Calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent as well as preparation method and application thereof

Abstract

The invention provides a calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent and a preparation method and application thereof, and the preparation method of the calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent comprises the following steps: respectively preparing a calcium salt solution, a silicate solution, a carbonate solution and a dispersant solution; under the stirring condition, the calcium salt solution, the silicate solution and the carbonate solution are dropwise added into the dispersing agent solution at the same time, the pH is controlled to be 10-14, stirring reaction continues after dropwise adding is completed, and the calcium carbonate / calcium silicate composite nanometer crystal nucleus early strength agent is obtained. By introducing carbonate ions, the adsorption of the dispersing agent to C-S-H calcium sites is enhanced, the anchoring capability of the dispersing agent is improved, crystal nucleus agglomeration is inhibited, the grain size of crystal nucleuses is refined, and the nucleation density is increased; particularly, the early strength effect in a mineral powder cement system is obviously improved.

Description

Technical Field

[0001] This invention relates to the field of building material admixtures, specifically to a calcium carbonate / calcium silicate composite nanocrystalline nucleus early strength agent, its preparation method, and its application. Background Technology

[0002] Using bulk industrial solid waste as auxiliary cementitious materials to replace part of the cement clinker can achieve efficient resource utilization of solid waste and significantly reduce the amount of cement clinker produced, thereby directly reducing the carbon emission level of the cement industry. This approach is considered one of the most widely used and effective carbon reduction methods in the cement sector. However, it should be noted that the early hydration activity of industrial solid waste is much lower than that of silicate cement. When large amounts of solid waste are used to replace cement, it will cause slow early strength growth of cement-based materials, making it difficult to meet the core requirements of high efficiency in construction projects. Therefore, improving the early strength of such cement-based materials has become a key issue that urgently needs to be addressed.

[0003] Current mainstream early-strength technologies have significant drawbacks: while steam curing can accelerate hydration through thermal activation, it consumes a lot of energy, generates large amounts of carbon, and leads to coarsening of the microstructure of the hydration product CSH gel, impairing later-stage durability; traditional chemical admixtures (such as calcium chloride and sodium sulfate) promote early hydration by altering ion balance, but easily disrupt long-term hydration equilibrium, causing strength reduction and volume stability problems. Therefore, developing an efficient, environmentally friendly early-strength agent that has no negative impact on later-stage strength has become a research hotspot. In recent years, researchers have explored various novel early-strength agents, such as CASH (calcium aluminosilicate) and CMSH (calcium magnesium silicate) gels. CASH gel, by introducing aluminum, can significantly improve the early strength of cement-based materials. CMSH gel, by introducing magnesium, accelerates the cement hydration process and enhances early strength. CSH / PCE (polycarboxylate) nanocomposites are highly similar to the main hydration product (CSH gel) in structure and chemical properties, thus serving as an ideal nucleation core. However, existing optimizations of CSH / PCE nanocrystals focus on cation modulation (such as Mg). 2+ Al 3+ Fe 3+The potential for regulating the anionic environment through modification and adjustment of synthesis parameters (pH, temperature, PCE type) has not been fully explored. Furthermore, these cationic modification strategies primarily target cement clinker itself, with the core mechanism being to accelerate the hydration process and promote the formation and hardening of hydration products. However, for commonly used mineral admixtures such as mineral powder, these strategies are insufficient to stimulate the reactivity of active components. The mineral admixtures often remain in an "inert" state and do not participate in early hydration reactions. This significantly limits the early strength enhancement effect of these modified nanocrystalline nuclei in mineral powder cement and other mineral admixture cement systems, making it difficult to meet the early strength requirements of such systems in precast engineering and other scenarios.

[0004] Therefore, it is of great significance to develop an early-strength agent that can simultaneously and efficiently stimulate the hydration of cement clinker and the activity of mineral admixtures without negatively impacting the later strength. Summary of the Invention

[0005] In view of the technical problems existing in the background art, the present invention provides a calcium carbonate / calcium silicate composite nanocrystalline nucleus early strength agent, its preparation method and application, aiming to solve the technical problem that the existing early strength agents have poor early strength effect in cement systems and mineral admixture cement systems.

[0006] In a first aspect, the present invention provides a method for preparing a calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent, comprising the following steps: Prepare calcium salt solutions, silicate solutions, carbonate solutions, and dispersant solutions separately; Under stirring conditions, calcium salt solution, silicate solution, and carbonate solution are simultaneously added dropwise to the dispersant solution, with the pH controlled at 10-14. After the addition is complete, the reaction is continued with stirring to obtain a calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent.

