An active-activated early-strength cement grinding aid composition and a method for preparing the same

Abstract

The application relates to the technical field of cement admixtures, and particularly discloses an active excitation type early-strength cement grinding aid composition and a preparation method thereof. The active excitation type early-strength cement grinding aid composition comprises the following raw materials in percentage by mass: 8-22% of a grinding aid component, 5-15% of an active excitation component, 5-18% of an early-strength component, 2-10% of a hydration regulation component, and the balance of water; and the hydration regulation component comprises at least one of a slow-release polymer or a pH-sensitive microcapsule. The composition can be used in a cement grinding process, has the advantages that grinding, active excitation, early strength and hydration regulation are integrated, and the cement grinding efficiency and the cement hydration performance are improved in a coordinated manner; in addition, the preparation method has the advantages that the dispersion uniformity of the components and the integrity of the microcapsules in the composition are ensured, and the product has good storage stability.

Description

Technical Field

[0001] This application relates to the field of cement admixture technology, and more specifically, to an active activating early-strength cement grinding aid composition and its preparation method. Background Technology

[0002] Cement grinding is the most energy-intensive step in cement production. Cement grinding aids significantly improve grinding efficiency and reduce power consumption by adsorbing onto the surface of cement particles during the grinding process, reducing particle surface energy, and preventing fine particle agglomeration. However, traditional liquid grinding aids have a single function, mainly focusing on the "grinding aid" effect, and it is difficult to take into account the activation of blended material activity, early strength improvement, and precise control of hydration process.

[0003] In existing technologies, chemical activators such as sulfates and chlorides are often added to activate blends such as slag and fly ash. However, these components have poor compatibility with grinding aids, easily leading to stratification and precipitation of the grinding aids. Furthermore, their activation effect is not matched with the cement hydration process, easily causing insufficient early strength or a decline in later strength. In addition, the components of traditional grinding aids are mostly simple physical mixtures, and the adsorption of each functional component on the surface of cement particles is competitive, making it difficult to achieve the synergistic effect of "grinding aid-activation-early strength-regulation". Especially for blends such as slag and fly ash commonly used by cement enterprises in North China, the low activation efficiency severely restricts the amount of blends in cement and the overall performance of cement products. Summary of the Invention

[0004] In order to overcome the technical bottlenecks of traditional liquid grinding aids, such as single function, disconnect between grinding aid and early strength, and separation of activity activation and hydration regulation, and to achieve synergistic improvement of cement grinding efficiency and cement hydration performance, this application provides an activity-activated early strength cement grinding aid and its hydration process regulation method.

[0005] In a first aspect, this application provides an active, activating, early-strength cement grinding aid, employing the following technical solution: An active activating early-strength cement grinding aid comprises the following raw materials by weight percentage: 8-22% grinding aid component, 5-15% active activating component, 5-18% early-strength component, 2-10% hydration regulating component, and the balance being water; wherein the hydration regulating component comprises at least one of a slow-release polymer or a pH-sensitive microcapsule.

[0006] By adopting the above technical solution, the four functions of grinding aid, activation, early strength, and hydration regulation are integrated into a single liquid system. The grinding aid component can reduce particle agglomeration during the grinding process, increase the hourly output of the grinding table by ≥15%, and reduce grinding power consumption by ≥8kWh / t; the activation component is specifically used to activate the potential activity of blended materials such as slag and fly ash, promoting their participation in the cement hydration reaction; the early strength component accelerates the hydration rate of cement clinker, forming early strength, achieving a 3-day strength increase of ≥30% and no shrinkage of 28-day strength; the hydration regulation component precisely regulates the hydration process through a slow-release or pH-responsive mechanism. The four components work synergistically to break through the technical bottleneck of traditional grinding aids where "grinding aid and early strength are disconnected, and activation and hydration regulation are separated," thereby improving the overall performance and application value of the product.

[0007] Preferably, the grinding aid component is one or more of the following: polymeric polyol, polyglycerol, polyethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, triethanolamine oleate, triethanolamine acetate, diethanolamine, lignin sulfonate, molasses, or sodium carboxymethyl cellulose. The active activating component is one or more of the following: triethanolamine, triisopropanolamine, diethanolmonoisopropanolamine, sodium sulfate, sodium thiosulfate, calcium chloride, and calcium nitrate. The early strength component is one or more of the following: calcium formate, nanocrystalline nuclei, nano-silica, nano-calcium carbonate, sodium silicate, and aluminum sulfate. The nanocrystalline nucleus material is CSH gel or calcium silicate.

