High-impermeability anti-freezing hydraulic concrete and preparation method thereof

Abstract

The invention discloses high-impermeability anti-freezing hydraulic concrete and a preparation method thereof, and relates to the technical field of hydraulic concrete.The high-impermeability anti-freezing hydraulic concrete is prepared from water, cement, fly ash, fibers, fine aggregate, coarse aggregate, an expanding agent, a water reducing agent and an air entraining agent. The concrete disclosed by the invention not only has excellent anti-seepage performance, can effectively reduce water permeation, but also has excellent anti-freezing performance, can keep the structure stable in repeated freezing and thawing cycles, and remarkably improves the durability and service life of a hydraulic concrete structure.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic concrete, and particularly relates to a high impermeability and frost resistance hydraulic concrete and a preparation method thereof. Background Art

[0002] Hydraulic concrete is widely used in water conservancy and hydropower projects, mainly for the construction of key structures such as dams, sluices, channels, tunnels, aqueducts, etc. However, the hydraulic concrete structure faces complex and harsh environmental challenges during service, such as long-term water immersion, freeze-thaw cycles, chemical erosion, etc.; these factors have a significant impact on the durability and safety of the concrete structure, and may lead to the degradation or even failure of the structural performance. The impermeability and frost resistance are the key indicators of the durability of hydraulic concrete, which are directly related to the service life of the concrete in harsh environments. Traditional hydraulic concrete has obvious defects in terms of impermeability and frost resistance. Especially in engineering projects in alpine regions or those in a long-term water environment, the concrete structure is prone to damage phenomena such as leakage and freeze-thaw spalling. These problems not only increase the cost of project maintenance and repair, but also significantly shorten the service life of the structure.

[0003] Therefore, it is of great practical significance to develop a hydraulic concrete with high impermeability and frost resistance. Summary of the Invention

[0004] The main purpose of the present invention is to provide a high impermeability and frost resistance hydraulic concrete and a preparation method thereof, aiming to solve the technical problem that the existing hydraulic concrete has obvious defects in terms of impermeability and frost resistance.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a high impermeability and frost resistance hydraulic concrete. The raw materials per cubic meter of the high impermeability and frost resistance hydraulic concrete include the following components:

[0007] Water 126 - 134 kg, cement 233.0 - 240.2 kg, fly ash 60.7 - 63.8 kg, fiber 3.0 - 5.0 kg, fine aggregate 1090 - 1117 kg, coarse aggregate 892 - 914 kg, expansive agent 10.0 - 20.0 kg, water reducing agent 1.65 - 1.91 kg, air entraining agent 0.957 - 1.944 kg.

[0008] Preferably, the cement is medium heat Portland cement, and the specific surface area of the medium heat Portland cement ≥ 336 kg / m3.

[0009] Preferably, the fiber is polyoxymethylene fiber, and the diameter of the polyoxymethylene fiber is 190 - 210 μm, and the length is 11 - 13 mm.

[0010] Preferably, the saturated surface dry apparent density of the coarse aggregate is ≥ 2750 kg / m 3 .

[0011] Preferably, the saturated surface dry apparent density of the coarse aggregate is ≥ 2750 kg / m 3 , the coarse aggregate is basalt aggregate including small stones and medium stones, the ratio of the small stones to the medium stones is 1:0.75 - 0.85, the particle size of the small stones is 5 - 20 mm, and the particle size of the medium stones is 20 - 40 mm.

[0012] Preferably, the fine aggregate is basalt aggregate with a fineness modulus of 2.5 - 2.7.

[0013] Preferably, the expansive agent is HP-CSA expansive agent; the water reducing agent is polycarboxylate water reducing agent; the air entraining agent is GYQ-I air entraining agent.

