A liquid cement enhancer and method of making same

Abstract

This application relates to the field of concrete admixtures and discloses a liquid cement reinforcing agent and its preparation method. The liquid cement reinforcing agent comprises the following components: polyamine siloxane hybrid molecules, sodium alginate microgel, glycine, polyvinylpyrrolidone, and the balance water; wherein, the sodium alginate microgel contains embedded nano-C-S-H seed crystals and an organic calcium source. Through the synergistic effect of multiple components, the reinforcing agent can effectively enhance early hydration activity, promote the directional nucleation and growth of C-S-H gel, significantly improve the early and late mechanical properties of cement-based materials, and simultaneously improve the rheological properties of the slurry and the stability of the system. The reinforcing agent has a simple preparation process, good stability, and is suitable for high-dosage admixture cement systems, showing good application prospects and industrialization value.

Description

Technical Field

[0001] This application relates to the field of concrete admixtures, specifically to a liquid cement reinforcing agent and its preparation method. Background Technology

[0002] Cement, as an indispensable basic cementitious material in the modern construction industry, is produced and applied throughout the entire life cycle of infrastructure construction, real estate development, and various engineering projects, occupying a pivotal position in the national economic system. Under the trend of low-carbon development in the cement industry, high-content blended cement systems face technical challenges such as insufficient hydration activity, slow early strength development, and weakened interfacial transition zones due to the reduced clinker ratio.

[0003] Traditional grinding aids (such as triethanolamine and ethylene glycol) have limited functions, mainly working by reducing grinding energy consumption or improving particle dispersibility. They are difficult to effectively regulate the hydration kinetics of cement, and the reinforcing effect of multi-component systems is often limited due to poor compatibility.

[0004] Furthermore, existing reinforcing agents often present deep-seated technical contradictions: on the one hand, relying solely on a single functional component (such as simply introducing an early-strength agent or a nucleation inducer) may yield a certain strength gain at a specific age, but it is difficult to balance the coordinated development of early and later strength, and it is prone to inducing volume stability risks due to excessively high local ion concentrations or unbalanced reaction rates; on the other hand, some pretreatment methods involve multi-component compounding, which is highly susceptible to chemical or physical incompatibility with existing grinding aid systems. For example, electrostatic repulsion or complexation precipitation between amines and anionic polymers not only weakens their respective effects but may also interfere with the normal setting behavior of cement paste, and even lead to serious engineering hazards such as poor stability. Summary of the Invention

[0005] To address these issues, this application proposes a liquid cement reinforcing agent to solve the technical problems caused by the continuous decrease in clinker consumption ratio, such as insufficient early hydration activity, deterioration of mechanical properties, and the single function and poor compatibility of traditional grinding aids and multi-component compound systems.

[0006] This application proposes a liquid cement reinforcing agent, which comprises, by mass percentage, the following components: 10%–20% polyamine siloxane hybrid molecules, 4%–8% sodium alginate microgel, 0.8%–1.5% glycine, 0.2%–0.4% polyvinylpyrrolidone, and the balance being water;

[0007] The sodium alginate microgel contains embedded nano-CSH seeds and an organic calcium source.

[0008] More specifically, in the above technical solution, the chemical structural formula of the polyamine siloxane hybrid molecule is H2N–(CH2)3–NH–(CH2)2–Si(OCH3)3.

[0009] More specifically, in the above technical solution, the particle size of the nano-CSH seed crystals is 5-20 nm, and the Ca / Si molar ratio is 1.6-1.8.

[0010] More specifically, in the above technical solution, the organic calcium source is calcium lactate or calcium gluconate.

[0011] More specifically, in the above technical solution, the particle size of the sodium alginate microgel is 50-200 nm.

[0012] More specifically, in the above technical solution, the average molecular weight of the polyvinylpyrrolidone is 40,000 g / mol; the reinforcing agent is a transparent colloidal dispersion with a pH value of 8.0 to 8.5.

