrete, water reducer plays a vital role in improving the working performance of concrete. It can not only greatly reduce the amount of water used in premixed concrete, but also make concrete have the advantages of large initial slump and high fluidity at low water consumption.

[0003] In recent years, a large amount of river sand resources have been gradually consumed. In order to find alternative resources, river sand used in concrete has been gradually replaced by machine-made sand. However, machine-made sand inevitably contains a certain amount of clay, which has caused an increase in the mud content of concrete, especially clay such as bentonite and kaolin, which can quickly adsorb water-reducing agent molecules to saturation adsorption in a short time, greatly destroying the actual effect of polycarboxylic acid water-reducing agent on concrete and affecting the performance of water-reducing agent used in concrete. Therefore, it is particularly important to develop a polycarboxylic acid water-reducing agent with small dosage, high water reduction rate and good net slurry fluidity.

[0004] The Chinese invention patent with publication number CN114956712A discloses a LC40 fully light pumped ceramsite concrete and a preparation method thereof. The ceramsite concrete comprises the following raw materials in parts by weight: 420-500 parts of cementitious material, 160-180 parts of mixing water, 800-840 parts of ceramic sand, 500-540 parts of ceramsite, and 1-5 parts of viscosity reducing and slump retaining agent; it has good compressive strength, but its water reduction rate and net slurry flowability are poor. Summary of the invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide a composite drag-reducing and viscosity-reducing concrete for high-lift pumping and a preparation method thereof.

[0006] To achieve the above object, the present invention is implemented through the following technical solutions:

[0007] A composite drag-reducing and viscosity-reducing concrete for high-lift pumping, wherein the viscosity-reducing concrete comprises the following raw materials in parts by weight: cement: 100-120 parts, machine-made sand: 50-70 parts, silica fume: 15-25 parts, deionized water: 30-50 parts, defoamer: 2-5 parts, modified polycarboxylate water reducer: 5-10 parts;

[0008] The modified polycarboxylate water reducer is prepared by the following method:

[0009] S1: Under nitrogen protection, add methanol and 9-amino-1-nonanol to the reactor, stir under an ice-water bath, then slowly dropwise add methyl 9-decenoate, react under an ice bath for 40-90 min, and then raise the temperature to 30-40 °C and react for 12-16 h. Carry out reduced-pressure distillation to obtain intermediate 1, and the reaction equation is shown as follows:

[0010]

[0011] S2: Under nitrogen protection, add DMSO, citric acid and intermediate 1 to the reactor, stir, raise the temperature to 95-125 °C, then add p-toluenesulfonic acid, react for 4-8 h, and carry out post-treatment to obtain intermediate 2, and the reaction equation is shown as follows:

[0012]

[0013] S3: Under nitrogen protection, add acetonitrile, intermediate 2 and potassium carbonate to the reactor, stir, slowly dropwise add acryloyl chloride under an ice bath, and react for 20-24 h under light-shielded conditions. Carry out post-treatment to obtain intermediate 3, and the reaction equation is shown as follows:

[0014]

[0015] S4: Add intermediate 3 and deionized water to the reactor, stir to dissolve, then add H2O2, stir for 15-25 min, and at the same time, dropwise add a mixed aqueous solution of ammonium persulfate aqueous solution, acrylic acid and sodium methallylsulfonate at a constant speed. After the dropping is completed, raise the temperature to 70-80 °C and keep the temperature for reaction for 2-3 h. Adjust the pH = 7 with sodium hydroxide aqueous solution to obtain the modified polycarboxylate water reducer, and the reaction equation is shown as follows:

[0016]

[0017] o, p, q are natural numbers.

[0018] In the step S1, the mass ratio of methanol, 9-amino-1-nonanol and methyl 9-decenoate is 50:(8-10):(10-25).

[0019] In step S2, the feeding mass ratio of DMSO, citric acid, intermediate 1 and p-toluenesulfonic acid is 50:(4-6):(12-18):(0.1-0.3).

[0020] In step S3, the feeding mass ratio of acetonitrile, intermediate 2, potassium carbonate and acryloyl chloride is 30:(5-7):(6-12):(3-6).

[0021] In step S4, the feeding mass ratio of deionized water, intermediate 3 and H2O2 is 50:(20-30):(4-6).