[0014] The present invention also provides a preparation method of high impermeability and frost resistance hydraulic concrete, including the following steps:

[0015] S1. Process the basalt aggregate into small stones with a particle size of 5 - 20 mm, medium stones with a particle size of 20 - 40 mm and fine aggregate with a fineness modulus of 2.5 - 2.8 respectively, and set aside;

[0016] S2. Prepare the coarse aggregate according to the ratio of small stones: medium stones = 1:0.75 - 0.85;

[0017] S3. Add the coarse aggregate, cement, fly ash, expansive agent and fine aggregate into the fiber and stir until the fiber is fully dispersed to obtain a dry mix;

[0018] S4. Mix the water reducing agent, air entraining agent and water evenly to obtain a mixture;

[0019] S5. Add the mixture in step S4 into the dry mix in step S3, and obtain high impermeability and frost resistance hydraulic concrete after mixing evenly.

[0020] Preferably, the stirring time in step S3 is 60 - 70 s, and the stirring rate is 40 - 60 revolutions per minute.

[0021] Preferably, the mixture in step S5 needs to be added into the dry mix within 10 s

[0022] The beneficial effects of the present invention are as follows:

[0023] 1. By incorporating polyoxymethylene fibers (POM), on the one hand, the porosity inside the concrete can be effectively reduced, especially the formation of large pores. The improvement of this micro-structure helps to reduce the penetration channels of water and other harmful substances, thus significantly enhancing the impermeability of the concrete. On the other hand, POM fibers can form a network structure inside the concrete to prevent the expansion and penetration of micro-cracks. Cracks are one of the main reasons for the increased permeability of concrete. The crack resistance of the fibers can effectively reduce the formation of cracks, thereby enhancing the impermeability of the concrete.

[0024] 2. By incorporating POM fibers and HP-CSA expansive agent, POM fibers form a three-dimensional network structure in the concrete, which can effectively restrain the pressure generated inside the concrete due to environmental temperature changes and reduce the crack expansion caused by freeze-thaw cycles. The bridging effect of these fibers can significantly improve the toughness and crack resistance of the concrete, thereby effectively reducing the mass loss rate, the reduction rate of relative dynamic elastic modulus, and the reduction rate of compressive strength of the concrete during freeze-thaw cycles. The expansive agent can compensate for the shrinkage of the concrete and reduce the generation of early and late cracks. Cracks are one of the important factors in freeze-thaw damage. By reducing the formation of cracks, the expansive agent can significantly improve the freeze-thaw resistance of the concrete. Specific embodiments

[0025] The technical solutions in the embodiments of the present application will be described clearly and completely below.

[0026] To verify the high impermeability and freeze-thaw resistance of the high impermeability and freeze-thaw resistant hydraulic concrete of the present invention, a comparative test was conducted between the concrete of the present invention and the existing concrete. There are many actual embodiments, and only the following representative embodiments are selected. The hydraulic concrete involved in the following embodiments is mainly used for the concrete panels of dams and reservoirs, and its function is to increase its impermeability and freeze-thaw resistance on the basis of ensuring high strength. Specifically as follows:

[0027] Embodiment 1

[0028] The high impermeability and freeze-thaw resistant hydraulic concrete provided in this embodiment, the raw materials per cubic meter of the high impermeability and freeze-thaw resistant hydraulic concrete include the following components:

[0029] Water: 134 kg / m 3 ; Medium heat Portland cement: 235.2 kg / m 3 ; Fly ash: 63.8 kg / m 3 ; POM fibers: 5.0 kg / m 3 ; Fine aggregate: 1090 kg / m 3 ; Coarse aggregate: 892 kg / m 3 ; HP-CSA expansive agent; 20.0 kg / m 3 ; Polycarboxylate superplasticizer: 1.91 kg / m3 ; Air-entraining agent GYQ-I: 1.944 kg / m 3 .

[0030] Among them, the specific surface area of medium-heat portland cement is 336 kg / m 3 ; The diameter of POM fiber is 190 - 210 μm, and the length is 11 - 13 mm; The surface-dry apparent density of coarse aggregate is 2750 kg / m 3 , and the coarse aggregate is composed of small basalt aggregates with a particle size of 5 - 20 mm and medium basalt aggregates with a particle size of 20 - 40 mm mixed in a ratio of 1:0.8; The fine aggregate is basalt aggregate with a fineness modulus of 2.6.

