A chemical admixture for synchronously promoting cement mineral hydration and preparation method thereof

Abstract

The present invention discloses a chemical admixture for synchronously promoting cement mineral hydration and a preparation method thereof. The chemical admixture for synchronously promoting cement mineral hydration described by Amin includes three mineral phase hydration promoting components, namely alite, belite and iron phase, and a balancing agent, wherein the hydration promoting components of each mineral phase are balanced by the balancing agent. The present invention adopts a multi-component composite modification method, selects hydration stimulating substances for three mineral phases, synchronously promotes the hydration process of each mineral phase in cement, and selects reasonable solvents and balancing agents to balance the compatibility of multiple compound components, and finally realizes the improvement of the hydration degree of cement-based materials, generates more hydration products per unit time, compacts the accumulation of hydration products and improves the strength, and realizes the regulation of the microstructure of cement-based materials and the effective improvement of durability.

Description

Technical Field

[0001] The invention belongs to the field of concrete admixtures, and in particular relates to a chemical admixture for synchronously promoting cement mineral hydration and a preparation method thereof. Background Art

[0002] Cement-based materials are the most widely used building materials in the world and are the basic building blocks of building structures. In the context of my country's strong transportation system, a large number of infrastructure planning and construction, including roads, subways, tunnels, etc., must be considered in the construction stage due to the safety and life requirements of major infrastructure. According to the concrete design standard specification "Concrete Structure Durability Design Code", a direct connection is established between concrete strength and structural failure probability, and strength has become the most important indicator in concrete design.

[0003] The improvement of the durability of concrete materials is mainly designed to improve the strength of concrete materials and the strength guarantee rate. The strength is mainly determined by the cementitious material formed after the cementitious material solidifies and hardens. The sand and gravel aggregates that play a filling role do not involve changes over time. The strength is mainly regulated by controlling the cement hydration process. Cement is composed of four minerals: alite, belite, aluminum phase and iron phase. The aluminum phase and alite react quickly in the early stage to provide strength, and the other two mineral phases react very slowly and have limited contribution to strength. Existing accelerators and enhancers promote the coagulation and strength development of cement concrete by accelerating the reaction of alite and aluminum phase. Synchronously promoting the hydration process of the four mineral phases to promote strength development is an important method to enhance cement-based materials.

[0004] There are relatively few patents and research on synchronously promoting the hydration process of four minerals in cement. Patent CN114380527A reports a strengthening modifier for concrete admixtures and its preparation method, which mainly improves the hydration rate of mineral-added cement by chemical admixtures to achieve improved hydration degree and strength. Patent CN110713358A reports a cement nanosuspension concrete early strength agent and its preparation method, which mainly promotes the hydration process of siliceous minerals in cement to achieve improved hydration degree of cement-based materials. The reported methods are mainly aimed at stimulating alite and aluminum phases, and there are certain limitations on the improvement of strength and the guarantee rate of strength improvement. Summary of the invention

[0005] Aiming at the application defect that the existing reinforcing agents mainly stimulate alite and aluminum phase mineral phases in cement, and the strength improvement range and strength guarantee rate are limited, the present invention provides a chemical admixture that synchronously promotes cement mineral hydration and a preparation method thereof.

[0006] The present invention aims at the characteristics of the hydration process of the four mineral phases in cement, and promotes the hydration process of the four mineral phases through a composite modification approach. A multi-component composite modification method is adopted, and hydration stimulating substances for the three mineral phases are selected to simultaneously promote the hydration process of each mineral phase in cement. On the other hand, reasonable solvents and balancing agents are selected to balance the compatibility of multiple compound components, and finally the hydration degree of cement-based materials is improved, more hydration products are generated per unit time, the hydration products are densely accumulated and the strength is improved, and the microstructure of cement-based materials is regulated and the durability is effectively improved.

