A composite amino ester type concrete binder reducing agent, its preparation method and application

Abstract

This invention provides a composite amino ester-type concrete binder reducing agent and its preparation method, which can be widely used in building materials with cement as the main cementitious system, belonging to the field of concrete admixture technology. The concrete binder reducing agent consists of the following components by weight percentage: 5%–8% composite amino ester, 2%–4% alkali-reactive optimizer, 3%–6% composite regulator, 1%–2% polymeric dispersant, 1.0%–1.5% stabilizer, and the balance being water. When this concrete binder reducing agent is applied to concrete at a dosage of 0.6 wt.% of the cementitious materials, it can save 8%–12% of cement usage while ensuring that the mechanical properties of the concrete do not decrease at all ages. It also effectively improves the workability, density, and durability of the concrete. The composite amino ester-type concrete binder reducing agent provided by this invention has a simple production process, readily available raw materials, and broad prospects for promotion and application.

Description

Technical Field

[0001] This invention belongs to the field of concrete admixture technology, specifically relating to a composite alkanolamine ester type concrete binder reducing agent and its preparation method, and also relating to the application of the above-mentioned composite alkanolamine ester type concrete binder reducing agent as an admixture for reducing cement usage. Background Technology

[0002] Concrete has become the most widely used building material in the world due to its numerous advantages, such as excellent plasticity, good water resistance, superior durability, and highly competitive economy. However, in traditional concrete, over 10% to 20% of the cement hydration reaction is incomplete after hardening. The cement merely acts as a micro-aggregate filler, failing to fully utilize its potential and representing a waste of resources. Therefore, reducing the amount of cement in concrete without compromising its performance is of paramount importance.

[0003] Concrete binder is an admixture that effectively reduces cement usage without affecting the 28-day compressive strength and condition of concrete. In practical use, it disperses aggregates, allowing cement particles to come into more complete contact with water and increasing their reactivity. Simultaneously, it activates potentially active mineral admixtures, thereby improving the hydration degree of the cementitious materials and achieving the goal of increasing concrete strength or reducing cement usage. Furthermore, the reduction in cement usage effectively lowers the risk of concrete cracking. Overall, binder is a reinforcing, green, and environmentally friendly admixture product.

[0004] In the application of concrete binder reducers, it is essential to first ensure that the actual properties of the concrete (air content, density, workability, etc.) meet the requirements, and only then can the binder's synergistic and binder-reducing effects be considered. While conventional concrete binder reducers can reduce cement usage to some extent in practical applications, they can easily lead to problems such as low initial slump and fluidity, poor coating properties, and poor saturation, negatively impacting the concrete's construction performance.

[0005] Based on this, a novel concrete binder is provided to solve the problems of low concrete binder reduction rate, poor adaptability and low early compressive strength in the existing technology, which is an urgent technical problem to be solved. Summary of the Invention

[0006] One of the objectives of this invention is to provide a composite amino ester type concrete adhesive reducing agent that is well-adapted to concrete, has a good adhesive-reducing effect, and does not affect the concrete construction state.

[0007] The second objective of this invention is to provide a method for preparing a composite alcohol amine ester type concrete binder reducing agent.

[0008] The third objective of this invention is to provide an application of a composite alcohol amine ester type concrete binder reducing agent.

[0009] One of the technical solutions adopted to achieve the objective of this invention is: to provide a composite amino ester type concrete binder reducing agent, which, by weight percentage, is composed of the following components:

[0010] The composition consists of 5%–8% compound amino esters, 2%–4% alkali activity optimizer, 3%–6% compound regulator, 1%–2% polymeric dispersant, 1.0%–1.5% stabilizer, and the balance being water.

[0011] The composite alcohol ester is prepared by esterification of diethanol monoisopropanolamine and benzoic acid under the catalysis of aminotrimethylenephosphonic acid.

[0012] The overall concept of the composite amino ester type concrete binder reducing agent provided by this invention is as follows:

[0013] On the one hand, the aforementioned binder contains a certain proportion of composite alkanolamine esters, which are prepared by esterification of diethanolmonoisopropanolamine and benzoic acid under the catalysis of aminotrimethylenephosphonic acid. This composite alkanolamine ester is weakly alkaline, effectively improving the hydration depth of cement. Simultaneously, aminotrimethylenephosphonic acid, as an organophosphonic acid, can effectively mitigate the negative impact of alkaline substances on the concrete condition under high-temperature conditions.

