An admixture material for improving comprehensive performance of cement and preparation method thereof

Abstract

Aiming at the problem that triethanolamine, triisopropanolamine and the durability of cement concrete buildings in the application process of the two are insufficient, the present invention provides an admixture material for improving the comprehensive performance of cement and a preparation method thereof. The present invention first uses an alcohol solvent as a reaction solvent, dichloroalkane Cl(CH2) n Cl reacts with triethanolamine at 70-100°C to produce compound SM. Using water as the reaction solvent, compound SM is then reacted with triisopropanolamine at 80-110°C to produce the admixture material TP. This material retains the molecular structures of triethanolamine and triisopropanolamine, improving both the early and late strengths of cement, as well as its long-term strength. It also perfectly matches the compatibility of water reducers and enhances building durability. It also reduces early cracking and improves the overall density of cement concrete. #imgabs0#

Description

Technical Field

[0001] The invention relates to an admixture material for improving comprehensive performance of cement and a preparation method thereof, belonging to the technical field of cement production. Background Art

[0002] Cement is a powdered, hydraulic, inorganic cementitious material. Common silicate cement uses limestone as its primary raw material. Raw material is crushed, batched, and ground into raw meal, which is then fed into a cement kiln and calcined into clinker. The clinker is then ground with an appropriate amount of gypsum (sometimes mixed materials or admixtures). The cement industry is environmentally damaging, unsustainable, and energy-intensive. Producing 10,000 tons of cement requires 15,500 tons of limestone, 1,200 tons of coal, 800,000 kWh of electricity, and generates 10,000 tons of carbon dioxide. Currently, cement grinding aids, as an important cement admixture, can improve cement grinding efficiency and performance, increasing cement hourly output and cement strength at various ages. As a crucial admixture in cement production, cement grinding aids have been widely recognized by cement companies and have become an indispensable part of cement production.

[0003] Typically, cement grinding aids primarily consist of alcoholamines, which improve both early and late strength. Triethanolamine is the best material for improving early strength, but its contribution to late strength is minimal. This is especially true when large amounts of industrial solid waste are added to cement, where late strength barely increases or even decreases. Triisopropanolamine, on the other hand, primarily improves late strength in cement grinding aids, but its contribution to early strength is minimal, especially when used in low-grade cement production. To compensate for the inherent shortcomings of triethanolamine and triisopropanolamine, the industry relies on multiple batches of tests, experimenting with varying ratios based on comparative results, and then conducting multiple industrial trials to adjust the formulation. This process requires significant human and material resources and is time-consuming. While the resulting grinding aids meet cement plants' initial 3-day and 28-day strength requirements, they contain large amounts of alcoholamines and inorganic salts to maximize their effectiveness, leading to poor concrete performance and even a decrease in long-term strength, ultimately resulting in insufficient building durability. After research and development, the present invention finally designed a new type of cement admixture material, which can not only improve the early strength of cement but also improve the late strength and even the long-term strength of cement, and can well match the adaptability of water reducers, and can further improve the durability of buildings, and can make up for the shortcomings of triethanolamine and triisopropanolamine in their applications. Summary of the Invention

[0004] The present invention aims to provide an admixture material and a preparation method thereof for improving the comprehensive performance of cement. The admixture material of the present invention is a compound that retains the chemical molecular structure of triethanolamine and triisopropanolamine while also taking into account early and late strength. In practical applications, it has better universal applicability, and after forming a quaternary ammonium salt, it reduces the alkalinity of alcoholamines, can improve cement working performance, and has better adaptability with late-stage concrete polycarboxylate water-reducing agents. At the same time, it can also reduce early cracking and improve the overall density of cement concrete, which is more conducive to the durability of the concrete monolithic structure, which is also beyond the reach of current traditional cement grinding aids.

[0005] The technical solution of the present invention is: a method for preparing an admixture material for improving the comprehensive performance of cement, which is characterized by:

[0006] 1) Using alcohol solvent as reaction solvent, dichloroalkane Cl(CH2) n Cl and triethanolamine are reacted at 70-100 ° C to obtain compound SM;

[0007] 2) Using water as the reaction solvent, the compound SM is reacted with triisopropanolamine at 80-110° C. to obtain the admixture material TP.

[0008] The synthetic route of TP is as follows:

[0009]

[0010] Where R is (—CH2—) n , n is 2-10, and the dichloroalkane is preferably 1,3-dichloropropane, 1,4-dichlorobutane or 1,2-dichloroethane.

[0011] Wherein, the alcohol substance is any one of ethanol, ethylene glycol, diethylene glycol, propylene glycol, etc.

