A UHPC based on hydrolyzed silane and preparation method thereof

Abstract

The invention discloses a UHPC based on hydrolyzed silane and a preparation method thereof. The UHPC based on hydrolyzed silane includes silica ash, and the UHPC also includes hydrolyzed silane. The hydrolyzed silane includes silane, anhydrous ethanol, and water, and m1 (silane): m2 (water): m3 (anhydrous ethanol) = 1: (2-4): (1-7). The mass of the silane is 0.5% to 2% of the mass of the silica ash. The invention can improve the dispersibility of the cementitious material in the UHPC, greatly reduce the viscosity of the UHPC slurry, improve the construction performance of the UHPC, and the strength is almost not reduced. The cost is low and the operation method is simple, and the invention can be applied to engineering practice.

Description

Technical Field

[0001] The present invention relates to UHPC, in particular to UHPC based on hydrolyzed silane and a preparation method thereof. Background Art

[0002] The design theory of ultra-high performance concrete (UHPC) is the maximum packing density theory (densified particle packing), and its constituent materials have different particle sizes that form the most dense packing in the best proportion, that is, the gaps between the millimeter-level particles (aggregates) are filled with micron-level particles (cement, fly ash, mineral powder), and the gaps between the micron-level particles are filled with submicron-level particles (silica fume). Dry powder usually includes silica fume, and may also include one or more of cement, mineral powder, quartz powder, quartz sand, and fly ash.

[0003] Ultra-high performance concrete (UHPC) has an extremely low water-cement ratio (0.14-0.20), and its high specific surface area and high dosage of cementitious materials, which results in high viscosity of freshly mixed UHPC slurry, poor working performance, and rapid loss over time, which is an important problem faced in its cast-in-place construction. Therefore, reducing the viscosity of UHPC slurry and improving its working performance have become one of the research driving forces to promote the development of UHPC.

[0004] In recent years, silane has attracted more and more attention in order to further improve and enhance the mechanical and construction properties of concrete. Silane is a chemical admixture with better dispersibility than polycarboxylic acid water reducer. Silane hydrolyzes to form silanol, and the silanol in the silanol reacts with the hydroxyl group on the surface of the cementitious material to form chemical adsorption, thereby improving the dispersibility of the cementitious material and reducing the viscosity of the fresh slurry. At present, there are many literatures involving the research on the process conditions of silane hydrolysis, but due to the different uses of silane, the optimal hydrolysis process conditions obtained are different.

[0005] For cement-based materials, the methods used by domestic and foreign scholars to modify UHPC components by hydrolysis of silane mainly include: grafting silane onto the main chain of polycarboxylic acid water-reducing agent to prepare a new water-reducing agent, first modifying silica fume with silane, and directly mixing silane with the mixture. Studies have shown that the technical route of silane-modified polycarboxylic acid water-reducing agent to reduce the viscosity of UHPC is not efficient, so it is necessary to find another method for silane-modified cement-based materials. In existing studies, the temperature conditions for silane to modify silica fume are divided into normal temperature and high temperature. Under normal temperature conditions, when preparing modified cement-silica fume samples, some scholars hydrolyzed aminosilane in tap water for 3 minutes, then mixed and stirred the hydrolyzed silane, water and silica fume, and then mixed with cement, water-reducing agent and other components. The expansion of the obtained modified cement-silica fume slurry is about 250mm. When preparing the unmodified cement-silica fume sample, the water reducer, water and silica fume are first mixed and stirred, and then cement is added and stirred to obtain an unmodified cement-silica fume slurry with an expansion of about 210 mm. Although the construction performance of the modified cement-silica fume slurry is improved compared with the unmodified cement-silica fume slurry, the expansion of the unmodified cement-silica fume slurry prepared by the scholar is much lower than that of cement-silica fume slurries with other mixing orders, indicating that the material mixing order has an important influence on the construction performance of cement-based materials. Under high temperature conditions, some scholars mixed silica fume and hydrolyzed silane, then filtered out and dried to obtain modified silica fume, but the preparation process is more complicated and the cost is higher. When directly mixing silane with the mixture, the silane hydrolysis method and dosage should be considered, but the existing literature in the field of cement-based materials has not yet considered the silane hydrolysis method.