[0007] Preferably, the molar ratio of calcium salt to silicate and carbonate in the calcium salt solution, silicate solution and carbonate solution is (0.5~2.0):1:(0.04~0.4).

[0008] Preferably, the concentration of the calcium salt solution is 5wt%~50wt%, the concentration of the silicate solution is 5wt%~35wt%, and the concentration of the carbonate solution is 5wt%~30wt%.

[0009] Preferably, the calcium salt includes at least one of calcium chloride, calcium nitrate, calcium formate, calcium acetate, calcium bicarbonate, and calcium gluconate; the silicate includes at least one of sodium silicate, potassium silicate, and lithium silicate; and the carbonate includes at least one of sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate.

[0010] Preferably, the mass of the dispersant is 1% to 10% of the total mass of the reaction system; the concentration of the dispersant solution is 1 wt% to 10 wt%.

[0011] Preferably, the dispersant includes a polycarboxylate superplasticizer.

[0012] Preferably, the temperature of the stirring reaction is 10℃~60℃, and the stirring speed is 100rpm~800rpm.

[0013] Preferably, the dripping time is 0.1~10h, and the stirring reaction time is 1~72h.

[0014] In a second aspect, the present invention provides a calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent, which is prepared by the preparation method described in the first aspect.

[0015] Thirdly, the present invention provides an application of a calcium carbonate / calcium silicate composite nanocrystalline nucleus early strength agent in early strength agents of cement-based materials and / or mineral admixture cement-based materials.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The calcium carbonate / calcium silicate composite nanocrystalline nucleus early strength agent provided by the present invention significantly improves the early strength of ordinary cement systems: In ordinary cement paste systems, the composite nanocrystalline nucleus can effectively increase the surface active sites of the early strength agent, thereby enhancing the promoting effect on early hydration of cement. Compared with conventional hydrated calcium silicate early strength agents, the 12-hour compressive strength of cement paste is significantly improved after adding the composite nanocrystalline nucleus early strength agent of the present invention.

[0017] (2) The calcium carbonate / calcium silicate composite nanocrystalline nucleus early strength agent provided by this invention is suitable for mineral powder cement systems and has a significant early strength effect: For mineral powder cement systems with a ratio of mineral powder to cement of 70:30, the composite nanocrystalline nucleus early strength agent of this invention exhibits excellent compatibility. It can not only effectively stimulate the early hydration activity of the system, but also has a significant and lasting early strength improvement effect. Data shows that it can increase the 3-day compressive strength of mineral powder cement paste by about 19% compared with ordinary hydrated calcium silicate early strength agent, and is more suitable for mineral powder cement systems such as mineral admixture cement.

[0018] (3) The calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent provided by the present invention optimizes the ion utilization efficiency of the hydration system: Through the synergistic effect of carbonate and silicate, the present invention can significantly reduce the concentration of free calcium ions in the cement hydration system by up to 20%, effectively improve the utilization rate of calcium ions, thereby further enhancing the promoting effect on the hydration process of cement and mineral powder cement system, and providing core technical support for improving early strength performance. Attached Figure Description

[0019] Figure 1 This is a graph showing the free calcium ion concentration of the nanocrystal nuclei prepared in the embodiments and comparative examples of the present invention; Figure 2The PCE adsorption diagrams are shown for the nanocrystal nuclei prepared in the embodiments and comparative examples of this invention. Figure 3 The following are DLS particle size distribution diagrams of the nanocrystal nuclei prepared in the embodiments and comparative examples of the present invention; Figure 4 The compressive strength of cement paste at different ages is shown in the figures for the nanocrystalline early-strength agents prepared by adding the present invention embodiments and comparative examples. Figure 5 The compressive strength of mineral powder cement paste at different ages is shown in the figures for the nanocrystalline nucleation early strength agents prepared by adding the present invention's embodiments and comparative examples. Detailed Implementation

[0020] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0021] To address the technical problem of poor early strength effect of existing early strength agents in cement systems and mineral admixture cement systems, this invention provides a calcium carbonate / calcium silicate composite nanocrystalline nucleus early strength agent, its preparation method, and its application. The calcium carbonate / calcium silicate composite nanocrystalline nucleus early strength agent is prepared by introducing anion regulation strategy of carbonate ions during the synthesis of CSH / dispersant nanocomposite materials.

[0022] In a first aspect, embodiments of the present invention provide a method for preparing a calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent, comprising the following steps: Prepare calcium salt solutions, silicate solutions, carbonate solutions, and dispersant solutions separately; Under stirring conditions, calcium salt solution, silicate solution, and carbonate solution are simultaneously added dropwise to the dispersant solution, with the pH controlled at 10-14. After the addition is complete, the reaction is continued with stirring to obtain a calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent.

