High-performance modified concrete as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of concrete, and particularly relates to high-performance modified concrete and a preparation method thereof. The concrete is prepared from the following raw materials in parts by weight: 100 to 120 parts of cement, 230 to 245 parts of coarse aggregate, 180 to 200 parts of fine aggregate, 10 to 20 parts of fly ash, 3 to 8 parts of modified basalt fiber, 2 to 6 parts of rubber powder, 1 to 4 parts of stabilizer, 0.5 to 1 part of water reducing agent and 50 to 70 parts of water. According to the high-performance modified concrete, the added rubber, the modified basalt fiber, the stabilizer and other components are matched for use, so that the mechanical property and stability of the concrete are effectively improved, the durability of the concrete is improved, the service life of the concrete is prolonged, the pavement performance and the bridge deck pavement quality of the concrete are improved, and an important promoting effect is achieved for accelerating economic construction; and the method is of great significance in improving the expressway network.

Description

Technical Field

[0001] This invention belongs to the field of concrete technology, specifically relating to a high-performance modified concrete, its preparation method, and its application. Background Technology

[0002] With the rapid development of the modern construction industry, concrete, as one of the most important building materials, faces increasingly stringent performance requirements. While traditional concrete boasts advantages such as low cost and high plasticity, it is prone to cracking, insufficient durability, and strength degradation under extreme environments (such as extreme cold, high temperatures, and strong corrosion) or high-load conditions, leading to shortened structural lifespan and safety hazards. Particularly in major projects such as high-rise buildings, cross-sea bridges, and nuclear power facilities, even higher demands are placed on the compressive strength, crack resistance, impermeability, and long-term stability of concrete.

[0003] Bridge deck pavement is an important part of the bridge structure, directly bearing the load of vehicles and the impact, shearing and wear of high-speed traffic. With the increase in traffic volume and heavy vehicles, the problem of damage to bridge deck pavement is becoming more and more serious. Bridge deck pavement problems are not only aesthetic issues, but can also easily lead to serious accidents.

[0004] In recent years, fiber-reinforced composites have shown significant potential in the field of concrete modification. Basalt fiber, as a natural inorganic fiber, possesses high strength, high temperature resistance, and corrosion resistance; however, its surface chemical inertness leads to weak interfacial bonding with the cement matrix, making it prone to agglomeration in concrete and hindering its reinforcing effect. Simultaneously, the calcium hydroxide crystals (CH) generated during concrete hydration, due to their loose structure, easily become weak points for microcrack propagation, reducing the density of the hydration product CSH gel and thus affecting the macroscopic properties of concrete. Furthermore, the inhomogeneity of the internal pore structure of concrete and the migration of free water easily lead to early shrinkage cracking, limiting its application in complex environments.

[0005] While existing technologies have made some progress, many problems remain. For example, fiber agglomeration is still prevalent, leading to insufficient reinforcement efficiency; and the long-term stability of concrete under complex stress and environments still needs improvement. Therefore, it is necessary to address these issues and prepare a high-performance modified concrete. Summary of the Invention

[0006] The primary objective of this invention is to provide a high-performance modified concrete. This invention incorporates waste rubber powder, modified basalt fiber, and stabilizers into the concrete, thereby improving its compressive strength, flexural strength, and durability, meeting the requirements of heavy traffic conditions, and enhancing the road performance of the concrete.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A high-performance modified concrete comprises the following raw materials in parts by weight: 100-120 parts cement, 230-245 parts coarse aggregate, 180-200 parts fine aggregate, 10-20 parts fly ash, 3-8 parts modified basalt fiber, 2-6 parts rubber powder, 1-4 parts stabilizer, 0.5-1 part water-reducing agent, and 50-70 parts water;

[0009] The preparation process of the modified basalt fiber is as follows:

[0010] (1) Pretreatment of basalt fibers;

[0011] (2) The basalt fiber pretreated in step (1) is added to a solvent containing γ-aminopropyltriethoxysilane and 3-methoxy-4-hydroxycinnamic acid, heated and stirred, and then filtered, washed and dried to obtain modified basalt fiber.

