A cement quick-setting and strength-enhancing agent, its preparation method and application

Abstract

The present invention relates to a cement accelerating and strengthening agent, its preparation method and application. The cement accelerating and strengthening agent comprises the following components in parts by mass: 50 parts of recycled concrete micropowder, 50 parts of water, 10 - 30 parts of ammonium sulfate, 5 parts of ammonium bicarbonate, 30 parts of acetic acid, 30 parts of ammonia water, 10 parts of triethanolamine, 0.1 - 2 parts of starch ether, and 1 - 2 parts of triethylamine hydrochloride. Compared with the prior art, through steps such as salt ion erosion, grinding and organic grafting, the present invention prepares organically modified C-S-H gel at the nanoscale, achieving the effect of increasing the early hydration depth, without changing the fluidity of the cement paste, capable of increasing the cement strength and adjusting the setting time, solving the problem in the prior art that it is difficult to balance the early strength and control the setting time, and at the same time being able to make full use of solid waste, with no pollution in the preparation process and having good environmental benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of cement preparation, and in particular to a cement quick-setting and strength-enhancing agent, a preparation method thereof, and an application thereof. Background Art

[0002] The large emission of carbon dioxide has led to global warming. Achieving carbon peak and carbon neutrality is a major strategic decision for China to achieve sustainable development, and the "carbon reduction" action is imperative. A large amount of carbon dioxide is generated during the production of portland cement. Increasing the cement strength and reducing the cement consumption can significantly reduce the carbon dioxide emission. Reducing the cement setting time can shorten the project duration, and the recycling of recycled concrete powder can achieve solid waste reduction and emission reduction. Therefore, designing a cement quick-setting and strength-enhancing agent can expand the application range of cement and reduce the cement consumption. Existing cement quick-setting agents such as hydrofluoric acid have obvious high-pollution characteristics. Existing cement quick-setting agents have at least the following limitations: (1) It causes the reduction of the early hydration strength of cement, especially the serious weakening of the hydration product skeleton; (2) The strengthening effect of some quick-setting agents comes from their water-reducing effect, resulting in the need to use more cement to prepare products of the same volume; (3) The preparation process of some quick-setting agents involves raw materials containing heavy metal ions; (4) It changes the fluidity of the cement paste and limits the application range of materials.

[0003] In view of the problems existing in the prior art solutions, how to synthesize a cement admixture that simultaneously has quick-setting and increases early strength is an urgent problem to be solved in the engineering field at the present stage. Summary of the Invention

[0004] The purpose of the present invention is to solve the above problems by providing a cement quick-setting and strength-enhancing agent and a preparation method thereof. Through steps such as salt ion erosion, grinding, and organic grafting, organic-modified C-S-H gels at the nanoscale are prepared, achieving the effect of increasing the early hydration depth, without changing the fluidity of the cement paste, increasing the cement strength and adjusting the setting time, solving the problem that it is difficult for the prior art to balance the early strength and control the setting time, and at the same time, being able to make full use of solid waste, with no pollution in the preparation process and good environmental benefits.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] The first purpose of the present invention is to provide a cement quick-setting and strength-enhancing agent, and the cement quick-setting and strength-enhancing agent includes the following components in parts by weight: 50 parts of recycled concrete powder, 50 parts of water, 10 - 30 parts of ammonium sulfate, 5 parts of ammonium bicarbonate, 30 parts of acetic acid, 30 parts of ammonia water, 10 parts of triethanolamine, 0.1 - 2 parts of starch ether, and 1 - 2 parts of triethylamine hydrochloride.

[0007] Preferably, the quick-setting cement enhancer comprises the following components in parts by weight: 50 parts of recycled concrete powder, 50 parts of water, 30 parts of ammonium sulfate, 5 parts of ammonium bicarbonate, 30 parts of acetic acid, 30 parts of ammonia water, 10 parts of triethanolamine, 2 parts of starch ether, and 2 parts of triethylamine hydrochloride.

[0008] Further, the recycled concrete powder is a powder with a particle size less than 1 mm during the production process of recycled concrete aggregates; the recycled concrete powder includes calcium silicate hydrate (C-S-H).