[0023] In the technical solution of this invention embodiment, the present invention introduces carbonate ions during the synthesis of CSH / dispersant nanocomposite materials to prepare a calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent, which is composed of CSH / dispersant and Ca2CO3 / dispersant nanoparticles, forming a biphase cluster; CO3 2- Complexation reduces free Ca 2+ The activity was enhanced, improving the adsorption of the dispersant to CSH calcium sites, increasing the anchoring ability of the dispersant, inhibiting crystal nucleus aggregation, refining the crystal nucleus size, and increasing the nucleation density; Ca 2+ -CO3 2--CSH surface reconstruction improves the stability and reactivity of nanocrystal nuclei. Carbonate-doped calcium silicate composite nanocrystal nuclei provide abundant heterogeneous nucleation sites, shorten the induction period, and accelerate C3S hydration.

[0024] Furthermore, in some embodiments, the molar ratio of calcium salt to silicate and carbonate in the calcium salt solution, silicate solution, and carbonate solution is (0.5~2.0):1:(0.04~0.4).

[0025] Furthermore, in some embodiments, the concentration of the calcium salt solution is 5wt% to 50wt%, the concentration of the silicate solution is 5wt% to 35wt%, and the concentration of the carbonate solution is 5wt% to 30wt%.

[0026] Furthermore, in some embodiments, the calcium salt includes at least one of calcium chloride, calcium nitrate, calcium formate, calcium acetate, calcium bicarbonate, and calcium gluconate; Silicates include at least one of sodium silicate, potassium silicate, and lithium silicate; Carbonates include at least one of sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate.

[0027] Furthermore, in some embodiments, the mass of the dispersant is 1% to 10% of the total mass of the reaction system.

[0028] Furthermore, in some embodiments, the concentration of the dispersant solution is 1wt% to 10wt%.

[0029] Furthermore, in some embodiments, the dispersant includes a polycarboxylate superplasticizer.

[0030] In the technical solution of this invention embodiment, polycarboxylate superplasticizer (PCE) molecules pass through Ca 2+ -Carboxylic acid complexation adsorbs onto the surface of the composite nanocrystal nucleus, effectively preventing the aggregation of nanocrystal nucleus particles through steric hindrance, significantly improving the dispersibility and stability of the composite nanocrystal nucleus, and maintaining high surface reactivity.

[0031] Furthermore, in some embodiments, the molecular weight of the polycarboxylate superplasticizer is 5000~100000 g / mol.

[0032] Furthermore, in some embodiments, the temperature of the stirring reaction is 10°C to 60°C, and the stirring speed is 100 rpm to 800 rpm.

[0033] Furthermore, in some embodiments, the dripping time is 0.1 to 10 hours, and the stirring reaction time is 1 to 72 hours.

[0034] Secondly, embodiments of the present invention provide a calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent, which is prepared by the preparation method described in the first aspect.

[0035] Furthermore, in some embodiments, the solid content of the calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent is 2% to 20%.

[0036] Thirdly, embodiments of the present invention provide an application of a calcium carbonate / calcium silicate composite nanocrystalline nucleus early strength agent in early strength agents for cement-based materials and / or early strength agents for mineral admixture cement-based materials.

[0037] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0038] In the following embodiments of the present invention, the polycarboxylate superplasticizers are all WQ-I type polycarboxylate superplasticizers produced by Wanqian Building Materials Co., Ltd., with a solid content of 40wt% and a molecular weight of 5000~100000g / mol.

[0039] Example 1 A method for preparing a calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent, the specific steps of which are as follows: (1) Weigh 23.62g of calcium nitrate tetrahydrate and dissolve it in water to 61.34g to prepare a calcium nitrate aqueous solution; weigh 28.4g of sodium silicate nonahydrate and dissolve it in water to 61.06g to prepare a sodium silicate aqueous solution; weigh 10.59g of sodium carbonate and dissolve it in water to 105.99g to prepare a sodium carbonate aqueous solution; (2) Add 14.2g of polycarboxylate superplasticizer and 86.2g of water to the reaction vessel, set the temperature to 25℃, and the stirring speed to 600rpm. After stirring for 10min, simultaneously add 24.54g of calcium nitrate solution, 19.54g of sodium silicate solution and 8.48g of sodium carbonate aqueous solution (the molar ratio of calcium salt, silicate and carbonate is 5:4:1). Continue stirring and control the dropping speed so that the dropping time is 1h and the pH is maintained at 11.7. After the dropping is completed, continue stirring for 12h to obtain the calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent.