[0031] Preparation method of high impermeability and frost resistance hydraulic concrete, including the following steps:

[0032] Step 1: Process basalt aggregates into small stones with a particle size of 5 - 20 mm, medium stones with a particle size of 20 - 40 mm, and fine aggregates with a fineness modulus of 2.6 respectively, and set aside;

[0033] Step 2: Prepare coarse aggregate according to small stone aggregate: medium stone aggregate = 1:0.8;

[0034] Step 3: Add 892 kg / m of coarse aggregate 3 , 235.2 kg / m of medium-heat portland cement 3 , 63.8 kg / m of Class I fly ash 3 , 20.0 kg / m of expansive agent 3 , 1090 kg / m of fine aggregate 3 into the mixer in sequence, and stir at a rate of 50 revolutions per minute for 60 s to obtain a uniform dry-mixed mixture.

[0035] Step 4: Mix 1.91 kg / m of water-reducing agent 3 and 1.944 kg / m of air-entraining agent 3 with 134 kg / m of mixing water 3 evenly.

[0036] Step 5: Start the mixer, slowly add the mixed liquid in Step 4 into the dry-mixed mixture obtained in Step 3 within 10 s, and fully mix and stir for 140 s to obtain high impermeability and frost resistance hydraulic concrete.

[0037] The slump of the above concrete is between 40 - 70 mm, and the air content is between 3.0% - 4.5%. According to the "Test Code for Hydraulic Concrete" DL / T5150 - 2017, the strength, impermeability grade, relative dynamic elastic modulus and mass loss rate of the concrete after 200 freeze-thaw cycles of the above concrete are detected, and its performance is shown in Table 1.

[0038] Example 2:

[0039] The high impermeability and frost-resistant hydraulic concrete provided in this embodiment, the raw materials per cubic meter of the high impermeability and frost-resistant hydraulic concrete include the following components:

[0040] Water: 134 kg / m 3 ; Medium heat Portland cement: 240.2 kg / m 3 ; Fly ash: 63.8 kg / m 3 ; POM fiber: 3.0 kg / m 3 ; Fine aggregate: 1090 kg / m 3 ; Coarse aggregate: 892 kg / m 3 ; HP-CSA expansive agent; 15.0 kg / m 3 ; Polycarboxylate water reducer: 1.75 kg / m 3 ; GYQ-I air-entraining agent: 0.957 kg / m 3 .

[0041] Among them, the specific surface area of the medium heat Portland cement is 340 kg / m 3 ; The diameter of the POM fiber is 190 - 210 μm, and the length is 11 - 13 mm; The surface-dry apparent density of the coarse aggregate is 2800 kg / m 3 , and the coarse aggregate is composed of small stone basalt aggregate with a particle size of 5 - 20 mm and medium stone basalt aggregate with a particle size of 20 - 40 mm mixed in a ratio of 1:0.75; The fine aggregate is basalt aggregate with a fineness modulus of 2.5.

[0042] A preparation method of high impermeability and frost-resistant hydraulic concrete specifically includes the following steps:

[0043] Step 1, process the basalt aggregate into small stones with a particle size of 5 - 20 mm, medium stones with a particle size of 20 - 40 mm and fine aggregate with a fineness modulus of 2.5 respectively, and set aside;

[0044] Step 2, prepare the coarse aggregate according to small stone aggregate: medium stone aggregate = 1:0.75;

[0045] Step 3, put 892 kg / m of coarse aggregate 3 , 240.2 kg / m of P·I type medium heat Portland cement 3 , 63.8 kg / m of Class I fly ash 3 , 15.0 kg / m of expansive agent 3 , 1090 kg / m of fine aggregate 3 , and add them into the mixer in sequence, and stir at a rate of 40 revolutions per minute for 60 s to obtain a uniform dry-mixed mixture.

[0046] Step 4, put 1.75 kg / m of water reducer 3And air-entraining agent 0.957 kg / m 3 With mixing water 134 kg / m 3 Mix evenly.

