A cement early strength agent, its preparation method and application

Abstract

This invention discloses a cement accelerator, its preparation method, and its application, belonging to the field of building materials technology. The cement accelerator provided by this invention, by weight, comprises the following raw materials: 49-55 parts of degummed artificial stone powder; 1-2 parts of a surface modifier; the surface modifier includes artificial stone powder modifier and sodium carbonate; the median particle size of the solids in the cement accelerator is 0.3-0.5 μm. The cement accelerator provided by this invention can effectively promote the early hydration of cement, reduce its porosity, and improve its flexural and compressive strength, while simultaneously achieving the reuse of solid waste from artificial stone and reducing costs. This invention also provides a preparation method and application of the above-mentioned cement accelerator.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to a cement early strength agent, its preparation method, and its application. Background Technology

[0002] As the core and foundation of the construction industry, precast concrete components are widely used in building engineering. Typically, well-mixed concrete needs high early strength to meet the basic requirement of rapid demolding, thus accelerating the production cycle and improving economic efficiency. Generally, to achieve rapid early strength improvement in silicate cement (PC) under non-oxygenated conditions, some nano-accelerators are added. The main reason is that these nanoparticles can act as nuclei to accelerate the formation of hydrates in the early stages.

[0003] The production of artificial stone generates a large amount of waste slurry from stone polishing. This waste slurry is typically transported and stockpiled after discharge, which not only reduces the economic benefits for artificial stone manufacturers but also causes environmental pollution. Analysis shows that the main component of this waste slurry is SiO2, accounting for approximately 85-92%, with a small amount of organic matter also present. Traditionally, this waste slurry (including organic matter) is used in concrete preparation, and it is generally believed that it improves the overall performance of the concrete.

[0004] However, in traditional technologies, concrete containing stone waste slurry lacks early strength performance. Summary of the Invention

[0005] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a cement early-strength agent that can effectively promote the early hydration of cement, reduce its porosity, and improve its flexural and compressive strength, while simultaneously achieving the goals of reusing solid waste in artificial stone and reducing costs.

[0006] The present invention also provides a method for preparing the above-mentioned cement early strength agent.

[0007] This invention also provides the application of the above-mentioned cement early strength agent.

[0008] According to an embodiment of the first aspect of the present invention, a cement accelerator is provided, wherein the raw materials for preparing the cement accelerator, by weight, include:

[0009] 49-55 parts of degummed artificial stone powder;

[0010] 1-2 parts of surface modifier;

[0011] The median particle size of the solids in the cement early strength agent is 0.3–0.5 μm.

[0012] The cement early-strength agent according to embodiments of the present invention has at least the following beneficial effects:

[0013] The large amount of waste slurry generated during the artificial stone production process is usually transported and stockpiled after discharge. The cost of processing each ton is about 40 yuan, which not only reduces the economic benefits of artificial stone manufacturers, but also causes environmental pollution.

[0014] Currently, there is technology that allows the direct addition of dried artificial stone waste slurry to concrete, and it is believed that the resin or the combination of resin and inorganic materials can improve the strength of concrete to a certain extent.

[0015] However, this invention has found that if waste slurry is directly applied to cement mortar systems (or building materials such as concrete), its high particle size and low activity make it difficult to positively influence the various properties of cement mortar, primarily its mechanical properties. Furthermore, organic matter traditionally considered beneficial to cement mortar systems is mostly in a solidified state, which reduces its bonding efficiency with the cement paste; therefore, organic matter can actually have a negative impact on the performance of cement mortar systems.

[0016] Materials such as silica and titanium dioxide show a significant promoting effect on early cement hydration, with the former showing a more pronounced effect; the inorganic components of artificial stone waste contain a large amount of silica; nanoparticles with lower particle size and chemical composition more similar to hydration products show greater potential as early strength agents. Specifically:

[0017] The cement early strength agent provided by this invention uses degummed artificial stone powder, that is, artificial stone waste with organic matter removed, which avoids the adverse effects of organic matter on the cement mortar system; at the same time, it limits the solid particle size in the cement early strength agent, that is, it limits the activity of the degummed artificial stone powder to a certain extent.

