Preparation method of modified iron sand, high-performance concrete and preparation method of high-performance concrete

Abstract

The invention provides a preparation method of modified iron sand, high-performance concrete and a preparation method of the high-performance concrete, the modified iron sand is obtained by carrying out silane coating modification on derusted iron sand, and the preparation method comprises the following specific steps: preparing silane hydrolysate from a silane coupling agent, ethanol and deionized water, immersing the derusted iron sand into the silane hydrolysate, and after the reaction is completed, carrying out vacuum drying to obtain the modified iron sand. And taking out the iron sand, and drying to obtain the modified iron sand. The modified iron sand and a cementing material formed by mixing cement, microbeads, fly ash and silica fume are subjected to dry mixing, then water and a water reducing agent are added for mixing, finally, steel fibers are added for uniform mixing, a high-performance concrete mixture is obtained, and the high-performance concrete can be obtained after the concrete mixture is subjected to pouring forming, curing and form removal.

Description

Technical Field

[0001] This invention relates to the field of concrete technology, and further to a method for preparing modified iron sand, high-performance concrete, and the method for preparing the same. Background Technology

[0002] As modern architecture continues to evolve towards super high-rise buildings, large spans, and heavy facilities, the performance requirements for concrete materials in engineering structures are also increasing. Simply possessing high strength is no longer sufficient to meet the comprehensive needs under complex working conditions; concrete must maintain ultra-high strength while also possessing excellent durability and structural load-bearing capacity, achieving a synergistic effect of multiple properties.

[0003] However, the compressive strength of conventional concrete currently in widespread use is mostly below 80 MPa, making it prone to cracking and deformation under heavy loads, seriously affecting structural safety and long-term service life. Faced with ever-increasing engineering demands, existing material systems and preparation processes are gradually becoming inadequate. Therefore, developing high-performance concrete and its supporting preparation methods, which combine high performance, controllable cost, and simple processes, has become crucial for promoting technological progress and engineering practice in the industry. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing modified iron sand involves modifying rust-removed iron sand with a silane coupling agent. The steps include: preparing a silane hydrolysate by mixing the silane coupling agent, ethanol, and deionized water; immersing the rust-removed iron sand in the silane hydrolysate; and removing and drying the iron sand after the reaction is complete to obtain the modified iron sand.

[0005] In some embodiments, the mass ratio of the silane coupling agent, the ethanol, and the water in the silane hydrolysate is 1:14:5; and / or, the preparation steps of the silane hydrolysate are as follows: mixing the ethanol and the deionized water evenly and adjusting the pH of the mixed solution to 4-5, then adding the silane coupling agent and stirring evenly to obtain the silane hydrolysate; and / or, the silane coupling agent is of type KH550.

[0006] In some embodiments, the reaction time of the rust-removed iron sand immersed in the silane hydrolysate is 30 minutes.

[0007] In some embodiments, the rust removal step of the iron sand is as follows: the rust-free iron sand is soaked in a 5% to 10% hydrochloric acid aqueous solution, and after the rust on the surface of the iron sand is removed, the rust-free iron sand is rinsed clean with deionized water.

[0008] In some embodiments, the process includes, prior to the rust removal step, screening the unremoved iron sand to obtain unremoved iron sand with uniform particle size, and then using an alkaline solution to remove oil stains from the surface of the unremoved iron sand.

[0009] In some embodiments, the step of removing oil stains from the surface of the unremoved iron sand using an alkaline solution includes: immersing the unremoved iron sand in a sodium carbonate solution with a concentration of 5% to 8%, soaking it at 60-80°C for 20 to 30 minutes, and then rinsing it with deionized water until the pH of the rinsing solution is neutral.

[0010] In some embodiments, the iron sand is 0-5mm continuously graded iron sand.

[0011] The present invention also provides a high-performance concrete comprising, by weight, the following raw materials: 2600-2850 parts of the above-mentioned modified iron sand, 750-850 parts of cement, 100-180 parts of microspheres, 60-100 parts of fly ash, 40-80 parts of silica fume, 180-220 parts of water, 200-260 parts of steel fiber, and 30-37 parts of water-reducing agent.

