Low temperature resistant ultra-high performance concrete and preparation method thereof

Abstract

The present application relates to the technical field of concrete, and specifically discloses a low-temperature resistant ultra-high performance concrete and a preparation method thereof. The low-temperature resistant ultra-high performance concrete disclosed in the present application comprises the following components: 840-880 parts of cement, 145-165 parts of steel fiber, 210-230 parts of auxiliary gel material, 1000-1140 parts of quartz sand, 10-15 parts of antifreeze aqueous solution, 5-10 parts of additives, and 160-180 parts of water; the antifreeze aqueous solution comprises the following components in concentration: 22-28 g / L of triethanolamine and 7-11 g / L of sodium pyruvate; the preparation method of the additive is: calcium sulfoaluminate, calcium sulfate, and activator aqueous solution are mixed evenly in a weight ratio of 5-11:3-8:50, reacted at room temperature, then dried, ball-milled, and the additive is obtained. Using the technical solution disclosed in the present application, the obtained concrete has excellent low-temperature resistance.

Description

Technical Field

[0001] The present application relates to the technical field of concrete, and in particular to a low-temperature resistant ultra-high performance concrete and a preparation method thereof. Background Art

[0002] At present, the curing temperature will affect the strength of concrete. The strength loss of cement-based materials is obvious in low temperature environment. Even if the concrete is restored to normal temperature, the strength loss is more than 40%. The ultra-high-strength concrete (UHPC) used in the project is not used in an environment below 5°C. The performance indicators of UHPC materials are currently based on normal temperature environments. The recommended operating temperature range of the material is 15-30°C, which is not suitable for low temperature use. At present, there is no UHPC material with excellent performance suitable for low temperature environments, so it is of great significance to develop low-temperature resistant ultra-high performance concrete. Summary of the invention

[0003] In order to solve the above technical problems, the present application provides a low-temperature resistant ultra-high performance concrete and a preparation method thereof.

[0004] The present application provides a low temperature resistant ultra-high performance concrete, specifically comprising the following components in parts by weight: 840-880 parts of cement, 145-165 parts of steel fiber, 210-230 parts of auxiliary gel material, 1000-1140 parts of quartz sand, 10-15 parts of antifreeze aqueous solution, 5-10 parts of additives, and 160-180 parts of water;

[0005] Wherein, the antifreeze aqueous solution is composed of the following components in concentrations: triethanolamine 22-28 g / L, sodium pyruvate 7-11 g / L, and organic phosphoric acid 13-18 g / L;

[0006] The preparation method of the auxiliary agent is as follows: calcium sulfoaluminate, calcium sulfate and an activator aqueous solution are uniformly mixed in a weight ratio of 5-11:3-8:50, stirred for reaction at room temperature for 40-60 minutes, then dried at 80-120°C, and then ball-milled to obtain the auxiliary agent; the activator aqueous solution is composed of components of the following concentrations: 30-40 g / L of diethylene glycol, 12-18 g / L of sodium stannate, and 5-10 g / L of benzotriazole.

[0007] In order to solve the problem of strength loss of ultra-high performance concrete during low-temperature construction, the present application provides a low-temperature resistant ultra-high performance concrete using the above technical solution. By using a specific concentration of triethanolamine, sodium pyruvate, and organic phosphoric acid to match and mix to form an antifreeze aqueous solution, triethanolamine can react with free calcium oxide in concrete to generate water-insoluble calcium salts, thereby reducing the strength loss of concrete under low temperature conditions; in addition, triethanolamine also has the effect of promoting the early strength development of concrete, which can shorten the construction period and improve engineering efficiency; and the inventors have found that the auxiliary effects of sodium pyruvate and organic phosphoric acid can promote the bonding strength between triethanolamine and free calcium oxide, thereby further reducing the strength loss of concrete under low temperature conditions.