[0014] On the other hand, to improve the compatibility of the binder with concrete materials and further enhance the workability of the concrete, the binder provided by this invention also contains a certain proportion of alkali-reactive optimizer, composite regulator, polymeric dispersant, and stabilizer. The alkali-reactive optimizer, used in conjunction with the composite amino ester provided by this invention, promotes the dispersion efficiency of cement particles and further enhances the hydration degree of cement through alkali activation. The composite regulator mitigates the negative impact of alkali-reactive substances on the concrete's condition. The polymeric dispersant improves the fullness of the paste in the concrete. Through the synergistic effect of these components, not only is the amount of cement significantly reduced, but the resulting concrete also possesses higher mechanical properties and better workability.

[0015] In this invention, aminotrimethylenephosphonic acid (ATPA) is used as a catalyst. Compared to other organophosphoric acids (such as glycolic acid diphosphate and aminotrimethylenephosphonic acid), APA exhibits better catalytic effects and promotes product formation. Preferably, the molar ratio of diethanolmonoisopropanolamine, benzoic acid, and APA is (1.1–1.3):1:(0.4–0.6). By controlling the feed ratio of the three components, the resulting composite amine ester can achieve higher conversion efficiency, thus resulting in better practical application effects. In particular, if the amount of APA exceeds the above range, the ester content of the product will decrease.

[0016] Furthermore, the esterification reaction is carried out at a temperature of 120–140°C for 5–8 hours. Under these reaction conditions, the conversion efficiency is highest. Studies have shown that changes in heating temperature lead to changes in the composition ratio of the single alcohol ester, and heating temperatures exceeding the above range result in a decrease in the overall ester content of the product. More preferably, the esterification reaction is carried out for 5–6 hours.

[0017] Preferably, after the esterification reaction is completed, the excess water is evaporated to obtain the crude product. The crude product is then washed successively with 0.05-0.2 mol / L NaOH solution and distilled water to obtain a complex amino ester mixed solution.

[0018] In some preferred embodiments, the composite amine ester is a mixture of diethanolamine benzoate monoisopropanolamine ester and isopropanolamine benzoate diethanolamine ester, with a mass ratio of (0.9-1.2):(4.0-4.2).

[0019] Preferably, the alkali activity optimizer is selected from one or more combinations of sodium metasilicate pentahydrate, sodium carbonate, and sodium dihydrogen phosphate.

[0020] Preferably, the composite regulator is prepared by mixing polycarboxylate superplasticizer mother liquor, sodium gluconate, OSB air-entraining agent, and water in a mass ratio of (4-6):(1-3):1:(1-3). More preferably, the mass ratio of the four components is 5:2:1:2.

[0021] Furthermore, the compounding method of the composite regulator includes: mixing the polycarboxylate superplasticizer mother liquor with water evenly, then adding sodium gluconate and OSB air-entraining agent in sequence, and stirring for 5 to 15 minutes at a speed of 200 to 250 r / min to obtain the composite regulator.

[0022] Preferably, the compounding is carried out at room temperature, and the resulting composite regulator is a light brown solution. In this invention, the composite regulator is in liquid form, which allows it to dissolve quickly in the finished product and exert its regulating effect.

[0023] Preferably, the polymeric dispersant is selected from polyethylene glycol with a molecular weight of 950 to 1050. In this invention, polyethylene glycol with the above molecular weight is selected as the polymeric dispersant because it has better compatibility with polymeric alcohol esters and superior solubility in solution.

[0024] Preferably, the stabilizer is selected from a combination of at least two of vitamin C, sodium citrate, and lactic acid. By using different types of stabilizers in combination, the synergistic effect between them can maximize the stability effect and ensure the product has good economic benefits.

[0025] The second objective of this invention is achieved by providing a method for preparing a composite amino ester type concrete binder reducing agent according to one objective of this invention, comprising the following steps:

[0026] S1. Weigh out the composite amino ester, alkali activity optimizer, composite regulator, polymeric dispersant, stabilizer and water according to the content of each component shown in claim 1;

[0027] S2. Mix water, polymeric dispersant, complex amino acid ester and alkali activity optimizer, and stir at a speed of 280-320 r / min until the mixture is brown and transparent;

[0028] S3. Add composite regulator and stabilizer to the mixture and continue stirring for 5-15 minutes to obtain the finished product of the adhesive reducing agent.

[0029] In step S2, when the mixture is brown and transparent, it indicates that the complex amino ester has been completely dispersed in the mixture, and subsequent operations can be carried out.

[0030] The third objective of this invention is to provide an application of the composite alcohol amine ester type concrete binder reducing agent according to one of the objectives of this invention.