[0007] To achieve the above objectives, the present invention provides a chemical admixture for synchronously promoting cement mineral hydration, including three mineral phase hydration promoting components, namely alite, belite and iron phase, and a balancing agent, wherein the balancing agent balances the hydration promoting components of each mineral phase, and the mass proportion of each component is as follows:

[0008] Alite hydration promoting component 10%-40%,

[0009] Belite hydration promoting component 10%-50%,

[0010] Iron phase hydration promoting component 10%-40%,

[0011] Balancer 5%-10%,

[0012] The sum of the mass percentages of each component is 100%;

[0013] The alite hydration promoting component is a small molecule alcohol amine with a molecular weight of 62-200 g / mol;

[0014] The belite hydration promoting component is an alkali metal organic matter;

[0015] The iron phase hydration promoting component is a metal chelating agent;

[0016] The balancing agent is selected from any one of unsaturated carboxylic acid, unsaturated alcohol and unsaturated amide or a mixture of two of them.

[0017] Furthermore, the small molecule alcohol amine of the present invention is selected from a mixture of any one or more of monoethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N,N-dimethylethanolamine, and 2-amino-2-methyl-1-propanol.

[0018] Furthermore, the alkali metal organic compound of the present invention is selected from any one or more of butyl lithium, phenyl lithium, lithium diisopropylamide, sodium lactate, and potassium tert-butoxide.

[0019] Furthermore, the metal chelating agent of the present invention is selected from any one or more of ethylenediamine, glycine and glutamic acid.

[0020] Furthermore, the balancing agent of the present invention is selected from any one of acrylic acid, acryl alcohol and acrylamide, or a mixture of two of them.

[0021] The present invention also provides a method for preparing the chemical admixture for synchronously promoting cement mineral hydration, comprising: pre-dissolving a balancing agent into an organic solvent to obtain a solution I, then dissolving an iron phase hydration promoting component into the above solution I to obtain a solution II, then dissolving a belite hydration promoting component into the solution II and stirring for 30-80 minutes to obtain a solution III, then dissolving an alite hydration promoting component into the solution III, and finally removing the solvent by distillation to obtain the chemical admixture of the present invention;

[0022] The organic solvent is toluene or ethanol.

[0023] The chemical admixture of the present invention is applied to cement-based materials, including cement concrete, cement mortar and pure cement products, etc. By adding the chemical admixture of the present invention to cement-based materials, the amount of the admixture is 0.01%-1.0% of the mass of the cementitious material, the hydration degree of silicate cement is improved, the concrete microstructure is improved, the durability of cement-based materials is improved, and the service life of the concrete structure is extended.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The chemical admixture of the present invention significantly enhances the overall hydration rate of cement-based materials, improves the strength of concrete, has a high strength guarantee rate, improves the durability of cement-based materials, and extends the service life of concrete structures; the enhancer has no chemical toxicity and does not introduce gas, the synthetic raw materials are non-toxic and easy to obtain, and the synthesis method is easy to implement and can be applicable to industrial production. DETAILED DESCRIPTION

[0026] To better illustrate the present invention, the following examples are listed. However, the specific material ratios, process conditions and results described in the examples are only used to illustrate the present invention, and should not and will not limit the claims in the present invention.

[0027] Unless otherwise specified in the examples of the present invention, the cement used is PO42.5 cement from Conch Cement Plant, and the chemical reagents are purchased from Aladdin Reagent Company.

[0028] Example 1

[0029] A chemical admixture for synchronously promoting cement mineral hydration comprises three mineral phase hydration promoting components, namely alite, belite and iron phase, and a balancing agent, wherein the balancing agent balances the hydration promoting components of each mineral phase. The specific preparation method thereof is as follows:

[0030] The chemical admixture is prepared by dissolving 20 g of propylene alcohol as a balance agent into ethanol, then dissolving 40 g of ethylenediamine as an iron phase hydration promoting component into the solution, then dissolving 70 g of sodium lactate as a belite hydration promoting component into the solution and stirring for 60 minutes, then dissolving 70 g of triethanolamine as an alite hydration promoting component into the solution, and finally removing the solvent by distillation.