[0006] A Chinese patent with publication number CN107473624B discloses a cement-based composite material based on steel fibers after silane surface treatment. The silane coupling agent is soluble in alcohol and water, and the steel fibers are modified using the silane coupling agent. Compared with the present application, the preparation of the surface treatment agent in this patent requires the addition of zirconium nitrate, titanium fluoride, zirconium fluoride, hexafluorozirconic acid and other substances, which further increases the cost. In addition, the pretreatment of the steel fibers in this patent requires dilute hydrochloric acid or corresponding stripping agents and strong alkalis, and the steel fibers modified by the silane solution also need to be dried at high temperature, which makes the preparation process complicated and the cost high.

[0007] The Chinese patent with publication number CN113185243A discloses a low-viscosity, low-shrinkage, ultra-high-performance concrete repair material and a method of use, wherein silane and water are stirred and then mixed with other materials. The patent requires mixing silane and water at high temperature, then adding fly ash, separating the solid fly ash from the mixed solution, and heating and drying the solid to obtain a modified mineral admixture. All test processes of the present application are carried out at room temperature, and the prepared hydrolyzed silane solution is directly added to the mixture, taking into account the hydrolysis method and the order of mixing with the materials. Therefore, compared with the present application, the patent does not consider the silane hydrolysis method, and the preparation process is complicated and the cost is relatively high.

[0008] The Chinese patent with publication number CN101223117B discloses a hydrophobic mineral and a filling material, wherein an acid hydrolysis catalyst is added to hydrolyze silane, and then the polysilane hydrolyzate is mixed with plaster. The aqueous solution containing the polysiloxane hydrolyzate composition prepared in the patent has a mass of 0.5-5% of the mass of the plaster. The hydrolyzed silane solution prepared in the present application has a mass of silane of 1% of the mass of silica fume (equivalent to 0.42% of the mass of cement). Compared with the present application, the patent has a higher cost. Summary of the invention

[0009] The technical problem to be solved by the present invention is to provide a UHPC based on hydrolyzed silane and a preparation method thereof to obtain low-viscosity UHPC. The method greatly reduces the viscosity of UHPC slurry, improves its construction performance, and has low cost and simple operation method.

[0010] In order to solve the above technical problems, the technical solution adopted by the present invention is: a UHPC based on hydrolyzed silane, the UHPC includes silica ash, and the UHPC also includes hydrolyzed silane, the hydrolyzed silane includes silane, anhydrous ethanol, and water, m1 (silane): m2 (water): m3 (anhydrous ethanol) = 1: (2-4): (1-7), and the mass of the silane is 0.5% to 2% of the mass of the silica ash.

[0011] Silane is easily soluble in water and organic solvents, and anhydrous ethanol plays a role in dissolving. The hydrolyzed silane solutions prepared by different hydrolysis methods have very different modification effects on UHPC. Experiments have found that the improvement of the rheological properties of UHPC by the hydrolysis of KH550 in only deionized water or anhydrous ethanol is less than that of KH550 hydrolyzed in a mixed solvent of water and anhydrous ethanol. Therefore, the method of hydrolyzing silane in a mixed solvent is adopted. In the present invention, m1 (silane): m2 (water): m3 (anhydrous ethanol) = 1: (2~4): (1~7), when the ratio of m1 (silane): m2 (water): m3 (anhydrous ethanol) exceeds this range, it will cause a significant decrease in mechanical properties.

[0012] The admixtures include water reducing agents and may also include defoaming agents.

[0013] Silica powder, also known as microsilica powder, scientifically known as silica fume, is the smoke and dust that escapes with the exhaust gas during the high-temperature smelting of industrial silicon and ferrosilicon in industrial electric furnaces, and is collected and processed by special capture devices. In the escaped smoke and dust, the SiO2 content accounts for about 90% of the total smoke and dust, and the particle size is very small, and the average particle size is almost nanometer level, so it is called silicon powder.

[0014] In a preferred embodiment of the present invention, the mass of the silane is 0.5% to 1% of the mass of the silica fume. Adding silane in this mass ratio greatly improves fluidity and rheology, the change in mechanical properties is negligible, and the cost is low.