[0022] The defoaming agent is one of polyether ester defoaming agent SGR1820 and silicone defoaming agent SGR1830.

[0023] A preparation method of a composite drag reduction and viscosity reduction concrete for high-lift pumping, comprising the following steps:

[0024] (1) Weigh by weight: cement: 100-120 parts, manufactured sand: 50-70 parts, silica fume: 15-25 parts, deionized water: 30-50 parts, defoaming agent: 2-5 parts, modified polycarboxylate water reducer: 5-10 parts;

[0025] (2) Mix the cement, modified polycarboxylate water reducer and defoaming agent evenly to obtain a mixture; then mix the mixture, manufactured sand, silica fume and deionized water evenly to obtain the composite drag reduction and viscosity reduction concrete.

[0026] Due to the above technical solutions, the beneficial effects of the present invention include:

[0027] (1) In the present invention, intermediate 1 is prepared by reacting 9-amino-1-nonanol with methyl dec-9-enoate, then intermediate 2 is prepared by reacting intermediate 1 with citric acid, and then intermediate 3 is prepared by reacting intermediate 2 with acryloyl chloride. Finally, acrylic acid, intermediate 3 and sodium methallylsulfonate are subjected to free radical polymerization to prepare a modified polycarboxylate water reducer.

[0028] (2) The intermediate 3 prepared by the present invention has a six-arm structure with a large number of methoxy groups at its ends, which increases the contact points between the water reducer and cement particles and improves the bonding force between the water reducer and cement particles; at the same time, the six-arm dendritic structure can increase the steric hindrance effect. When it is added to cement, it can make the cement have better dispersibility, prevent the agglomeration of cement, and make the prepared concrete have good fluidity even under the condition of a low dosage.

[0029] (3) The modified polycarboxylate water reducer prepared in the present invention synthesizes a six-armed side-chain modified polycarboxylate water reducer by using intermediate 3 and acrylic acid monomer through aqueous solution free radical copolymerization method. The main chain of the prepared water reducer contains carboxyl group and sulfonic acid group, which are attached to the surface of cement particles by complexing with calcium ions. When cement particles approach each other, the long side chains of the water reducer will produce steric hindrance, making it difficult for cement particles to approach each other, improving the release of free water in the cement system, and thus achieving the water reducing effect. Detailed implementation mode

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

[0031] Example 1

[0032] Preparation of modified polycarboxylate water reducer:

[0033] S1: Under nitrogen protection, add 500 g of methanol and 80 g of 9-amino-1-nonanol to the reactor, stir under an ice-water bath, and then slowly dropwise add 100 g of methyl dec-9-enoate. The dropping time is 0.5 h. After dropping, react for 40 min under an ice bath, then raise the temperature to 30 °C and react for 16 h. Distill under reduced pressure at 50 °C for 40 min to obtain intermediate 1;

[0034] S2: Under nitrogen protection, add 500 g of DMSO, 40 g of citric acid and 120 g of intermediate 1 to the reactor, stir, raise the temperature to 95 °C, then add 1 g of p-toluenesulfonic acid, react for 4 - 8 h, wash with saturated NaHCO3 solution until neutral, and distill under reduced pressure at 50 °C for 2 h to obtain intermediate 2;

[0035] S3: Under nitrogen protection, add 300 g of acetonitrile, 50 g of intermediate 2 and 60 g of potassium carbonate to the reactor, stir, and slowly dropwise add 30 g of acryloyl chloride under an ice bath. The dropping time is 10 min. React for 24 h under light protection, filter, and dry under vacuum at 50 °C for 3 h to obtain intermediate 3;

[0036] S4: Add 200 g of intermediate 3 and 500 g of deionized water to the reactor, stir to dissolve, then add 40 g of H2O2, stir for 15 min, and at the same time, dropwise add ammonium persulfate aqueous solution (2 g of ammonium persulfate dissolved in 30 g of deionized water), acrylic acid and sodium methallylsulfonate mixed solution (25 g of acrylic acid and 50 g of sodium methallylsulfonate dissolved in 100 g of deionized water) at a constant speed. The dropping time is 1 h. After dropping, raise the temperature to 70 °C and keep the temperature for reaction for 3 h. Adjust the pH = 7 with 30 wt% sodium hydroxide aqueous solution to obtain the modified polycarboxylate water reducer.