[0009] Further, the recycled concrete powder also includes unhydrated cement particles, calcium hydroxide, silicon dioxide, etc.

[0010] Further, the starch ether is selected from one or more of hydroxyetherified starch, acyletherified starch, and phospholipid etherified starch.

[0011] Further, the quick-setting cement enhancer is a soluble white solid powder.

[0012] The second object of the present invention is to provide a preparation method of the above quick-setting cement enhancer, comprising the following steps:

[0013] (1) Grind the recycled concrete powder to 50 - 100 μm;

[0014] (2) Mix the ground recycled concrete powder with ammonium sulfate and ammonium bicarbonate solutions;

[0015] (3) Stir at 60 °C and then let it stand in a water bath at 60 °C;

[0016] (4) Add ammonia water, acetic acid, and triethanolamine to adjust the pH, and add triethylamine hydrochloride and starch ether to make a paste;

[0017] (5) Grind the paste;

[0018] (6) Dry the ground paste at 50 °C and grind it to 10 μm.

[0019] Further, the concentrations of the ammonium sulfate and ammonium bicarbonate solutions are both 20% - 50% (mass fraction).

[0020] Further, in step (3), the stirring time is 4 - 24 h; in step (3), the standing time is 1 - 7 d.

[0021] Further, in step (4), the pH is adjusted to 8 - 9.

[0022] Further, in step (5), the grinding time is 24 h.

[0023] The third object of the present invention is to provide an application of the above cement accelerating and strengthening agent, which is used to prepare cement.

[0024] Furthermore, the cement accelerating and strengthening agent is used to prepare dry powder admixture or water agent.

[0025] The mechanism of this application is as follows: The present invention proposes a cement accelerating and strengthening agent and its preparation method. The mechanism involves steps such as salt ion erosion, grinding by ammonium sulfate, ammonium bicarbonate, etc., and grafting of one or more starch ether organic matters to erode and dissociate the hydrated C-S-H gel and regulate the structure, that is, preparing an organic matter-modified C-S-H gel at the nanoscale as the cement accelerating and strengthening agent. Among them, after the C-S-H is eroded, a silicon-oxygen tetrahedron chain (inorganic Si-OH) mainly composed of Q 3 is formed, which has the function of enhancing and guiding nucleation after being adsorbed by the organic matter. Therefore, this cement accelerating and strengthening agent has the effect of increasing the early hydration depth, does not change the fluidity of the cement paste, can increase the cement strength and adjust the setting time.

[0026] Compared with the prior art, the beneficial effects of the present invention are reflected in the following aspects:

[0027] 1) A cement accelerating and strengthening agent and its preparation method proposed by the present invention. The present invention proposes to synthesize a new type of active admixture, which has both the functions of accelerating setting and regulating the early hydration rate, does not affect the fluidity of the cement paste, has wide engineering applicability, and obvious environmental benefits.

[0028] 2) A cement accelerating and strengthening agent and its preparation method proposed by the present invention. The hydrated C-S-H gel regulates the structure through steps such as salt ion erosion, grinding, and organic matter grafting, so that the structure is enhanced and plays a role in guiding nucleation, increasing the early hydration depth, and does not change the fluidity of the cement paste, achieving the effect of increasing the cement strength and adjusting the setting time.

[0029] 3) For the cement accelerating and strengthening agent of the present invention, the recycling of concrete powder in the raw materials can achieve solid waste reduction and emission reduction. At the same time, the process temperature for production is normal temperature and low temperature, and the production energy consumption is low.

[0030] 4) The cement accelerating and strengthening agent of the present invention is a soluble white solid powder with a fast dissolution rate, can be used to prepare dry powder admixture, and can also be used in water agent. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a comparison chart of the initial setting / final setting time of the cement accelerating and strengthening agent prepared in Examples 1 to 6 and the pure Portland cement without adding accelerating agent.

[0032] Figure 2Comparison chart of 3-day flexural strength between the cement quick-setting and strength enhancer prepared in Examples 1-6 and pure portland cement without adding quick-setting agent.

