High-performance modified concrete and preparation method and application thereof

Abstract

The present application belongs to the technical field of concrete, and particularly relates to high-performance modified concrete and a preparation method thereof. The concrete comprises the following raw materials in parts by weight: cement 100-120 parts, coarse aggregate 230-245 parts, fine aggregate 180-200 parts, fly ash 10-20 parts, modified basalt fiber 3-8 parts, rubber powder 2-6 parts, stabilizer 1-4 parts, water reducing agent 0.5-1 part, and water 50-70 parts. The high-performance modified concrete of the present application uses rubber, modified basalt fiber, stabilizer and other ingredients in combination, effectively improves the mechanical properties and stability of the concrete, improves the durability and service life of the concrete, improves the road performance and bridge deck paving quality of the concrete, and has important promoting effects on accelerating economic construction and important significance for perfecting the highway network.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of concrete, and particularly relates to high-performance modified concrete as well as a preparation method and application thereof. BACKGROUND

[0002] With the rapid development of modern construction industry, the performance requirements of concrete, as one of the most important building materials, are increasingly stringent. Although traditional concrete has the advantages of low cost and strong plasticity, it is prone to cracking, insufficient durability and strength degradation under extreme environments (such as severe cold, high temperature and strong corrosion) or high load working conditions, resulting in shortened structure life and safety hazards. In particular, in major projects such as high-rise buildings, cross-sea bridges and nuclear power facilities, higher requirements are put forward for the compressive strength, crack resistance, impermeability and long-term stability of concrete.

[0003] The bridge deck pavement layer is an important part of the bridge structure, directly bearing the action of vehicle load and the impact, shear and abrasion of high-speed driving. With the increase of traffic volume and heavy vehicles, the damage problem of bridge deck pavement is becoming more and more serious, and the bridge deck pavement problem is not only an appearance problem, but also can easily cause serious accidents.

[0004] In recent years, fiber reinforced composites have shown significant potential in the field of concrete modification. Basalt fiber, as a kind of natural inorganic fiber, has the characteristics of high strength, high temperature resistance and corrosion resistance. However, its surface chemical inertness leads to weak interfacial bonding with the cement matrix, and it is prone to aggregation in concrete, making it difficult to fully exert its reinforcing effect. At the same time, calcium hydroxide crystals (CH) generated during the hydration process of concrete are easy to become weak links for micro-crack propagation due to their loose structure, which reduces the compactness of C-S-H gel and further affects the macroscopic performance of concrete. In addition, the non-uniformity of the pore structure and the migration of free water in concrete can easily lead to early shrinkage cracking, limiting its application in complex environments.

[0005] Although the existing technology has made some progress, there are still many problems. For example, the problem of fiber aggregation is still widespread, resulting in insufficient reinforcing efficiency; the long-term stability of concrete under complex stress and environment still needs to be improved. Therefore, it is necessary to improve the above problems and prepare a kind of modified concrete with high performance. SUMMARY

[0006] The first object of the present application is to provide a kind of high-performance modified concrete. In the present application, waste rubber powder, modified basalt fiber and stabilizer are mixed in concrete, which improves the compressive strength, flexural strength and durability of concrete, can meet the requirements of heavy traffic, and improves the road performance of concrete.

[0007] To achieve the above object, the technical scheme adopted by the present application is:

[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 is made by modifying basalt fibers with γ-aminopropyltriethoxysilane and 3-methoxy-4-hydroxycinnamic acid. The phenolic hydroxyl groups in the modified basalt fibers are adsorbed onto the cement surface through hydrogen bonding, reducing the fiber surface energy and improving the dispersibility of the basalt fibers in concrete. Simultaneously, the formation of the hydrogen bond network can suppress 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 7d compressive strength (MPa) 28d compressive strength (MPa) 28d 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 days electric flux (C) 56-day diffusion coefficient (x 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 cement 100-120 parts, coarse aggregate 230-245 parts, fine aggregate 180-200 parts, fly ash 10-20 parts, modified basalt fiber 3-8 parts, rubber powder 2-6 parts, stabilizer 1-4 parts, water reducing agent 0.5-1 part, and water 50-70 parts by weight; The preparation process of the modified basalt fiber is as follows: (1) pretreating basalt fiber; (2) adding the pretreated basalt fiber in step (1) into a solvent containing γ-aminopropyl triethoxysilane and 3-methoxy-4-hydroxycinnamic acid, heating and stirring, and then filtering, washing, and drying to obtain modified basalt fiber; The preparation process of the stabilizer is as follows: adding mullite whisker into a solvent containing hexadecyl triethoxysilane, and then heating to obtain the stabilizer; The mass ratio of the pretreated basalt fiber, γ-aminopropyl triethoxysilane, and 3-methoxy-4-hydroxycinnamic acid is (20-30):(1.5-2):(0.03-0.2). The mass ratio of the mullite whisker and hexadecyl triethoxysilane is 1:(0.01-0.05).

2. The high performance modified concrete according to claim 1, characterized in that, In step (1), the pretreatment process of the basalt fiber is as follows: immersing basalt fiber in acetone, taking out, immersing and washing with water, taking out, and drying.

3. The high performance modified concrete as claimed in claim 1, wherein, In step (2), the concentration of the pretreated basalt fiber in the solvent is 10-15 mg / mL, and the solvent is an ethanol aqueous solution prepared by mixing ethanol and water in a volume ratio of (2-5):

1.

4. The high performance modified concrete according to claim 1, wherein In step (2), the heating temperature is 50-65℃, and the heating time is 2-5 h.

5. The high performance modified concrete as claimed in claim 1, wherein, In the preparation process of the stabilizer, the solvent is a methanol aqueous solution prepared by mixing methanol and water in a volume ratio of 1:(0.1-0.3).

6. The high performance modified concrete according to claim 1, wherein In the preparation process of the stabilizer, the heating reaction temperature is 110-150℃, and the heating reaction time is 5-10 min.

7. The high performance modified concrete according to claim 1, wherein The water reducing agent is a polycarboxylic acid 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.

8. A method for preparing high-performance modified concrete as described in any one of claims 1 to 7, characterized in that, The preparation steps are as follows: Mixing the cement, coarse aggregate, fine aggregate, fly ash, modified basalt fiber, and rubber powder uniformly, then adding water, stabilizer, and water reducing agent, stirring uniformly, and then pouring and curing to obtain high-performance modified concrete.

9. Use of the high-performance modified concrete according to any one of claims 1-7 in preparing bridge deck pavement materials.