[0008] By adopting the above technical solutions, the specific material sources of the grinding aid component, the activation component, and the early strength component are extensive and the effects are stable. Among them, diethanol monoisopropanolamine has both grinding aid and certain activation functions. When compounded with polymeric polyol, it can form a denser adsorption layer on the surface of cement particles, significantly reducing crushing resistance. Triisopropanolamine can effectively destroy the Si-O and Al-O bonds on the surface of slag glass. Sodium sulfate provides sulfate ions to react with the active alumina in fly ash to generate ettringite. The combination of the two can significantly activate the potential activity of the blend. Calcium formate is compounded with CSH gel crystal nuclei. Calcium formate accelerates the hydration rate of tricalcium silicate in cement, and the nanocrystalline nuclei provide nucleation sites for the generation of hydration products. The combination of the two can achieve a significant increase in 3-day strength while preventing shrinkage of 28-day strength.

[0009] Preferably, the slow-release polymer is a hydrolyzable ester bond type polycarboxylic acid comb copolymer, which is copolymerized from at least one of acrylic acid, methacrylic acid, maleic anhydride, and sodium propylene sulfonate with polyethylene glycol monomethyl ether acrylate and polyethylene glycol monomethyl ether methacrylate. The weight-average molecular weight of the slow-release polymer is 20,000-60,000, the acid-ether molar ratio is (1.5-4):1, and the molecular weight of the polyethylene glycol monomethyl ether segment is 500-2,000. The side chains of the polymer are linked to polyethylene glycol monomethyl ether segments via hydrolyzable ester bonds, with a hydrolysis half-life of 1-8 hours.

[0010] By adopting the above technical solution, the ester bonds of the slow-release polymer gradually break under the alkaline conditions of cement hydration, slowly releasing the polycarboxylic acid side chains, providing continuous dispersion and hydration control, and avoiding the later strength reduction caused by excessive hydration.

[0011] Preferably, the microcapsules are single-layer pH-sensitive microcapsules, and the wall material is at least one of chitosan, sodium alginate, polylactic acid-glycolic acid copolymer, and dimethylaminoethyl methacrylate copolymer; the core of the microcapsules is a coagulating component or a retarding component; the average particle size of the microcapsules is 5-30 μm, and the wall material thickness is 0.5-2 μm.

[0012] By adopting the above technical solution, the pH-sensitive microcapsules rupture when the pH of the cement paste rises above 12, releasing the internal regulating components, thus achieving "on-demand regulation" of the hydration process. The combination of slow-release polymers and pH-sensitive microcapsules enables precise control of the hydration rate.

[0013] Preferably, the grinding aid composition further comprises 0.5-5% modified nanoparticles; the modified nanoparticles are nano-calcium carbonate or nano-silica with an average particle size of 20-100 nm, and their surfaces are pre-adsorbed with an anionic polymer dispersant; the anionic polymer dispersant is sodium polyacrylate or polycarboxylate.

[0014] By adopting the above technical solution, the anionic polymer dispersant pre-adsorbed on the surface of the modified nanoparticles can form an electric double layer around the nanoparticles, effectively preventing them from agglomerating in the liquid grinding aid, ensuring the long-term stable storage and uniform dispersion of the nanoparticles, and allowing the nanoparticles to fill the micropores of cement particles, playing a dual role of physical filling and crystal nucleation induction.

[0015] Preferably, the grinding aid composition further comprises 0.5-6% of a dispersion stabilizing component; the dispersion stabilizing component is one or two of polycarboxylate anionic dispersant, polyvinyl alcohol, or polyethylene glycol.

[0016] By adopting the above technical solution, the dispersion and stabilization components improve the suspension stability of the entire liquid system and prevent the sedimentation of microcapsules and modified nanopowders.

[0017] Preferably, the grinding aid composition further comprises 0.1-2% of an interface remodeling agent; the interface remodeling agent is a polyethylene glycol-polyacrylic acid block copolymer, wherein the polyethylene glycol segment has a molecular weight of 2000-5000 and the polyacrylic acid segment has a degree of polymerization of 20-50.

[0018] By adopting the above technical solution, the interface reconstruction agent optimizes the adsorption layer structure of grinding aid molecules on the surface of cement particles, improves the interfacial compatibility between newly generated cement particles and grinding aid, and further enhances grinding efficiency and dispersibility.