[0012] The basalt fibers in this invention, after being soaked in acetone, can have organic matter or oil stains removed from their surface. Furthermore, acetone may slightly etch the surface of the basalt fibers, improving the interfacial bonding between the basalt fibers and other materials.

[0013] The modified basalt fiber provided by this invention involves modifying the basalt fiber with γ-aminopropyltriethoxysilane and 3-methoxy-4-hydroxycinnamic acid. The phenolic hydroxyl groups in the modified basalt fiber are adsorbed onto the cement surface through hydrogen bonding, reducing the fiber surface energy and improving the dispersibility of the basalt fiber in concrete. Simultaneously, the formation of the hydrogen bond network inhibits van der Waals forces between fibers, preventing agglomeration.

[0014] On the other hand, Ca generated in the early stages of cement hydration 2+ Ions coordinate with the phenolic hydroxyl groups on the fiber surface to form stable chelates, which inhibit the crystallization of calcium hydroxide, improve the density of hydrated calcium silicate (CSH gel), and thus improve the performance of concrete.

[0015] Furthermore, the preparation process of the stabilizer is as follows: mullite whiskers are added to a solvent containing hexadecyltriethoxysilane, and the stabilizer is obtained after heating and reaction.

[0016] The stabilizer provided by this invention uses hexadecyltriethoxysilane to treat mullite whiskers. The long-chain alkane structure and the gel during cement hydration produce molecular entanglement, thereby improving the stability and service life of concrete.

[0017] Further, in step (1), the basalt fiber pretreatment process is as follows: the basalt fiber is soaked in acetone and then taken out, then soaked and washed in water, and then dried.

[0018] Furthermore, the soaking time is 8 to 15 hours.

[0019] Furthermore, the length of the basalt fiber is 10–20 mm.

[0020] Further, in step (2), the mass ratio of the pretreated basalt fiber, γ-aminopropyltriethoxysilane and 3-methoxy-4-hydroxycinnamic acid is (20-30):(1.5-2):(0.03-0.2), the concentration of the pretreated basalt fiber in the solvent is 10-15 mg / mL, and the solvent is an aqueous ethanol solution prepared by mixing ethanol and water in a volume ratio of (2-5):1.

[0021] Furthermore, in step (2), the heating temperature is 50-65°C and the heating time is 2-5 hours.

[0022] Furthermore, the mass ratio of the mullite whiskers to hexadecyltriethoxysilane is 1:(0.01-0.05), and the solvent is an aqueous methanol solution prepared by mixing methanol and water in a volume ratio of 1:(0.1-0.3).

[0023] Furthermore, the heating reaction is carried out at a temperature of 110–150°C for a duration of 5–10 min.

[0024] Furthermore, the water-reducing agent is a polycarboxylate superplasticizer; the rubber powder is waste tire powder; the coarse aggregate is crushed stone; the fine aggregate is quartz sand or river sand; and the cement is high aluminate cement.

[0025] The second objective of this invention is to provide a method for preparing high-performance modified concrete.

[0026] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0027] A method for preparing high-performance modified concrete includes the following preparation steps:

[0028] Cement, coarse aggregate, fine aggregate, fly ash, modified basalt fiber, and rubber powder are mixed evenly, and then water, stabilizer, and water-reducing agent are added and stirred evenly. After pouring and curing, high-performance modified concrete is obtained.

[0029] A third objective of this invention is to provide an application of high-performance modified concrete.

[0030] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0031] Application of a high-performance modified concrete in the preparation of bridge deck pavement materials.