[0012] In some embodiments, the cement is silicate cement, the strength grade of the silicate cement is P.II 52.5, the specific surface area of ​​the silicate cement is 455 m² / kg, the apparent density of the silicate cement is 3050 kg / m³, and the bulk density of the silicate cement is 1250 kg / m³; and / or, the fly ash is Class I F fly ash; and / or, the microspheres are fly ash microspheres; and / or, the silicon content in the silica fume is >94%; and / or, the water-reducing agent is a polycarboxylate-type water-reducing agent, the water reduction rate of the water-reducing agent is >25%, the solid content of the water-reducing agent is 24%, and the density of the water-reducing agent is 1020–1080 kg / m³. The present invention also provides a method for preparing the above-mentioned high-performance concrete, comprising the following steps: mixing the above-mentioned amounts of cement, microspheres, fly ash and silica fume evenly to form a cementitious material; then dry-mixing the modified iron sand with the cementitious material; adding the water and the water-reducing agent and mixing; and finally adding the steel fiber and mixing evenly to obtain the high-performance concrete.

[0013] Compared with the prior art, the modified iron sand preparation method, high-performance concrete and preparation method thereof provided by the present invention have the following beneficial effects: This invention involves acid pickling and rust removal followed by silane coating modification of iron sand, constructing a dual structure of "chemical bonding + network coating" on its surface. This structure, through Si-O-Fe covalent bonds and a Si-O-Si network film, enhances the interfacial bonding strength to 3-5 MPa. Utilizing this modified iron sand with strong interfacial bonding capabilities as a high-strength skeleton support for high-performance concrete fundamentally avoids the risk of aggregate-grout separation under load, which is key to achieving a stable compressive strength exceeding 150 MPa and ensuring long-term service stability. Furthermore, the dense network film also endows the iron sand with excellent rust resistance, further guaranteeing the material's durability. Detailed Implementation

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, specific implementation methods of the present invention will be described below. Obviously, the following description is merely some embodiments of the present invention; those skilled in the art can obtain other implementation methods without creative effort.

[0015] In this article, "one" can mean not only "only one", but also "more than one".

[0016] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0017] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0018] Furthermore, in the description of this invention, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0019] This invention provides a method for preparing modified iron sand, which involves first removing rust from the iron sand, and then modifying the iron sand using a silane coupling agent. Specific steps include: Step S10: Pre-treat the iron sand: S11. Screen out iron sand with uniform particle size and remove impurities such as lumps and stones that are too large.

[0020] It is preferred to use iron sand with a continuous gradation of 0-5mm particle size, and screen it with a 5mm standard sieve to ensure that all iron sand particles are within a controllable size range, providing a raw material basis with controllable size for subsequent chemical treatment and modification processes.

[0021] S12. Alkaline washing to remove oil stains from the surface of iron sand: Soak the iron sand in a 5% to 8% sodium carbonate solution at 60-80℃ for 20 to 30 minutes, then rinse repeatedly with deionized water 3 to 4 times until the pH of the rinsing solution is neutral and no oil floats.

[0022] Oil stains on iron shot pose an obstacle to subsequent pickling and silane modification, as they prevent chemical reagents from contacting the metal surface. Sodium carbonate solution can thoroughly remove these organic contaminants through saponification and emulsification.

[0023] Step S20: Remove rust from iron sand: Soak the iron sand in a 5% to 10% hydrochloric acid solution for 10 to 20 minutes and observe the surface of the iron sand. When the surface of the iron sand is free of reddish-brown floating rust and presents a uniform silver-gray color, rinse it with deionized water until it is neutral (pH=6.5-7.5) to prevent residual acid from accelerating subsequent corrosion.

[0024] Hydrochloric acid reacts with the reddish-brown rust (iron oxide) on the surface of the iron sand, dissolving it and exposing the metal matrix. Pickling not only removes the macroscopic rust but also the invisible oxide film, creating a highly chemically reactive iron sand surface through slight corrosion. The iron sand surface is covered with numerous hydroxyl groups (-OH, chemically represented as HO-Fe), providing anchor points for the subsequent formation of strong chemical bonds (Si-O-Fe) with a silane coupling agent.

[0025] It should be noted that the method of removing rust from iron sand is not limited to pickling with hydrochloric acid. Other chemical reagents such as sulfuric acid and organic acids can also be used for pickling, and other rust removal methods can also be used.