[0019] Secondly, this application provides a method for preparing an active, activating, early-strength cement grinding aid, employing the following technical solution: A method for preparing an active, early-strength cement grinding aid includes the following steps: (1) Add the prescribed amount of water to the reactor, and under normal temperature stirring conditions, first add the grinding aid component and the active activation component, and stir until completely dissolved; (2) Add the early-strength component to the reactor; (3) Control the system temperature to 20-40℃ and keep it warm while stirring for 20-40 minutes; (4) Add the hydration regulating component and stir at low speed for 30-60 minutes; (5) After constant temperature standing and defoaming, use an 80-mesh flexible filter screen for low-pressure filtration to obtain a liquid active activating early strength cement grinding aid composition.

[0020] Through the above technical solution, the preparation method of this application involves stepwise and graded mixing of each component based on its physicochemical properties. The grinding aid and activation components are readily soluble in water and dissolve preferentially. The early-strength component and modified nanoparticles are pre-dispersed via high-speed shearing to overcome the problem of nanoparticle agglomeration. The microcapsules in the hydration regulation component are sensitive to shear force; therefore, they are added in the final step with low-speed stirring to ensure their structural integrity. Finally, the addition of an interface reconstruction agent and a low-pressure filtration step effectively remove trace amounts of insoluble matter and bubbles, resulting in a uniform, stable, and high-performance liquid product.

[0021] In summary, this application has the following beneficial effects: 1. Because this application adopts a scientific compounding of grinding aid components, activation components, early strength components and hydration regulation components, it integrates the four functions of grinding aid, activation, early strength and hydration regulation into the same liquid system. The four components work together to increase the hourly output of the grinding table by ≥15%, reduce the grinding power consumption by ≥8kWh / t, increase the 3d strength by ≥30% and have no shrinkage in 28d strength. It has achieved the effect of breaking through the technical bottleneck of traditional grinding aids having a single function, the disconnect between grinding aid and early strength, and the separation of activation and hydration regulation.

[0022] 2. In this application, triisopropanolamine and sodium sulfate are preferably used as the active activating components. Considering the chemical composition characteristics of fly ash and slag in North China, triisopropanolamine can effectively break the chemical bonds on the surface of the slag glass, and sodium sulfate provides sulfate ions to react with fly ash to generate ettringite, thereby significantly improving the hydration participation of the mixed material and achieving the effect of highly efficient activation of the activity of the mixed material.

[0023] 3. In this application, slow-release polymers and pH-sensitive microcapsules are preferred as hydration regulating components. The slow-release polymers gradually hydrolyze under alkaline conditions to continuously release dispersion and hydration-controlling functional groups, while the pH-sensitive microcapsules rupture and release regulating components when the pH increases. The combination of the two achieves precise control of the hydration rate and avoids the problems of strength reduction or abnormal coagulation caused by hydration that is too fast or too slow.

[0024] 4. The preparation method of this application, through steps such as stepwise mixing, high-speed shear pre-dispersion, and low-speed stirring microcapsule formation, effectively ensures the uniform dispersion of each component in the composition and the integrity of the microcapsules. The resulting liquid grinding aid is a uniform transparent to pale yellow transparent liquid at room temperature, with a kinematic viscosity of 15-80 mmHg. 2 / s, sealed, room temperature, and protected from light, with a storage period of ≥6 months and a performance degradation rate of ≤3%, achieving good storage stability and industrial applicability. Detailed Implementation

[0025] The present application will be further described in detail below with reference to the embodiments. Preparation Examples of Slow-Release Polymers 1-2

[0026] Preparation Example 1 The sustained-release polymer is a hydrolyzable ester-bonded polycarboxylic acid comb copolymer. The preparation method includes the following steps: 400g of deionized water is added to a reaction vessel, the temperature is raised to 80℃, and a monomer mixture consisting of 120g of acrylic acid and 80g of polyethylene glycol monomethyl ether methacrylate, as well as an initiator solution consisting of 5g of ammonium persulfate and 50g of water, is added dropwise over 3 hours. After the addition is complete, the reaction is maintained at this temperature for 2 hours. After the reaction is completed, the temperature is cooled to 40℃, and the pH is adjusted to 6.5 with 30% sodium hydroxide solution to obtain a sustained-release polymer with a weight-average molecular weight of 40,000 and an acid-ether molar ratio of 2.5:1. The hydrolysis half-life in an alkaline solution at pH=12.5 is approximately 4 hours.