[0032] The beneficial technical effects of this invention are as follows:

[0033] 1. This invention provides a high-performance modified concrete, which incorporates rubber, modified basalt fiber, stabilizers, and other components to effectively improve the mechanical properties and stability of concrete, enhance its durability and service life, and improve its road performance. Specifically, γ-aminopropyltriethoxysilane and 3-methoxy-4-hydroxycinnamic acid are used to modify the basalt fiber, improving its dispersibility in the concrete and enhancing its mechanical properties; hexadecyltriethoxysilane is used to treat the mullite whiskers, improving the concrete's stability and extending its service life.

[0034] 2. The present invention provides a method for preparing the above-mentioned high-performance modified concrete. The method is simple and easy to operate, which is conducive to realizing industrial production.

[0035] 3. This invention provides the application of the above-mentioned high-performance modified concrete as a bridge deck pavement material. This concrete can improve concrete durability and bridge deck pavement quality, which plays an important role in accelerating economic development and is of great significance to improving the highway network. Detailed Implementation

[0036] The technical solutions of the present invention will be clearly and completely described below with reference to specific 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] The basalt fibers in this invention have a length of 10-20 mm and an average diameter of 8-12 μm; the rubber powder is waste tire powder with a particle size of 0.3-5 mm; the coarse aggregate is crushed stone with a particle size of 10-19 mm; the fine aggregate is quartz sand with a particle size of 0.5-5 mm; the fly ash has a particle size of 5-10 μm; the mullite whiskers have a diameter of 0.2-3 μm and a length of 5-200 μm; the water-reducing agent is a polycarboxylate high-efficiency water-reducing agent with a water reduction rate ≥25%; and the cement is high aluminate cement.

[0038] Example 1

[0039] A high-performance modified concrete comprises the following raw materials in parts by weight: 110 parts cement, 235 parts coarse aggregate, 190 parts fine aggregate, 15 parts fly ash, 5 parts modified basalt fiber, 4 parts rubber powder, 3 parts stabilizer, 0.8 parts water-reducing agent, and 60 parts water.

[0040] The preparation process of the modified basalt fiber is as follows:

[0041] (1) Soak the basalt fiber in acetone for 12 hours, then take it out, soak it in deionized water for 2 hours and wash it to remove the acetone residue. Take out the pretreated basalt fiber and dry it to obtain the product.

[0042] (2) First, weigh ethanol and water at a volume ratio of 2:1 and mix them evenly to obtain an ethanol-water solution. Then, add γ-aminopropyltriethoxysilane and stir evenly. Then, add pretreated basalt fiber and 3-methoxy-4-hydroxycinnamic acid to obtain a mixture. Control the mass ratio of pretreated basalt fiber, γ-aminopropyltriethoxysilane and 3-methoxy-4-hydroxycinnamic acid to be 25:1.8:0.1. The concentration of pretreated basalt fiber in the ethanol-water solution is 13 mg / mL. Stir the mixture at 55°C for 3 h. Then filter the treated solution and wash it three times with deionized water. Dry the product at 80°C for 12 h to obtain modified basalt fiber.

[0043] The preparation process of the stabilizer is as follows: First, methanol and water are weighed separately according to a volume ratio of 1:0.3 and mixed evenly to obtain a methanol aqueous solution. Then, an equal volume of hexadecyltriethoxysilane is added to it to obtain a methanol aqueous solution of hexadecyltriethoxysilane. Subsequently, mullite whiskers (the mass ratio of mullite whiskers to hexadecyltriethoxysilane is 1:0.03) are added, and the mixture is reacted at 130°C for 7 minutes to obtain the stabilizer.

[0044] The preparation method of the high-performance modified concrete includes the following preparation steps: cement, coarse aggregate, fine aggregate, fly ash, modified basalt fiber, and rubber powder are mixed evenly, and then water, stabilizer, and water-reducing agent are added and stirred evenly. The mixture is then poured and cured to obtain high-performance modified concrete. The curing temperature is 20°C and the relative humidity is greater than 95%.

