High-durability anti-erosion concrete and preparation method thereof

Abstract

The invention provides high-durability anti-erosion concrete, which is prepared from the following raw materials in parts by weight: 30 to 40 parts of Portland cement, 20 to 30 parts of aluminoferrite cement, 10 to 20 parts of mineral admixture, 40 to 60 parts of coarse aggregate, 35 to 55 parts of fine aggregate, 0.06 to 0.2 part of boric acid, 0.1 to 1 part of water reducing agent, 5 to 10 parts of bauxite powder, 0.5 to 5 parts of silane solution and 0.5 to 3 parts of alkaline activating agent, and the water-binder ratio of the concrete is 0.25 to 0.4. The mass ratio of the Portland cement to the aluminoferrite cement is (1-2): 1, the mineral admixture accounts for 15%-25% of the total mass of the cementing material composed of the Portland cement, the aluminoferrite cement and the mineral admixture, and the addition amount of the bauxite powder accounts for 5%-15% of the total mass of the cementing material. The concrete has high chloride ion erosion resistance and long-term durability.

Description

Technical Field

[0001] The invention relates to the technical field of concrete, and in particular to a high-durability erosion-resistant concrete and a preparation method thereof. Background Art

[0002] Concrete is widely used in construction projects due to its good mechanical properties and economy. However, it faces many challenges in corrosive environments. For example, chloride ions in the marine environment can penetrate the concrete structure and react with cement hydration products to form compounds that are harmful to the concrete structure and accelerate the degradation of the material. Therefore, it is particularly important to enhance the corrosion resistance of concrete and improve its long-term stability. Summary of the invention

[0003] In order to solve the problems existing in the background technology, the present invention provides a high-durability erosion-resistant concrete and a preparation method thereof, wherein the high-durability erosion-resistant concrete can significantly reduce the penetration rate of chloride ions, thereby inhibiting the concrete degradation induced by chloride ions, and significantly improving the concrete's resistance to chloride ion erosion and long-term durability. The technical solution of the present invention to solve the above technical problems is as follows: In a first aspect, the present invention provides a highly durable erosion-resistant concrete, comprising the following raw materials in parts by weight: 30-40 parts of Portland cement, 20-30 parts of ferroaluminate cement, 10-20 parts of mineral admixture, 40-60 parts of coarse aggregate, 35-55 parts of fine aggregate, 0.06-0.2 parts of boric acid, 0.1-1 parts of water reducer, 5-10 parts of bauxite powder, 0.5-5 parts of silane solution, and 0.5-3 parts of alkaline activator, wherein the water-cement ratio of the concrete is 0.25-0.4; the mass ratio of the Portland cement to the ferroaluminate cement is (1-2): 1, the mineral admixture accounts for 15%-25% of the total mass of the cementitious material composed of the Portland cement, the ferroaluminate cement and the mineral admixture, and the addition amount of the bauxite powder is 5%-15% of the total mass of the cementitious material.

[0004] In the present invention, Portland cement (OPC) and ferroaluminate cement (FAC) are compounded, wherein the ferroaluminate cement releases aluminum ions during hydration and rapidly generates ettringite to fill pores. During the hydration process of Portland cement, silicate and calcium ions are continuously released, and part of CSH and aluminum ions generate CASH. On the one hand, the generated CASH and ettringite work together to effectively inhibit the enrichment of Ca(OH)2, which can reduce the risk of chloride ions reacting with Ca(OH)2 to generate calcium chloride and thus weaken the performance of concrete, and improve the chemical stability of the material. On the other hand, the layered structure of the formed CASH not only fills the pores and improves the density of the material, but also shows a higher adsorption capacity, which can capture corrosive substances such as chloride ions and shorten the migration path of corrosive ions, thereby greatly improving the chloride ion corrosion resistance of the concrete. During the hydration process, bauxite powder dissolves under alkaline conditions, releasing silicate and aluminate, thereby participating in the hydration reaction of ferroaluminate cement (FAC) and silicate cement (OPC), increasing the generation of CASH, and the silane solution reacts chemically with the FAC hydration product to form a hydrophobic film to reduce the diffusion of corrosive ions.