[0033] Figure 3 Comparison chart of 3-day compressive strength between the cement quick-setting and strength enhancer prepared in Examples 1-6 and pure portland cement without adding quick-setting agent. Detailed implementation manners

[0034] The present invention will be described in detail below with reference to specific embodiments, but it is by no means a limitation to the present invention. Features such as preparation means, materials, structures or composition ratios not clearly described in this technical solution are regarded as common technical features disclosed in the prior art.

[0035] Unless otherwise specified, there are no special requirements for the sources of the components in the cement quick-setting and strength enhancer of the present invention, and those well-known to those skilled in the art can be used.

[0036] Among them, after the recycled concrete powder passes through a jaw crusher, particles smaller than 1 cm are screened, and then ground with a Raymond mill; the starch ether is selected from hydroxy, acyl and phospholipid etherified starches.

[0037] Example 1

[0038] The cement quick-setting and strength enhancer in this example includes the following raw materials in parts by weight: 50 parts of recycled concrete powder, 50 parts of water, 30 parts of ammonium sulfate, 5 parts of ammonium bicarbonate, 30 parts of acetic acid, 30 parts of ammonia water, 10 parts of triethanolamine, 2 parts of starch ether, and 2 parts of triethylamine hydrochloride.

[0039] The preparation process steps of the above cement quick-setting and strength enhancer:

[0040] (1) First, grind the recycled concrete powder to 50 μm.

[0041] (2) Subsequently, mix the recycled concrete powder with ammonium sulfate and ammonium bicarbonate solutions.

[0042] (3) Stir at 60 °C for 24 h, and then stand in a water bath at 60 °C for 7 d.

[0043] (4) Add ammonia water, acetic acid and triethanolamine to adjust the pH to 9, and add triethylamine hydrochloride and starch ether to make a paste.

[0044] (5) Subsequently, grind the paste for 24 h.

[0045] (6) Dry the paste at 50 °C and grind it to 10 μm to obtain the cement quick-setting and strength enhancer, sample number: P1.

[0046] The above grinding is carried out by using a jaw crusher, screening particles smaller than 1 cm, and then grinding with a Raymond mill.

[0047] Example 2

[0048] The quick-setting and strength-enhancing agent for cement in this example comprises raw materials with the following parts by weight: 50 parts of recycled concrete micropowder, 50 parts of water, 30 parts of ammonium sulfate, 5 parts of ammonium bicarbonate, 30 parts of acetic acid, 30 parts of ammonia water, 10 parts of triethanolamine, 2 parts of starch ether, and 2 parts of triethylamine hydrochloride.

[0049] The preparation process steps of the above quick-setting and strength-enhancing agent for cement are as follows:

[0050] (1) First, grind the recycled concrete micropowder to 100 μm.

[0051] (2) Subsequently, mix the recycled concrete micropowder with ammonium sulfate and ammonium bicarbonate solutions.

[0052] (3) Stir at 60 °C for 24 h, and then add and let stand in a water bath at 60 °C for 7 d.

[0053] (4) Add ammonia water, acetic acid, and triethanolamine to adjust the pH to 9, and add triethylamine hydrochloride and starch ether to make a paste.

[0054] (5) Subsequently, grind the paste for 24 h.

[0055] (6) Dry the paste at 50 °C and grind it to 10 μm to obtain the quick-setting and strength-enhancing agent for cement, sample number: P2.

[0056] Example 3

[0057] The quick-setting and strength-enhancing agent for cement in this example comprises raw materials with the following parts by weight: 50 parts of recycled concrete micropowder, 50 parts of water, 30 parts of ammonium sulfate, 5 parts of ammonium bicarbonate, 30 parts of acetic acid, 30 parts of ammonia water, 10 parts of triethanolamine, 2 parts of starch ether, and 2 parts of triethylamine hydrochloride.

[0058] The preparation process steps of the above quick-setting and strength-enhancing agent for cement are as follows:

[0059] (1) First, grind the recycled concrete micropowder to 50 μm.

[0060] (2) Subsequently, mix the recycled concrete micropowder with ammonium sulfate and ammonium bicarbonate solutions.

[0061] (3) Stir at 60 °C for 4 h, and then add and let stand in a water bath at 60 °C for 1 d.