[0013] This application also proposes a method for preparing the above-mentioned liquid cement reinforcing agent, comprising the following steps:

[0014] The polyamine siloxane hybrid molecule was dissolved in water to prepare a first solution with a concentration of 20% to 40%, and the pH was adjusted to 8.5.

[0015] The sodium alginate microgel was added to the first solution and stirred until well mixed; then the glycine and polyvinylpyrrolidone were added in sequence and stirred until well mixed.

[0016] The pH of the first solution was adjusted to 8.0-8.5, and the solution was aged under constant temperature conditions to obtain the liquid cement reinforcing agent.

[0017] More specifically, in the above technical solution, the method for synthesizing the polyamine siloxane hybrid molecule includes: using 3-aminopropyltrimethoxysilane and ethylenediamine as raw materials and anhydrous ethanol as solvent, reacting at 50-70°C for 3-5 hours, and obtaining the polyamine siloxane hybrid molecule by vacuum distillation after the reaction is completed.

[0018] More specifically, in the above technical solution, the preparation method of the sodium alginate microgel includes: dissolving sodium alginate in water to prepare a second solution with a mass-volume concentration of 1.0% to 2.0%; adding 0.6% to 3% of the nano-CSH seed crystals and 0.4% to 2% of the organic calcium source to the liquid cement reinforcing agent by mass percentage; ultrasonically dispersing the mixture; then adding it dropwise to a 0.05 to 0.15 mol / L calcium chloride solution; allowing it to stand for cross-linking; and after centrifugation and washing, redispersing it in water to obtain the sodium alginate microgel with a solid content of 10% to 15%.

[0019] More specifically, in the above technical solution, the feeding rate of the sodium alginate microgel is 1-3 mL / min, and the stirring speed is 200-400 rpm;

[0020] Adjust the pH using a 0.1 mol / L sodium hydroxide solution or hydrochloric acid solution; the aging temperature is 20–30℃, and the aging time is 1–3 hours.

[0021] Compared with the prior art, the embodiments of this application have the following beneficial effects:

[0022] This application constructs a multifunctional and highly stable liquid cement reinforcing agent through molecular design, microstructure construction, and multi-scale functional integration. During the cement hydration process, the polyamine siloxane hybrid molecules in the reinforcing agent are adsorbed onto the surface of clinker and blended material particles during grinding, reducing surface energy and inhibiting fine particle agglomeration. At the same time, the silanols generated by its hydrolysis form chemical bonds with the active silica-alumina components in the blended material, improving the interfacial bonding strength.

[0023] Sodium alginate microgels rupture during the cement slurry mixing stage, releasing nano-CSH seed crystals and an organic calcium source. The former immediately induces heterogeneous nucleation of the CSH gel, while the latter achieves Ca synthesis through a complexation-dissociation equilibrium mechanism. 2+ The gradient release synergistically promotes the depth of volcanic ash reaction.

[0024] By leveraging multiple synergistic mechanisms, it achieves a unified approach to rapid early strength development, sustained later strength growth, and microstructural densification in high-content blended cement systems. This provides reliable technical support for reducing clinker consumption by 3% to 8% in the cement industry, while simultaneously meeting the dual goals of green and low-carbon development and economic feasibility. Detailed Implementation

[0025] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0026] The experimental reagents and instruments used in the embodiments of this application are all commercially available.

[0027] This application proposes a liquid cement reinforcing agent, which is a single-component fusion liquid cement reinforcing agent that integrates nanocrystal seed induction, organic calcium source slow release, polyamine siloxane interface modification and stable dispersion functions, so as to achieve efficient, stable and synergistic reinforcing effect in complex and multi-component cement-admixture systems.