[0037] Example 2

[0038] Preparation of modified polycarboxylate water reducer:

[0039] S1: Under nitrogen protection, add 500 g of methanol and 90 g of 9-amino-1-nonanol into the reactor, stir under an ice-water bath, then slowly dropwise add 175 g of methyl non-9-enoate dropwise over 0.5 h. After the addition, react for 1 h under the ice bath, then raise the temperature to 35 °C and react for 14 h. Distill under reduced pressure at 50 °C for 40 min to obtain Intermediate 1;

[0040] S2: Under nitrogen protection, add 500 g of DMSO, 50 g of citric acid and 150 g of Intermediate 1 into the reactor, stir, raise the temperature to 110 °C, then add 2 g of p-toluenesulfonic acid, react for 6 h, wash with saturated NaHCO3 solution until neutral, and distill under reduced pressure at 60 °C for 1.5 h to obtain Intermediate 2;

[0041] S3: Under nitrogen protection, add 300 g of acetonitrile, 60 g of Intermediate 2 and 90 g of potassium carbonate into the reactor, stir, slowly dropwise add 45 g of acryloyl chloride dropwise under an ice bath over 12 min, react for 22 h under light protection, filter, and dry in vacuo at 60 °C for 3 h to obtain Intermediate 3;

[0042] S4: Add 250 g of Intermediate 3 and 500 g of deionized water into the reactor, stir to dissolve, then add 50 g of H2O2, stir for 20 min, and at the same time, dropwise add an aqueous solution of ammonium persulfate (3 g of ammonium persulfate dissolved in 35 g of deionized water), a mixed solution of acrylic acid and sodium methallylsulfonate (30 g of acrylic acid and 60 g of sodium methallylsulfonate dissolved in 125 g of deionized water) dropwise over 1 h. After the addition, raise the temperature to 75 °C and hold the temperature for reaction for 2.5 h, and adjust the pH = 7 with 30 wt% aqueous sodium hydroxide solution to obtain the modified polycarboxylate water reducer.

[0043] Example 3

[0044] Preparation of the modified polycarboxylate water reducer:

[0045] S1: Under nitrogen protection, add 500 g of methanol and 100 g of 9-amino-1-nonanol into the reactor, stir under an ice-water bath, then slowly dropwise add 250 g of methyl non-9-enoate dropwise over 0.5 h. After the addition, react for 90 min under the ice bath, then raise the temperature to 40 °C and react for 12 h. Distill under reduced pressure at 50 °C for 60 min to obtain Intermediate 1;

[0046] S2: Under nitrogen protection, add 500 g of DMSO, 60 g of citric acid and 180 g of Intermediate 1 into the reactor, stir, raise the temperature to 125 °C, then add 3 g of p-toluenesulfonic acid, react for 4 h, wash with saturated NaHCO3 solution until neutral, and distill under reduced pressure at 70 °C for 1 h to obtain Intermediate 2;

[0047] S3: Under nitrogen protection, add 300 g of acetonitrile, 70 g of intermediate 2, and 120 g of potassium carbonate to the reactor, stir, slowly add 60 g of acryloyl chloride dropwise under an ice bath, react for 20 h under light-shielded conditions for 15 min of dropping, filter, and vacuum dry at 65 °C for 3 h to obtain intermediate 3;

[0048] S4: Add 300 g of intermediate 3 and 500 g of deionized water to the reactor, stir and dissolve, then add 60 g of H2O2, stir for 25 min, and simultaneously and uniformly add dropwise an aqueous solution of ammonium persulfate (5 g of ammonium persulfate dissolved in 50 g of deionized water), a mixed solution of acrylic acid and sodium methallylsulfonate (40 g of acrylic acid and 70 g of sodium methallylsulfonate dissolved in 150 g of deionized water), add dropwise for 1 h, after completion of dropping, raise the temperature to 80 °C and keep the temperature for reaction for 2 h, adjust the pH = 7 with 30 wt% aqueous sodium hydroxide solution to obtain a modified polycarboxylate water reducer.