[0062] (4) Add ammonia water, acetic acid, and triethanolamine to adjust the pH to 9, and add triethylamine hydrochloride and starch ether to make a paste.

[0063] (5) Subsequently, grind the paste for 24 h.

[0064] (6) Dry the paste at 50 °C and grind it to 10 μm to obtain a cement accelerating and strengthening agent, sample number: P3.

[0065] Example 4

[0066] The cement accelerating and strengthening agent in this example includes the following raw materials by weight: 50 parts of recycled concrete powder, 50 parts of water, 30 parts of ammonium sulfate, 5 parts of ammonium bicarbonate, 30 parts of acetic acid, 30 parts of ammonia water, 10 parts of triethanolamine, 2 parts of starch ether, and 2 parts of triethylamine hydrochloride.

[0067] The preparation process steps of the above cement accelerating and strengthening agent are as follows:

[0068] (1) First, grind the recycled concrete powder to 50 μm.

[0069] (2) Subsequently, mix the recycled concrete powder with ammonium sulfate and ammonium bicarbonate solution.

[0070] (3) Stir at 60 °C for 4 h, and then add and let stand in a 60 °C water bath for 1 day.

[0071] (4) Add ammonia water, acetic acid and triethanolamine to adjust the pH to 8, and add triethylamine hydrochloride and starch ether to make a paste.

[0072] (5) Then grind the paste for 24 h.

[0073] (6) Dry the paste at 50 °C and grind it to 10 μm to obtain a cement accelerating and strengthening agent, sample number: P4.

[0074] Secondly, control the process to be consistent and clarify the functions of the key phases in the formula:

[0075] Example 5

[0076] The cement accelerating and strengthening agent in this example includes the following raw materials by weight: 50 parts of recycled concrete powder, 50 parts of water, 30 parts of ammonium sulfate, 5 parts of ammonium bicarbonate, 30 parts of acetic acid, 30 parts of ammonia water, 10 parts of triethanolamine, 0.1 part of starch ether, and 1 part of triethylamine hydrochloride.

[0077] The preparation process steps of the above cement accelerating and strengthening agent are as follows:

[0078] (1) First, grind the recycled concrete powder to 50 μm.

[0079] (2) Subsequently, mix the recycled concrete powder with ammonium sulfate and ammonium bicarbonate solution.

[0080] (3) Stir at 60 °C for 4 h, and then add and let stand in a 60 °C water bath for 1 day.

[0081] (4) Add ammonia water, acetic acid and triethanolamine to adjust the pH to 8, and add triethylamine hydrochloride and starch ether to make a paste.

[0082] (5) Then grind the paste for 24 h.

[0083] (6) Dry the paste at 50 °C and grind it to 10 μm to obtain a cement quick-setting and strength-enhancing agent, sample number: P5.

[0084] Example 6

[0085] The cement quick-setting and strength-enhancing agent in this example comprises the following raw materials in parts by weight: 50 parts of recycled concrete micropowder, 50 parts of water, 10 parts of ammonium sulfate, 5 parts of ammonium bicarbonate, 30 parts of acetic acid, 30 parts of ammonia water, 10 parts of triethanolamine, 2 parts of starch ether, and 2 parts of triethylamine hydrochloride.

[0086] The preparation process steps of the above cement quick-setting and strength-enhancing agent are as follows:

[0087] (1) First, grind the recycled concrete micropowder to 50 μm.

[0088] (2) Then, mix the recycled concrete micropowder with ammonium sulfate and ammonium bicarbonate solutions.

[0089] (3) Stir at 60 °C for 4 h, and then leave it to stand in a 60 °C water bath for 1 d.

[0090] (4) Add ammonia water, acetic acid and triethanolamine to adjust the pH to 8, and add triethylamine hydrochloride and starch ether to make a paste.

[0091] (5) Then grind the paste for 24 h.

[0092] (6) Dry the paste at 50 °C and grind it to 10 μm to obtain a cement quick-setting and strength-enhancing agent, sample number: P6.

[0093] Mix the cement quick-setting agents prepared in Examples 1 to 6 by the external admixture method with pure Portland cement at 5% (by mass), add water and cast into shape. And test the setting time, flexural strength and compressive strength of the test blocks. The test results are shown in Table 1, and the test results are as Figures 1 to 3 shown.