[0045] Example 2

[0046] A high-performance modified concrete comprises the following raw materials in parts by weight: 100 parts cement, 230 parts coarse aggregate, 180 parts fine aggregate, 10 parts fly ash, 3 parts modified basalt fiber, 2 parts rubber powder, 1 part stabilizer, 0.5 parts water-reducing agent, and 50 parts water.

[0047] The preparation process of the modified basalt fiber is as follows:

[0048] (1) Soak the basalt fiber in acetone for 8 hours, then take it out, soak it in deionized water for 2 hours and wash it to remove the acetone residue. Take out the pretreated basalt fiber and dry it to obtain the product.

[0049] (2) First, weigh ethanol and water at a volume ratio of 2:1 and mix them evenly to obtain an ethanol-water solution. Then, add γ-aminopropyltriethoxysilane and stir evenly. Then, add pretreated basalt fiber and 3-methoxy-4-hydroxycinnamic acid to obtain a mixture. Control the mass ratio of pretreated basalt fiber, γ-aminopropyltriethoxysilane and 3-methoxy-4-hydroxycinnamic acid to be 20:1.5:0.03. The concentration of pretreated basalt fiber in the ethanol-water solution is 10 mg / mL. Stir the mixture at 50°C for 5 h. Then, filter the treated solution and wash it three times with deionized water. Dry the product at 80°C for 12 h to obtain modified basalt fiber.

[0050] The preparation process of the stabilizer is as follows: First, methanol and water are weighed separately according to a volume ratio of 1:0.3 and mixed evenly to obtain a methanol aqueous solution. Then, an equal volume of hexadecyltriethoxysilane is added to it to obtain a methanol aqueous solution of hexadecyltriethoxysilane. Subsequently, mullite whiskers (the mass ratio of mullite whiskers to hexadecyltriethoxysilane is 1:0.01) are added, and the mixture is reacted at 150°C for 5 minutes to obtain the stabilizer.

[0051] The preparation method of the high-performance modified concrete includes the following steps: cement, coarse aggregate, fine aggregate, fly ash, modified basalt fiber, and rubber powder are mixed evenly, then water, stabilizer, and water-reducing agent are added and stirred evenly. The mixture is then poured and cured to obtain the high-performance modified concrete. The curing temperature is 18℃, and the relative humidity is greater than 95%.

[0052] Example 3

[0053] A high-performance modified concrete comprises the following raw materials in parts by weight: 120 parts cement, 245 parts coarse aggregate, 200 parts fine aggregate, 20 parts fly ash, 8 parts modified basalt fiber, 6 parts rubber powder, 4 parts stabilizer, 1 part water-reducing agent, and 70 parts water.

[0054] The preparation process of the modified basalt fiber is as follows:

[0055] (1) Soak the basalt fiber in acetone for 15 hours, then take it out, soak it in deionized water for 2 hours and wash it to remove the acetone residue. Take out the pretreated basalt fiber and dry it to obtain the product.

[0056] (2) First, weigh ethanol and water at a volume ratio of 3:1 and mix them evenly to obtain an ethanol-water solution. Then, add γ-aminopropyltriethoxysilane and stir evenly. Then, add pretreated basalt fiber and 3-methoxy-4-hydroxycinnamic acid to obtain a mixture. Control the mass ratio of pretreated basalt fiber, γ-aminopropyltriethoxysilane and 3-methoxy-4-hydroxycinnamic acid to be 30:2:0.2. The concentration of pretreated basalt fiber in the ethanol-water solution is 15 mg / mL. Stir the mixture at 65°C for 2 h. Then filter the treated solution and wash it three times with deionized water. Dry the product at 80°C for 12 h to obtain modified basalt fiber.