[0031] Example 2

[0032] A chemical admixture for synchronously promoting cement mineral hydration comprises three mineral phase hydration promoting components, namely alite, belite and iron phase, and a balancing agent, wherein the balancing agent balances the hydration promoting components of each mineral phase. The specific preparation method thereof is as follows:

[0033] The chemical admixture is prepared by dissolving 20 g of propylene alcohol as a balancing agent into ethanol, then dissolving 30 g of glycine, a component promoting hydration of the iron phase, into the solution, then dissolving 70 g of lithium diisopropylamide, a component promoting hydration of belite, into the solution and stirring for 60 minutes, then dissolving 80 g of N-methyldiethanolamine, a component promoting hydration of alite, into the solution, and finally removing the solvent by distillation.

[0034] Example 3

[0035] A chemical admixture for synchronously promoting cement mineral hydration comprises three mineral phase hydration promoting components, namely alite, belite and iron phase, and a balancing agent, wherein the balancing agent balances the hydration promoting components of each mineral phase. The specific preparation method thereof is as follows:

[0036] The chemical admixture is prepared by dissolving 20 g of propylene alcohol as a balance agent into ethanol, then dissolving 40 g of glycine as an iron phase hydration promoting component into the solution, then dissolving 70 g of potassium tert-butoxide as a belite hydration promoting component into the solution and stirring for 60 minutes, then dissolving 70 g of N-methyldiethanolamine as an alite hydration promoting component into the solution, and finally removing the solvent by distillation.

[0037] Example 4

[0038] A chemical admixture for synchronously promoting cement mineral hydration comprises three mineral phase hydration promoting components, namely alite, belite and iron phase, and a balancing agent, wherein the balancing agent balances the hydration promoting components of each mineral phase. The specific preparation method thereof is as follows:

[0039] The chemical admixture is prepared by dissolving 20 g of propylene alcohol as a balance agent into ethanol, then dissolving 40 g of glycine as an iron phase hydration promoting component into the solution, then dissolving 70 g of potassium tert-butoxide as a belite hydration promoting component into the solution and stirring for 60 minutes, then dissolving 70 g of N-methyldiethanolamine as an alite hydration promoting component into the solution, and finally removing the solvent by distillation.

[0040] Example 5

[0041] A chemical admixture for synchronously promoting cement mineral hydration comprises three mineral phase hydration promoting components, namely alite, belite and iron phase, and a balancing agent, wherein the balancing agent balances the hydration promoting components of each mineral phase. The specific preparation method thereof is as follows:

[0042] The chemical admixture is prepared by dissolving 20 g of propylene alcohol as a balance agent into ethanol, then dissolving 40 g of glycine as an iron phase hydration promoting component into the solution, then dissolving 70 g of potassium tert-butoxide as a belite hydration promoting component into the solution and stirring for 60 minutes, then dissolving 40 g of N-methyldiethanolamine as an alite hydration promoting component into the solution, and finally removing the solvent by distillation.

[0043] Example 6

[0044] A chemical admixture for synchronously promoting cement mineral hydration comprises three mineral phase hydration promoting components, namely alite, belite and iron phase, and a balancing agent, wherein the balancing agent balances the hydration promoting components of each mineral phase. The specific preparation method thereof is as follows:

[0045] The chemical admixture is prepared by dissolving 20 g of propylene alcohol as a balance agent into ethanol, then dissolving 50 g of glycine as an iron phase hydration promoting component into the solution, then dissolving 80 g of potassium tert-butoxide as a belite hydration promoting component into the solution and stirring for 60 minutes, then dissolving 50 g of N-methyldiethanolamine as an alite hydration promoting component into the solution, and finally removing the solvent by distillation.