[0049] Example 4

[0050] Preparation of viscosity-reducing concrete:

[0051] S1: Weigh: cement: 1000 g, manufactured sand: 500 g, silica fume: 150 g, deionized water: 300 g, defoamer (organosilicon defoamer SGR1830): 20 g, modified polycarboxylate water reducer (prepared in Example 1): 50 g;

[0052] S2: Stir and mix the cement, modified polycarboxylate water reducer, and defoamer for 20 min to obtain a mixture; then stir and mix the mixture, manufactured sand, silica fume, and deionized water for 25 min to obtain a composite drag-reducing and viscosity-reducing concrete.

[0053] Example 5

[0054] Preparation of viscosity-reducing concrete:

[0055] S1: Weigh: cement: 1100 g, manufactured sand: 600 g, silica fume: 200 g, deionized water: 400 g, defoamer (polyether ester defoamer SGR1820): 35 g, modified polycarboxylate water reducer (prepared in Example 2): 75 g;

[0056] S2: Stir and mix the cement, modified polycarboxylate water reducer, and defoamer for 20 min to obtain a mixture; then stir and mix the mixture, manufactured sand, silica fume, and deionized water for 30 min to obtain a composite drag-reducing and viscosity-reducing concrete.

[0057] Example 6

[0058] Preparation of viscosity-reducing concrete:

[0059] S1: Weigh: Cement: 1200 g, manufactured sand: 700 g, silica fume: 250 g, deionized water: 500 g, defoamer (organosilicon defoamer SGR1830): 50 g, modified polycarboxylate superplasticizer (prepared in Example 3): 100 g;

[0060] S2: Stir and mix the cement, modified polycarboxylate superplasticizer, and defoamer for 20 min to obtain a mixture; then stir and mix the mixture, manufactured sand, silica fume, and deionized water for 40 min to obtain the composite drag reduction and viscosity reduction concrete.

[0061] Comparative Example 1

[0062] The raw material composition and process of the viscosity reduction concrete are basically the same as those in Example 5, except that the modified polycarboxylate superplasticizer is not added to the components.

[0063] Comparative Example 2

[0064] The raw material composition and process of the viscosity reduction concrete are basically the same as those in Example 5, except that the modified polycarboxylate superplasticizer is replaced with an equal weight of polycarboxylate superplasticizer prepared by the following method:

[0065] S1: Under nitrogen protection, add 500 g of methanol and 90 g of 9-amino-1-nonanol to the reactor, stir under an ice-water bath, and then slowly add 175 g of methyl dec-9-enoate dropwise. The dropping takes 0.5 h. After the dropping is completed, continue the reaction for 1 h under the ice bath, and then react at 35 °C for 14 h. Distill under reduced pressure at 50 °C for 40 min to obtain Intermediate 1;

[0066] S2: Under nitrogen protection, add 500 g of DMSO, 50 g of DL-malic acid, and 150 g of Intermediate 1 to the reactor, stir, heat up to 110 °C, then add 2 g of p-toluenesulfonic acid, react for 6 h, wash with saturated NaHCO3 solution until neutral, and distill under reduced pressure at 60 °C for 1.5 h to obtain Intermediate 2;

[0067] S3: Under nitrogen protection, add 300 g of acetonitrile, 60 g of Intermediate 2, and 90 g of potassium carbonate to the reactor, stir, slowly add 45 g of acryloyl chloride dropwise under an ice bath. The dropping takes 12 min, and react for 22 h under light-shielded conditions. Filter and dry in vacuo at 60 °C for 1.5 h to obtain Intermediate 3;

[0068] S4: Add 250 g of Intermediate 3 and 500 g of deionized water to the reactor, stir to dissolve, then add 50 g of H2O2, stir for 20 min, and simultaneously and uniformly dropwise add an aqueous solution of ammonium persulfate (3 g of ammonium persulfate dissolved in 35 g of deionized water), a mixed solution of acrylic acid and sodium methallylsulfonate (30 g of acrylic acid and 60 g of sodium methallylsulfonate dissolved in 125 g of deionized water). The dropping takes 1 h. After the dropping is completed, raise the temperature to 75 °C and keep the reaction for 2.5 h. Adjust the pH to 7 with 30 wt% aqueous sodium hydroxide solution to obtain the modified polycarboxylate water reducer.