[0018] Therefore, the provided cement early strength agent can not only play a high-strength physical filling role in cement-based materials, but also act as a crystal nucleus to induce cement hydration and accelerate the early hydration reaction. It has a significant effect on improving the early strength performance and long-term mechanical properties of cement-containing building materials. At the same time, it also improves the utilization rate of artificial stone waste and the added value of its products, thereby improving economic and environmental benefits.

[0019] According to some embodiments of the present invention, the mass percentage of silica in the degummed artificial stone powder is 88-94%.

[0020] According to some embodiments of the present invention, the degummed artificial stone powder further includes at least one of illite, microcline, MgO, CaO and Al2O3.

[0021] In the degummed artificial stone powder, the sum of the mass percentages of all components is 100%.

[0022] According to some embodiments of the present invention, the surface modifier includes artificial stone powder modifier and sodium carbonate.

[0023] According to some embodiments of the present invention, the artificial stone powder modifier includes at least one of titanate modifiers and stearate modifiers.

[0024] According to some embodiments of the present invention, the titanate modifier includes at least one of monoalkoxy titanate and alkoxypyrophosphate titanate.

[0025] According to some embodiments of the present invention, the titanate coupling agent includes TC-201.

[0026] According to some embodiments of the present invention, the stearate modifier includes stearic acid SA1801.

[0027] According to some embodiments of the present invention, the mass ratio of the artificial stone powder modifier to sodium carbonate is 2 to 4:1.

[0028] According to some embodiments of the present invention, the mass ratio of the artificial stone powder modifier to sodium carbonate is 2.5 to 3.5:1.

[0029] According to some embodiments of the present invention, the mass ratio of the artificial stone powder modifier to sodium carbonate is approximately 3:1.

[0030] According to some embodiments of the present invention, the mass ratio of the degummed artificial stone powder to the surface modifier is 24.5 to 55:1.

[0031] According to some embodiments of the present invention, the mass ratio of the degummed artificial stone powder to the surface modifier is 25 to 54:1.

[0032] According to some embodiments of the present invention, the mass ratio of the degummed artificial stone powder to the surface modifier is 34 to 53:1.

[0033] According to some embodiments of the present invention, the mass ratio of the degummed artificial stone powder to the surface modifier is 34.5 to 35:1.

[0034] According to some embodiments of the present invention, the raw materials for preparing the cement early strength agent further include water, and the weight ratio of the degummed artificial stone powder to water is 49-55:44-49.

[0035] According to some embodiments of the present invention, the water content in the raw materials for preparing the cement early strength agent is 44-50% by mass.

[0036] According to some embodiments of the present invention, the water content in the raw materials for preparing the cement early strength agent is 45-49% by mass.

[0037] According to some embodiments of the present invention, the water content in the raw materials for preparing the cement early strength agent is 46-48% by mass.

[0038] According to some embodiments of the present invention, the water content in the raw materials for preparing the cement early strength agent is 46.5% to 47% by mass.

[0039] According to some embodiments of the present invention, the median particle size of the solids in the cement early strength agent is 0.35 to 0.45 μm.

[0040] According to some embodiments of the present invention, the median particle size of the solids in the cement early strength agent is 0.3 to 0.4 μm.

[0041] According to some embodiments of the present invention, the median particle size of the solids in the cement early strength agent is about 0.4 μm.

[0042] Unless otherwise specified, the median particle size in this invention is D50.

[0043] According to some embodiments of the present invention, the raw materials for preparing the cement early strength agent, by weight, include:

[0044] 49-55 parts of degummed artificial stone powder;

[0045] 44-49 parts water;

[0046] 1-2 parts of surface modifier.