[0015] Further, the mass ratio of the hydrolyzed silane is m1 (silane): m2 (water): m3 (anhydrous ethanol) = 1: (2-4): (2.5-5). Further preferably, the mass ratio of the hydrolyzed silane is m1 (silane): m2 (water): m3 (anhydrous ethanol) = 1: (2-3): (2.5-5).

[0016] The present invention also discloses a method for preparing UHPC based on hydrolyzed silane, comprising the following steps:

[0017] Preparation of hydrolyzed silane: adding silane, water and anhydrous ethanol according to the mass ratio, mixing evenly and standing for hydrolysis to obtain a hydrolyzed silane solution;

[0018] Adding the prepared hydrolyzed silane solution according to the mass ratio of the silane to the silica fume, and mixing with UHPC to prepare a silane-modified UHPC mixture;

[0019] The prepared silane-modified UHPC mixture is molded, cured, demoulded, and steamed to obtain the silane-modified UHPC.

[0020] In a preferred embodiment of the present invention, the hydrolyzed silane solution is allowed to stand for hydrolysis for ≥ 2 h.

[0021] In a preferred embodiment of the present invention, the method for preparing the silane-modified UHPC mixture comprises the following steps:

[0022] Firstly, the dry powder material and the steel fiber are mixed and dry-mixed, and then the prepared hydrolyzed silane solution, admixture and water are added and stirred evenly to form a silane-modified UHPC mixture.

[0023] In a preferred embodiment of the present invention, the dry powder and steel fiber are mixed and dry-mixed for a time of 0.5 min to 20 min.

[0024] In a preferred embodiment of the present invention, the method for preparing the silane-modified UHPC mixture comprises the following steps:

[0025] First, the prepared hydrolyzed silane solution, silica fume and water are stirred evenly, and then the admixture, all dry powder materials except silica fume and steel fiber are added and stirred evenly to form a silane-modified UHPC mixture.

[0026] The viscosity of UHPC is mainly related to the dispersion of silica fume. In the present invention, hydrolyzed silane can be mixed with silica fume first, and then low-viscosity UHPC can be prepared.

[0027] The hydrolyzed silane solution prepared by the method of the present application can not only be added after the dry powder and steel fiber are mixed and dry-mixed, but also the hydrolyzed silane solution, silica ash and water can be first stirred evenly together, and then the admixture, all the dry powder except silica ash and steel fiber are added, which can achieve the effect of greatly improving fluidity and rheology, and is easy to operate, simple in process, energy-saving and low in cost.

[0028] In a preferred embodiment of the present invention, the prepared hydrolyzed silane solution, silica fume and water are mixed and stirred for 0.5 min to 20 min.

[0029] In a preferred embodiment of the present invention, the mass ratio of cement, silica fume, quartz sand, and powder A (a kind of quartz powder and mineral powder) in step (1) is 1:0.3-05:0.9-1.1:0.15-0.35, the water-cement ratio is 0.1-0.3, the mass ratio of the solid content of the water reducer to the cementitious material is 1.0-2.0%, and the steel fiber content (volume content) is 1.5-2.5%.

[0030] Compared with the prior art, the present invention has the following beneficial effects: the preparation method of the silane-modified low-viscosity UHPC of the present invention specifically relates to the preparation of hydrolyzed silane, the dosage and the mixing order of the hydrolyzed silane with the components in the UHPC. The method hydrolyzes silane at room temperature, and then mixes the hydrolyzed silane with silica fume or directly with the UHPC mixture to obtain a low-viscosity UHPC. The method greatly reduces the viscosity of the UHPC slurry and improves its construction performance. This is because silane is hydrolyzed to generate silanol, and the silanol in the silanol reacts with the hydroxyl group on the surface of the cementitious material to form chemical adsorption, thereby improving the dispersibility of the cementitious material and reducing the viscosity of the fresh slurry. On the other hand, the amino functional group in the aminosilane is positively charged, which can greatly increase the surface potential of the silica fume particles, increase the adsorption amount of the silica fume on the water reducer (negatively charged), improve its dispersibility, reduce the viscosity of the slurry, and improve the fluidity. The method for preparing low-viscosity UHPC is simple and low-cost, easy to implement in actual production, and thus has broad application prospects. DETAILED DESCRIPTION

[0031] The present invention is further described below in conjunction with examples. The following description is only exemplary and does not limit its content.