[0069] Comparative Example 3

[0070] The raw material composition and process of the viscosity-reducing concrete are basically the same as those of Example 5, except that the modified polycarboxylate water reducer is replaced with an equal weight of polycarboxylate water reducer prepared by the following method:

[0071] (1) Add 25 ml of methanol and 7 ml of ethanolamine to the reactor, protect with ice bath and nitrogen, slowly dropwise add 30 ml of methyl acrylate, the dropping takes half an hour, continue the ice bath reaction for half an hour, and then react at 30 °C under light-shielded conditions for 16 h. Evaporate to dryness under reduced pressure at 30 °C to obtain a colorless oily substance, which is the 0.5-generation polyamidoamine dendrimer (PAMAM) hyperbranched molecule (G0.5).

[0072] (2) Use ethanol as the single-component eluent for the obtained G0.5, pass it through a silica gel column, collect the fractions, and evaporate to dryness under reduced pressure to obtain relatively pure G0.5.

[0073] (3) Take 5.8 g of purified G0.5 and add 25 mL of methanol. Drop it into a mixed solution of 40 mL of ethylenediamine and 25 mL of methanol under ice bath conditions, and complete the dropping under nitrogen protection within half an hour. Continue the ice bath for half an hour, and then react at 30 °C under nitrogen protection and light-shielded conditions for 48 h. Evaporate to dryness under reduced pressure at 55 °C, and then azeotrope with a mixed solution of methanol:toluene 1:9 for 2 - 3 times to remove the excess ethylenediamine, and then azeotrope with methanol for 2 - 3 times to remove the residual toluene to obtain a colorless viscous oily substance, which is the 1.0-generation PAMAM hyperbranched molecule (G1).

[0074] (4) Take 0.1 mol of chloromethoxypolyethylene glycol (Mn = 600), put it into 100 mL of acetonitrile, add 0.2 mol of potassium carbonate, 1% by mass of potassium iodide based on the total mass of the reaction substances, and 0.02 mol of G1. Under nitrogen protection, reflux at 85 °C under light-shielded conditions for 24 h, filter with a sintered glass funnel, and evaporate to dryness. Add all the products obtained in the previous step to 80 mL of acetonitrile, then add 0.2 mol of potassium carbonate, and 0.06 mol of acrylamide dissolved in 20 mL of acetonitrile. Dropwise add under ice bath, and react under light-shielded nitrogen protection for 24 h. After filtration, evaporate to dryness to obtain a four-armed hyperbranched polyoxyethylene ether macromonomer.

[0075] (5) Add 250 g of tetra-armed hyperbranched polyoxyethylene ether macromonomer and 500 g of deionized water to the reactor, stir to dissolve, then add 50 g of H2O2, stir for 20 min, and then simultaneously and uniformly dropwise add an aqueous solution of ammonium persulfate (3 g of ammonium persulfate dissolved in 35 g of deionized water), a mixed solution of acrylic acid and sodium methallylsulfonate (30 g of acrylic acid and 60 g of sodium methallylsulfonate dissolved in 125 g of deionized water). The dropping takes 1 h. After the dropping is completed, raise the temperature to 75 °C and keep the temperature for reaction for 2.5 h. Adjust the pH = 7 with 30 wt% aqueous sodium hydroxide solution to obtain a modified polycarboxylate water reducer.

[0076] Comparative Example 4

[0077] The raw material composition and process of the viscosity-reducing concrete are basically the same as those of Example 5, except that the modified polycarboxylate water reducer is replaced with an equal weight of polycarboxylate high-performance water reducer (SPC-100).

[0078] Comparative Example 5

[0079] The raw material composition and process of the viscosity-reducing concrete are basically the same as those of Example 5, except that the modified polycarboxylate water reducer is replaced with an equal weight of polycarboxylate water reducer prepared by the following method:

[0080] Add 200 g of ethylene glycol mono vinyl polyethylene glycol ether (EPEG3000) and 500 g of deionized water to the reactor, stir for 10 min, add 2 g of initiator H2O2 to the reactor, stir for 5 min, and then simultaneously dropwise add a mixed solution of 50 g of acrylic acid, 5 g of ascorbic acid and 25 g of allyl sulfonate. The dropping takes 15 min. After the dropping is completed, keep the temperature for 2 h. After the reaction is completed, adjust the pH = 7 with 30 wt% aqueous sodium hydroxide solution to obtain a transparent viscous polycarboxylate water reducer.