[0028] The liquid cement reinforcing agent, calculated by mass percentage, includes the following components: 10%–20% polyamine siloxane hybrid molecules, 4%–8% sodium alginate microgel, 0.8%–1.5% glycine, 0.2%–0.4% polyvinylpyrrolidone, and the balance being water;

[0029] The sodium alginate microgel contains embedded nano-CSH seeds and organic calcium sources.

[0030] The liquid cement reinforcing agent provided by this invention, through molecular design, microstructure construction, and multi-scale functional integration, constructs a multifunctional and highly stable liquid cement reinforcing agent. During cement hydration, the polyamine-siloxane hybrid molecules in the reinforcing agent are first adsorbed onto the surface of clinker and blended material particles during grinding, reducing surface energy and inhibiting fine particle agglomeration. Simultaneously, the silanol groups generated by hydrolysis form chemical bonds with the active silica-alumina components in the blended materials, enhancing interfacial bonding strength. Sodium alginate microgels rupture during the cement slurry mixing stage, releasing nano-CSH seed crystals and an organic calcium source. The former immediately induces heterogeneous nucleation of the CSH gel, while the latter achieves Ca2+ nucleation through a complexation-dissociation equilibrium mechanism. 2+ The gradient release synergistically promotes the in-depth reaction of volcanic ash. Glycine, as an amphoteric amino acid, exists in anionic form in an alkaline environment and can chelate Al in solution. 3+ Fe 3+ Metal ions are added to prevent interference with the crystallization process of CSH gel and to adjust the ionic strength of the slurry to optimize hydration kinetics. Polyvinylpyrrolidone maintains the colloidal stability of the nanocomponents throughout the storage and use cycle, ensuring the consistency of the reinforcing agent's performance.

[0031] By leveraging multiple synergistic mechanisms, it achieves a unified approach to rapid early strength development, sustained later strength growth, and microstructural densification in high-content blended cement systems. This provides reliable technical support for reducing clinker consumption by 3% to 8% in the cement industry, while simultaneously meeting the dual goals of green and low-carbon development and economic feasibility.

[0032] In some embodiments, the sodium alginate microgel has a particle size of 50–200 nm and is formed by the cross-linking of sodium alginate molecular chains with calcium ions to create a three-dimensional network structure. The nano-CSH seeds embedded inside the sodium alginate microgel have a particle size of 5–20 nm and a Ca / Si molar ratio of 1.6–1.8. As heterogeneous nucleation cores, they provide a large number of active sites in the early stages of cement hydration, accelerating the precipitation and densification of CSH gel.

[0033] In some embodiments, the chemical structural formula of the polyamine siloxane hybrid molecule is H2N–(CH2)3–NH–(CH2)2–Si(OCH3)3.

[0034] This molecule possesses primary and secondary amine functional groups as well as hydrolyzable siloxane groups. In an alkaline environment, it can undergo partial hydrolysis and condensation to form an organic-inorganic hybrid interface layer with a three-dimensional network structure, which effectively anchors to the surface of cement particles and promotes the directional nucleation and growth of CSH gel.

[0035] In some embodiments, the sustained-release organic calcium source comprises calcium lactate and / or calcium gluconate, which gradually releases Ca in an alkaline slurry environment. 2+ Ions continuously replenish the calcium source required for the hydration reaction, prolong the effective time window of the volcanic ash reaction, and suppress structural defects caused by a sudden drop in local calcium ion concentration.

[0036] In some embodiments, the average molecular weight of polyvinylpyrrolidone is 40,000 g / mol; the reinforcing agent is a transparent colloidal dispersion with a pH value of 8.0 to 8.5.

[0037] The lactam groups on the polyvinylpyrrolidone molecular chain have a strong adsorption capacity for cement particles and nanocrystals. Through the steric hindrance effect, they maintain the long-term dispersion stability of each functional component in the system, prevent the agglomeration and sedimentation of nano CSH crystals, and improve the rheological compatibility between the reinforcing agent and the cement paste.