[0057] The preparation process of the stabilizer is as follows: First, methanol and water are weighed separately according to a volume ratio of 1:0.3 and mixed evenly to obtain a methanol aqueous solution. Then, an equal volume of hexadecyltriethoxysilane is added to it to obtain a methanol aqueous solution of hexadecyltriethoxysilane. Subsequently, mullite whiskers (the mass ratio of mullite whiskers to hexadecyltriethoxysilane is 1:0.05) are added, and the mixture is reacted at 150°C for 5 minutes to obtain the stabilizer.

[0058] The preparation method of the high-performance modified concrete includes the following steps: cement, coarse aggregate, fine aggregate, fly ash, modified basalt fiber, and rubber powder are mixed evenly; then water, stabilizer, and water-reducing agent are added and stirred evenly; the mixture is then poured and cured to obtain the high-performance modified concrete. The curing temperature is 22℃, and the relative humidity is greater than 95%.

[0059] Comparative Example 1

[0060] Comparative Example 1 is basically the same as Example 1, except that the modified basalt fiber is replaced with basalt fiber.

[0061] Comparative Example 2

[0062] Comparative Example 2 is basically the same as Example 1, except that 3-methoxy-4-hydroxycinnamic acid is omitted in the preparation process of modified basalt fiber.

[0063] Comparative Example 3

[0064] Comparative Example 3 is basically the same as Example 1, except that the hexadecyltriethoxysilane in the stabilizer preparation process is replaced with γ-aminopropyltriethoxysilane.

[0065] Test case

[0066] (1) The concrete prepared in Examples 1-3 and Comparative Examples 1-3 were used as test objects. The compressive strength and flexural strength of the concrete on the 7th day and the 28th day were tested according to the standard test of GB / T 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete". The results are shown in Table 1.

[0067] (2) The concrete prepared in Examples 1-3 and Comparative Examples 1-3 were used as test objects. The electrical flux and diffusion coefficient of the concrete were tested in accordance with the standard of GB / T50082-2024 "Standard for Test Methods of Long-term Performance and Durability of Concrete". The test results are shown in Table 2.

[0068] Table 1

[0069] Group 7-day compressive strength (MPa) 28-day compressive strength (MPa) 28-day flexural strength (MPa) Example 1 55.7 72.1 7.6 Example 2 53.3 69.6 7.4 Example 3 54.1 71.3 7.5 Comparative Example 1 39.3 52.8 5.1 Comparative Example 2 42.5 58.7 6.0 Comparative Example 3 48.1 64.1 6.7

[0070] As shown in Table 1, the compressive and flexural strengths of the concrete in Examples 1-3 of this invention are significantly greater than those in Comparative Examples 1-3, indicating that the concrete obtained by this invention can significantly improve the road performance of concrete. Compared with Example 1, Comparative Example 1 replaced the modified basalt fiber with basalt fiber; Comparative Example 2 omitted 3-methoxy-4-hydroxycinnamic acid in the preparation process of modified basalt fiber; and Comparative Example 3 replaced hexadecyltriethoxysilane in the stabilizer preparation process with γ-aminopropyltriethoxysilane. Comparative Example 1 had the worst compressive and flexural strengths. The above results may be attributed to the fact that the phenolic hydroxyl groups in the modified basalt fiber are adsorbed on the cement surface through hydrogen bonding, reducing the fiber surface energy and improving the dispersibility of basalt fiber in concrete. At the same time, the formation of the hydrogen bond network can inhibit the van der Waals forces between fibers and avoid agglomeration. In addition, the addition of modified basalt fiber reduces the Ca generated in the early stage of cement hydration. 2+ Ions coordinate with phenolic hydroxyl groups on the fiber surface to form stable chelates, which inhibit the crystallization of calcium hydroxide, improve the density of calcium silicate hydrate (CSH) gel, and thus improve the performance of concrete.

[0071] In addition, the long-chain alkane structure contained in the stabilizer introduced in this invention causes molecular entanglement with the gel during the cement hydration process, affecting the mechanical properties and stability of concrete.