[0005] The highly durable erosion-resistant concrete can be used in the construction of docks or submarine tunnels in marine engineering to improve the ability to resist chloride ion corrosion.

[0006] According to the above scheme, the mass fraction of aluminum oxide in the bauxite powder is 50% to 70%, and the total amount of impurities does not exceed 10%.

[0007] According to the above scheme, the addition amount of the bauxite powder is 10% to 15% of the total mass of the cementitious material.

[0008] Preferably, the amount of the ferroaluminate cement is 25% to 35% of the total mass of the gel material to ensure effective generation of CASH and maintain a balance between early strength and long-term durability.

[0009] According to the above scheme, the silane solution is a methyltriethoxysilane solution or an octyltriethoxysilane solution, the concentration of the methyltriethoxysilane solution is 5% to 10%, the concentration of the octyltriethoxysilane solution is 2% to 5%, and the amount of the silane solution added is 0.5% to 5% of the total mass of the cementitious material. Silane reacts with CASH generated by hydration of ferroaluminate cement (FAC), giving the material hydrophobicity and reducing the diffusion path of water and corrosive ions.

[0010] According to the above solution, the mineral admixture is fly ash.

[0011] According to the above scheme, the coarse aggregate is limestone crushed stone or basalt crushed stone, and the fine aggregate is quartz sand or river sand.

[0012] According to the above scheme, the particle size range of the coarse aggregate is 5~20mm.

[0013] According to the above scheme, the alkaline activator is sodium hydroxide or potassium hydroxide solution with a concentration of 5% to 10%.

[0014] In a second aspect, the present invention provides a method for preparing the above-mentioned high-durability erosion-resistant concrete, comprising the following steps: S1. Weigh each raw material component by weight; S2. Mix the silicate cement, ferroaluminate cement, mineral admixture and bauxite powder, gradually add the coarse aggregate and fine aggregate, continue mixing until the dry materials are mixed evenly, pre-mix water, water reducer, silane solution, alkaline activator and boric acid, add them to the dry materials during stirring, continue stirring to obtain a slurry; S3. The slurry is formed and cured to obtain the highly durable erosion-resistant concrete.

[0015] The stirring time in step S2 is controlled within 3 to 5 minutes.

[0016] The beneficial effects of the present invention are: The reaction of ferroaluminate in the early stage of hydration produces CASH and ettringite, which fill the pores and quickly improve the early strength, reducing the time and risk of the structure being exposed to the corrosive environment; as the OPC continues to hydrate, silicate is further released and more CASH is formed, further optimizing the density and long-term strength of the material. The ratio of silicate cement to ferroaluminate cement affects the balance between early strength and long-term durability. The structural characteristics of CASH are significantly optimized by introducing bauxite powder, silane solution and alkaline activator into silicate cement and ferroaluminate cement. The active ingredients of bauxite powder can provide additional silicon and aluminum sources in the hydration reaction, which makes the generated CASH have a higher aluminum-silicon ratio, thereby significantly improving its cross-linking degree, making the structure denser and more chemically stable. While enhancing the strength of concrete, it can better regulate the early strength and long-term durability, and achieve a balance between full reaction and performance improvement. The silane solution further prevents the diffusion of corrosive ions by forming a hydrophobic protective layer on the surface of the matrix, significantly enhancing the material's impermeability. The reaction rate of ferroaluminate cement and fly ash is further accelerated by combining with an alkaline activator, thereby improving the generation efficiency of CASH and rapidly improving the early strength. Through the synergistic effect of the raw materials in the above system, not only a more stable CASH is generated, but also a high content of ettringite is formed through hydration reaction, which further fills the micropores, optimizes the density of the matrix, and further cooperates with silicon to improve the impermeability of the material. In complex corrosive environments (such as marine environments), this optimized CASH structure and the improvement of matrix density and impermeability can significantly reduce the penetration rate of chloride ions, thereby inhibiting the degradation of concrete induced by chloride ions, and significantly improving the concrete's resistance to chloride ion corrosion and long-term durability. DETAILED DESCRIPTION

[0017] The principles and features of the present invention are described below in conjunction with specific embodiments. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0018] In the following specific embodiments, the cement used is 42.5 grade ordinary Portland cement, the fine aggregate is quartz sand, the coarse aggregate is limestone crushed stone, the particle size range is 5-20 mm, the fly ash is Class I fly ash, the water reducer is HPWR-AUHPC60-1 type water reducer, the boric acid is anhydrous boric acid, the silane solution is 5% methyltriethoxysilane, and the alkaline activator is 5% sodium hydroxide solution.