[0032] Comparative Example 1

[0033] The present invention provides a method for preparing low-viscosity UHPC by first mixing hydrolyzed silane with silica fume, which specifically comprises:

[0034] (1) Prepare raw materials: including water, cement, mineral powder, silica fume, quartz sand, steel fiber, water reducer, defoamer and γ-aminopropyltriethoxysilane (KH550), and weigh the raw materials according to the required proportion;

[0035] (2) Preparation of hydrolyzed silane: silane and deionized water are uniformly mixed to form a hydrolyzed silane solution;

[0036] (3) Preparation of silane-modified UHPC: First, hydrolyzed silane, silica fume and water were poured into a mixer and stirred for 5 min. Then, a water reducer was added and stirred for 2 min. Then, cement, quartz sand and mineral powder were added and stirred for 3 min to obtain a homogeneous slurry. Then, steel fiber was added and stirred for another 3 min to form a modified UHPC mixture.

[0037] (4) The UHPC mixture prepared in step (3) is molded, demolded after standard curing for 72 hours, and placed in a high-temperature steam environment at 90° C. for steam curing for 48 hours to obtain the silane-modified UHPC.

[0038] The mixing water in step (1) is city tap water; the cement is ordinary Portland cement with a P·O 52.5 and a specific surface area of ​​0.445 m 2 / g; the mineral powder is S95 premium product; the silica ash is light grey in appearance, the main component is SiO2, and the specific surface area is 21.8m 2 / g; the quartz sand particle size is 26-40 mesh (0.7mm-0.425mm) refined quartz sand; the steel fiber is copper-plated straight steel fiber, with a length of 13mm and a diameter of 0.20mm; the water reducer is a CM6 polycarboxylic acid high-performance water reducer produced by a certain company, with a light yellow viscous liquid appearance, a solid content of 40%, and a water reduction rate of 30%; the KH550 is alkaline, with an appearance of colorless transparent liquid and a density of 0.946g / cm 3 , molecular weight 221.4, content ≥97%;

[0039] The mass ratio of cement, silica fume, quartz sand and mineral powder in step (1) is 1:0.42:1:0.27, the water-cement ratio is 0.17 (the water consumption includes the water consumption for hydrolyzing silane), the water reducing agent dosage is 1.7% (the mass ratio of the solid content of the water reducing agent to the cementitious material), and the steel fiber dosage (volume dosage) is 2%;

[0040] The silane content in step (2) is 1% of the mass of the silicon ash in step (1), and the mixing ratio (mass ratio) of hydrolyzed silane is m1 (KH550): m2 (deionized water) = 1:3;

[0041] In step (2), the components are mixed according to the mixing ratio, stirred with a glass rod for 3 minutes, and then allowed to stand for more than 2 hours (hydrolysis for 2 hours) to obtain a hydrolyzed silane solution;

[0042] In step (4), the curing temperature is 20°C ± 2°C, and the relative humidity is > 95%.

[0043] Comparative Example 2

[0044] The present invention provides a method for preparing low-viscosity UHPC by first mixing hydrolyzed silane with silica fume, which specifically comprises:

[0045] (1) Prepare raw materials: including water, cement, mineral powder, silica fume, quartz sand, steel fiber, water reducer, defoamer and γ-aminopropyltriethoxysilane (KH550), and weigh the raw materials according to the required proportion;

[0046] (2) Preparation of hydrolyzed silane: silane and deionized water are uniformly mixed to form a hydrolyzed silane solution;

[0047] (3) Preparation of silane-modified UHPC: first, hydrolyzed silane, silica fume and water were poured into a mixer and stirred for 5 min. Then, a water reducer was added and stirred for 2 min. Then, cement, quartz sand and mineral powder were added and stirred for 3 min to obtain a homogeneous slurry. Then, steel fiber was added and stirred for another 3 min to form a modified UHPC mixture.

[0048] (4) The UHPC mixture prepared in step (3) is molded, demolded after standard curing for 72 hours, and placed in a high-temperature steam environment at 90° C. for steam curing for 48 hours to obtain the silane-modified UHPC.