[0012] Its specific preparation method is:

[0013] 1) Add alcohol solvent and dichloroalkane Cl(CH2) into the reaction vessel n Cl, stirring and heating to 50-60°C, slowly adding triethanolamine dropwise, and after the addition is complete, heating to 70-100°C, maintaining the temperature and stirring for 2-3 hours; after the reaction is complete, cooling to room temperature, filtering, and washing the filter cake with an alcohol solvent, filtering, and then rinsing with an alcohol solvent, and drying to obtain solid particles, namely compound SM;

[0014] 2) Add TIPA (triisopropanolamine) and water to a reaction vessel, stir and heat to 60-70°C, begin dropwise addition of the SM aqueous solution, and after completion of the addition, heat to 80-110°C and react for 4-6 hours to obtain an aqueous solution containing compound TP, which is used directly.

[0015] The above dichloroalkane Cl(CH2) n The molar ratio of Cl to triethanolamine is 1:0.9-1; the molar ratio of TIPA (triisopropanolamine) to compound SM is 1:0.9-1.

[0016] The mechanism of action of the present invention is as follows: the TP compound of the present invention retains the molecular structure of triethanolamine and triisopropanolamine, so that it has the function of improving the early strength and late strength of cement, and its alkalinity is lower than that of alcoholamine substances, which is beneficial to improving the working performance of cement and improving the compatibility with polycarboxylate water-reducing agent for concrete.

[0017] Precautions for use with this product: 1. Store sealed in a cool, well-ventilated place. Avoid direct sunlight. 2. This substance is an organic compound and is strictly prohibited from consumption. 3. If this substance comes into contact with skin, rinse immediately with clean water.

[0018] The beneficial effects of the present invention are:

[0019] 1. The admixture material TP of the present invention has a substantially equivalent effect on the 3-day compressive strength of cement compared to triethanolamine; compared to triisopropanolamine, the compressive strength of cement at 28 days, 90 days, and 180 days is increased by 2.1, 3.2, and 3.5 MPa, respectively. It can be seen that its long-term effect is more obvious.

[0020] 2. When cement produced using the admixture material TP of the present invention is used in concrete, under the same mix ratio, the early cracking area of the concrete is reduced by more than 40%, and the electrical flux of the concrete is reduced by more than 20%;

[0021] 3. The final product of the present invention is an aqueous solution containing TP, which can be directly used as a cement admixture material without further purification, and can completely replace the currently used triethanolamine and triisopropanolamine. The process is relatively simple and is conducive to large-scale industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 These are electron microscope scans of cement added with different admixtures 28 days ago, where Figure A is an electron microscope scan of blank cement 28 days ago; Figure B is an electron microscope scan of cement added with TEA+TIPA 28 days ago; and Figure C is an electron microscope scan of cement added with TP 28 days ago. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0024] Example 1:

[0025] In a reaction flask, add 100 ml of ethylene glycol and 1 mol of 1,3-dichloropropane. Then, stir and heat to 50°C. Slowly add 0.9 mol of triethanolamine dropwise. After the addition is complete, heat to 90°C and stir for 3 hours. After the reaction is complete, cool to room temperature and filter. The filter cake is washed with ethylene glycol, filtered, rinsed with ethylene glycol again, and dried to obtain solid particles, namely compound SM.

[0026] In a clean reaction flask, add 1 mol of TIPA (triisopropanolamine) and 30 ml of water, stir and heat to 70°C, begin to dropwise add 0.95 mol of 50% SM aqueous solution, after the addition is complete, heat to 100°C, and keep warm for 6 hours to obtain an aqueous solution containing compound TP (the aqueous solution containing compound TP can be used directly as a cement admixture material without further purification, and the dosage in Table 1 below is calculated based on the molar number of the SM compound).

[0027] The laboratory used a φ500mm*500mm test mill to prepare 10kg of P.O42.5 cement, using a mass ratio of 75% clinker, 5% desulfurized gypsum, 5% limestone, 8% fly ash, and 7% slag. Triethanolamine (TEA), triisopropanolamine (TIPA), a combination of triethanolamine and triisopropanolamine, and TP were blended and molded according to GB / T17671-2021, "Test Methods for Cement Mortar Strength (ISO) Method," to verify the effects of the four substances on the compressive strength of cement at 3, 28, 90, and 180 days. Electron microscopy scanning was performed on cement mortar specimens containing different admixtures to observe their density.

[0028] The effects of different admixtures on the strength of cement mortar are shown in Table 1. The effects of different admixtures on the internal density of cement mortar specimens are shown in Table 1. Figure 1 shown.

[0029] Table 1: Effects of different admixtures on cement mortar strength

[0030]

[0031] Note: TEA (triethanolamine) and TIPA (triisopropanolamine) are both industrial products provided by Fushun Jiahua Chemical Co., Ltd.