[0026] Step S30: Modify the iron sand with silane: S31. Preparation of silane hydrolysate: First, mix ethanol and deionized water evenly, and adjust the pH of the solution to 4-5 with acetic acid; then slowly add silane coupling agent while stirring for 15-20 minutes to form a uniform and transparent silane hydrolysate; let the silane hydrolysate stand for 5-10 minutes for later use.

[0027] In the above silane hydrolysate, the mass ratio of silane coupling agent, ethanol and water is 1:14:5.

[0028] The aforementioned silane coupling agent is model KH550, and the mass percentage of the silane coupling agent is ≥98.1%.

[0029] S32. Immerse the rust-removed iron sand completely in the silane hydrolysis solution for 30 minutes. The silane hydrolysis solution undergoes the following condensation reaction on the surface of the iron sand:

[0030] At the same time, reactions also occur between adjacent silane molecules:

[0031] A three-dimensional, dense Si-O-Si network structure is formed between silane molecules, covering the surface of iron sand like a net, and finally forming a protective coating of chemical bonding and cross-linking network on the surface of iron sand.

[0032] Stir every 5 minutes during the iron sand soaking process to prevent iron sand from accumulating and causing localized areas without coating.

[0033] After the reaction between iron sand and silane molecules is complete, modified iron sand can be obtained.

[0034] S33. Curing of modified iron sand: Spread the modified iron sand evenly in a ventilated and dry place and let it stand for 24 to 48 hours until the surface is no longer sticky.

[0035] Preferably, the drying temperature is 20-30℃ and the drying humidity is ≤60%.

[0036] Step S40, Quality Inspection of Modified Iron Shot: Use a 5mm sieve to screen the cured modified iron sand to remove lumps formed by coating adhesion. This is because during the modification process, iron sand particles may clump together due to the adhesion of the coating. These lumps will affect the gradation and performance of the product (such as workability in concrete), so they must be screened out again.

[0037] The sieved modified iron sand is placed in an oven and dried at 80°C for 1 hour to ensure that the moisture content is ≤0.5%.

[0038] Finally, a random inspection of the iron sand surface was conducted: no powder fell off when touched by hand, and water droplets on the surface were hydrophobic (water droplets rolled off without wetting), indicating that the coating was qualified and the modified iron sand was finally obtained.

[0039] This invention provides a high-performance concrete and its preparation method. The high-performance concrete uses the modified iron sand mentioned above as aggregate and contains the following raw materials by weight: 2600-2850 parts modified iron sand, 750-850 parts cement, 100-180 parts microspheres, 60-100 parts fly ash, 40-80 parts silica fume, 180-220 parts water, 200-260 parts steel fiber, and 30-37 parts water-reducing agent.

[0040] The preparation method of this high-performance concrete is as follows: First, the above-mentioned proportions of cement, microspheres, fly ash, and silica fume are mixed evenly to form a cementitious material. Then, modified iron sand is dry-mixed with the cementitious material, and water and a water-reducing agent are added and mixed. Finally, steel fibers are added and mixed evenly to obtain high-performance concrete. This high-performance concrete is then poured into molds, cured, and demolded to obtain high-performance concrete components.

[0041] This high-performance concrete uses modified iron sand as aggregate. First, rust is removed by acid washing to enhance its surface activity. Then, an innovative silane coating treatment is introduced. The active silanol groups in the silane hydrolysate undergo a condensation reaction with the hydroxyl groups on the iron sand surface, forming strong covalent bonds that firmly connect the organosilane molecules to the iron sand matrix. Simultaneously, the silane molecules undergo self-polymerization and cross-linking, forming a dense Si-O-Si three-dimensional network protective film. This dual effect of "chemical bonding + network coating" results in an interfacial bond strength of 3-5 MPa between the modified iron sand and the cementitious paste, which is 2-3 times that of smooth, porous natural sand (1-2 MPa). This strengthening effect effectively prevents aggregate-paste separation under heavy loads due to weak interfaces. The strong interfacial bonding force of the modified iron sand is key to the concrete's compressive strength consistently exceeding 150 MPa and its long-term service stability, ultimately achieving synergistic optimization of the material's microstructure and macroscopic properties.