[0019] Example 1 The present embodiment provides a highly durable and erosion-resistant concrete, the raw materials of which include: 3.0 kg of ordinary Portland cement, 1.8 kg of ferroaluminate cement, 1.2 kg of fly ash, 13.4 kg of crushed stone, 8.9 kg of quartz sand, 1.68 kg of water, 0.084 kg of water reducer, 0.0096 kg of boric acid, 0.3 kg of bauxite powder (5% of the total mass of cementitious materials), 0.05 kg of silane solution, and 0.52 kg of sodium hydroxide solution.

[0020] The preparation method is as follows: First, mix the ordinary Portland cement, ferroaluminate cement, fly ash and bauxite powder evenly, then gradually add quartz sand and crushed stone, and continue to mix until the dry materials are evenly mixed. During the mixing process of the dry materials, add water, water reducer, silane solution, sodium hydroxide solution and boric acid, and continue to stir to ensure that the ordinary Portland cement, ferroaluminate cement, fly ash, bauxite powder, water, silane solution, sodium hydroxide, water reducer and boric acid are fully mixed to form a uniform concrete material.

[0021] According to the above production process, high-durability erosion-resistant concrete samples were prepared and cast in cylindrical molds of 100mm×100mm×400mm, 100mm×100mm×100mm and ф50mm×50mm. After curing for 24 hours under standard conditions, the samples were demolded. After demolding, the samples were placed in an artificially prepared seawater solution and cured to the corresponding age. The artificial seawater was configured according to the ASTMD1141-98 standard. The compressive performance, flexural performance and electrical flux of the samples immersed in seawater were tested at the corresponding age.

[0022] Example 2 The present embodiment provides a highly durable and erosion-resistant concrete, the raw materials of which include: 3.0 kg of ordinary Portland cement, 1.8 kg of ferroaluminate cement, 1.2 kg of fly ash, 13.4 kg of crushed stone, 8.9 kg of quartz sand, 1.68 kg of water, 0.084 kg of water reducer, 0.0096 kg of boric acid, 0.6 kg of bauxite powder (10% of the total mass of cementitious materials), 0.05 kg of silane solution, and 0.52 kg of sodium hydroxide solution.

[0023] The preparation method and testing method of high-durability erosion-resistant concrete are the same as those in Example 1.

[0024] Example 3 The present embodiment provides a highly durable erosion-resistant concrete, the raw materials of which include: 3.0 kg of ordinary Portland cement, 1.8 kg of ferroaluminate cement, 1.2 kg of fly ash, 13.4 kg of crushed stone, 8.9 kg of quartz sand, 1.68 kg of water, 0.084 kg of water reducer, 0.0096 kg of boric acid, 0.9 kg of bauxite powder (15% of the total mass of cementitious materials), 0.05 kg of silane solution, and 0.52 kg of sodium hydroxide solution.

[0025] The preparation method and testing method of high-durability erosion-resistant concrete are the same as those in Example 1.

[0026] Comparative Example 1 This comparative example provides a concrete, which is different from Example 1, Example 2 and Example 3 in that no bauxite powder is added, and the amount of each raw material used is 3.0 kg of ordinary Portland cement, 1.8 kg of ferroaluminate cement, 1.2 kg of fly ash, 13.4 kg of crushed stone, 8.9 kg of quartz sand, 1.68 kg of water, 0.0096 kg of boric acid, 0.05 kg of silane solution, and 0.52 kg of sodium hydroxide.