[0046] Comparative Example 1

[0047] A chemical admixture for synchronously promoting cement mineral hydration, comprising alite, an iron phase mineral phase hydration promoting component and a balancing agent, wherein the balancing agent is used to balance the hydration promoting components of each mineral phase, and the specific preparation method thereof is as follows:

[0048] The chemical admixture is prepared by dissolving 20 g of propylene alcohol as a balancing agent into ethanol, then dissolving 30 g of glycine, an iron phase hydration promoting component, into the solution and stirring for 60 minutes, then dissolving 70 g of N-methyldiethanolamine, an alite hydration promoting component, into the solution, and removing the solvent by distillation.

[0049] Application Examples

[0050] Application Example 1

[0051] The water-cement ratio of the concrete specimens was set to 0.5, and the dosage of chemical admixtures was 0.02%, 0.05%, and 0.10% of the cementitious material. The raw materials used were 350kg cement, 1075kg gravel, 777kg sand, and 175kg tap water to prepare concrete specimens with a strength of C30. There were 5 groups of molded concrete specimens. After standard curing for 28 days, the results are shown in Table 1. There was no chemical admixture in the baseline group.

[0052] Table 1 28-day strength of concrete with chemical admixtures

[0053]

[0054] From the data in Table 1, it can be found that by comparing the comparative example with the data of the example, the 28-day strength of the concrete material to which the reinforcing agent of the example of the present invention is added increases significantly with the increase in the dosage, and the standard deviation of the strength is less than 3.5, which has a good reinforcing effect. The reinforcing effect of lacking one of the mineral phases is slightly weaker than that of other examples, and the iron phase plays a more important role in promoting the reinforcement.

Claims

1. A chemical admixture for synchronously promoting cement mineral hydration, characterized in that: It is composed of three mineral phase hydration promoting components, namely alite, belite and iron phase, and a balancing agent, wherein the balancing agent is used to balance the hydration promoting components of each mineral phase. The mass proportion of each component is as follows: Alite hydration promoting component 10%-40%, Belite hydration promoting component 10%-50%, Iron phase hydration promoting component 10%-40%, Balancer 5%-10%, The sum of the mass percentages of each component is 100%; The alite hydration promoting component is a small molecule alcohol amine with a molecular weight of 62-200 g / mol; The Belite hydration promoting component is an alkali metal organic compound; the alkali metal organic compound is selected from a mixture of any one or more of lithium diisopropylamide, sodium lactate, and potassium tert-butoxide; The iron phase hydration promoting component is a metal chelating agent; the metal chelating agent is selected from any one or more of ethylenediamine, glycine, and glutamic acid; The balancing agent is selected from any one of unsaturated carboxylic acid, unsaturated alcohol and unsaturated amide or a mixture of two thereof.

2. A chemical admixture for synchronously promoting cement mineral hydration according to claim 1, characterized in that: The small molecule alcohol amine is selected from a mixture of any one or more of monoethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N,N-dimethylethanolamine, and 2-amino-2-methyl-1-propanol.

3. A chemical admixture for synchronously promoting cement mineral hydration according to claim 1, characterized in that: The balancing agent is selected from any one of acrylic acid, acryl alcohol and acrylamide or a mixture of two thereof.

4. A method for preparing the chemical admixture for synchronously promoting cement mineral hydration according to any one of claims 1 to 3, characterized in that: include: Solution I is obtained by pre-dissolving the balancing agent into an organic solvent, then dissolving the iron phase hydration promoting component into the above solution I to obtain solution II, then dissolving the belite hydration promoting component into solution II and stirring for 30-80 minutes to obtain solution III, then dissolving the alite hydration promoting component into solution III, and finally removing the solvent by distillation to obtain the chemical admixture.

5. The preparation method according to claim 4, characterized in that: The organic solvent is toluene or ethanol.

6. A method for applying the chemical admixture for synchronously promoting cement mineral hydration according to any one of claims 1 to 3, characterized in that: The chemical admixture is applied to cement-based materials, and its addition amount is 0.01%-1.0% of the mass of the cementitious material.

Images