[0027] Preparation Example 2 The difference between Preparation Example 2 and Preparation Example 1 is that in Preparation Example 2, the amount of acrylic acid added is 200g, the amount of polyethylene glycol monomethyl ether methacrylate added is 40g, the weight average molecular weight of the obtained slow-release polymer is 18000, and the acid-ether molar ratio is 5.2:1. Preparation of pH-sensitive microcapsules: Examples 3-4

[0028] Preparation Example 3 The preparation method of pH-sensitive microcapsules includes the following steps: 15g of chitosan is dissolved in 500mL of 2wt% acetic acid solution as the aqueous phase; 5g of triethanolamine and 2g of Span 80 are dissolved in 100mL of ethyl acetate as the oil phase; the oil phase is slowly added dropwise to the aqueous phase at 10000rpm to form an O / W emulsion; 50mL of 2wt% sodium tripolyphosphate aqueous solution is slowly added dropwise, and the reaction is stirred for 2h; after the reaction is complete, the mixture is centrifuged, washed three times each with deionized water and ethanol, and dried under vacuum at 40℃ to obtain pH-sensitive microcapsules. The obtained microcapsules have an average particle size of 18μm and a wall thickness of approximately 1.2μm.

[0029] Preparation Example 4 The difference between Preparation Example 4 and Preparation Example 3 is that in Preparation Example 4, the amount of chitosan added was 5g, and the average particle size of the resulting pH-sensitive microcapsules was 45μm, with a wall material thickness of approximately 0.3μm. Preparation Examples of Modified Nanopowders 5-6

[0030] Preparation Example 5 The preparation method of modified nanopowder includes the following steps: 100g of nano-calcium carbonate powder with an average particle size of 50nm is dispersed in 1L of deionized water, 5g of sodium polyacrylate is added, ultrasonically dispersed for 30min, stirred for 2h, centrifuged, washed twice with deionized water, vacuum dried at 80℃, and ground to obtain modified nano-calcium carbonate with sodium polyacrylate pre-adsorbed on the surface.

[0031] Preparation Example 6 The difference between Preparation Example 6 and Preparation Example 5 is that in Preparation Example 6, sodium polyacrylate was not added, and the nano-calcium carbonate powder was directly dispersed in deionized water. After ultrasonic dispersion for 30 minutes, it was centrifuged, dried, and ground to obtain unmodified nano-calcium carbonate. Example

[0032] Example 1 An active activating early-strength cement grinding aid composition comprises the following raw materials in weight percentage: 15% grinding aid component, 10% active activating component, 12% early-strength component, 5% hydration regulating component, 2% modified nanoparticles, 3% dispersing stabilizing component, 1% interface reconstruction agent, and the balance being water.

[0033] The grinding aid component is a mixture of diethylene glycol and diethanolamine in a mass ratio of 2:1; the activation component is a mixture of triisopropanolamine and sodium sulfate in a mass ratio of 1:1; the early strength component is a mixture of calcium formate and CSH gel nanocrystal nuclei in a mass ratio of 1:2; the hydration regulating component is a mixture of the sustained-release polymer obtained in Preparation Example 1 and the pH-sensitive microcapsules obtained in Preparation Example 3 in a mass ratio of 1:1; the modified nanopowder is the modified nanopowder obtained in Preparation Example 5; the dispersion stabilizing component is polyethylene glycol 400; and the interface reconstruction agent is a polyethylene glycol-polyacrylic acid block copolymer.

[0034] The preparation method of the above-mentioned active activating early-strength cement grinding aid composition includes the following steps: (1) Add water to the reactor, and under normal temperature stirring conditions, first add the grinding aid component and the active activation component, and stir until completely dissolved; (2) The early strength component and modified nanoparticles were pre-dispersed with the dispersion stabilizing component under high-speed shear at 8000 rpm for 10 min, and then added to the reaction vessel; (3) Control the system temperature to 30℃ and keep it warm while stirring for 30 minutes; (4) Add the hydration regulating component and disperse at 300 rpm for 45 min to avoid microcapsule rupture; (5) After being kept at a constant temperature for 30 minutes to remove foam, low-pressure filtration is performed using an 80-mesh flexible filter screen; (6) Add the interface reconstruction agent to the filtered composition and stir evenly to obtain the liquid active activated early strength cement grinding aid composition.

[0035] Example 2

[0036] The difference between Example 2 and Example 1 is that in Example 2, the mass percentage of each raw material is: 22% grinding aid component, 5% activation component, 18% early strength component, 2% hydration regulation component, 5% modified nanoparticle, 0.5% dispersion stabilizing component, 0.1% interface reconstruction agent, and the balance is water; in the preparation method, the system temperature in step (3) is controlled at 20℃ and kept warm and stirred for 40 min; in step (4), low-speed stirring is carried out for 60 min.