[0027] Comparative Example 2 This comparative example provides a concrete, which is different from Example 3 in that: no silane solution and sodium hydroxide solution are added, and the amount of each raw material is: 3.0 kg of ordinary Portland cement, 1.8 kg of ferroaluminate cement, 1.2 kg of fly ash, 13.4 kg of crushed stone, 8.9 kg of quartz sand, 1.68 kg of water, 0.084 kg of water reducer, 0.0096 kg of boric acid, and 0.9 kg of bauxite powder.

[0028] The flexural strength, compressive strength and electric flux data of the samples prepared in Example 1, Example 2, Example 3 and Comparative Examples 1 and 2 in seawater are shown in Tables 1 and 2.

[0029] Table 128d Strength and electric flux test data

[0030] Table 290d strength and electric flux test data

[0031] From the data in Table 1 and Table 2, it can be seen that the high-durability anti-corrosion concrete prepared by the present invention can increase its compressive strength and flexural strength in the seawater environment, and at the same time improve its resistance to chloride ion corrosion. The concrete mixed with bauxite powder, silane solution and sodium hydroxide solution has significantly enhanced anti-corrosion ability, and its service performance in seawater is enhanced, which has broad application prospects in the field of marine environment.

[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A highly durable erosion-resistant concrete, characterized in that: The concrete comprises the following raw materials in parts by weight: 30-40 parts of silicate cement, 20-30 parts of ferroaluminate cement, 10-20 parts of mineral admixture, 40-60 parts of coarse aggregate, 35-55 parts of fine aggregate, 0.06-0.2 parts of boric acid, 0.1-1 parts of water reducing agent, 5-10 parts of bauxite powder, 0.5-5 parts of silane solution, and 0.5-3 parts of alkaline activator, and the water-cement ratio of the concrete is 0.25-0.4; The mass ratio of the silicate cement to the ferroaluminate cement is (1-2):1, the mineral admixture accounts for 15%-25% of the total mass of the cementitious material composed of the silicate cement, ferroaluminate cement and the mineral admixture, and the addition amount of the bauxite powder is 5%-15% of the total mass of the cementitious material.

2. The highly durable erosion-resistant concrete according to claim 1, characterized in that: The mass fraction of aluminum oxide in the bauxite powder is 50% to 70%, and the total amount of impurities does not exceed 10%.

3. The highly durable erosion-resistant concrete according to claim 2, characterized in that: The amount of bauxite powder added is 10% to 15% of the total mass of the cementitious material.

4. The highly durable erosion-resistant concrete according to claim 1, characterized in that: The amount of the ferroaluminate cement added is 25% to 35% of the total mass of the gel material.

5. The highly durable erosion-resistant concrete according to claim 1, characterized in that: The silane solution is a methyltriethoxysilane solution or an octyltriethoxysilane solution, the concentration of the methyltriethoxysilane solution is 5% to 10%, the concentration of the octyltriethoxysilane solution is 2% to 5%, and the addition amount of the silane solution is 0.5% to 5% of the total mass of the cementitious material.

6. The highly durable erosion-resistant concrete according to claim 1, characterized in that: The mineral admixture is fly ash.

7. The highly durable erosion-resistant concrete according to claim 1, characterized in that: The coarse aggregate is limestone crushed stone or basalt crushed stone, and the fine aggregate is quartz sand or river sand.

8. The highly durable erosion-resistant concrete according to claim 7, characterized in that: The particle size of the coarse aggregate is in the range of 5 to 20 mm.

9. The highly durable erosion-resistant concrete according to claim 1, characterized in that: The alkaline activator is sodium hydroxide or potassium hydroxide solution with a concentration of 5% to 10%.

10. The method for preparing highly durable erosion-resistant concrete according to any one of claims 1 to 9, characterized in that: The steps include: S1. Weigh each raw material component by weight; S2. Mix the silicate cement, ferroaluminate cement, mineral admixture and bauxite powder, gradually add coarse aggregate and fine aggregate, continue mixing until the dry materials are mixed evenly, add water, water reducer, silane solution, alkaline activator and boric acid during the mixing of the dry materials, continue stirring to obtain a slurry; S3. The slurry is formed and cured to obtain the highly durable erosion-resistant concrete.

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