[0081] Comparative Example 6

[0082] A kind of LC40 all-light pumped ceramsite concrete prepared with the raw material composition and process of Example 1 of the Chinese invention patent with the publication number CN114956712A.

[0083] The mechanism sand used in the examples and comparative examples of this application has a specification of 1.55 - 4.75 mm and is purchased from Wuhan Deyi Environmental Protection New Materials Co., Ltd.; the cement is road Portland cement 42.5 grade (code P.R7.5) and is purchased from Shanxi Zhuoyue Cement Co., Ltd.; the polyether ester defoamer SGR1820 and the silicone defoamer SGR1830 are purchased from Xingre (Shandong) Environmental Technology Co., Ltd.; the silica fume has a specification of 40 - 200 mesh and is purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; ethylene glycol mono vinyl polyethylene glycol ether (EPEG3000) is purchased from Liaoning OK Chemical Co., Ltd.; the polycarboxylate high-performance water reducer (SPC-100) is purchased from Liaoning Kelong Fine Chemical Co., Ltd.

[0084] The concrete that has been fully stirred by a concrete mixer is molded and sampled, and then placed in a curing box with a temperature of 20 ± 5°C and a humidity of 95% for curing. After 8 days of curing, it is demolded, and the demolded specimens are placed in the curing box for continued curing. When it reaches the specified age, its compressive strength is measured using a compressive strength testing machine.

[0085] The compressive strength of the concrete is measured according to GB / T 50081-2002.

[0086] The water reducing rate and the fluidity of neat cement paste of the concrete are measured according to GB / T 8077-2012.

[0087] Table 1 Concrete performance indicators

[0088]

[0089]

[0090] It can be seen from Table 1 that the composite drag reduction and viscosity reduction concrete prepared in Examples 4-6 of this application has excellent compressive strength, water reducing rate and fluidity of neat cement paste.

[0091] Comparative Example 1 is a comparative example prepared without adding a modified polycarboxylate water reducing agent. It can be seen from the data in Table 1 that after 28 days, its compressive strength is 42.3 MPa, the water reducing rate is 20%, and the fluidity of neat cement paste at 60 minutes is 245 mm. The compressive strength of the prepared concrete is poor, and the fluidity loss performance of neat cement paste over time is poor.

[0092] In Comparative Example 2, the citric acid added in Step S2 during the preparation of the modified polycarboxylate water reducing agent is replaced by DL-malic acid. It can be seen from Table 1 that after 28 days, its compressive strength is 52.9 MPa, the water reducing rate is 31%, and the fluidity of neat cement paste at 60 minutes is 286 mm. The compressive strength of the prepared concrete is poorer than that prepared in Example 5, and the fluidity loss performance of neat cement paste over time is average.

[0093] In Comparative Example 3, the intermediate 3 prepared in Step S3 during the preparation of the modified polycarboxylate water reducing agent is replaced by an equal weight of a four-arm hyperbranched polyoxyethylene ether macromonomer. It can be seen from Table 1 that after 28 days, its compressive strength is 47.7 MPa, the water reducing rate is 25%, and the fluidity of neat cement paste at 60 minutes is 256 mm. It shows that the fluidity loss performance of neat cement paste over time using the four-arm hyperbranched macromonomer is average compared to Example 5.

[0094] In Comparative Example 4, the modified polycarboxylate water reducer added was a polycarboxylate superplasticizer (SPC-100). As can be seen from Table 1, its compressive strength after 28 days was 49.4 MPa, the water reduction rate was 27%, and the fluidity of the neat cement paste at 60 minutes was 261 mm, indicating that the fluidity loss performance of the concrete prepared with this water reducer was average over time.

[0095] Comparative Example 5 was a polycarboxylate water reducer prepared using ethylene glycol mono vinyl polyethylene glycol ether. As can be seen from Table 1, its compressive strength after 28 days was 51.2 MPa, the water reduction rate was 28%, and the fluidity of the neat cement paste at 60 minutes was 273 mm. Its compressive strength was good, but the fluidity loss performance of the neat cement paste over time was average.