[0049] The mixing water in step (1) is city tap water; the cement is ordinary Portland cement with a P·O 52.5 and a specific surface area of ​​0.445 m 2 / g; the mineral powder is S95 premium product; the silica ash is light grey in appearance, the main component is SiO2, and the specific surface area is 21.8m 2 / g; the quartz sand particle size is 26-40 mesh (0.7mm-0.425mm) refined quartz sand; the steel fiber is copper-plated straight steel fiber, with a length of 13mm and a diameter of 0.20mm; the water reducer is a CM6 polycarboxylic acid high-performance water reducer produced by a certain company, with a light yellow viscous liquid appearance, a solid content of 40%, and a water reduction rate of 30%; the KH550 is alkaline, with an appearance of colorless transparent liquid and a density of 0.946g / cm 3 , molecular weight 221.4, content ≥97%;

[0050] The mass ratio of cement, silica fume, quartz sand and mineral powder in step (1) is 1:0.42:1:0.27, the water-cement ratio is 0.17 (the water consumption includes the water consumption for hydrolyzing silane), the water reducing agent dosage is 1.7% (the mass ratio of the solid content of the water reducing agent to the cementitious material), and the steel fiber dosage (volume dosage) is 2%;

[0051] The silane content in step (2) is 3% of the mass of the silicon ash in step (1), and the mixing ratio (mass ratio) of hydrolyzed silane is m1 (KH550): m2 (deionized water) = 3:9;

[0052] In step (2), the components are mixed according to the mixing ratio, stirred with a glass rod for 3 minutes, and then allowed to stand for more than 2 hours (hydrolysis for 2 hours) to obtain a hydrolyzed silane solution;

[0053] In step (4), the curing temperature is 20°C ± 2°C, and the relative humidity is > 95%.

[0054] Comparative Example 3

[0055] The present invention provides a method for preparing low-viscosity UHPC by first mixing hydrolyzed silane with silica fume, which specifically comprises:

[0056] (1) Prepare raw materials: including water, cement, mineral powder, silica fume, quartz sand, steel fiber, water reducer, defoamer, γ-aminopropyltriethoxysilane (KH550) and anhydrous ethanol, and weigh the raw materials according to the required proportion;

[0057] (2) Preparation of hydrolyzed silane: silane and anhydrous ethanol are uniformly mixed to form a hydrolyzed silane solution;

[0058] (3) Preparation of silane-modified UHPC: first, hydrolyzed silane, silica fume and water were poured into a mixer and stirred for 5 min. Then, a water reducer was added and stirred for 2 min. Then, cement, quartz sand and mineral powder were added and stirred for 3 min to obtain a homogeneous slurry. Then, steel fiber was added and stirred for another 3 min to form a modified UHPC mixture.

[0059] (4) The UHPC mixture prepared in step (3) is molded, demolded after standard curing for 72 hours, and placed in a high-temperature steam environment at 90° C. for steam curing for 48 hours to obtain the silane-modified UHPC.

[0060] The mixing water in step (1) is city tap water; the cement is ordinary Portland cement with a P·O 52.5 and a specific surface area of ​​0.445 m 2 / g; the mineral powder is S95 premium product; the silica ash is light grey in appearance, the main component is SiO2, and the specific surface area is 21.8m 2 / g; the quartz sand particle size is 26-40 mesh (0.7mm-0.425mm) refined quartz sand; the steel fiber is copper-plated straight steel fiber, with a length of 13mm and a diameter of 0.20mm; the water reducer is a CM6 polycarboxylic acid high-performance water reducer produced by a certain company, with a light yellow viscous liquid appearance, a solid content of 40%, and a water reduction rate of 30%; the KH550 is alkaline, with an appearance of colorless transparent liquid and a density of 0.946g / cm 3 , molecular weight 221.4, content ≥97%; anhydrous ethanol is a colorless liquid, density: 0.79g / cm 3 , molecular weight 46.07, ethanol content ≥ 99.7%, water content ≤ 0.3%;

[0061] The mass ratio of cement, silica fume, quartz sand and mineral powder in step (1) is 1:0.42:1:0.27, the water-cement ratio is 0.17 (the water consumption includes the water consumption for hydrolyzing silane), the water reducing agent dosage is 1.7% (the mass ratio of the solid content of the water reducing agent to the cementitious material), and the steel fiber dosage (volume dosage) is 2%;