[0042] Secondly, the quality of natural sand is affected by its place of origin, and its core parameters such as particle shape, mud content, and moisture content are uncontrollable. This uncontrollability of raw material quality is directly transmitted to the concrete mixture, resulting in large dispersion and poor stability of the final product's mechanical properties, becoming a bottleneck restricting the large-scale and stable production of 150MPa-grade high-performance concrete. In contrast, the industrially processed iron sand used in this invention exhibits a standardization advantage that natural sand cannot match. Industrially processed iron sand can strictly control particle size distribution (0-5mm continuous gradation), moisture content (≤0.5%), and impurity content, resulting in a small quality fluctuation range and high stability.

[0043] In some embodiments, the cement is silicate cement with a strength grade of P.Ⅱ52.5, a specific surface area of ​​455 m² / kg, an apparent density of 3050 kg / m³, and a bulk density of 1250 kg / m³.

[0044] The fly ash mentioned above is Class I, F type fly ash.

[0045] The aforementioned microspheres are fly ash microspheres; The silicon content in the aforementioned silica fume is >94%, and it is preferred to use type 94 silica fume produced by Beijing Zhengyuan Yiqing New Material Technology Co., Ltd.

[0046] The aforementioned water-reducing agent is a polycarboxylate-type water-reducing agent with a water reduction rate >25%, a solid content of 24%, and a density of 1020-1080 kg / m³.

[0047] In some implementations, the test blocks of high-performance concrete are 100cm*100cm*100cm in size, and the curing process involves placing them in a standard curing room for 12 to 24 hours.

[0048] The performance of the high-performance concrete provided by the present invention will be further described in detail below with reference to the embodiments. Example 1

[0049] First, prepare the modified iron sand: Screen the iron sand using a 5mm standard sieve to remove large lumps, stones, and other impurities. Soak the iron sand in a 5%–8% sodium carbonate solution at 60–80℃ for 20–30 minutes, then rinse repeatedly with deionized water 3–4 times until the rinse solution has a neutral pH and no oil scum floats. Soak the iron sand in a 5%–10% hydrochloric acid solution for 10–20 minutes, observing the surface: when the surface is free of reddish-brown rust and has a uniform silvery-gray color, immediately rinse with deionized water until neutral. Mix ethanol and deionized water thoroughly, and adjust the pH to 4–5 with acetic acid. Slowly add the silane coupling agent while stirring for 15–20 minutes to form a uniform and transparent silane hydrolysate. Let it stand for 5–10 minutes. Completely immerse the rust-removed iron sand in the silane hydrolysate for 30 minutes, stirring every 5 minutes. Spread the coated iron sand evenly in a well-ventilated and dry place, and let it stand for 24–48 hours until the surface is no longer sticky. Use a sieve to screen the cured iron sand to remove any lumps formed by coating adhesion. Place the sieved iron sand in an oven and dry at 80°C for 1 hour, ensuring the moisture content is ≤0.5%. Randomly inspect the iron sand surface: if no powder falls off when touched, and water droplets are hydrophobic on the surface, the coating is qualified, and the modified iron sand is obtained.

[0050] Preparation of high-performance concrete: Weigh out 2725 parts by weight of the modified iron sand, 750 parts by weight of cement, 150 parts by weight of microspheres, 70 parts by weight of fly ash, 80 parts by weight of silica fume, 200 parts by weight of water, 230 parts by weight of steel fiber, and 31 parts by weight of water-reducing agent. Mix the above-mentioned amounts of cement, microspheres, fly ash, and silica fume evenly to form a cementitious material. Then, dry-mix the modified iron sand with the cementitious material, add water and water-reducing agent, and mix. Finally, add steel fiber and mix evenly to obtain high-performance concrete. Cast the high-performance concrete into specimens with a size of 100cm*100cm*100cm. After curing in a standard curing room for 12-24 hours, remove the mold to obtain high-performance concrete component A1. The compressive strength of high-performance concrete component A1 was tested, and the test results are shown in Table 2. Example 2

[0051] The steps for preparing modified iron sand are the same as in Example 1.

[0052] Preparation of high-performance concrete: 2725 parts by weight of the modified iron sand, 800 parts by weight of cement, 120 parts by weight of microspheres, 80 parts by weight of fly ash, 50 parts by weight of silica fume, 200 parts by weight of water, 230 parts by weight of steel fiber, and 31 parts by weight of water-reducing agent were weighed. The remaining steps were the same as in Example 1, resulting in high-performance concrete component A2. The compressive strength of high-performance concrete component A2 was tested, and the test results are shown in Table 2. Example 3

[0053] The steps for preparing modified iron sand are the same as in Example 1.