[0096] Comparative Example 6 was LC40 all-light pumped ceramsite concrete with the raw material composition and manufacturing process in Example 1 of the Chinese invention patent CN114956712A. As can be seen from Table 1, its compressive strength after 28 days was 51.7 MPa, the water reduction rate was 30%, and the fluidity of the neat cement paste at 60 minutes was 277 mm. Although its compressive strength was high, its fluidity loss performance of the neat cement paste over time was poor.

[0097] 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 changes 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 protection scope of the technical solution of the present invention.

Claims

1. A composite drag-reducing and viscosity-reducing concrete for high-lift pumping, characterized in that: The composite drag-reducing and viscosity-reducing concrete comprises the following raw materials in parts by weight: Cement: 100-120 parts, Machine-made sand: 50-70 parts, Silicon powder: 15-25 parts, Deionized water: 30-50 parts, Defoaming agent: 2-5 parts, Modified polycarboxylic acid water reducer: 5-10 parts; The modified polycarboxylate water-reducing agent is prepared by the following method: S1: Under nitrogen protection, methanol and 9-amino-1-nonanol were added to the reactor, stirred in an ice-water bath, and then dec-9-enoic acid methyl ester was slowly added dropwise, reacted in an ice bath for 40-90 min, then heated to 30-40° C. and reacted for 12-16 h, and distilled under reduced pressure to obtain intermediate 1; S2: Under nitrogen protection, add DMSO, citric acid and intermediate 1 to the reactor, stir, heat to 95-125°C, then add p-toluenesulfonic acid, react for 4-8h, and post-treat to obtain intermediate 2; S3: Under nitrogen protection, acetonitrile, intermediate 2 and potassium carbonate were added to the reactor, stirred, and acryloyl chloride was slowly added dropwise under ice bath, reacted for 20-24 hours under light-proof conditions, and post-treated to obtain intermediate 3; S4: Add intermediate 3 and deionized water to the reactor, stir to dissolve, then add H2O2, stir for 15-25 minutes, and at the same time, uniformly add aqueous solution of ammonium persulfate, acrylic acid and sodium methacrylic acid mixed aqueous solution. After the addition is complete, heat to 70-80°C and keep warm for 2-3 hours. Adjust pH to 7 with aqueous sodium hydroxide to obtain a modified polycarboxylic acid water reducer.

2. The composite drag-reducing and viscosity-reducing concrete for high-lift pumping according to claim 1, characterized in that: In the step S1, the feed mass ratio of methanol, 9-amino-1-nonanol, and dec-9-enoic acid methyl ester is 50:(8-10):(10-25).

3. The composite drag-reducing and viscosity-reducing concrete for high-lift pumping according to claim 1, characterized in that: In the step S2, the mass ratio of DMSO, citric acid, intermediate 1 and p-toluenesulfonic acid is 50:(4-6):(12-18):(0.1-0.3).

4. The composite drag-reducing and viscosity-reducing concrete for high-lift pumping according to claim 1, characterized in that: In the step S3, the feed mass ratio of acetonitrile, intermediate 2, potassium carbonate and acryloyl chloride is 30:(5-7):(6-12):(3-6).

5. The composite drag-reducing and viscosity-reducing concrete for high-lift pumping according to claim 1, characterized in that: In the step S4, the feed mass ratio of deionized water, intermediate 3 and H2O2 is 50:(20-30):(4-6).

6. The composite drag-reducing and viscosity-reducing concrete for high-lift pumping according to claim 1, characterized in that: The defoamer is one of polyether ester defoamer SGR1820 and silicone defoamer SGR1830.

7. A method for preparing the composite drag-reducing and viscosity-reducing concrete for high-lift pumping according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Weigh by weight: cement: 100-120 parts, machine-made sand: 50-70 parts, silica fume: 15-25 parts, deionized water: 30-50 parts, defoamer: 2-5 parts, modified polycarboxylic acid water reducer: 5-10 parts; (2) Cement, modified polycarboxylic acid water-reducing agent and defoaming agent are mixed evenly to obtain a mixture; then the mixture, machine-made sand, silica powder and deionized water are mixed evenly to obtain a composite drag-reducing and viscosity-reducing concrete.

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