[0040] Example 2 A method for preparing a calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent, the specific steps of which are as follows: (1) Weigh 23.62g of calcium nitrate tetrahydrate and dissolve it in water to 61.34g to prepare a calcium nitrate aqueous solution; weigh 28.4g of sodium silicate nonahydrate and dissolve it in water to 61.06g to prepare a sodium silicate aqueous solution; weigh 10.59g of sodium carbonate and dissolve it in water to 105.99g to prepare a sodium carbonate aqueous solution; (2) Add 14.2g of polycarboxylate superplasticizer and 86.2g of water to the reaction vessel, set the temperature to 25℃, and the stirring speed to 600rpm. After stirring for 10min, simultaneously add 24.54g of calcium nitrate solution, 21.98g of sodium silicate solution and 4.24g of sodium carbonate aqueous solution (the molar ratio of calcium salt, silicate and carbonate is 10:9:1). Continue stirring and control the dropping speed so that the dropping time is 4h and the pH is maintained at 11.7. After the dropping is completed, continue stirring for 20h to obtain the calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent.

[0041] Comparative Example 1 A method for preparing calcium silicate nanocrystal nuclei, the specific steps of which are as follows: (1) Weigh 23.62g of calcium nitrate tetrahydrate, dissolve it in water to 61.34g to prepare a calcium nitrate aqueous solution, and weigh 28.4g of sodium silicate nonahydrate, dissolve it in water to 61.06g to prepare a sodium silicate aqueous solution; (2) Add 14.2g of polycarboxylate superplasticizer and 86.2g of water to the reaction vessel. Set the temperature to 25℃ and the stirring rate to 600rpm. After stirring for 10min, simultaneously add 24.54g of calcium nitrate solution and 19.54g of sodium silicate solution. Continue stirring and control the dropping rate to ensure a dropping time of 1h, while maintaining the pH at 11.7. Continue stirring for 12h after the dropping is complete to obtain calcium silicate nanocrystals.

[0042] Comparative Example 2 The difference between this comparative example and Example 1 lies in the stepwise synthesis of the calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent. The specific steps are as follows: (1) Weigh 23.62g of calcium nitrate tetrahydrate, dissolve it in water to 61.34g to prepare a calcium nitrate aqueous solution; weigh 28.4g of sodium silicate nonahydrate, dissolve it in water to 61.06g to prepare a sodium silicate aqueous solution; weigh 10.59g of sodium carbonate, dissolve it in water to 105.99g to prepare a sodium carbonate aqueous solution. (2) Add 20.10g of water to the reaction vessel, and then add 4.91g of calcium nitrate solution and 8.48g of sodium carbonate solution at the same time. Set the temperature to 25℃, the stirring speed to 600rpm, and control the dropping speed so that the dropping time is 20min. After the dropping is completed, continue stirring. After stirring for 40min, add 19.63g of calcium nitrate solution and 19.54g of sodium silicate solution at the same time. Continue stirring and control the dropping speed so that the dropping time is 1h, and keep the pH at 11.7. After the dropping is completed, continue stirring for 12h to obtain the calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent.

[0043] Performance testing The nanocrystalline nucleus early-strength agents prepared in each embodiment and comparative example were characterized by free calcium ion concentration testing, PCE adsorption, DLS particle size distribution, and early-strength effect testing in cement systems / mineral powder cement systems; the test methods and results are as follows: (1) Free calcium ion concentration test A portion of the obtained nanocrystalline nucleus early-strength agent was centrifuged at 10,000 rpm for 30 minutes. The resulting filtrate was diluted with acid, and the calcium ion concentration was tested. The results are as follows. Figure 1 As shown.

[0044] (2) Early strength effect test The dosage of each group of early-strength agents was 0.5% of the weight of the cementitious material, and the water-cement ratio was set at 0.4. The cementitious material in the cement group consisted entirely of cement, while the cementitious material ratio in the mineral powder cement group was 70:30 (mineral powder:cement). The cementitious material was placed in a mixer; simultaneously, the nanocrystalline nucleus early-strength agent and tap water were mixed and dispersed in an ultrasonic disperser for 5 minutes. The mixture was then poured into the mixer and stirred for 3 minutes. Next, it was poured into a 40mm×40mm×40mm mold, and the mold was subjected to standard curing. After 12 hours and 24 hours of curing, compressive strength tests were conducted to evaluate the early-strength effect of the nanocrystalline nucleus early-strength agents prepared in Examples 1-2 and Comparative Examples 1-2. The cement was purchased from China United Cement Co., Ltd., and the grade was P·I 42.5.