[0008] In order to further optimize the performance of concrete, the cement of the technical solution provided by the present application is also mixed with an additive to improve the strength and crack resistance of concrete, reduce the shrinkage rate of concrete, and reduce the occurrence of cracks. The additive is made of calcium sulfoaluminate and calcium sulfate as the main components, and an appropriate amount of a specific type of mineral activator as an auxiliary component. It is added to concrete or mortar with silicate series cement as the adhesive material, and is a powdery material that can improve the early and late strength and reduce volume shrinkage.

[0009] Preferably, the low-temperature resistant ultra-high performance concrete specifically comprises the following components in parts by weight: 850-870 parts of cement, 150-160 parts of steel fiber, 215-225 parts of auxiliary gel material, 1040-1100 parts of quartz sand, 11-14 parts of antifreeze aqueous solution, 6-9 parts of additives, and 165-175 parts of water.

[0010] Preferably, the antifreeze aqueous solution consists of components with the following concentrations: triethanolamine 22-28 g / L, sodium pyruvate 7-11 g / L, and organic phosphoric acid 14-16 g / L.

[0011] Preferably, the antifreeze aqueous solution consists of components with the following concentrations: 25 g / L triethanolamine, 9 g / L sodium pyruvate, and 15 g / L organic phosphoric acid.

[0012] Preferably, the organic phosphoric acid is selected from any one or more of ethylenediaminetetramethylene phosphate, aminotrimethylene phosphate, ethyltriaminepentamethylenephosphonic acid, and diethylenetriaminepentamethylenephosphonic acid.

[0013] Preferably, in the preparation method of the auxiliary agent, the weight ratio of the calcium sulfoaluminate, calcium sulfate and activator aqueous solution is 7-9:4-7:50.

[0014] Preferably, in the preparation method of the auxiliary agent, the weight ratio of the calcium sulfoaluminate, calcium sulfate and activator aqueous solution is 8:5:50.

[0015] Preferably, in the preparation method of the auxiliary agent, the activator aqueous solution is composed of components with the following concentrations: diethylene glycol 33-38 g / L, sodium stannate 14-16 g / L, and benzotriazole 6-8 g / L.

[0016] Preferably, the auxiliary gel material is composed of a mixture of micro beads and silica fume in a weight ratio of 0.5-1.5:0.5-1.5.

[0017] The present application provides a method for preparing the above-mentioned low-temperature resistant ultra-high performance concrete, which specifically comprises the following steps:

[0018] Cement, steel fiber, auxiliary gel material, quartz sand and additives are added to water and mixed evenly, then antifreeze aqueous solution is added, stirred and mixed evenly, and after curing, the low temperature resistant ultra-high performance concrete is obtained.

[0019] In summary, the technical solution of this application has the following effects:

[0020] The present application utilizes a specific concentration of triethanolamine, sodium pyruvate, and organic phosphoric acid to match and mix to form an antifreeze aqueous solution, which can effectively react with free calcium oxide in concrete to generate water-insoluble calcium salts, while improving the density of concrete, thereby reducing the strength loss of concrete under low temperature conditions and improving the low-temperature resistance of concrete.

[0021] The technical solution provided in the present application adds additives to cement to improve the strength and crack resistance of concrete, reduce the shrinkage rate of concrete, and reduce the occurrence of cracks; at the same time, the low-temperature resistance of concrete is further improved. DETAILED DESCRIPTION

[0022] The present application is further described in detail below in conjunction with examples, comparative examples and performance testing experiments. These examples should not be construed as limiting the scope of protection claimed in the present application.

[0023] Example

[0024] Examples 1-3

[0025] Embodiments 1-3 respectively provide a low-temperature resistant ultra-high performance concrete.

[0026] The difference between the low temperature resistant ultra-high performance concrete in the above embodiments is that the amounts of the raw material components are different, as shown in Table 1.