[0054] Preparation of high-performance concrete: 2725 parts by weight of the modified iron sand, 850 parts by weight of cement, 100 parts by weight of microspheres, 60 parts by weight of fly ash, 40 parts by weight of silica fume, 200 parts by weight of water, 230 parts by weight of steel fiber, and 31 parts by weight of water-reducing agent were weighed. The remaining steps were the same as in Example 1, resulting in high-performance concrete component A3. The compressive strength of high-performance concrete component A3 was tested, and the results are shown in Table 2.

[0055] Comparative Example 1 Preparation of high-performance concrete: Weigh out 2725 parts by weight of unmodified iron sand, 800 parts by weight of cement, 120 parts by weight of microspheres, 80 parts by weight of fly ash, 50 parts by weight of silica fume, 200 parts by weight of water, 230 parts by weight of steel fiber, and 31 parts by weight of water-reducing agent. Mix the above-mentioned amounts of cement, microspheres, fly ash, and silica fume evenly to form a cementitious material. Then, dry-mix the unmodified iron sand with the cementitious material, add water and water-reducing agent, and mix. Add steel fiber to obtain the concrete mixture. Pour the concrete mixture into molds, with the molded component specimens measuring 100cm*100cm*100cm. After curing in a standard curing room for 12–24 hours, remove the mold to obtain concrete component A4. Perform compressive strength tests on concrete component A4; the test results are shown in Table 2.

[0056] Comparative Example 2 Preparation of high-performance concrete: Weigh out 1300 parts by weight of natural sand (with the same continuous gradation and the same volume as modified and unmodified iron sand), 800 parts by weight of cement, 120 parts by weight of microspheres, 80 parts by weight of fly ash, 50 parts by weight of silica fume, 200 parts by weight of water, 230 parts by weight of steel fiber, and 31 parts by weight of water-reducing agent. Mix the above-mentioned amounts of cement, microspheres, fly ash, and silica fume evenly to form a cementitious material. Then, dry-mix the natural sand with the cementitious material, add water and water-reducing agent, and mix. Add steel fiber to obtain the concrete mixture. Cast the concrete mixture into specimens with a size of 100cm*100cm*100cm. After curing in a standard curing room for 12-24 hours, remove the mold to obtain concrete component A5. The compressive strength of concrete component A5 is tested, and the performance test results are shown in Table 2.

[0057] The raw material components of Examples 1-3 and Comparative Examples 1-2 are shown in Table 1 below.

[0058]

[0059]

[0060] The comparison results of Examples 1, 2, and 3 show that increasing the cement content generates more hydration products, thus significantly improving the early strength (7-day compressive strength) of concrete. However, excessively high cement content reduces the amount of microspheres, fly ash, and silica fume incorporated. Microspheres, with their smaller particle size than cement, can fill the gaps between cement particles, making the internal structure of the concrete more compact. However, if too much cement is used, the filling effect of microspheres and other materials becomes insufficient, resulting in more tiny pores inside the concrete, which in turn reduces the overall density and final long-term strength.

[0061] The comparison between Example 2 and Comparative Example 1 clearly reveals the decisive influence of iron sand surface modification treatment on concrete performance. Comparative Example 1, using unmodified iron sand, exhibits a significant decrease in compressive strength. The fundamental reason is that the surface rust adhering to the iron sand was not effectively removed. The rust layer acts as an isolation layer, severely damaging the effective bond between the iron sand and the cementitious paste. In contrast, modified iron sand is tightly bonded to the paste through Si-O-Fe chemical bonds, achieving an interfacial bond strength as high as 3-5 MPa. The presence of the rust layer causes this strength to plummet to below 1 MPa, leading to easy delamination of the aggregate from the paste under load.

[0062] Moreover, the rust layer on the surface of unremoved iron sand is often unevenly distributed, with some areas free of rust and others thickly rusted. This creates a weak interface with extremely uneven performance inside the concrete. The thick rust area becomes a stress concentration source when under stress, cracking first and ultimately leading to a significant increase in the dispersion of the strength of the test block. In large-scale production, this can easily cause quality risks such as some components failing to meet strength standards.

[0063] Furthermore, in actual production processes, these untreated iron sands can cause an abnormal increase in the viscosity of freshly mixed concrete slurry and a significant decrease in its fluidity, severely impairing its workability and posing a challenge to its construction applications.