[0047] According to some embodiments of the present invention, the raw materials for preparing the cement early strength agent, by weight, include:

[0048] 54-55 parts of degummed artificial stone powder;

[0049] 44-45 parts water;

[0050] One part of surface modifier. According to an embodiment of the second aspect of the present invention, a method for preparing the cement early strength agent is provided, the method comprising grinding and mixing the raw materials for preparing the cement early strength agent.

[0051] The preparation method according to embodiments of the present invention has at least the following beneficial effects:

[0052] (1) In the preparation method described above, grinding and mixing not only have a mixing effect but also an ultrafine crushing effect. Therefore, cement early strength agents with nanoscale solid particle sizes can be obtained, which enhances the ability of cement early strength agents to induce cement hydration as crystal nuclei. In other words, the preparation method uses grinding technology in conjunction with surface modifiers to ultrafine waste slurry powder. The resulting cement early strength agent, after being added to cement mortar in small amounts, can significantly improve the mechanical properties of cement-based materials. This provides a new method for preparing nanocrystalline nucleus early strength agents and solves the problems of low resource utilization rate and low product added value of stone waste slurry.

[0053] (2) During the mixing and grinding process, the surfactant can promote grinding and reduce agglomeration, that is, reduce the agglomeration of nanoparticles, thereby preparing a cement early strength agent with submicron particle size.

[0054] (3) The preparation method provided by the present invention is simple, saves costs significantly, and improves efficiency; moreover, it realizes the efficient utilization of industrial solid waste, reduces environmental pollution, and is conducive to its promotion and application.

[0055] According to some embodiments of the present invention, the method for obtaining the degummed artificial stone powder includes calcining and crushing artificial stone waste slurry.

[0056] According to some embodiments of the present invention, the artificial stone waste slurry includes at least one of the solid waste generated during the polishing process of artificial stone, and the crushed products of decommissioned and / or recycled artificial stone.

[0057] According to some embodiments of the present invention, the calcination temperature is 375–400°C, and the calcination time is 2–4 hours. The organic matter in artificial stone waste powder is mostly in a solidified state, typically accounting for about 10 wt%, which significantly reduces the bonding efficiency between the waste powder and cement paste. Based on previous experiments, the present invention has identified a suitable calcination temperature range for pre-treatment, removing the organic matter from the waste powder, which is of great significance for improving its utilization efficiency and activity.

[0058] Furthermore, compared with traditional chemical degumming methods, the calcination method avoids the introduction of new corrosive chemical degumming agents, significantly simplifies the composition of the early strength agent, and improves economic efficiency and environmental friendliness.

[0059] According to some embodiments of the present invention, the calcination temperature is 380–390°C.

[0060] According to some embodiments of the present invention, the calcination temperature is approximately 385°C.

[0061] According to some embodiments of the present invention, the calcination time is 2.5 to 3.5 hours.

[0062] According to some embodiments of the present invention, the calcination time is approximately 3 hours.

[0063] As the calcination temperature and time increase, the removal rate of organic matter in artificial stone waste improves; however, further increasing the temperature leads to energy waste. Therefore, this invention limits the calcination conditions to ensure both the removal of organic matter and energy conservation.

[0064] According to some embodiments of the present invention, the method for obtaining the degummed artificial stone powder further includes cooling between the calcination and the crushing. This improves the safety of the operation process.

[0065] According to some embodiments of the present invention, the crushing method includes dry grinding.

[0066] According to some embodiments of the present invention, the instrument used for crushing includes a pulverizer. Specifically, it may be an abrasive pulverizer (ACM).

[0067] According to some embodiments of the present invention, the method for obtaining the degummed artificial stone powder further includes sieving the resulting crushed powder after crushing. Specifically, it can be sieved through a 300-mesh sieve and the undersize material is obtained. This achieves preliminary particle size control of the solids in the cement accelerator and simultaneously performs preliminary surface activation of the solids.