[0027] The preparation method of the low temperature resistant ultra-high performance concrete in the above embodiment is specifically as follows:

[0028] The preparation method of the antifreeze aqueous solution is as follows: 25 g of triethanolamine, 9 g of sodium pyruvate, and 15 g of ethyltriamine penta methylene phosphonic acid are added into water, the volume is fixed to 1 L, and mixed evenly to obtain an antifreeze aqueous solution containing 25 g / L of triethanolamine, 9 g / L of sodium pyruvate, and 15 g / L of ethyltriamine penta methylene phosphonic acid;

[0029] The preparation method of the auxiliary agent is as follows: 35g of diethylene glycol, 15g of sodium stannate, and 7g of benzotriazole are added into water, the volume is adjusted to 1L, and mixed evenly to obtain an activator aqueous solution containing 35g / L of diethylene glycol, 15g / L of sodium stannate, and 7g / L of benzotriazole; 8g of calcium sulfoaluminate, 5g of calcium sulfate, and 50g of the activator aqueous solution are mixed evenly according to a weight ratio of 8:5:50, stirred and reacted at room temperature for 50min, and then dried at 100°C, and then ball milled to obtain an auxiliary agent with a particle size of 2-5mm;

[0030] According to Table 1, weigh the corresponding weights of the raw material components, cement, steel fiber, auxiliary gel material (composed of microspheres and silica fume mixed in a weight ratio of 1:2; the particle size of the microspheres is ≤10μm and the sphere density is 2.5g / cm 3 , bulk density 0.7kg / cm 3 Silica fume is silicon powder with a specific surface area of ​​28±5m 2 / g), quartz sand and additives are added into water, mixed evenly, and then antifreeze aqueous solution is added, stirred and mixed evenly, and after curing, low temperature resistant ultra-high performance concrete is obtained.

[0031] Table 1 Amount of each raw material component of low temperature resistant ultra-high performance concrete in Examples 1-3

[0032]

[0033] Embodiment 4-9

[0034] Examples 4-9 respectively provide a low-temperature resistant ultra-high performance concrete.

[0035] The difference between the low temperature resistant ultra-high performance concrete in the above embodiments is that the preparation method of the antifreeze aqueous solution is different, as shown below.

[0036] In Example 4: the antifreeze aqueous solution includes components with the following concentrations: 25 g of triethanolamine, 9 g of sodium pyruvate, and 15 g of ethylenediaminetetramethylene phosphate are added to water, the volume is fixed to 1 L, and mixed evenly to obtain the antifreeze aqueous solution.

[0037] In Example 5: the antifreeze aqueous solution includes components with the following concentrations: 25 g of triethanolamine, 9 g of sodium pyruvate, and 15 g of aminotrimethylene phosphate are added to water, the volume is fixed to 1 L, and mixed evenly to obtain the antifreeze aqueous solution.

[0038] In Example 6: the antifreeze aqueous solution includes components with the following concentrations: 25 g of triethanolamine, 9 g of sodium pyruvate, and 15 g of diethylenetriamine penta-methylenephosphonic acid are added to water, the volume is fixed to 1 L, and mixed evenly to obtain the antifreeze aqueous solution.

[0039] In Example 7: the antifreeze aqueous solution includes components with the following concentrations: 24 g of triethanolamine, 9 g of sodium pyruvate, and 10 g of ethyltriamine penta-methylenephosphonic acid are added to water, the volume is fixed to 1 L, and mixed evenly to obtain the antifreeze aqueous solution.

[0040] In Example 8: the antifreeze aqueous solution includes components with the following concentrations: 24 g of triethanolamine, 9 g of sodium pyruvate, and 13 g of ethyltriamine penta-methylenephosphonic acid are added to water, the volume is fixed to 1 L, and mixed evenly to obtain the antifreeze aqueous solution.

[0041] In Example 9: the antifreeze aqueous solution includes components with the following concentrations: 24 g of triethanolamine, 9 g of sodium pyruvate, and 18 g of ethyltriamine penta-methylenephosphonic acid are added to water, the volume is fixed to 1 L, and mixed evenly to obtain the antifreeze aqueous solution.

[0042] The remaining components, the amounts of each raw material component and the method for preparing concrete in the above embodiment are the same as those in embodiment 2.

[0043] Examples 10-16

[0044] Examples 10-16 respectively provide a low-temperature resistant ultra-high performance concrete.