[0038] This application also proposes a method for preparing the above-mentioned liquid cement reinforcing agent, specifically including the following steps:

[0039] The polyamine siloxane hybrid molecules were dissolved in water to prepare a first solution with a concentration of 20% to 40%, and the pH was adjusted to 8.5.

[0040] Under stirring conditions, sodium alginate microgel was added to the first solution and stirred until well mixed; then glycine and polyvinylpyrrolidone were added in sequence and stirred until fully mixed.

[0041] The pH of the first solution was adjusted to 8.0–8.5, and the solution was aged under constant temperature conditions to obtain a liquid cement reinforcing agent.

[0042] In some embodiments, the method for synthesizing polyamine siloxane hybrid molecules includes: using 3-aminopropyltrimethoxysilane and ethylenediamine as raw materials and anhydrous ethanol as solvent, reacting at 50-70°C for 3-5 hours, and removing the solvent and byproducts by vacuum distillation after the reaction to obtain polyamine siloxane hybrid molecules.

[0043] In some embodiments, sodium alginate is dissolved in water to prepare a second solution with a mass-volume concentration of 1.0% to 2.0%. Nano-CSH seed crystals and an organic calcium source are added, and after ultrasonic dispersion, the solution is added dropwise to a calcium chloride solution of 0.05 to 0.15 mol / L. After standing and cross-linking, the solution is centrifuged, washed, and redispersed in water to obtain sodium alginate microgel with a solid content of 10% to 15%.

[0044] In some embodiments, the feeding rate of sodium alginate microgel is 1-3 mL / min, and the stirring speed is 200-400 rpm;

[0045] Adjust the pH using a 0.1 mol / L sodium hydroxide solution or hydrochloric acid solution; the aging temperature is 20–30℃, and the aging time is 1–3 hours.

[0046] Preferably, the water used in the above preparation method is deionized water.

[0047] It is understood that the polyamine siloxane hybrid molecules and sodium alginate microgels in the embodiments or comparative examples of this application were prepared using the above-described preparation method.

[0048] When the liquid cement reinforcing agent prepared by this invention is used, it is added to the grinding system at an additional rate of 0.1% to 0.2% of the cement mass and used in conjunction with conventional grinding aids without adjusting the original process parameters.

[0049] Unless otherwise specified, the raw materials and equipment used in this application are commonly used in the field; unless otherwise specified, the methods used in this application are conventional methods in the field.

[0050] Unless otherwise specified, the terms used in this specification have the same meaning as those commonly understood by those skilled in the art; however, in the event of any conflict, the definitions in this specification shall prevail.

[0051] To better illustrate the purpose, technical solution, and advantages of this application, the following will provide further explanation of this application in conjunction with specific embodiments.

[0052] Example 1

[0053] A liquid cement reinforcing agent is composed of the following components by mass percentage: 15% polyamine siloxane hybrid molecules, 6% sodium alginate microgel (in the liquid cement reinforcing agent, it contains 1.2% nano-CSH seed crystals and 0.9% calcium gluconate by percentage content), 1.2% glycine, 0.3% polyvinylpyrrolidone, and the balance deionized water.

[0054] The preparation method of the liquid cement reinforcing agent is carried out according to the following process flow:

[0055] S1. Dissolve the polyamine siloxane hybrid molecules in deionized water to prepare a 30% solution, and adjust the pH to 8.5 using 0.1 mol / L sodium hydroxide solution;

[0056] S2. Under stirring conditions, the sodium alginate microgel dispersion is slowly added to the solution obtained in step S1 and stirred to mix; wherein, the solid content of the sodium alginate microgel dispersion is 10% to 15%, the feeding rate is controlled at 1.5 mL / min, and the stirring speed is 300 rpm.

[0057] S3. Add glycine and polyvinylpyrrolidone sequentially to the mixture obtained in step S2, and continue stirring to mix them thoroughly.