[0032] Comparative results show that the three-day strength of cements incorporating TP compounds is essentially equivalent to that of cements formulated with triethanolamine or triethanolamine / triisopropanolamine. However, at 28 days and even for a longer period of 180 days, the strength is significantly higher than that of cements formulated with triisopropanolamine or triethanolamine / triisopropanolamine. Electron microscopic scanning of internal sections of cement mortar specimens reveals a significant increase in density compared to blank cement and cements formulated with triethanolamine and triisopropanolamine. Numerous dense needle-like crystals can be observed, effectively filling microcracks and micropores within the specimens. This suggests that TP products offer greater durability to cement than traditional triethanolamine and triisopropanolamine.

[0033] The laboratory used cement prepared with triethanolamine and triisopropanolamine, and cement prepared with TP, respectively, using the same concrete mix ratio (230 kg cement, 70 kg mineral powder, 80 kg fly ash, 850 kg sand, 980 kg gravel, 170 kg water, and 8 kg polycarboxylate superplasticizer per cubic meter of concrete) to prepare C30 benchmark concrete and C30 test concrete. The crack area and electrical flux of the C30 benchmark concrete and the C30 test concrete were then tested in accordance with GB50082-2009, "Test Method for Long-term Properties and Durability of Ordinary Concrete." The results are shown in Table 2.

[0034] Table 2: Test results are shown in the table below

[0035]

[0036] Comparisons of concrete cracking area and electrical flux reveal that cement prepared with TP can significantly reduce concrete cracking area (by 44.9%) and concrete electrical flux (by 22.2%) when used in concrete production, thereby improving the durability of the concrete. This is presumably due to the formation of quaternary ammonium salts, which reduces the alkalinity of the alcoholamine, slowing the early hydration heat of the cement, making the early hydration process smoother and reducing the risk of early cracking. Furthermore, cement prepared with TP generates a large number of dense needle-shaped crystals during hydration, which better fill the internal micro-voids and make the interior denser, thereby reducing the electrical flux and thus being more beneficial to the durability of cement concrete buildings.

[0037] Example 2:

[0038] In a reaction flask, add 100 ml of propylene glycol solvent and 1 mol of 1,4-dichlorobutane. Then, with stirring, heat the mixture to 50°C. Slowly add 1 mol of triethanolamine dropwise. After the addition is complete, heat the mixture to 80°C and stir for 3 hours. After the reaction is complete, cool the mixture to room temperature and filter. The filter cake is washed with propylene glycol solvent, filtered, rinsed again with propylene glycol solvent, and dried to obtain white solid particles, namely compound SM.

[0039] In a clean reaction flask, add 1 mol of TIPA (triisopropanolamine) and 30 ml of water, stir and heat to 60°C, start adding 1 mol of 50% SM aqueous solution dropwise, after the addition is complete, heat to 90°C, keep warm and react for 6 hours to obtain an aqueous solution containing compound TP.

Claims

1. A method for preparing an admixture material for improving the comprehensive performance of cement, characterized in that: The following steps are involved: 1) using an alcohol solvent as a reaction solvent, reacting 1,3-dichloropropane and triethanolamine at 70-100° C. to obtain compound SM; 2) using water as a reaction solvent, the compound SM is reacted with triisopropanolamine at 80-110° C. to obtain the admixture material TP; 2. The preparation method according to claim 1, wherein The alcohol solvent is any one of ethanol, ethylene glycol, diethylene glycol and propylene glycol.

3. The preparation method according to claim 1 or 2, characterized in that: The following steps are involved: 1) Add an alcohol solvent and 1,3-dichloropropane to a reaction vessel, stir and heat to 50-60°C, slowly add triethanolamine dropwise, and after the addition is complete, heat to 70-100°C, keep stirring and react for 2-3 hours; after the reaction is complete, post-process to obtain compound SM; 2) Add triisopropanolamine and water to a reaction vessel, stir and heat to 60-70°C, begin to dropwise add the SM aqueous solution, and after the addition is complete, heat to 80-110°C and keep warm for 4-6 hours to obtain an aqueous solution containing compound TP.

4. The preparation method according to claim 3, wherein: The post-treatment of step 1) is as follows: after the reaction is completed, the temperature is cooled to room temperature, filtered, the filter cake is slurried with an alcohol solvent, filtered, rinsed with an alcohol solvent, and dried to obtain compound SM.

5. The preparation method according to claim 3, wherein: The molar ratio of the 1,3-dichloropropane to triethanolamine is 1:0.9-1.

6. The preparation method according to claim 3, wherein: The molar ratio of triisopropanolamine to compound SM is 1:0.9-1.

7. An admixture material for improving the comprehensive properties of cement prepared by the preparation method according to any one of claims 3 to 6.

8. Use of the admixture material according to claim 7 in improving the durability of cement concrete buildings.

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