[0031] Furthermore, the dosage of the composite amino ester type concrete binder-reducing agent accounts for 0.4 wt.% to 0.6 wt.% of the total weight of the cementitious materials, and its application effect increases with the increase of the dosage of the binder-reducing agent. Preferably, the dosage of the composite amino ester type concrete binder-reducing agent is 0.6 wt.%.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] (1) The composite amino ester type concrete binder provided by the present invention uses composite amino ester as the main reinforcing and dispersing component, alkali activity optimizer as auxiliary reinforcing agent, and stabilizer to improve the stability of composite amino ester in the system. The two components work synergistically to achieve the purpose of concrete efficiency enhancement and binder reduction. At the same time, the polymer dispersant can improve the emulsification and dispersion efficiency of the composite regulator in concrete, and significantly improve the construction performance of concrete.

[0034] (2) The preparation process of the composite amino ester type concrete binder provided by the present invention is simple. The composite amino ester type concrete binder obtained can effectively reduce the amount of cement in a single cubic meter of concrete (8% to 12%) at a low dosage (0.6 wt.% of cement and other cementitious materials). It can also improve the growth of compressive strength of concrete at all ages. It is a high-efficiency, green and environmentally friendly admixture product.

[0035] (3) The composite amino ester type concrete binder provided by this invention is composed of a variety of reinforcing and regulating components, and has good adaptability. It can be applied to different types of concrete materials. At the same time, the use of modified materials (dispersant and composite regulator) can improve the construction condition of the binder-reduced concrete and further improve the concrete's encapsulation and saturation. The synthesis process of this concrete binder is simple, and the main materials do not require further fine processing to meet the usage requirements. It is suitable for industrial production and application and has broad prospects for promotion and application. Attached Figure Description

[0036] Figure 1 This is a schematic flowchart illustrating the preparation method of a composite alcohol amine ester type concrete binder provided by the present invention. Detailed Implementation

[0037] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0038] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0039] The present invention will be further described below with reference to specific embodiments, but these are not intended to limit the scope of the invention.

[0040] The main components and their mass percentages (wt.%) involved in the various embodiments of the present invention are shown in Table 1 below:

[0041] Table 1

[0042]

[0043]

[0044] In the above table,

[0045] The preparation method of the composite alkanolamine esters used in each embodiment is as follows: A mixture of diethanol monoisopropanolamine, benzoic acid, and aminotrimethylenephosphonic acid in a molar ratio of 1.2:1:0.5 is added to a round-bottom flask. The flask is heated to 120–140°C and reacted for 6 hours. Excess water is evaporated to obtain the crude product. The crude product is then washed successively with 0.1 mol / L NaOH solution and distilled water to obtain the composite alkanolamine ester mixed solution. In this composite alkanolamine ester mixed solution, the mass ratio of diethanol monoisopropanolamine benzoate to isopropanol diethanolamine benzoate is 1.1:4.2.

[0046] The composite regulator used in each embodiment is a liquid composed of polycarboxylate superplasticizer mother liquor, sodium gluconate, OSB air-entraining agent, and water in a mass ratio of 5:2:1:2. The polymeric dispersant is selected from polyethylene glycol (PEG) with a molecular weight of 1000.

[0047] Example 1

[0048] A method for preparing a composite amino ester type concrete binder reducing agent includes the following steps:

[0049] Step 1: Prepare each raw material component according to the mass fraction shown in Table 1;

[0050] Step 2: According to the weight proportions, add 85 parts of water, 2 parts of polymeric dispersant, 5 parts of composite amino ester and 2 parts of sodium metasilicate pentahydrate to the reaction vessel in sequence, adjust the rotation speed to 300 r / min, until the solution in the reaction vessel turns brown and transparent.

[0051] Step 3: Add 5 parts of the composite regulator, 0.5 parts of vitamin C and 0.5 parts of sodium citrate to the reaction vessel in sequence, and continue stirring for 10 minutes under this condition to obtain the finished product of the adhesive reducing agent.

[0052] Example 2

[0053] A method for preparing a composite amino ester type concrete binder reducing agent includes the following steps:

[0054] Step 1: Prepare each raw material component according to the mass fraction shown in Table 1;

[0055] Step 2: According to the weight proportions, add 85 parts of water, 2 parts of polymeric dispersant, 5 parts of complex amino ester and 3 parts of sodium metasilicate pentahydrate to the reaction vessel in sequence, adjust the rotation speed to 280 r / min until the solution in the reaction vessel turns brown and transparent.