[0037] Example 3

[0038] The difference between Example 3 and Example 1 is that in Example 3, the mass percentage of each raw material is: 8% grinding aid component, 15% activation component, 5% early strength component, 10% hydration regulation component, 0.5% modified nanoparticle, 6% dispersion stabilizing component, 2% interface reconstruction agent, and the balance is water; in the preparation method, the system temperature in step (3) is controlled at 40℃ and kept warm and stirred for 20min; in step (4), low-speed stirring is carried out for 30min.

[0039] Example 4

[0040] The difference between Example 4 and Example 1 is that in Example 4, the slow-release polymer in the hydration regulation component is the slow-release polymer obtained in Preparation Example 2.

[0041] Example 5

[0042] The difference between Example 5 and Example 1 is that in Example 5, the pH-sensitive microcapsules in the hydration regulation component are the microcapsules prepared in Preparation Example 4.

[0043] Example 6

[0044] The difference between Example 6 and Example 1 is that in Example 6, the modified nanopowder is the unmodified nano-calcium carbonate obtained in Preparation Example 6.

[0045] Example 7

[0046] The difference between Example 7 and Example 1 is that in Example 7, no modified nanopowder, dispersing stabilizing components and interface reconstruction agents are added.

[0047] Example 8

[0048] The difference between Example 8 and Example 1 is that in Example 8, the hydration control component uses only the sustained-release polymer prepared in Preparation Example 1, with an addition amount of 5%, and no pH-sensitive microcapsules are added.

[0049] Example 9

[0050] The difference between Example 9 and Example 1 is that in Example 9, the hydration control component uses only the pH-sensitive microcapsules prepared in Preparation Example 3, with an addition amount of 5%, and no sustained-release polymer is added.

[0051] Example 10

[0052] The difference between Example 10 and Example 1 is that in Example 10, the active activating component is a mixture of triisopropanolamine and sodium sulfate in a mass ratio of 1:3, and the early strength component is a mixture of calcium formate and CSH gel nanocrystal core material in a mass ratio of 3:1. Comparative Example

[0053] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that no hydration control component is added in Comparative Example 1.

[0054] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the hydration control component in Comparative Example 2 is replaced with an equal mass of sodium gluconate.

[0055] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that in Comparative Example 3, the active activating component, early strength component, hydration regulating component, modified nanoparticle, dispersion stabilizing component, and interface reconstruction agent in the composition are replaced with grinding aid components in equal amounts, that is, the total content of grinding aid components is 48%.

[0056] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that in Comparative Example 4, the mass percentage of each raw material is as follows: 25% grinding aid component, 3% activity activating component, 20% early strength component, 1% hydration regulating component, 0.2% modified nanoparticle, 0.3% dispersion stabilizing component, 0.05% interface reconstruction agent, and the balance is water.

[0057] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that in the preparation method of Comparative Example 5, when adding the hydration control component in step (4), the stirring is carried out at 5000 rpm for 45 min. Performance testing

[0058] The active activating early strength cement grinding aid compositions prepared in Examples 1-10 and Comparative Examples 1-5 were subjected to the following tests, and the results are recorded in Table 1.

[0059] Grinding efficiency test: The test was conducted in a standard Φ500mm×500mm test mill in the laboratory, referring to the GB / T-26748-2011 standard "Cement Grinding Aids". The grinding aids prepared in each example and comparative example were added at 0.1% of the cement mass and ground together with P·O-42.5 ordinary Portland cement clinker (with 20% fly ash and 20% slag) for 30 minutes. The specific surface area of ​​the cement after grinding (m² / kg) was measured, and the grinding power consumption (kWh / t) was recorded to evaluate the grinding efficiency. A higher specific surface area and lower power consumption indicated better grinding efficiency.

[0060] Cement mortar strength test: Refer to GB / T-17671-2021 "Test method for strength of cement mortar (ISO method)" to determine the 3-day compressive strength (MPa) and 28-day compressive strength (MPa) of cement after adding grinding aid. The 3-day strength reflects the early strength effect, and the 28-day strength reflects the later strength development to prevent shrinkage.

[0061] Hydration process test / setting time: Refer to GB / T-1346-2011 "Standard consistency water requirement, setting time and soundness test method for cement" to determine the initial setting time and final setting time of cement and evaluate the ability of hydration regulating components to regulate the hydration process.