[0094] Table 1 Sample parameters of examples (the addition amount of the quick-setting and strength-enhancing agent is 5 wt%, and P0 is pure Portland cement without adding the quick-setting agent).

[0095]

[0096] As can be seen from Table 1, combined with Figure 1, compared with the pure Portland cement sample P0, the initial setting time and final setting time of the samples added with 0.2% of P1, P2, P3, and P4 additives can be shortened, and the initial setting time and final setting time of P1 and P4 can reach within 1 h; combined with Figure 2 , the flexural strengths of the samples added with 0.2% of P1, P2, P3, and P4 additives increased by 51.2%, 21.9%, 31.7%, and 58.5% respectively; combined with Figure 3 , the compressive strengths of the samples added with 0.2% of P1, P2, P3, and P4 additives increased by 27.3%, 6.4%, 16.9%, and 32.3% respectively. Compared with P0, the flexural strengths of P5 and P6 increased by 39.0% and 53.6% respectively, and the compressive strengths increased by 23.0% and 28.9% respectively.

[0097] The above description of the embodiments is to enable those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A cement quick-setting and strength-enhancing agent, characterized in that, the cement quick-setting and strength-enhancing agent comprises the following components in parts by weight: 50 parts of recycled concrete micropowder, 50 parts of water, 10 - 30 parts of ammonium sulfate, 5 parts of ammonium bicarbonate, 30 parts of acetic acid, 30 parts of ammonia water, 10 parts of triethanolamine, 0.1 - 2 parts of starch ether, 1 - 2 parts of triethylamine hydrochloride; the preparation method of the cement quick-setting and strength-enhancing agent comprises the following steps: (1) Grinding the recycled concrete micropowder to 50 - 100 μm; (2) Mixing the ground recycled concrete micropowder with ammonium sulfate and ammonium bicarbonate solution; (3) Stirring at 60°C, and then standing in a water bath at 60°C; (4) Adding ammonia water, acetic acid and triethanolamine to adjust the pH, and adding triethylamine hydrochloride and starch ether to make a paste; (5) Grinding the paste; (6) Drying the ground paste at 50°C and grinding it to 10 μm to obtain the cement quick-setting and strength-enhancing agent.

2. The cement quick-setting and strength-enhancing agent according to claim 1, characterized in that, the cement quick-setting and strength-enhancing agent comprises the following components in parts by weight: 50 parts of recycled concrete micropowder, 50 parts of water, 30 parts of ammonium sulfate, 5 parts of ammonium bicarbonate, 30 parts of acetic acid, 30 parts of ammonia water, 10 parts of triethanolamine, 2 parts of starch ether, 2 parts of triethylamine hydrochloride.

3. The cement quick-setting and strength-enhancing agent according to claim 1, characterized in that, the recycled concrete micropowder is a powder with a particle size less than 1 mm in the production process of recycled concrete aggregate; the recycled concrete micropowder comprises calcium silicate hydrate.

4. The cement quick-setting and strength-enhancing agent according to claim 1, characterized in that, the starch ether is selected from one or more of hydroxyetherified starch, acyletherified starch and phospholipid etherified starch.

5. A preparation method of the cement quick-setting and strength-enhancing agent according to any one of claims 1 - 4.

6. The preparation method of the cement quick-setting and strength-enhancing agent according to claim 5, characterized in that, in step (3), the stirring time is 4 - 24 h; in step (3), the standing time is 1 - 7 d.

7. The preparation method of the cement quick-setting and strength-enhancing agent according to claim 5, characterized in that, in step (4), the pH is adjusted to 8 - 9.

8. The preparation method of the cement quick-setting and strength-enhancing agent according to claim 5, characterized in that, in step (5), the grinding time is 24 h.

9. An application of the cement quick-setting and strength-enhancing agent according to any one of claims 1 - 4, characterized in that, the cement quick-setting and strength-enhancing agent is used for preparing cement.

10. The application of the cement quick-setting and strength-enhancing agent according to claim 9, characterized in that, the cement quick-setting and strength-enhancing agent is used for preparing dry powder admixture or for water agent.

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