[0056] Step 3: Add 4 parts of composite regulator, 0.5 parts of vitamin C and 0.5 parts of lactic acid to the reaction vessel in sequence, and continue stirring for 12 minutes under this condition to obtain the finished product of the adhesive reducing agent.

[0057] Example 3

[0058] A method for preparing a composite amino ester type concrete binder reducing agent includes the following steps:

[0059] Step 1: Prepare each raw material component according to the mass fraction shown in Table 1;

[0060] Step 2: According to the weight proportions, add 86.5 parts of water, 2 parts of polymeric dispersant, 5 parts of compound amino ester and 2 parts of sodium carbonate to the reaction vessel in sequence, adjust the rotation speed to 320 r / min until the solution in the reaction vessel turns brown and transparent.

[0061] Step 3: Add 3 parts of composite regulator, 0.5 parts of vitamin C and 0.5 parts of lactic acid to the reaction vessel in sequence, and continue stirring for 12 minutes under this condition to obtain the finished product of the adhesive reducing agent.

[0062] Example 4

[0063] A method for preparing a composite amino ester type concrete binder reducing agent includes the following steps:

[0064] Step 1: Prepare each raw material component according to the mass fraction shown in Table 1;

[0065] Step 2: According to the weight proportions, add 82 parts of water, 1 part of polymeric dispersant, 7 parts of compound amino ester and 4 parts of sodium dihydrogen phosphate to the reaction vessel in sequence, adjust the rotation speed to 300 r / min until the solution in the reaction vessel turns brown and transparent.

[0066] Step 3: Add 5 parts of the composite regulator, 0.5 parts of vitamin C and 0.5 parts of sodium citrate to the reaction vessel in sequence, and continue stirring for 10 minutes under this condition to obtain the finished product of the adhesive reducing agent.

[0067] Example 5

[0068] A method for preparing a composite amino ester type concrete binder reducing agent includes the following steps:

[0069] Step 1: Prepare each raw material component according to the mass fraction shown in Table 1;

[0070] Step 2: According to the weight proportions, add 83 parts water, 1 part polymeric dispersant, 8 parts compound amino ester and 3 parts sodium dihydrogen phosphate to the reaction vessel in sequence, adjust the rotation speed to 300 r / min until the solution in the reaction vessel turns brown and transparent.

[0071] Step 3: Add 4 parts of the composite regulator, 0.5 parts of vitamin C and 0.5 parts of sodium citrate to the reaction vessel in sequence, and continue stirring for 10 minutes under this condition to obtain the finished product of the adhesive reducing agent.

[0072] Example 6

[0073] A method for preparing a composite amino ester type concrete binder reducing agent includes the following steps:

[0074] Step 1: Prepare each raw material component according to the mass fraction shown in Table 1;

[0075] Step 2: According to the weight proportions, add 83 parts water, 1 part polymeric dispersant, 8 parts compound amino ester and 2 parts sodium dihydrogen phosphate to the reaction vessel in sequence, adjust the rotation speed to 300 r / min until the solution in the reaction vessel turns brown and transparent.

[0076] Step 3: Add 4 parts of composite regulator, 0.5 parts of lactic acid and 0.5 parts of sodium citrate to the reaction vessel in sequence, and continue stirring for 10 minutes under this condition to obtain the finished product of the adhesive reducing agent.

[0077] Example 7

[0078] A method for preparing a composite amino ester type concrete binder reducing agent includes the following steps:

[0079] Step 1: Prepare each raw material component according to the mass fraction shown in Table 1;

[0080] Step 2: According to the weight proportions, add 83 parts water, 1 part polymeric dispersant, 6 parts compound amino ester, 2 parts sodium dihydrogen phosphate and 2 parts sodium metasilicate pentahydrate to the reaction vessel in sequence, adjust the rotation speed to 300 r / min until the solution in the reaction vessel turns brown and transparent.

[0081] Step 3: Add 5 parts of composite regulator, 0.5 parts of lactic acid and 0.5 parts of sodium citrate to the reaction vessel in sequence, and continue stirring for 10 minutes under this condition to obtain the finished product of the adhesive reducing agent.

[0082] Example 8

[0083] A method for preparing a composite amino ester type concrete binder reducing agent includes the following steps:

[0084] Step 1: Prepare each raw material component according to the mass fraction shown in Table 1;

[0085] Step 2: According to the weight proportions, add 82 parts of water, 1 part of polymeric dispersant, 6 parts of compound amino ester, 1 part of sodium carbonate and 2 parts of sodium metasilicate pentahydrate to the reaction vessel in sequence, adjust the rotation speed to 300 r / min until the solution in the reaction vessel turns brown and transparent.