[0062] Table 1. Test results of grinding aid performance Example 1 428 30.0 34.2 55.0 195 275 Example 2 420 31.2 33.5 54.2 188 268 Example 3 418 31.5 33.0 54.0 202 282 Example 4 422 30.8 33.8 54.5 185 262 Example 5 416 31.8 32.5 53.5 178 255 Example 6 408 32.5 31.8 52.8 190 270 Example 7 395 34.0 30.5 51.5 192 272 Example 8 420 31.0 34.6 52.0 210 295 Example 9 418 31.2 31.8 53.0 165 235 Example 10 415 32.0 31.5 53.2 190 270 Comparative Example 1 400 33.5 26.5 48.5 155 220 Comparative Example 2 402 33.2 29.5 49.5 245 340 Comparative Example 3 380 40.0 22.8 44.5 145 210 Comparative Example 4 392 35.0 27.5 49.0 160 225 Comparative Example 5 410 32.8 31.2 51.8 175 250 As can be seen from Table 1, Examples 1-3 and Comparative Example 1, the active activating early strength cement grinding aid compositions prepared in Examples 1-3 have excellent grinding efficiency, early strength effect and later strength retention ability, and can effectively regulate the cement hydration process to keep the setting time within a reasonable range; the grinding aids in Examples 1-3 contain grinding aid components, active activating components, early strength components and hydration regulating components, and the four work synergistically.

[0063] The grinding aid component reduces the surface energy of cement particles during grinding, reducing fine particle agglomeration, thereby significantly increasing the specific surface area and reducing grinding power consumption. The triisopropanolamine in the activation component breaks the Si-O and Al-O bonds on the surface of the slag glass, and sodium sulfate provides sulfate ions to react with the active alumina in fly ash to generate ettringite. The combination of the two effectively activates the potential activity of the blend. The calcium formate in the early strength component accelerates the hydration rate of tricalcium silicate, and CSH gel nanocrystal nuclei provide nucleation sites for hydration products. The combination of the two achieves a significant increase in 3-day strength and no shrinkage in 28-day strength. The hydration regulation component precisely controls the hydration process by gradually hydrolyzing the ester bonds of the slow-release polymer and releasing the regulation component by breaking down pH-sensitive microcapsules under alkaline conditions, avoiding abnormal strength or setting time caused by excessively fast or slow hydration.

[0064] In contrast, Comparative Example 1, which did not contain any hydration regulators, showed a significant decrease in 3-day strength to 26.5 MPa and 28-day strength to 48.5 MPa. Furthermore, the initial setting time was shortened to 155 min and the final setting time to only 220 min, indicating that the hydration process was out of control. The excessively rapid early hydration led to a reduction in later strength, thus confirming the effectiveness of hydration regulators in maintaining later strength and controlling setting time.

[0065] Comparative Example 2 replaced the hydration regulating component with an equal mass of the traditional retarder sodium gluconate. Although the initial setting time was extended to 245 min and the final setting time to 340 min, the 3-day strength was only 29.5 MPa and the 28-day strength was 49.5 MPa, both significantly lower than in Example 1. This is because although sodium gluconate can delay hydration, it does not possess the gradual release characteristics of a slow-release polymer or the pH-responsive on-demand release function of microcapsules. This results in excessive early retardation and insufficient later regulation, failing to achieve precise matching of the hydration rate, thus sacrificing early strength and failing to improve later strength.

[0066] Comparative Example 3 replaced all the active activating components, early strength components, and hydration regulating components with grinding aid components, resulting in the grinding aid having only a grinding aid function, and its specific surface area decreased to 380m². 2The grinding efficiency was as high as 40.0 kWh / t, indicating that the grinding efficiency decreased after the lack of synergy between the active activation and early strength components. At the same time, the 3d strength was only 22.8 MPa and the 28d strength was only 44.5 MPa, which was far lower than that of Example 1. This shows that the simple grinding aid effect cannot activate the activity of the mixed material or accelerate hydration. The integration of the four functions is a necessary condition for achieving synergistic improvement.

[0067] In Comparative Example 4, the grinding aid component was too high while the active activating component and hydration regulating component were too low, resulting in a specific surface area of ​​392 m². 2 The powder has a weight of 1 kg, a grinding power consumption of 35.0 kWh / t, a 3d strength of 27.5 MPa, and a 28d strength of 49.0 MPa. All of these properties are inferior to those of Examples 1-3, indicating that when the dosage ratio is unbalanced, the synergistic effect of each component is weakened, and the best grinding aid, activation, early strength and regulation effects cannot be achieved.