[0045] The difference between the low temperature resistant ultra-high performance concrete in the above embodiments is that the preparation method of the additive is different, as shown below.

[0046] In Example 10: The preparation method of the auxiliary agent is as follows: 35 g of diethylene glycol, 15 g of sodium stannate, and 7 g of benzotriazole are added to water, the volume is adjusted to 1 L, and mixed evenly to obtain an activator aqueous solution containing 35 g / L of diethylene glycol, 15 g / L of sodium stannate, and 7 g / L of benzotriazole; 5 g of calcium sulfoaluminate, 8 g of calcium sulfate, and 50 g of the activator aqueous solution are mixed evenly, stirred at room temperature for 50 minutes, and then dried at 100°C, and then ball milled to obtain an auxiliary agent with a particle size of 2-5 mm.

[0047] In Example 11: The preparation method of the auxiliary agent is as follows: 35 g of diethylene glycol, 15 g of sodium stannate, and 7 g of benzotriazole are added to water, the volume is adjusted to 1 L, and mixed evenly to obtain an activator aqueous solution containing 35 g / L of diethylene glycol, 15 g / L of sodium stannate, and 7 g / L of benzotriazole; 11 g of calcium sulfoaluminate, 3 g of calcium sulfate, and 50 g of the activator aqueous solution are mixed evenly in a ratio of 8:5:50, stirred and reacted at room temperature for 50 minutes, then dried at 100°C, and then ball milled to obtain an auxiliary agent with a particle size of 2-5 mm.

[0048] In Example 12: The preparation method of the auxiliary agent is as follows: 35 g of diethylene glycol, 15 g of sodium stannate, and 7 g of benzotriazole are added to water, the volume is adjusted to 1 L, and mixed evenly to obtain an activator aqueous solution containing 35 g / L of diethylene glycol, 15 g / L of sodium stannate, and 7 g / L of benzotriazole; 7 g of calcium sulfoaluminate, 7 g of calcium sulfate, and 50 g of the activator aqueous solution are mixed evenly, stirred for reaction at room temperature for 50 min, and then dried at 100°C, and then ball milled to obtain an auxiliary agent with a particle size of 2-5 mm.

[0049] In Example 13: The preparation method of the auxiliary agent is as follows: 40 g of diethylene glycol, 12 g of sodium stannate, and 10 g of benzotriazole are added to water, fixed to 1 L, and mixed evenly to obtain an activator aqueous solution; 8 g of calcium sulfoaluminate, 5 g of calcium sulfate, and 50 g of the activator aqueous solution are mixed evenly in a weight ratio of 8:5:50, stirred and reacted at room temperature for 50 minutes, then dried at 100°C, and then ball-milled to obtain an auxiliary agent with a particle size of 2-5 mm.

[0050] In Example 14: The preparation method of the auxiliary agent is as follows: 30 g of diethylene glycol, 18 g of sodium stannate, and 10 g of benzotriazole are added to water, fixed to 1 L, and mixed evenly to obtain an activator aqueous solution; 8 g of calcium sulfoaluminate, 5 g of calcium sulfate, and 50 g of the activator aqueous solution are mixed evenly in a weight ratio of 8:5:50, stirred and reacted at room temperature for 50 minutes, then dried at 100°C, and then ball-milled to obtain an auxiliary agent with a particle size of 2-5 mm.

[0051] In Example 15: The preparation method of the auxiliary agent is as follows: 33 g of diethylene glycol, 16 g of sodium stannate, and 6 g of benzotriazole are added to water, fixed to 1 L, and mixed evenly to obtain an activator aqueous solution; 8 g of calcium sulfoaluminate, 5 g of calcium sulfate, and 50 g of the activator aqueous solution are mixed evenly in a weight ratio of 8:5:50, stirred and reacted at room temperature for 50 minutes, then dried at 100°C, and then ball-milled to obtain an auxiliary agent with a particle size of 2-5 mm.