[0086] Step 3: Add 5 parts of composite regulator, 0.5 parts of lactic acid and 0.5 parts of sodium citrate to the reaction vessel in sequence, and continue stirring for 10 minutes under this condition to obtain the finished product of the adhesive reducing agent.

[0087] Application performance testing

[0088] The eight groups of adhesive-reducing agents prepared in Examples 1-8 above were tested for their actual application effects. In each example, the amount of adhesive-reducing agent accounted for 0.6% of the mass of cementitious materials. The testing standard was JC / T 2469-2018 "Concrete Adhesive-Reducing Agent". The following is a specific experimental test and analysis of the performance of the finished products in the above examples based on C35 concrete and C50 concrete (using PO 42.5 cement for villas).

[0089] The concrete performance of each binder-reducing agent prepared in Examples 1-8 was verified. Table 2 shows the performance requirements of the binder-reducing agent products in the standard JC / T2469-2018 "Concrete Binding Agents". Table 3 shows the mix proportions of C35 and C50 concrete used in the experiment. Table 4 shows the experimental results of C35 concrete. Table 5 shows the experimental results of C50 concrete.

[0090] Table 2 Performance test indicators of adhesive reducing agents

[0091]

[0092] Table 3 Concrete mix proportions (kg / m³) 3 )

[0093]

[0094] Table 4: Compressive Strength Test Data of C35 Concrete

[0095]

[0096]

[0097] Table 5: Compressive Strength Test Data of C50 Concrete

[0098]

[0099] The data in the table shows that,

[0100] The quick-setting agents prepared in Examples 1-8 all meet the performance requirements specified in standard JC / T2469-2018 "Concrete Adhesive Reducing Agents". Compared with the standard requirements, they have higher 7-day and 28-day compressive strength properties and better workability in C35 and C50 concrete. The adhesive reduction rates of the test products are 8.1% and 12.1%, respectively.

[0101] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the content of this specification should be included within the protection scope of the present invention.

Claims

1. A composite amino ester type concrete binder reducing agent, characterized in that, By weight percentage, it consists of the following components: 5%~8% compound amino ester, 2%~4% alkali activity optimizer, 3%~6% compound regulator, 1%~2% polymeric dispersant, 1.0%~1.5% stabilizer, and the balance being water; The composite alcohol ester is prepared by esterification of diethanol monoisopropanolamine and benzoic acid under the catalysis of aminotrimethylenephosphonic acid; the molar ratio of diethanol monoisopropanolamine, benzoic acid and aminotrimethylenephosphonic acid is (1.1~1.3):1:(0.4~0.6); the reaction temperature of the esterification reaction is 120~140℃; The alkali activity optimizer is selected from one or more combinations of sodium metasilicate pentahydrate, sodium carbonate, and sodium dihydrogen phosphate; the composite regulator is composed of polycarboxylate superplasticizer mother liquor, sodium gluconate, OSB air-entraining agent, and water in a mass ratio of (4~6):(1~3):1:(1~3); the polymeric dispersant is selected from polyethylene glycol with a molecular weight of 950~1050; the stabilizer is a composite of two of vitamin C, sodium citrate, and lactic acid in a mass ratio of 1:

1.

2. The composite amino ester type concrete binder reducer according to claim 1, characterized in that, The compounding method of the composite regulator includes: mixing the polycarboxylate superplasticizer mother liquor with water evenly, then adding sodium gluconate and OSB air-entraining agent in sequence, and stirring for 5 to 15 minutes at a speed of 200 to 250 r / min to obtain the composite regulator.

3. A method for preparing a composite amino ester type concrete binder reducing agent according to claim 1 or 2, characterized in that, Includes the following steps: S1. Weigh out the compound amino ester, alkali activity optimizer, compound regulator, polymeric dispersant, stabilizer and water according to the content of each component; S2. Mix water, polymeric dispersant, compound amino ester and alkali activity optimizer, and stir at 280~320 r / min until the mixture is brown and transparent. S3. Add composite regulator and stabilizer to the mixture and continue stirring for 5-15 minutes to obtain the finished product of the adhesive reducing agent.

4. An application of the composite amino ester type concrete binder reducing agent according to claim 1 or 2, characterized in that, The composite amino ester type concrete binder is added during the concrete preparation process, and its dosage accounts for 0.4 wt.% to 0.6 wt.% of the total weight of the cementitious materials.

Images