[0068] In the preparation method of Comparative Example 5, a high-speed stirring at 5000 rpm was used when adding the hydration regulating component, and its specific surface area was 410 m². 2 The pH / kg, 3d strength of 31.2 MPa, and 28d strength of 51.8 MPa are all lower than those of Example 1. Furthermore, the initial setting time is 175 min and the final setting time is 250 min. This indicates that the strong shear force generated by high-speed stirring damages the wall material structure of the pH-sensitive microcapsules, causing some regulating components to leak prematurely. As a result, the performance of the grinding aid decreases during storage, and the hydration regulation ability decreases in actual use. In contrast, Example 1 uses low-speed stirring at 300 rpm, which effectively protects the integrity of the microcapsules and ensures the storage stability and performance of the product.

[0069] Compared to Example 1, Example 4 used a slow-release polymer with a higher acid-ether molar ratio and lower molecular weight, resulting in a reduced specific surface area of ​​422 m². 2 / kg, the 28-day strength dropped to 54.5 MPa, slightly lower than in Example 1, indicating that an excessively high acid-ether ratio intensifies the adsorption competition of the polymer on the surface of cement particles, partially interfering with the adsorption of grinding aid components; an excessively low molecular weight weakens the steric hindrance effect of the side chains, reducing dispersion and hydration control capabilities, indicating that the molecular structure and acid-ether ratio of the slow-release polymer need to be optimized to achieve the best effect.

[0070] Compared to Example 1, Example 5 used pH-sensitive microcapsules with thinner walls and larger particle sizes, resulting in a specific surface area of ​​416 m². 2 The performance of the material was lower than that of Example 1, with a thickness of 32.5 MPa, a 3-day strength of 32.5 MPa, and a final setting time of 255 min. This indicates that the thin wall material caused some microcapsules to rupture prematurely during storage or stirring. The large particle size reduced the uniformity of its distribution in the cement paste and decreased the spatiotemporal precision of the controlled component release, thus affecting the early strength effect and the accuracy of hydration control.

[0071] Compared to Example 1, Example 6 used unmodified nano-calcium carbonate with a specific surface area of ​​408 m². 2 The unmodified nanoparticles exhibited strengths of 31.8 MPa (6 kg / kg), 3-day strength of 31.8 MPa, and 28-day strength of 52.8 MPa, all lower than those in Example 1. This indicates that the unmodified nanoparticles lack pre-adsorption of anionic polymer dispersants on their surface, making them prone to agglomeration and sedimentation in liquid grinding aids. Consequently, they cannot be uniformly dispersed in cement particles, significantly reducing their filling and nucleation induction effects. This demonstrates that modification treatment is crucial for the stable dispersion of nanoparticles in grinding aid systems.

[0072] Example 7, without the addition of modified nanoparticles, dispersing stabilizers, and interface remodeling agents, showed a specific surface area reduced to 395 m². 2 The grinding power consumption increased to 34.0 kWh / t, the 3d strength was 30.5 MPa, and the 28d strength was 51.5 MPa. The lack of nanoparticles weakened the micropore filling and crystal nucleation induction effects; the lack of dispersing and stabilizing components led to a decrease in the suspension stability of the system, and microcapsules and a small amount of insoluble matter were prone to sedimentation; the lack of interface reconstruction agent resulted in an unoptimized adsorption layer structure of grinding aid molecules on the surface of cement particles, and poor interfacial compatibility, which together led to a comprehensive decline in grinding efficiency and hydration performance.

[0073] Example 8 used only a slow-release polymer as the hydration control component and did not use pH-sensitive microcapsules. Although its 3-day strength reached 34.6 MPa, its 28-day strength dropped to 52.0 MPa, and the final setting time was extended to 295 min. This indicates that the single slow-release polymer mainly provides continuous dispersion and slow-release hydration control, but lacks the on-demand rapid release capability of pH-sensitive microcapsules in alkaline environments. This results in insufficient release of the hydration control component in the early stage and an excessively long duration of the slow-release effect in the later stage. The early strength is acceptable, but the setting is too slow, and the later strength decreases slightly.

[0074] Example 9 used only pH-sensitive microcapsules as the hydration control component and did not use a slow-release polymer. Its 28-day strength was 53.0 MPa, but its 3-day strength was only 31.8 MPa. The initial setting time was 165 min and the final setting time was 235 min. This indicates that the control component was released in a concentrated manner after the microcapsules ruptured. The lack of long-term continuous control by the slow-release polymer led to excessive release of the control component in the early stage, which delayed the early hydration. In the later stage, there was a lack of continuous dispersion and hydration control effect, resulting in low early strength and short setting time.