[0047] Step 5, start the mixer, slowly add the mixed liquid in Step 4 to the dry-mixed mixture obtained in Step 3 within 10 s, and mix and stir fully for 150 s to obtain the high impermeability and frost-resistant hydraulic concrete.

[0048] The slump of the above concrete is between 40 and 70 mm, and the air content is between 3.0% and 4.5%. According to the "Test Code for Hydraulic Concrete" DL / T 5150-2017, the strength, impermeability grade, relative dynamic elastic modulus and mass loss rate of the concrete after 200 freeze-thaw cycles of the above concrete are detected, and its performance is shown in Table 1.

[0049] Example 3:

[0050] The high impermeability and frost-resistant hydraulic concrete provided in this example, the raw materials per cubic meter of high impermeability and frost-resistant hydraulic concrete include the following components:

[0051] Water: 126 kg / m 3 ; Medium-heat portland cement: 230.0 kg / m 3 ; Fly ash: 60.7 kg / m 3 ; POM fiber: 3.0 kg / m 3 ; Fine aggregate: 1117 kg / m 3 ; Coarse aggregate: 914 kg / m 3 ; HP-CSA expansive agent: 10.0 kg / m 3 ; Polycarboxylate water reducer: 1.65 kg / m 3 ; GYQ-I air-entraining agent: 1.263 kg / m 3 .

[0052] The preparation method of high impermeability and frost-resistant hydraulic concrete specifically includes the following steps:

[0053] Step 1, process basalt aggregate into small stones with a particle size of 5-20 mm, medium-sized stone aggregates with a particle size of 20-40 mm and fine aggregates with a fineness modulus of 2.8 respectively, and set aside;

[0054] Step 2, prepare coarse aggregate according to small stone aggregate: medium-sized stone aggregate = 1:0.85;

[0055] Step 3, the coarse aggregate 914 kg / m 3 , P·I type medium-heat portland cement 230.0 kg / m 3 , Class I fly ash 60.7 kg / m 3 , expansive agent 10.0 kg / m 3, fine aggregate 1117 kg / m 3 , are successively added into a mixer and stirred at a rate of 60 revolutions per minute for 65 s to obtain a uniform dry-mixed mixture.

[0056] Step 4, add 1.65 kg / m of water-reducing agent 3 and 1.263 kg / m of air-entraining agent 3 and mix them uniformly with 126 kg / m of mixing water 3 .

[0057] Step 5, start the mixer, slowly add the mixed liquid in Step 2 to the dry-mixed mixture obtained in Step 1 within 10 s, and mix and stir fully for 130 s to obtain the high impermeability and frost resistance hydraulic concrete.

[0058] The slump of the above concrete is between 40 and 70 mm, and the air content is between 3.0% and 4.5%. According to the "Test Code for Hydraulic Concrete" DL / T5150-2017, the strength, impermeability grade, relative dynamic elastic modulus and mass loss rate of the concrete after 200 freeze-thaw cycles of the above concrete are detected, and its performance is shown in Table 1.

[0059] Comparative Example 1:

[0060] The difference between Comparative Example 1 and Example 1 is that POM fibers are not added.

[0061] Comparative Example 2:

[0062] The difference between Comparative Example 2 and Example 2 is that expansive agent is not added.

[0063] The performance comparison of the concrete prepared by Examples 1, 2, 3 and Comparative Examples 1, 2 is shown in Table 1.

[0064] Table 1

[0065]

[0066] By comparing the concrete performance of Examples 1-3 with Comparative Examples 1 and 2, the high impermeability and frost resistance hydraulic concrete of Examples 1-3 of the present invention is significantly superior to the corresponding concrete of Comparative Examples 1-2 in terms of impermeability grade and frost resistance performance. It shows that the concrete prepared by the above raw materials and preparation method of the present invention has high impermeability and high frost resistance performance. The high impermeability and frost resistance hydraulic concrete described in the present invention is superior to the concrete prepared without adding POM fibers or without adding expansive agent and POM fibers in the prior art.