[0062] The silane content in step (2) is 1% of the mass of the silicon ash in step (1), and the mixing ratio (mass ratio) of hydrolyzed silane is m1 (KH550): m3 (anhydrous ethanol) = 1:5;

[0063] In step (2), the components are mixed according to the mixing ratio, stirred with a glass rod for 3 minutes, and then allowed to stand for more than 2 hours (hydrolysis for 2 hours) to obtain a hydrolyzed silane solution;

[0064] In step (4), the curing temperature is 20°C ± 2°C, and the relative humidity is > 95%.

[0065] Example 1

[0066] The present invention provides a method for preparing low-viscosity UHPC by first mixing hydrolyzed silane with silica fume, which specifically comprises:

[0067] (1) Prepare raw materials: including water, cement, mineral powder, silica fume, quartz sand, steel fiber, water reducer, defoamer, γ-aminopropyltriethoxysilane (KH550) and anhydrous ethanol, and weigh the raw materials according to the required proportion;

[0068] (2) Preparation of hydrolyzed silane: silane, deionized water and anhydrous ethanol are uniformly mixed to form a hydrolyzed silane solution;

[0069] (3) Preparation of silane-modified UHPC: first, hydrolyzed silane, silica fume and water were poured into a mixer and stirred for 5 min. Then, a water reducer was added and stirred for 2 min. Then, cement, quartz sand and mineral powder were added and stirred for 3 min to obtain a homogeneous slurry. Then, steel fiber was added and stirred for another 3 min to form a modified UHPC mixture.

[0070] (4) The UHPC mixture prepared in step (3) is molded, demolded after standard curing for 72 hours, and placed in a high-temperature steam environment at 90° C. for steam curing for 48 hours to obtain the silane-modified UHPC.

[0071] The mixing water in step (1) is city tap water; the cement is ordinary Portland cement with a P·O 52.5 and a specific surface area of ​​0.445 m 2 / g; the mineral powder is S95 premium product; the silica ash is light grey in appearance, the main component is SiO2, and the specific surface area is 21.8m 2 / g; the quartz sand particle size is 26-40 mesh (0.7mm-0.425mm) refined quartz sand; the steel fiber is copper-plated straight steel fiber, with a length of 13mm and a diameter of 0.20mm; the water reducer is a CM6 polycarboxylic acid high-performance water reducer produced by a certain company, with a light yellow viscous liquid appearance, a solid content of 40%, and a water reduction rate of 30%; the KH550 is alkaline, with an appearance of colorless transparent liquid and a density of 0.946g / cm 3 , molecular weight 221.4, content ≥97%; anhydrous ethanol is a colorless liquid, density: 0.79g / cm 3 , molecular weight 46.07, ethanol content ≥ 99.7%, water content ≤ 0.3%;

[0072] The mass ratio of cement, silica fume, quartz sand and mineral powder in step (1) is 1:0.42:1:0.27, the water-cement ratio is 0.17 (the water consumption includes the water consumption for hydrolyzing silane), the water reducing agent dosage is 1.7% (the mass ratio of the solid content of the water reducing agent to the cementitious material), and the steel fiber dosage (volume dosage) is 2%;

[0073] The silane content in step (2) is 1% of the mass of the silicon ash in step (1), and the mixing ratio (mass ratio) of hydrolyzed silane is m1 (KH550): m2 (deionized water): m3 (anhydrous ethanol) = 1:3:2.5;

[0074] In step (2), the components are mixed according to the mixing ratio, stirred with a glass rod for 3 minutes, and then allowed to stand for more than 2 hours (hydrolysis for 2 hours) to obtain a hydrolyzed silane solution;

[0075] In step (4), the curing temperature is 20°C ± 2°C, and the relative humidity is > 95%.