[0075] Example 10 adjusted the ratio of the active activating component and the early-strength component, resulting in a specific surface area of ​​415 m². 2The strength of 3d (31.5 MPa) and 28d (53.2 MPa) were all lower than those of Example 1, indicating that an excessively high proportion of sodium sulfate in the active activating component would lead to an excess of sulfate ions, which may cause excessive formation of ettringite and delay early hydration. An excessively high proportion of calcium formate and insufficient CSH gel in the early strength component would result in a lack of sufficient crystal nucleation sites, thus limiting the early strength effect. This indicates that optimizing the ratio between components is the key to achieving synergistic effects.

[0076] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A composition of an active, activating, early-strength cement grinding aid, characterized in that, The raw materials comprise the following percentages by weight: 8-22% grinding aid, 5-15% activation component, 5-18% early strength component, 2-10% hydration control component, with the balance being water; the hydration control component comprises at least one of a slow-release polymer or a pH-sensitive microcapsule.

2. The active activating early-strength cement grinding aid composition according to claim 1, characterized in that, The grinding aid component is one or more of the following: polyol, polyglycerol, polyethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, triethanolamine oleate, triethanolamine acetate, diethanolamine, lignin sulfonate, molasses, or sodium carboxymethyl cellulose. The active activating component is one or more of the following: triethanolamine, triisopropanolamine, diethanolmonoisopropanolamine, sodium sulfate, sodium thiosulfate, calcium chloride, and calcium nitrate. The early strength component is one or more of the following: calcium formate, nanocrystalline nuclei, nano-silica, nano-calcium carbonate, sodium silicate, and aluminum sulfate. The nanocrystalline nucleus material is CSH gel or calcium silicate.

3. The active activating early-strength cement grinding aid composition according to claim 1, characterized in that, The slow-release polymer is a hydrolyzable ester bond type polycarboxylic acid comb copolymer, which is copolymerized from at least one of acrylic acid, methacrylic acid, maleic anhydride, and sodium propylene sulfonate with polyethylene glycol monomethyl ether acrylate and polyethylene glycol monomethyl ether methacrylate. The weight-average molecular weight of the slow-release polymer is 20,000-60,000, the acid-ether molar ratio is (1.5-4):1, and the molecular weight of the polyethylene glycol monomethyl ether segment is 500-2,000. The side chains of the polymer are linked to polyethylene glycol monomethyl ether segments via hydrolyzable ester bonds, with a hydrolysis half-life of 1-8 hours.

4. The active activating early-strength cement grinding aid composition according to claim 1, characterized in that, The microcapsules are single-layer pH-sensitive microcapsules, and the wall material is at least one of chitosan, sodium alginate, polylactic acid-glycolic acid copolymer, and dimethylaminoethyl methacrylate copolymer; the core of the microcapsules is a coagulating component or a retarding component; the average particle size of the microcapsules is 5-30 μm, and the wall material thickness is 0.5-2 μm.

5. The active activating early-strength cement grinding aid composition according to claim 1, characterized in that: The grinding aid composition further comprises 0.5-5% modified nanoparticles; the modified nanoparticles are nano-calcium carbonate or nano-silica with an average particle size of 20-100 nm, and their surfaces are pre-adsorbed with an anionic polymer dispersant; the anionic polymer dispersant is sodium polyacrylate or polycarboxylate.

6. The active activating early-strength cement grinding aid composition according to claim 1, characterized in that: The grinding aid composition further comprises 0.5-6% of a dispersion stabilizing component; the dispersion stabilizing component is one or two of polycarboxylate anionic dispersant, polyvinyl alcohol, or polyethylene glycol.

7. The active activating early-strength cement grinding aid composition according to claim 1, characterized in that: The grinding aid composition further comprises 0.1-2% of an interface reconstructing agent; the interface reconstructing agent is a polyethylene glycol-polyacrylic acid block copolymer, wherein the polyethylene glycol segment has a molecular weight of 2000-5000 and the polyacrylic acid segment has a degree of polymerization of 20-50.

8. A method for preparing the active activating early-strength cement grinding aid composition according to any one of claims 1-7, characterized in that, Includes the following steps: (1) Add the prescribed amount of water to the reactor, and under normal temperature stirring conditions, first add the grinding aid component and the active activation component, and stir until completely dissolved; (2) Add the early-strength component to the reactor; (3) Control the system temperature to 20-40℃ and keep it warm while stirring for 20-40 minutes; (4) Add the hydration regulating component and stir at low speed for 30-60 minutes; (5) After constant temperature standing and defoaming, use an 80-mesh flexible filter screen for low-pressure filtration to obtain a liquid active activating early strength cement grinding aid composition.