[0072] Table 2

[0073] Group 56-day electrical flux (C) <![CDATA[Diffusion coefficient at 56 days (×10 -12 m 2 / s)]]> Example 1 525 1.1 Example 2 562 1.3 Example 3 543 1.2 Comparative Example 1 819 1.7 Comparative Example 2 745 1.6 Comparative Example 3 906 2.1

[0074] The electric flux and diffusion coefficient of Examples 1-3 of this invention are all lower than those of Comparative Examples 1-3. The lower the electric flux value, the better the impermeability and durability. This indicates that the stabilizer and modified basalt fiber work synergistically. In particular, the addition of the stabilizer can form a dense structure with the concrete during the cement hydration process, improving the resistance to chloride ion penetration and stability, and extending the service life of the concrete.

[0075] The above content is merely an example and illustration of the concept of the present invention. Any modifications or additions to the specific embodiments described, or substitutions made by those skilled in the art, shall fall within the scope of protection claimed by the present invention.

Claims

1. A high-performance modified concrete, characterized in that, The raw materials include the following parts by weight: 100-120 parts cement, 230-245 parts coarse aggregate, 180-200 parts fine aggregate, 10-20 parts fly ash, 3-8 parts modified basalt fiber, 2-6 parts rubber powder, 1-4 parts stabilizer, 0.5-1 part water-reducing agent, and 50-70 parts water. The preparation process of the modified basalt fiber is as follows: (1) Pretreatment of basalt fibers; (2) The basalt fiber pretreated in step (1) is added to a solvent containing γ-aminopropyltriethoxysilane and 3-methoxy-4-hydroxycinnamic acid, heated and stirred, and then filtered, washed and dried to obtain modified basalt fiber.

2. The high-performance modified concrete according to claim 1, characterized in that, The stabilizer is prepared as follows: mullite whiskers are added to a solvent containing hexadecyltriethoxysilane, and the stabilizer is obtained after heating and reaction.

3. The high-performance modified concrete according to claim 1, characterized in that, In step (1), the basalt fiber pretreatment process is as follows: the basalt fiber is soaked in acetone and then taken out, then soaked and washed in water, and then dried.

4. The high-performance modified concrete according to claim 1, characterized in that, In step (2), the mass ratio of the pretreated basalt fiber, γ-aminopropyltriethoxysilane and 3-methoxy-4-hydroxycinnamic acid is (20-30):(1.5-2):(0.03-0.2), the concentration of the pretreated basalt fiber in the solvent is 10-15 mg / mL, and the solvent is an aqueous ethanol solution prepared by mixing ethanol and water in a volume ratio of (2-5):

1.

5. The high-performance modified concrete according to claim 1, characterized in that, In step (2), the heating temperature is 50-65°C and the heating time is 2-5 hours.

6. The high-performance modified concrete according to claim 2, characterized in that, The mass ratio of mullite whiskers to hexadecyltriethoxysilane is 1:(0.01-0.05), and the solvent is an aqueous methanol solution prepared by mixing methanol and water in a volume ratio of 1:(0.1-0.3).

7. The high-performance modified concrete according to claim 2, characterized in that, The heating reaction is carried out at a temperature of 110–150°C for 5–10 minutes.

8. The high-performance modified concrete according to claim 1, characterized in that, The water-reducing agent is a polycarboxylate superplasticizer; the rubber powder is waste tire powder; the coarse aggregate is crushed stone; the fine aggregate is quartz sand or river sand; and the cement is high aluminate cement.

9. A method for preparing high-performance modified concrete as described in any one of claims 1 to 8, characterized in that, The preparation steps include the following: The cement, coarse aggregate, fine aggregate, fly ash, modified basalt fiber, and rubber powder are mixed evenly, and then water, stabilizer, and water-reducing agent are added and stirred evenly. After pouring and curing, high-performance modified concrete is obtained.

10. The application of the high-performance modified concrete as described in any one of claims 1 to 8 in the preparation of bridge deck pavement materials.