[0076] Example 2

[0077] The present invention provides a method for preparing low-viscosity UHPC by first mixing hydrolyzed silane with silica fume, which specifically comprises:

[0078] (1) Prepare raw materials: including water, cement, mineral powder, silica fume, quartz sand, steel fiber, water reducer, defoamer, γ-aminopropyltriethoxysilane (KH550) and anhydrous ethanol, and weigh the raw materials according to the required proportion;

[0079] (2) Preparation of hydrolyzed silane: silane, deionized water and anhydrous ethanol are uniformly mixed to form a hydrolyzed silane solution;

[0080] (3) Preparation of silane-modified UHPC: first, hydrolyzed silane, silica fume and water were poured into a mixer and stirred for 5 min. Then, a water reducer was added and stirred for 2 min. Then, cement, quartz sand and mineral powder were added and stirred for 3 min to obtain a homogeneous slurry. Then, steel fiber was added and stirred for another 3 min to form a modified UHPC mixture.

[0081] (4) The UHPC mixture prepared in step (3) is molded, demolded after standard curing for 72 hours, and placed in a high-temperature steam environment at 90° C. for steam curing for 48 hours to obtain the silane-modified UHPC.

[0082] The mixing water in step (1) is city tap water; the cement is ordinary Portland cement with a P·O 52.5 and a specific surface area of ​​0.445 m 2 / g; the mineral powder is S95 premium product; the silica ash is light grey in appearance, the main component is SiO2, and the specific surface area is 21.8m 2 / g; the quartz sand particle size is 26-40 mesh (0.7mm-0.425mm) refined quartz sand; the steel fiber is copper-plated straight steel fiber, with a length of 13mm and a diameter of 0.20mm; the water reducer is a CM6 polycarboxylic acid high-performance water reducer produced by a certain company, with a light yellow viscous liquid appearance, a solid content of 40%, and a water reduction rate of 30%; the KH550 is alkaline, with an appearance of colorless transparent liquid and a density of 0.946g / cm 3 , molecular weight 221.4, content ≥97%; anhydrous ethanol is a colorless liquid, density: 0.79g / cm 3 , molecular weight 46.07, ethanol content ≥ 99.7%, water content ≤ 0.3%;

[0083] The mass ratio of cement, silica fume, quartz sand and mineral powder in step (1) is 1:0.42:1:0.27, the water-cement ratio is 0.17 (the water consumption includes the water consumption for hydrolyzing silane), the water reducing agent dosage is 1.7% (the mass ratio of the solid content of the water reducing agent to the cementitious material), and the steel fiber dosage (volume dosage) is 2%;

[0084] The silane content in step (2) is 1% of the mass of the silicon ash in step (1), and the mixing ratio (mass ratio) of hydrolyzed silane is m1 (KH550): m2 (deionized water): m3 (anhydrous ethanol) = 1:3:5;

[0085] In step (2), the components are mixed according to the mixing ratio, stirred with a glass rod for 3 minutes, and then allowed to stand for more than 2 hours (hydrolysis for 2 hours) to obtain a hydrolyzed silane solution;

[0086] In step (4), the curing temperature is 20°C ± 2°C, and the relative humidity is > 95%.

[0087] Comparative Example 4

[0088] The present invention provides a method for preparing low-viscosity UHPC by first mixing hydrolyzed silane with silica fume, which specifically comprises:

[0089] (1) Prepare raw materials: including water, cement, mineral powder, silica fume, quartz sand, steel fiber, water reducer, defoamer, γ-aminopropyltriethoxysilane (KH550) and anhydrous ethanol, and weigh the raw materials according to the required proportion;

[0090] (2) Preparation of hydrolyzed silane: silane, deionized water and anhydrous ethanol are uniformly mixed to form a hydrolyzed silane solution;

[0091] (3) Preparation of silane-modified UHPC: first, hydrolyzed silane, silica fume and water were poured into a mixer and stirred for 5 min. Then, a water reducer was added and stirred for 2 min. Then, cement, quartz sand and mineral powder were added and stirred for 3 min to obtain a homogeneous slurry. Then, steel fiber was added and stirred for another 3 min to form a modified UHPC mixture.

[0092] (4) The UHPC mixture prepared in step (3) is molded, demolded after standard curing for 72 hours, and placed in a high-temperature steam environment at 90° C. for steam curing for 48 hours to obtain the silane-modified UHPC.