[0068] According to some embodiments of the present invention, the particle size of the degummed artificial stone powder is ≤48μm, specifically 8-40μm. More specifically, it can be 20-30μm.

[0069] According to some embodiments of the present invention, the apparatus used for grinding and mixing includes a ball mill. Specifically, it may be a planetary ball mill.

[0070] According to some embodiments of the present invention, the grinding media used in the grinding and mixing process are agate balls.

[0071] According to some embodiments of the present invention, the particle size of the grinding media used in the grinding and mixing process is 10 mm, 5 mm, and 3 mm. Specifically, the mass ratio (hereinafter referred to as gradation) of the 10 mm, 5 mm, and 3 mm grinding media is 1:4 to 6:1. In ball milling, the gradation of the grinding media will affect the performance of the resulting product to a certain extent. Specifically, grinding media with larger particle sizes tend to have a crushing effect, while grinding media with smaller particle sizes tend to have a dispersing effect. Unlike general stirring and mixing, grinding media with different gradations compress and collide with the workpiece, and also have a surface modification effect. The present invention uses grinding media of various particle sizes in a mixed manner, and the grinding and mixing process is equivalent to ultrafine crushing and surface modification.

[0072] According to some embodiments of the present invention, the gradation of the grinding media used in the grinding mixture is approximately 1:5:1.

[0073] The raw materials for preparing the cement early strength agent of this invention include water. Therefore, the grinding and mixing is actually a wet grinding process. Traditional dry ball milling can only reduce the median particle size of stone waste slurry powder to 6-9 μm at most, which is difficult to play a nucleation induction role in the cement hydration system. However, the use of wet grinding in conjunction with surface modifiers can greatly improve grinding efficiency and enable the particle size of waste slurry to quickly break through the micron threshold.

[0074] According to some embodiments of the present invention, in the grinding and mixing process, the mass ratio of the grinding media to the degummed artificial stone powder is 1.4 to 1.8:1.

[0075] According to some embodiments of the present invention, in the grinding and mixing process, the mass ratio of the grinding media to the degummed artificial stone powder is 1.4 to 1.6:1.

[0076] According to some embodiments of the present invention, in the grinding and mixing process, the mass ratio of the grinding media to the degummed artificial stone powder is 1.45 to 1.55:1.

[0077] According to some embodiments of the present invention, the grinding and mixing time is 2 to 4 hours.

[0078] According to some embodiments of the present invention, the grinding and mixing time is 2.5 to 3.5 hours.

[0079] According to some embodiments of the present invention, the grinding and mixing time is approximately 3 hours.

[0080] According to some embodiments of the present invention, the grinding and mixing process is carried out at a rotation speed of 300 to 400 rpm.

[0081] According to some embodiments of the present invention, the grinding and mixing process is carried out at a rotation speed of 320 to 380 rpm.

[0082] According to some embodiments of the present invention, the grinding and mixing process is carried out at a rotation speed of 340 to 360 rpm.

[0083] According to some embodiments of the present invention, the grinding and mixing process is carried out at a rotation speed of approximately 350 rpm.

[0084] Within the range of grinding and mixing parameters provided, as the rotation speed increases and the grinding time increases, the particle size of the solids in the cement early strength agent decreases, and the improvement of the early strength of cement-based building materials becomes more obvious. However, if the parameters continue to increase, the effect of reducing the particle size will not increase significantly. That is, within the grinding and mixing parameters provided by this invention, the particle size of the solids in the obtained cement early strength agent and the grinding efficiency can be balanced.

[0085] According to some embodiments of the present invention, the preparation method further includes filtering the mixture obtained after grinding and mixing.

[0086] The parameters in the grinding and mixing process essentially determine the particle size of the solids in the resulting cement accelerator. The presence of the surfactant effectively prevents the re-agglomeration of micro- and nano-sized solid particles in the cement accelerator. The filtration process can effectively separate the grinding media and the cement accelerator.

[0087] According to an embodiment of a third aspect of the present invention, the application of the aforementioned cement accelerator in cement-based building materials is provided.