[0058] S4. Adjust the pH of the system obtained in step S3 to 8.0 using 0.1 mol / L sodium hydroxide solution or hydrochloric acid solution, and then age it under constant temperature conditions to obtain the liquid cement reinforcing agent; wherein, the aging temperature is 25°C and the aging time is 2 hours.

[0059] Example 2

[0060] A liquid cement reinforcing agent is composed of the following components by mass percentage: 10% polyamine siloxane hybrid molecules, 4% sodium alginate microgel (in the liquid cement reinforcing agent, by percentage content, it contains 0.8% nano CSH seed crystals and 0.6% calcium lactate), 0.8% glycine, 0.2% polyvinylpyrrolidone, and the balance deionized water.

[0061] The preparation method of the liquid cement reinforcing agent is carried out according to the following process flow:

[0062] S1. Dissolve the polyamine siloxane hybrid molecules in deionized water to prepare a 30% solution, and adjust the pH to 8.5 using 0.1 mol / L sodium hydroxide solution;

[0063] S2. Under stirring conditions, the sodium alginate microgel dispersion is slowly added to the solution obtained in step S1 and stirred to mix; wherein, the solid content of the sodium alginate microgel dispersion is 10% to 15%, the feeding rate is controlled at 1.3 mL / min, and the stirring speed is 20 rpm.

[0064] S3. Add glycine and polyvinylpyrrolidone sequentially to the mixture obtained in step S2, and continue stirring to mix them thoroughly.

[0065] S4. Adjust the pH of the system obtained in step S3 to 8.3 using 0.1 mol / L sodium hydroxide solution or hydrochloric acid solution, and then age it under constant temperature conditions to obtain the liquid cement reinforcing agent; wherein, the aging temperature is 20°C and the aging time is 1 hour.

[0066] Example 3

[0067] A liquid cement reinforcing agent is composed of the following components by mass percentage: 20% polyamine siloxane hybrid molecules, 8% sodium alginate microgel (in the liquid cement reinforcing agent, by percentage content, it contains 2.0% nano CSH seed crystals and 1.6% calcium gluconate), 1.5% glycine, 0.4% polyvinylpyrrolidone, and the balance deionized water.

[0068] The preparation method of the liquid cement reinforcing agent is carried out according to the following process flow:

[0069] S1. Dissolve the polyamine siloxane hybrid molecules in deionized water to prepare a 40% solution, and adjust the pH to 8.5 using 0.1 mol / L sodium hydroxide solution;

[0070] S2. Under stirring conditions, the sodium alginate microgel dispersion is slowly added to the solution obtained in step S1 and stirred to mix; wherein, the solid content of the sodium alginate microgel dispersion is 10% to 15%, the feeding rate is controlled at 3 mL / min, and the stirring speed is 400 rpm.

[0071] S3. Add glycine and polyvinylpyrrolidone sequentially to the mixture obtained in step S2, and continue stirring to mix them thoroughly.

[0072] S4. Adjust the pH of the system obtained in step S3 to 8.5 using 0.1 mol / L sodium hydroxide solution or hydrochloric acid solution, and then age it under constant temperature conditions to obtain the liquid cement reinforcing agent; wherein, the aging temperature is 30°C and the aging time is 3 hours.

[0073] Example 4

[0074] A liquid cement reinforcing agent is composed of the following components by mass percentage: 12% polyamine siloxane hybrid molecules, 5% sodium alginate microgel (in the liquid cement reinforcing agent, it contains 0.75% nano CSH seed crystals and 0.5% calcium lactate by percentage), 1.0% glycine, 0.3% polyvinylpyrrolidone, and the balance deionized water.

[0075] The preparation method of the liquid cement reinforcing agent is carried out according to the following process flow:

[0076] S1. Dissolve the polyamine siloxane hybrid molecules in deionized water to prepare a 35% solution, and adjust the pH to 8.5 using 0.1 mol / L sodium hydroxide solution;

[0077] S2. Under stirring conditions, the sodium alginate microgel dispersion is slowly added to the solution obtained in step S1 and stirred to mix; wherein, the solid content of the sodium alginate microgel dispersion is 10% to 15%, the feeding rate is controlled at 1.5 mL / min, and the stirring speed is 250 rpm.