[0045] Figure 1 The graph shows the concentration of free calcium ions in each group of crystal nuclei. This graph reflects the calcium ion utilization rate of the nanocrystal nuclei, and it can be seen that the calcium ion reaction in Example 1 is more thorough.

[0046] Figure 2 The PCE adsorption diagrams for each group of crystal nuclei show that the calcium carbonate / calcium silicate composite nanocrystal nuclei early strength agent has a higher PCE adsorption efficiency. This indicates that the carbonate optimizes the adsorption interface of CSH, enabling the composite nanocrystal nuclei to better promote hydration.

[0047] Figure 3The DLS particle size distribution diagrams for each group of crystal nuclei show that, with higher PCE utilization, the calcium carbonate / calcium silicate composite nanocrystals have smaller particle sizes and larger specific surface areas, effectively promoting early cement hydration.

[0048] Figure 4 The diagram shows the compressive strength of cement paste at different ages. Figure 4 It can be seen that the calcium carbonate / calcium silicate composite nanocrystalline nucleus early-strength agent prepared in the embodiments of the present invention can significantly improve the early strength of ordinary cement paste, and the 12-hour compressive strength is increased by 3-4 MPa compared with the conventional hydrated calcium silicate early-strength agent (Comparative Example 1). The poor strength of Comparative Example 2 is because the calcium carbonate synthesized stepwise by chemical precipitation grows rapidly and then mixes with CSH / PCE. The two only undergo mechanical physical mixing, without the in-situ interaction between carbonate ions and CSH / PCE during the synthesis process. If nano-calcium carbonate is directly used in the synthesis of hydrated calcium silicate, the synthesis cost of the composite material will be significantly increased. In the synthesis process of the embodiments of the present invention, the complexation of carbonate ions and calcium ions inhibits the aggregation of CSH particles, enhances the adsorption effect of PCE, and realizes the synergistic effect of calcium carbonate and calcium silicate nanocrystalline nuclei.

[0049] Figure 5 The graph shows the compressive strength of mineral powder cement paste at different ages. Figure 5 It can be seen that the composite nanocrystalline nuclei also significantly improve the performance of the mineral powder cement system, and the 3-day compressive strength is still increased by about 19%. This indicates that the composite nanocrystalline nuclei are more suitable for application in mineral powder cement systems than ordinary CSH nanocrystalline nuclei.

[0050] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. A method for preparing a calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent, characterized in that, Includes the following steps: Prepare calcium salt solutions, silicate solutions, carbonate solutions, and dispersant solutions separately; Under stirring conditions, the calcium salt solution, the silicate solution, and the carbonate solution are simultaneously added dropwise to the dispersant solution, with the pH controlled at 10-14. After the addition is complete, the reaction is continued with stirring to obtain the calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent.

2. The preparation method of the calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent according to claim 1, characterized in that, The molar ratio of calcium salt to silicate and carbonate in the calcium salt solution, silicate solution and carbonate solution is (0.5~2.0):1:(0.04~0.4).

3. The method for preparing a calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent according to claim 1, characterized in that, The concentration of the calcium salt solution is 5wt%~50wt%, the concentration of the silicate solution is 5wt%~35wt%, and the concentration of the carbonate solution is 5wt%~30wt%.

4. The preparation method of the calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent according to claim 1, characterized in that, The calcium salt includes at least one of calcium chloride, calcium nitrate, calcium formate, calcium acetate, calcium bicarbonate, and calcium gluconate. And / or, the silicate includes at least one of sodium silicate, potassium silicate, and lithium silicate; And / or, the carbonate includes at least one of sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate.

5. The method for preparing a calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent according to claim 1, characterized in that, The mass of the dispersant is 1% to 10% of the total mass of the reaction system; the concentration of the dispersant solution is 1 wt% to 10 wt%.

6. The method for preparing a calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent according to claim 1, characterized in that, The dispersant includes a polycarboxylate superplasticizer.

7. The method for preparing a calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent according to claim 1, characterized in that, The temperature of the stirring reaction is 10℃~60℃, and the stirring speed is 100rpm~800rpm.

8. The method for preparing a calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent according to claim 1, characterized in that, The dripping time is 0.1~10h, and the stirring reaction time is 1~72h.

9. A calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent, characterized in that, It is prepared by the method for preparing the calcium carbonate / calcium silicate composite nanocrystal nucleus early strength agent according to any one of claims 1 to 8.

10. The application of the calcium carbonate / calcium silicate composite nanocrystalline nucleus early strength agent as described in claim 9 in early strength agents for cement-based materials and / or early strength agents for mineral admixture cement-based materials.

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