[0088] Since the application adopts all the technical solutions of the cement early strength agent of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments.

[0089] According to some embodiments of the present invention, the cement-based building material includes at least one of cement paste, cement mortar, cement grout, cement-mixed mortar, and cement concrete.

[0090] According to some embodiments of the present invention, the cement early strength agent is added to the cement-based building material at a dosage of 1 to 6 wt%.

[0091] The calculation method for the amount of cementitious early-strength agent is the external admixture method, which is the mass percentage of cement early-strength agent in the solid matter of cement-based building materials.

[0092] In the solution provided by this invention, as the amount of folding and solid content increases, the early strength of the resulting cement-based building material gradually increases within the same time period. After exceeding the above range, the increase ratio decreases. Therefore, by controlling it within the above ratio range, both early strength and cost can be taken into account.

[0093] According to some embodiments of the present invention, the cement early strength agent is added to the cement-based building material at a dosage of 2-5 wt%.

[0094] According to some embodiments of the present invention, the cement early strength agent is added to the cement-based building material at a dosage of 3-4 wt%.

[0095] According to some embodiments of the present invention, when the cement-based building material is selected from the cement mortar, the flexural strength of the cement mortar can be increased by 8 to 40% after adding the cement accelerator compared with the cement accelerator without it.

[0096] According to some embodiments of the present invention, when the cement-based building material is selected from the cement mortar, the flexural strength of the cement mortar can be increased by 15-20% after adding the cement accelerator compared with the cement accelerator without it.

[0097] According to some embodiments of the present invention, when the cement-based building material is selected from the cement mortar, the flexural strength of the cement mortar can be increased by 23-28% after adding the cement accelerator compared with the cement accelerator without it.

[0098] According to some embodiments of the present invention, when the cement-based building material is selected from the cement mortar, the flexural strength of the cement mortar can be increased by 30-35% after adding the cement accelerator compared with the cement accelerator without it.

[0099] According to some embodiments of the present invention, when the cement-based building material is selected from the cement mortar, the compressive strength of the cement mortar can be increased by 8 to 100% after adding the cement accelerator compared with not adding the cement accelerator.

[0100] According to some embodiments of the present invention, when the cement-based building material is selected from the cement mortar, the compressive strength of the cement mortar can be increased by 9-10% after adding the cement early-strength agent compared with not adding the cement early-strength agent.

[0101] According to some embodiments of the present invention, when the cement-based building material is selected from the cement mortar, the compressive strength of the cement mortar can be increased by 20-25% after adding the cement early strength agent compared with not adding the cement early strength agent.

[0102] According to some embodiments of the present invention, when the cement-based building material is selected from the cement mortar, the compressive strength of the cement mortar can be increased by 35-40% after adding the cement accelerator compared with not adding the cement accelerator.

[0103] According to some embodiments of the present invention, when the cement-based building material is selected from the cement mortar, the compressive strength of the cement mortar can be increased by 55-60% after adding the cement accelerator compared with not adding the cement accelerator.

[0104] According to some embodiments of the present invention, when the cement-based building material is selected from the cement mortar, the compressive strength of the cement mortar can be increased by 65-70% after adding the cement accelerator compared with not adding the cement accelerator.

[0105] According to some embodiments of the present invention, when the cement-based building material is selected from the cement mortar, the compressive strength of the cement mortar can be increased by 80-85% after adding the cement accelerator compared with not adding the cement accelerator.

[0106] Unless otherwise specified, the term "about" in this invention actually means that the error is allowed to be within ±2%, for example, about 100 is actually 100 ± 2% × 100.

[0107] Unless otherwise specified, "between" in this invention includes the number itself, for example, "between 2 and 3" includes the endpoint values ​​2 and 3.