[0052] In Example 16: The preparation method of the auxiliary agent is as follows: 38 g of diethylene glycol, 14 g of sodium stannate, and 8 g of benzotriazole are added to water, the volume is fixed to 1 L, and mixed evenly to obtain an activator aqueous solution; 8 g of calcium sulfoaluminate, 5 g of calcium sulfate, and 50 g of the activator aqueous solution are mixed evenly in a weight ratio of 8:5:50, stirred and reacted at room temperature for 50 minutes, and then dried at 100°C, and then ball-milled to obtain an auxiliary agent with a particle size of 2-5 mm.

[0053] The remaining components, the amounts of each raw material component and the method for preparing concrete in the above embodiment are the same as those in embodiment 2.

[0054] Comparative Example

[0055] Comparative Examples 1-6

[0056] Comparative Examples 1-6 each provide a kind of concrete.

[0057] The differences of the low temperature resistant ultra-high performance concrete in the above comparative examples are specifically as follows.

[0058] In Comparative Example 1: no antifreeze aqueous solution was added.

[0059] In Comparative Example 2: In the method for preparing the antifreeze aqueous solution, an equal amount of sodium sulfate was used instead of sodium pyruvate.

[0060] In Comparative Example 3: The preparation method of the antifreeze aqueous solution is as follows: 25 g of triethanolamine, 10 g of ethylene glycol, 9 g of sodium pyruvate, and 15 g of ethyltriamine penta-methylenephosphonic acid are added to water, the volume is fixed to 1 L, and mixed evenly to obtain an antifreeze aqueous solution containing 25 g / L of triethanolamine, 9 g / L of sodium pyruvate, and 15 g / L of ethyltriamine penta-methylenephosphonic acid.

[0061] In Comparative Example 4: The preparation method of the auxiliary agent is: 8g of calcium sulfoaluminate, 5g of calcium sulfate, and 50g of water are mixed uniformly in a weight ratio of 8:5:50, stirred and reacted at room temperature for 50min, then dried at 100°C, and then ball-milled to obtain an auxiliary agent with a particle size of 2-5mm.

[0062] In Comparative Example 5: In the preparation method of the auxiliary agent, an equal amount of sorbitol is used instead of diethylene glycol to prepare an activator aqueous solution.

[0063] In Comparative Example 6: In the preparation method of the auxiliary agent, an equal amount of mercaptobenzothiazole is used instead of benzotriazole to prepare an activator aqueous solution.

[0064] The remaining components, the amounts of the various raw material components and the method for preparing the concrete in the comparative example are the same as those in Example 2.

[0065] Performance testing

[0066] The low temperature curing environment is achieved through a low temperature test chamber, and the temperature control accuracy of the low temperature test chamber is ±2°C. After adding water, the concrete is molded for 2 hours and placed in a low temperature environment for curing to a specific age, then removed from the mold and subjected to standard curing. The following description of the test method is for reference:

[0067] Low temperature curing test is used to study the low temperature resistance of concrete during the critical period of strength development. According to GB / T50476-2019 "Concrete Structure Durability Design Standard", the average temperature is divided into slightly frozen areas (-3℃≤t≤2.5℃), cold areas (-8℃<t<-3℃) and severely cold areas (t≤-8℃). According to the temperature classification conditions and combined with the actual application in the north, the test temperatures are 5℃ and -15℃ respectively.

[0068] The low-temperature curing environment is achieved through a low-temperature test chamber, and the temperature control accuracy of the low-temperature test chamber is ±2°C. After adding water, the concrete is molded for 2 hours and placed in a low-temperature environment for curing to a specific age, then taken out and demolded for standard curing; the size of the compression test specimen is 100mm×100mm×100mm; the size of the flexural test specimen is 100mm×100mm×400mm; the size of the tensile test specimen is 100mm×100mm×400mm.

[0069] The compressive strength and flexural strength of concrete are measured in accordance with GB / T50081-2019 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete". The tensile strength of concrete is measured in accordance with the no-stud test method in Appendix B of T / CCPA7-2018 "Basic Properties and Test Methods of Ultra-High Performance Concrete".

[0070] Test results: as shown in Table 2.