[0078] S3. Add glycine and polyvinylpyrrolidone sequentially to the mixture obtained in step S2, and continue stirring to mix them thoroughly.

[0079] S4. Adjust the pH of the system obtained in step S3 to 8 using 0.1 mol / L sodium hydroxide solution or hydrochloric acid solution, and then age it under constant temperature conditions to obtain the liquid cement reinforcing agent; wherein, the aging temperature is 27°C and the aging time is 2 hours.

[0080] Comparative Example 1 (without polyamine siloxane hybrid molecules, replaced by traditional grinding aids)

[0081] A liquid cement reinforcing agent is composed of the following components in weight percentage: 15% triethanolamine, 6% sodium alginate microgel (in the liquid cement reinforcing agent, it contains 1.2% nano-CSH seed crystals and 0.9% calcium gluconate, calculated as a percentage), 1.2% glycine, 0.3% polyvinylpyrrolidone, and the balance deionized water.

[0082] The preparation method of the liquid cement reinforcing agent is carried out according to the following process flow:

[0083] Except for step S1, in which triethanolamine is used instead of polyamine siloxane hybrid molecules and pH adjustment is not required (the natural pH of the triethanolamine solution is about 9.0), the remaining steps are completely consistent with those in Example 1.

[0084] Comparative Example 2 (no sodium alginate microgel, direct addition of seed crystals and calcium source)

[0085] A liquid cement reinforcing agent comprises the following components by mass percentage: 15% polyamine siloxane hybrid molecules, 1.2% nano-CSH seed crystals, 0.9% calcium gluconate, 1.2% glycine, 0.3% polyvinylpyrrolidone, and the balance deionized water. The preparation method of the liquid cement reinforcing agent is carried out according to the following process flow:

[0086] S1, consistent with step S1 in Example 1;

[0087] S2. Under stirring at 300 rpm, the nano CSH seeds and calcium gluconate were directly added to the S1 solution. After ultrasonic dispersion for 20 minutes, stirring was continued for another 30 minutes.

[0088] Steps S3 and S4 are the same as in Example 1.

[0089] Comparative Example 3 (without seed crystals or calcium source)

[0090] A liquid cement reinforcing agent comprises the following components by mass percentage: 15% polyamine siloxane hybrid molecules, 6% sodium alginate microgel (preparation method is the same as above except that nano-CSH seeds and calcium gluconate are not added), 0.3% polyvinylpyrrolidone, and the balance deionized water. The preparation method of the liquid cement reinforcing agent is carried out according to the following process flow:

[0091] S1, consistent with step S1 in Example 1;

[0092] S2, Add sodium alginate microgel that does not contain nano-CSH seeds and calcium gluconate;

[0093] Steps S3 and S4 are the same as in Example 1.

[0094] Comparative Example 4 (without glycine)

[0095] A liquid cement reinforcing agent is composed of the following components in weight percentage: 15% polyamine siloxane hybrid molecules, 6% sodium alginate microgel (in the liquid cement reinforcing agent, it contains 1.2% nano-CSH seed crystals and 0.9% calcium gluconate, calculated as a percentage), 0.3% polyvinylpyrrolidone, and the balance being deionized water.

[0096] The preparation method of the liquid cement reinforcing agent is carried out according to the following process flow:

[0097] Except for step S3, in which glycine is not added, the other steps are exactly the same as in Example 1.