[0108] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Detailed Implementation

[0109] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0110] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0111] Example 1

[0112] This example demonstrates the preparation of a cement early-strength agent. Specifically, referring to the proportions in Table 1, degummed artificial stone powder, water, and surfactant were ground and mixed in a planetary ball mill. The resulting ground mixture was then sieved to remove the grinding media. The grinding media are shown in Table 1, and the grinding parameters are shown in Table 2.

[0113] In this example, the steps for obtaining degummed artificial stone powder are as follows:

[0114] S1. Place the artificial stone waste slurry into a calcining furnace for calcination, and remove it after cooling; the specific calcination conditions in this step are shown in Table 2.

[0115] The calcined product contains 88-94% silica, with the remainder being illite, microcline, magnesium oxide, calcium oxide, and aluminum oxide. The composition of different batches of artificial stone waste slurry varies slightly, but within the above range, it has almost no impact on the performance of the resulting cement accelerator.

[0116] S2. Place the powder obtained in step S1 into a pulverizer and dry grind it until it can pass through a 300-mesh sieve.

[0117] Examples 2-8 respectively prepared a cement early strength agent. The specific difference from Example 1 is that the amount of material or the preparation parameters are slightly different. For details, please refer to Table 1 or Table 2.

[0118] Table 1. Raw material ratios for the preparation of cement early strength agents in Examples 2-8.

[0119]

[0120] In Table 1, "parts" refers to "parts by weight"; the gradation of the grinding media refers to the mass ratio of three types of grinding balls: 10mm, 5mm, and 3mm. The artificial stone powder modifier is specifically a mixture of TC-201 and stearic acid SA1801 in a 1:1 mass ratio.

[0121] Table 2. Calcination, grinding and mixing parameters for Examples 1-8

[0122]

[0123] Comparative Example 1

[0124] This example demonstrates the preparation of a cement early-strength agent, specifically:

[0125] Using the same artificial stone waste slurry as in Example 1, the material was dried by forced air at 60°C and then crushed until it could pass through a 300-mesh sieve. The resulting product was then mixed with water at a mass ratio of 56:44 (without grinding).

[0126] Comparative Example 2

[0127] This example prepares a cement early strength agent, which differs from Example 7 in that:

[0128] In step S1, calcination is not performed; drying is only carried out at 60°C using forced air. All other conditions are the same as in Example 7.

[0129] Comparative Example 3

[0130] This example prepares a cement early strength agent, which differs from Example 7 in that:

[0131] The degummed artificial stone powder, water, and surfactant are mixed using only simple mechanical stirring, rather than grinding and mixing using a planetary ball mill.

[0132] Application examples

[0133] This example demonstrates the preparation of a type of cement mortar:

[0134] The mixture should be prepared according to the proportions specified in GB / T 17671-2021, specifically one part cement (42.5 silicate cement), three parts Chinese ISO standard sand, and half a part water (including the water in the cement accelerator). A certain amount of the cement accelerator obtained in the examples or comparative examples should also be added, and a blank sample (without cement accelerator) should be prepared. The mixture should be mixed, molded, and cured according to the methods specified in GB / T17671-2021. The dosage of the cement accelerator is shown in Table 3.

[0135] Test case

[0136] This example tests the compressive strength and flexural strength of the samples obtained from the application example after 12 hours, and calculates the comparison between the two and the blank sample. The specific calculation method is as follows: Percentage increase in compressive strength = (12-hour compressive strength of each cement mortar sample - 12-hour compressive strength of the blank cement mortar sample) / 12-hour compressive strength of the blank cement mortar sample × 100%. The specific test results are shown in Table 3.

[0137] Table 3 shows the parameters and dosage of the cement accelerator used in the application examples, as well as the performance of the obtained cement mortar samples.

[0138]

[0139]

[0140] The comparison between Examples 1-8 and the blank sample shows that the cement early strength agent provided by the present invention has a significant promoting effect on the 12-hour mechanical strength of cement mortar. Moreover, the mechanical strength increases with the increase of grinding and mixing time, early strength agent dosage, calcination time and temperature. The percentage increase in flexural strength can reach 40%, and the percentage increase in compressive strength can reach 100%.