[0071] Table 2 Performance test results of concrete in Examples 1-16 and Comparative Examples 1-6

[0072]

[0073]

[0074] Combined with Table 2, by comparing the performance test results of the concrete in Examples 1-16 and Comparative Examples 1-6, it can be seen that by utilizing the technical solution provided in the present application, an ultra-high performance concrete with excellent low temperature resistance can be obtained.

[0075] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A low temperature resistant ultra-high performance concrete, characterized in that: Specifically, it includes the following components in parts by weight: 840-880 parts of cement, 145-165 parts of steel fiber, 210-230 parts of auxiliary gel material, 1000-1140 parts of quartz sand, 10-15 parts of antifreeze aqueous solution, 5-10 parts of additives, and 160-180 parts of water; The antifreeze aqueous solution is composed of the following components: triethanolamine 22-28 g / L, sodium pyruvate 7-11 g / L, and organic phosphoric acid 13-18 g / L; the organic phosphoric acid is selected from any one or more of ethylenediaminetetramethylene phosphate, aminotrimethylene phosphate, ethyltriaminepentamethylenephosphonic acid, and diethylenetriaminepentamethylenephosphonic acid; The preparation method of the auxiliary agent is as follows: calcium sulfoaluminate, calcium sulfate and an activator aqueous solution are uniformly mixed in a weight ratio of 5-11:3-8:50, stirred for reaction at room temperature for 40-60 minutes, then dried at 80-120°C, and then ball-milled to obtain the auxiliary agent; the activator aqueous solution is composed of components of the following concentrations: 30-40 g / L of diethylene glycol, 12-18 g / L of sodium stannate, and 5-10 g / L of benzotriazole.

2. The low temperature resistant ultra-high performance concrete according to claim 1, characterized in that: Specifically, the invention comprises the following components in parts by weight: 850-870 parts of cement, 150-160 parts of steel fiber, 215-225 parts of auxiliary gel material, 1040-1100 parts of quartz sand, 11-14 parts of antifreeze aqueous solution, 6-9 parts of auxiliary agent and 165-175 parts of water.

3. The low temperature resistant ultra-high performance concrete according to claim 1, characterized in that: The antifreeze aqueous solution is composed of components with the following concentrations: 22-28 g / L of triethanolamine, 7-11 g / L of sodium pyruvate, and 14-16 g / L of organic phosphoric acid.

4. The low temperature resistant ultra-high performance concrete according to claim 3, characterized in that: The antifreeze aqueous solution is composed of components with the following concentrations: 25 g / L triethanolamine, 9 g / L sodium pyruvate, and 15 g / L organic phosphoric acid.

5. The low temperature resistant ultra-high performance concrete according to claim 1, characterized in that: In the preparation method of the auxiliary agent, the weight ratio of the calcium sulfoaluminate, calcium sulfate and activator aqueous solution is 7-9:4-7:

50.

6. The low temperature resistant ultra-high performance concrete according to claim 1, characterized in that: In the preparation method of the auxiliary agent, the weight ratio of the calcium sulfoaluminate, calcium sulfate and activator aqueous solution is 8:5:

50.

7. The low temperature resistant ultra-high performance concrete according to claim 1, characterized in that: In the preparation method of the auxiliary agent, the activator aqueous solution is composed of components with the following concentrations: 33-38 g / L of diethylene glycol, 14-16 g / L of sodium stannate, and 6-8 g / L of benzotriazole.

8. The low temperature resistant ultra-high performance concrete according to claim 1, characterized in that: The auxiliary gel material is composed of a mixture of micro beads and silica fume in a weight ratio of 0.5-1.5:0.5-1.

5.

9. The method for preparing low temperature resistant ultra-high performance concrete according to any one of claims 1 to 8, characterized in that: The specific steps include: Cement, steel fiber, auxiliary gel material, quartz sand and additives are added to water and mixed evenly, then antifreeze aqueous solution is added, stirred and mixed evenly, and after curing, the low temperature resistant ultra-high performance concrete is obtained.

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