[0067] Example 4

[0068] The high impermeability and frost resistance hydraulic concrete provided in this example, the raw materials per cubic meter of high impermeability and frost resistance hydraulic concrete include the following components:

[0069] Water: 130 kg / m 3 ; Medium heat portland cement: 233.0 kg / m 3 ; Fly ash: 62.3 kg / m 3 ; POM fiber: 4.0 kg / m 3 ; Fine aggregate: 1100 kg / m 3 ; Coarse aggregate: 900 kg / m 3 ; HP-CSA expansive agent; 15.0 kg / m 3 ; Polycarboxylate water reducer: 1.80 kg / m 3 ; GYQ-I air-entraining agent: 1.5415 kg / m 3 。

[0070] Among them, the specific surface area of the medium heat portland cement is 380 kg / m 3 ; The diameter of the POM fiber is 190 - 210 μm, and the length is 11 - 13 mm; The surface-dry apparent density of the coarse aggregate is 2930 kg / m 3 , and the coarse aggregate is composed of small stone basalt aggregate with a particle size of 5 - 20 mm and medium stone basalt aggregate with a particle size of 20 - 40 mm mixed in a ratio of 1:0.8; The fine aggregate is basalt aggregate with a fineness modulus of 2.6.

[0071] Preparation method of high impermeability and frost resistance hydraulic concrete, including the following steps:

[0072] Step 1: Process basalt aggregate into small stones with a particle size of 5 - 20 mm, medium stones with a particle size of 20 - 40 mm and fine aggregate with a fineness modulus of 2.6 respectively, and set aside;

[0073] Step 2: Prepare the coarse aggregate according to small stone aggregate: medium stone aggregate = 1:0.8;

[0074] Step 3: Add 900 kg / m of coarse aggregate 3 , 233.0 kg / m of medium heat portland cement 3 , 62.3 kg / m of Class I fly ash 3 , 15.0 kg / m of expansive agent 3 , 1100 kg / m of fine aggregate 3 , into the mixer in sequence, and stir at a rate of 50 revolutions per minute for 60 s to obtain a uniform dry-mixed mixture.

[0075] Step 4: Mix 1.80 kg / m of water reducer 3 and 1.5415 kg / m of air-entraining agent 3 uniformly with 130 kg / m of mixing water 3 .

[0076] Step 5: Start the mixer, slowly add the mixed liquid obtained in Step 4 into the dry-mixed mixture obtained in Step 3 within 10 s, and fully mix and stir for 140 s to obtain high impermeability and frost-resistant hydraulic concrete.

[0077] In addition, the concrete formulations with different components other than Examples 1-4 can be designed and selected according to the requirements of specific projects and the actual on-site conditions. The optimal mix ratio of concrete needs to be comprehensively considered and designed based on multiple factors such as the load that the concrete has to bear, the use environment, and the construction technology. Therefore, the design of the optimal mix ratio of concrete needs to be adjusted and optimized in combination with specific situations to meet the needs of actual projects.

[0078] In summary, by incorporating polyoxymethylene fiber (POM), on the one hand, the porosity inside the concrete can be effectively reduced, especially the formation of large pores. The improvement of this microscopic structure helps to reduce the penetration channels of water and other harmful substances, thus significantly improving the impermeability of the concrete. On the other hand, POM fibers can form a network structure inside the concrete to prevent the expansion and penetration of microcracks. Cracks are one of the main reasons for the increase in the permeability of concrete. The crack resistance of the fibers can effectively reduce the formation of cracks, thereby enhancing the impermeability of the concrete. By incorporating POM fibers and HP-CSA expansive agent, POM fibers form a three-dimensional network structure in the concrete, which can effectively restrain the pressure generated inside the concrete due to environmental temperature changes and reduce the crack expansion caused by freeze-thaw cycles. The bridging effect of these fibers can significantly improve the toughness and crack resistance of the concrete, thereby effectively reducing the mass loss rate, the reduction rate of relative dynamic elastic modulus, and the reduction rate of compressive strength of the concrete during freeze-thaw cycles. The expansive agent can compensate for the shrinkage of the concrete and reduce the generation of early and late cracks. Cracks are one of the important factors for freeze-thaw damage. By reducing the formation of cracks, the expansive agent can significantly improve the freeze-thaw resistance of the concrete. The hydraulic concrete of the present invention not only has excellent impermeability and can effectively reduce the penetration of water, but also has excellent frost resistance, can maintain the structural stability during repeated freeze-thaw cycles, significantly improve the durability and service life of the hydraulic concrete structure, significantly improve the overall quality of the project, and reduce the later operation and maintenance costs.