[0098] Comparative Example 5 (without polyvinylpyrrolidone)

[0099] A liquid cement reinforcing agent comprises the following components by mass percentage: 15% polyamine siloxane hybrid molecules, 6% sodium alginate microgel (in the liquid cement reinforcing agent, by percentage content, it contains 1.2% nano-CSH seed crystals and 0.9% calcium gluconate), 1.2% glycine, and the balance being deionized water. The preparation method of the liquid cement reinforcing agent is carried out according to the following process flow:

[0100] Except for step S3, in which polyvinylpyrrolidone is not added, the other steps are exactly the same as in Example 1.

[0101] Application Example 1

[0102] The reinforcing agents of Examples 1-4 and Comparative Examples 1-5 were added to a cement system with a clinker consumption ratio of 76% at 0.15% of the cement mass (see Table 1 for the ingredient list). They were used together with 0.05% of a conventional grinding aid (the main components of which are triethanolamine, diethanol monoisopropanolamine, liquid sodium thiocyanate, industrial salt, molasses, and glycerin). The compressive strength at 3 days and 28 days was tested according to GB / T 17671-2021. At the same time, the stability of the reinforcing agent after 7 days of storage was observed (whether there was precipitation or stratification).

[0103] Table 1. P·O 42.5 Ordinary Portland Cement Batching Table

[0104]

[0105] Note: Both grinding aid and reinforcing agent are external admixtures, with dosages of 0.05% and 0.15%, respectively.

[0106] Table 2 Cement performance test results

[0107]

[0108] As shown in Table 2, the cement performance test results indicate that the 3-day compressive strength of the liquid cement reinforcing agents from Examples 1-4 of this invention is ≥28.0 MPa, and the 28-day compressive strength is ≥53.2 MPa. Compared with the blank sample (25.6 / 49.3 MPa), the 3-day strength is increased by approximately 9.4% to 12.5%, and the 28-day strength is increased by approximately 7.9% to 9.5%, which is better than the comparative examples lacking any single component, indicating that the cement reinforcing agent has a good reinforcing effect. Furthermore, the liquid cement reinforcing agents from Examples 1-4 did not separate after 7 days of storage, demonstrating the stability of the system. The standard consistency water requirement of Examples 1-4 is between 26.5% and 27.0%, close to the 26.4% of the blank sample, indicating that the addition of the reinforcing agent will not cause a significant increase in the cement water requirement, thus avoiding any impact on the cement's workability.

[0109] Comparative Examples 1-5 are comparison examples based on Example 1, each with one component omitted. The results show that the strength of the comparative examples is significantly lower than that of Examples 1-4, fully demonstrating the role of each component. Comparative Example 1, based on Example 1, omits the polyamine siloxane hybrid molecule and replaces it with the traditional grinding aid triethanolamine; its strength is also significantly weakened, fully verifying the role of the core enhancing component. Comparative Example 2, based on Example 1, removes the sodium alginate microgel and directly adds nano-CSH seeds and a calcium source; the product shows slight precipitation after 7 days of storage, verifying the carrier and sustained-release effect of the microgel. Comparative Example 3, based on Example 1, adds sodium alginate microgel without seeds and a calcium source; its strength is significantly lower than that of Example 1, fully verifying the strength-enhancing effect of seeds and a calcium source. Comparative Example 4, based on Example 1, omits glycine; its strength is significantly lower than that of Example 1, indicating that the absence of amphoteric amino acids prevents it from reacting with Al. 3 ⁺、Fe 3 High-valence metal ions (⁺, etc.) form soluble complexes, delaying the rapid hydration of the aluminum phase and thus coordinating the differences in hydration rates between different mineral phases. This fully verifies that the additive can assist in promoting the cement hydration process and synergistically improve the cement compressive strength. Comparative Example 5, which omits polyvinylpyrrolidone from Example 1, showed severe stratification after 7 days of storage, verifying that the additive is a key component ensuring storage stability.