[0064] The comparison results of Example 2 and Comparative Example 2 intuitively reveal the advantages of modified iron sand compared to traditional natural sand. The high-performance concrete prepared using modified iron sand as aggregate exhibits significantly higher compressive strength at 7 days and 28 days than concrete prepared with traditional natural sand. This high-strength framework provides support, breaking through the strength limit of traditional natural sand. Simultaneously, stronger interfacial bonding reduces strength loss. Modified iron sand, with its high hardness and high density, constructs a robust mechanical framework for the concrete that far exceeds the strength of traditional natural sand. Furthermore, the strong interfacial bonding achieved through Si-O-Fe chemical bonds effectively reduces strength loss under load, which is key to the concrete's ability to consistently exceed 150 MPa.

[0065] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing modified iron sand, characterized in that, The modification of rust-removed iron sand using silane coupling agents includes the following steps: The silane coupling agent, ethanol, and deionized water are mixed to form a silane hydrolysate. The rust-removed iron sand is then immersed in the silane hydrolysate. After the reaction is complete, the iron sand is removed and dried to obtain the modified iron sand.

2. The method for preparing modified iron sand according to claim 1, characterized in that, In the silane hydrolysate, the mass ratio of the silane coupling agent, the ethanol, and the water is 1:14:5; and / or, The preparation steps of the silane hydrolysate are as follows: Ethanol and deionized water are mixed evenly, and the pH of the mixed solution is adjusted to 4-5. Then, the silane coupling agent is added and stirred evenly to obtain the silane hydrolysate; and / or, The silane coupling agent is designated as KH550.

3. The method for preparing modified iron sand according to claim 1, characterized in that, The reaction time for the iron sand after rust removal to be immersed in the silane hydrolysate is 30 minutes.

4. The method for preparing modified iron sand according to claim 1, characterized in that, The rust removal steps for the iron sand are as follows: the unremoved iron sand is soaked in a 5% to 10% hydrochloric acid aqueous solution. After the rust on the surface of the iron sand is removed, the iron sand is rinsed clean with deionized water.

5. The method for preparing modified iron sand according to claim 1 or 4, characterized in that, Before the rust removal step, the process further includes: screening the unremoved iron sand to obtain unremoved iron sand with uniform particle size, and then using an alkaline solution to remove oil stains from the surface of the unremoved iron sand.

6. The method for preparing modified iron sand according to claim 5, characterized in that, The step of removing oil stains from the surface of the unrusted iron sand using an alkaline solution includes: immersing the unrusted iron sand in a sodium carbonate solution with a concentration of 5% to 8%, soaking it at 60-80°C for 20 to 30 minutes, and then rinsing it with deionized water until the pH of the rinsing solution is neutral.

7. The method for preparing modified iron sand according to claim 1, characterized in that, The iron sand is 0-5mm continuously graded iron sand.

8. A high-performance concrete, characterized in that, It contains the following ingredients by weight: 2600-2850 parts of modified iron sand as described in any one of claims 1-7, 750-850 parts of cement, 100-180 parts of microspheres, 60-100 parts of fly ash, 40-80 parts of silica fume, 180-220 parts of water, 200-260 parts of steel fiber, and 30-37 parts of water-reducing agent.

9. The high-performance concrete according to claim 8, characterized in that, The cement is silicate cement, the strength grade of the silicate cement is P.II52.5, the specific surface area of ​​the silicate cement is 455 m² / kg, the apparent density of the silicate cement is 3050 kg / m³, and the bulk density of the silicate cement is 1250 kg / m³; and / or, The fly ash is Class I, F type fly ash; and / or The microspheres are fly ash microspheres; and / or, The silicon content in the silica fume is >94%; and / or, The water-reducing agent is a polycarboxylate-type water-reducing agent, the water reduction rate of the water-reducing agent is >25%, the solid content of the water-reducing agent is 24%, and the density of the water-reducing agent is 1020~1080 kg / m³.

10. A method for preparing high-performance concrete as described in any one of claims 8-9, characterized in that, step include: The cement, microspheres, fly ash, and silica fume in the above-mentioned proportions are mixed evenly to form a cementitious material. The modified iron sand is then dry-mixed with the cementitious material, and water and water-reducing agent are added and mixed. Finally, the steel fibers are added and mixed evenly to obtain the high-performance concrete.

Images