[0141] Examples 1-8 and Comparative Example 1 illustrate that in the preparation method of the cement accelerator provided by this invention, the grinding and mixing of all raw materials can significantly reduce the particle size of the solids, breaking through the micron-level limitation and significantly improving its activity as an accelerator. If the organic matter in the artificial stone powder is not removed and it is not crushed, it will have a negative impact on the mechanical properties of cement-based building materials.

[0142] The comparison between Examples 7 and 8 illustrates that while increasing the amount of grinding media does not significantly affect the median particle size, it does affect the particle size distribution of the cement early strength agent to some extent, thereby improving the compressive strength to a certain degree.

[0143] Comparing Comparative Example 2 and Example 7, it is evident that without the calcination step, the resin adhesive in the artificial stone waste slurry cannot be removed. Therefore, even with subsequent grinding, the particle size of the cement accelerator cannot be effectively reduced. Furthermore, due to the side reactions occurring between the resin adhesive and the surfactant during the grinding process, the various mechanical properties of the cement mortar are further reduced.

[0144] Comparing Comparative Example 3 and Example 7, it can be seen that simple mechanical stirring breaks down the loose bonds in the debonded artificial stone powder, but the particle size of the cement accelerator does not decrease to the submicron level, and the interaction between the debonded artificial stone powder and the surface modifier can still occur sufficiently. Therefore, when used as a cement accelerator, it can improve the mechanical properties of cement mortar to a certain extent, but the improvement in performance is significantly lower than that in Example 7.

[0145] As shown in Table 2, the cement early strength agent provided by this invention has a significant effect on improving the early strength of cement-based building materials and is expected to be widely used in cement mortar, cement mortar, cement mixed mortar and cement concrete.

[0146] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A cement early-strength agent, characterized in that, The raw materials for preparing the cement early strength agent, by weight, include: 49-55 parts of degummed artificial stone powder; 1-2 parts of surface modifier; The median particle size of the solids in the cement early strength agent is 0.3~0.5μm; The method for obtaining the degummed artificial stone powder includes calcining and crushing artificial stone waste slurry; the calcination temperature is 375~400℃, and the calcination time is 2~4h; The surface modifier includes engineered stone powder modifier and sodium carbonate; The modified stone powder includes at least one of titanate modifiers and stearate modifiers.

2. The cement early-strength agent according to claim 1, characterized in that, The mass ratio of the modified artificial stone powder to sodium carbonate is 2~4:

1.

3. The cement early-strength agent according to claim 1 or 2, characterized in that, The raw materials for preparing the cement early strength agent also include water, and the weight ratio of the degummed artificial stone powder to water is 49~55:44~49.

4. A method for preparing a cement accelerator as described in any one of claims 1 to 3, characterized in that, The preparation method includes grinding and mixing the raw materials for preparing the cement early strength agent.

5. The preparation method according to claim 4, characterized in that, The method for obtaining the degummed artificial stone powder includes calcining and crushing artificial stone waste slurry.

6. The preparation method according to claim 5, characterized in that, The calcination temperature is 375~400℃, and the calcination time is 2~4h.

7. The preparation method according to claim 4, characterized in that, In the grinding and mixing process, the mass ratio of the grinding media to the degummed artificial stone powder is 1.4~1.8:1; and / or, the grinding and mixing time is 2~4 hours.

8. The preparation method according to claim 7, characterized in that, During the grinding and mixing process, the rotation speed is 300~400 rpm.

9. The application of the cement accelerator as described in any one of claims 1 to 3 in cement-based building materials.

10. The application according to claim 9, characterized in that, The cement-based building materials include at least one of cement paste, cement mortar, cement grout, and cement concrete.

11. The application according to claim 9 or 10, characterized in that, The cement early strength agent is added to the cement-based building material at a dosage of 1~6wt%.

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