[0110] This invention, through precise design of the molecular structure of polyamine siloxane hybrid molecules, construction of a sodium alginate microgel encapsulation system, optimization of the synergistic ratio of glycine and polyvinylpyrrolidone, and strict control of preparation process parameters, has successfully developed a single-component liquid cement reinforcing agent that combines early activation, late-stage strengthening, interface optimization, and colloidal stability. This reinforcing agent not only effectively overcomes the technical bottlenecks of insufficient hydration activity and loose structure in high-dosage blended cement systems, but also exhibits good compatibility, stability, and environmental friendliness in engineering applications, providing a practical and feasible technical path for the cement industry to achieve deep carbon reduction, cost optimization, and performance improvement. Those skilled in the art can repeat this invention and obtain the expected technical effects based on the technical details disclosed in this specific embodiment.

[0111] The technical features of the above-described embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0112] The embodiments described above are merely illustrative of several implementations of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the scope of protection of this patent application should be determined by the appended claims.

Claims

1. A liquid cement reinforcing agent, characterized in that, The liquid cement reinforcing agent comprises, by weight percentage, the following components: 10%–20% polyamine siloxane hybrid molecules, 4%–8% sodium alginate microgel, 0.8%–1.5% glycine, 0.2%–0.4% polyvinylpyrrolidone, and the balance being water; The sodium alginate microgel contains embedded nano-CSH seeds and an organic calcium source. The chemical structural formula of the polyamine siloxane hybrid molecule is H2N-(CH2)3-NH-(CH2)2-Si(OCH3)3; The organic calcium source is calcium lactate or calcium gluconate.

2. The liquid cement reinforcing agent according to claim 1, characterized in that, The nano-CSH seed crystals have a particle size of 5–20 nm and a Ca / Si molar ratio of 1.6–1.

8.

3. The liquid cement reinforcing agent according to claim 2, characterized in that, The sodium alginate microgel has a particle size of 50–200 nm.

4. The liquid cement reinforcing agent according to claim 1, characterized in that, The polyvinylpyrrolidone has an average molecular weight of 40,000 g / mol; the reinforcing agent is a transparent colloidal dispersion with a pH value of 8.0–8.

5.

5. A method for preparing the liquid cement reinforcing agent according to any one of claims 1-4, characterized in that, Includes the following steps: The polyamine siloxane hybrid molecule was dissolved in water to prepare a first solution with a concentration of 20% to 40%, and the pH was adjusted to 8.

5. The sodium alginate microgel was added to the first solution and stirred until well mixed; then the glycine and polyvinylpyrrolidone were added in sequence and stirred until well mixed. The pH of the first solution was adjusted to 8.0-8.5, and the solution was aged under constant temperature conditions to obtain the liquid cement reinforcing agent.

6. The preparation method according to claim 5, characterized in that, The method for synthesizing the polyamine siloxane hybrid molecule includes: using 3-aminopropyltrimethoxysilane and ethylenediamine as raw materials and anhydrous ethanol as solvent, reacting at 50-70°C for 3-5 hours, and then distilling under reduced pressure after the reaction to obtain the polyamine siloxane hybrid molecule.

7. The preparation method according to claim 6, characterized in that, The preparation method of the sodium alginate microgel includes: dissolving sodium alginate in water to prepare a second solution with a concentration of 1.0% to 2.0%; adding 0.6% to 3% of the nano-CSH seed crystals and 0.4% to 2% of the organic calcium source to the liquid cement reinforcing agent by mass percentage; ultrasonically dispersing the solution; adding the solution dropwise to a 0.05 to 0.15 mol / L calcium chloride solution; allowing it to stand for cross-linking; centrifuging and washing; and redispersing the solution in water to obtain the sodium alginate microgel with a solid content of 10% to 15%.

8. The preparation method according to claim 5, characterized in that, The feeding rate of the sodium alginate microgel is 1-3 mL / min, and the stirring speed is 200-400 rpm; Adjust the pH using a 0.1 mol / L sodium hydroxide solution or hydrochloric acid solution; the aging temperature is 20–30℃, and the aging time is 1–3 hours.

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