[0079] The specific embodiments of the invention have been described in detail above, but they are only examples, and the invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modification or substitution of the invention is also within the scope of the invention. Therefore, all equivalent transformations, modifications, and improvements made without departing from the spirit and principles of the invention should be covered within the scope of the invention.

Claims

1. A high impermeability and frost resistance hydraulic concrete, characterized in that, The raw materials of every cubic meter of the high impermeability and frost resistance hydraulic concrete include the following components: Water 126 - 134 kg, cement 233.0 - 240.2 kg, fly ash 60.7 - 63.8 kg, fiber 3.0 - 5.0 kg, fine aggregate 1090 - 1117 kg, coarse aggregate 892 - 914 kg, expansive agent 10.0 - 20.0 kg, water reducing agent 1.65 - 1.91 kg, air entraining agent 0.957 - 1.944 kg.

2. The high impermeability and frost-resistant hydraulic concrete according to claim 1, wherein, The cement is medium heat Portland cement, and the specific surface area of the medium heat Portland cement ≥ 336 kg / m 3 .

3. The high impermeability and frost resistance hydraulic concrete according to claim 1, characterized in that, The fiber is polyoxymethylene fiber, the diameter of the polyoxymethylene fiber is 190 - 210 μm, and the length is 11 - 13 mm.

4. The high impermeability and frost resistance hydraulic concrete according to claim 1, characterized in that, The saturated surface dry apparent density of the coarse aggregate ≥ 2750 kg / m 3 .

5. The high impermeability and frost resistance hydraulic concrete according to claim 4, characterized in that, The saturated surface dry apparent density of the coarse aggregate is ≥ 2750 kg / m 3 , the coarse aggregate is basalt aggregate including small stones and medium stones, the ratio of the small stones to the medium stones is 1:0.75 - 0.85, the particle size of the small stones is 5 - 20 mm, and the particle size of the medium stones is 20 - 40 mm.

6. The high impermeability and frost resistance hydraulic concrete according to claim 1, wherein The fine aggregate is basalt aggregate with a fineness modulus of 2.5 - 2.

7.

7. The high impermeability and frost-resistant hydraulic concrete according to claim 1, characterized in that, The expansive agent is HP-CSA expansive agent; the water reducing agent is polycarboxylate water reducing agent; the air entraining agent is GYQ-I air entraining agent.

8. A method for preparing a high impermeability and frost resistance hydraulic concrete according to any one of claims 1-7, characterized in that, It includes the following steps: S1. Process the basalt aggregate into small stones with a particle size of 5 - 20 mm, medium-sized stone materials with a particle size of 20 - 40 mm and fine aggregate with a fineness modulus of 2.5 - 2.8 respectively, and set aside; S2. Prepare the coarse aggregate according to small stones: medium-sized stones = 1:0.75 - 0.85; S3. Add the coarse aggregate, cement, fly ash, expansive agent, and fine aggregate into the fiber and stir until the fiber is fully dispersed to obtain a dry-mixed mixture; S4. Mix the water reducing agent, air entraining agent and water evenly to obtain a mixture; S5. Add the mixture in step S4 into the dry-mixed mixture in step S3, and after mixing evenly, obtain the high impermeability and frost resistance hydraulic concrete.

9. The preparation method of the high impermeability and frost resistance hydraulic concrete according to claim 8, characterized in that, The stirring time in step S3 is 60 - 70 s, and the stirring rate is 40 - 60 revolutions per minute.

10. The preparation method of the high impermeability and frost resistance hydraulic concrete according to claim 8, characterized in that, The mixture in step S5 needs to be added into the dry-mixed mixture within 10 s.

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