[0093] The mixing water in step (1) is city tap water; the cement is ordinary Portland cement with a P·O 52.5 and a specific surface area of ​​0.445 m 2 / g; the mineral powder is S95 premium product; the silica ash is light grey in appearance, the main component is SiO2, and the specific surface area is 21.8m 2 / g; the quartz sand particle size is 26-40 mesh (0.7mm-0.425mm) refined quartz sand; the steel fiber is copper-plated straight steel fiber, with a length of 13mm and a diameter of 0.20mm; the water reducer is a CM6 polycarboxylic acid high-performance water reducer produced by a certain company, with a light yellow viscous liquid appearance, a solid content of 40%, and a water reduction rate of 30%; the KH550 is alkaline, with an appearance of colorless transparent liquid and a density of 0.946g / cm 3 , molecular weight 221.4, content ≥97%; anhydrous ethanol is a colorless liquid, density: 0.79g / cm 3 , molecular weight 46.07, ethanol content ≥ 99.7%, water content ≤ 0.3%;

[0094] The mass ratio of cement, silica fume, quartz sand and mineral powder in step (1) is 1:0.42:1:0.27, the water-cement ratio is 0.17 (the water consumption includes the water consumption for hydrolyzing silane), the water reducing agent dosage is 1.7% (the mass ratio of the solid content of the water reducing agent to the cementitious material), and the steel fiber dosage (volume dosage) is 2%;

[0095] The silane content in step (2) is 3% of the mass of the silicon ash in step (1), and the mixing ratio (mass ratio) of hydrolyzed silane is m1 (KH550): m2 (deionized water): m3 (anhydrous ethanol) = 3:9:15;

[0096] In step (2), the components are mixed according to the mixing ratio, stirred with a glass rod for 3 minutes, and then allowed to stand for more than 2 hours (hydrolysis for 2 hours) to obtain a hydrolyzed silane solution;

[0097] In step (4), the curing temperature is 20°C ± 2°C, and the relative humidity is > 95%.

[0098] Example 3

[0099] The present invention provides a method for preparing low-viscosity UHPC by first mixing hydrolyzed silane with silica fume, which specifically comprises:

[0100] (1) Prepare raw materials: including water, cement, mineral powder, silica fume, quartz sand, steel fiber, water reducer, defoamer, γ-aminopropyltriethoxysilane (KH550) and anhydrous ethanol, and weigh the raw materials according to the required proportion;

[0101] (2) Preparation of hydrolyzed silane: silane, tap water and anhydrous ethanol are uniformly mixed to form a hydrolyzed silane solution;

[0102] (3) Preparation of silane-modified UHPC: first, hydrolyzed silane, silica fume and water were poured into a mixer and stirred for 5 min. Then, a water reducer was added and stirred for 2 min. Then, cement, quartz sand and mineral powder were added and stirred for 3 min to obtain a homogeneous slurry. Then, steel fiber was added and stirred for another 3 min to form a modified UHPC mixture.

[0103] (4) The UHPC mixture prepared in step (3) is molded, demolded after standard curing for 72 hours, and placed in a high-temperature steam environment at 90° C. for steam curing for 48 hours to obtain the silane-modified UHPC.

[0104] The mixing water in step (1) is city tap water; the cement is ordinary Portland cement with a P·O 52.5 and a specific surface area of ​​0.445 m 2 / g; the mineral powder is S95 premium product; the silica ash is light grey in appearance, the main component is SiO2, and the specific surface area is 21.8m 2 / g; the quartz sand particle size is 26-40 mesh (0.7mm-0.425mm) refined quartz sand; the steel fiber is copper-plated straight steel fiber, with a length of 13mm and a diameter of 0.20mm; the water reducer is a CM6 polycarboxylic acid high-performance water reducer produced by a certain company, with a light yellow viscous liquid appearance, a solid content of 40%, and a water reduction rate of 30%; the KH550 is alkaline, with an appearance of colorless transparent liquid and a density of 0.946g / cm 3, molecular weight 221.4, content ≥97%; anhydrous ethanol is a colorless liquid, density: 0.79g / cm 3 , molecular weight 46.07, ethanol content ≥ 99.7%, water content ≤ 0.3%;

[0105] The mass ratio of cement, silica fume, quartz sand and mineral powder in step (1) is 1:0.42:1:0.27, the water-cement ratio is 0.17 (the water consumption includes the water consumption for hydrolyzing silane), the water reducing agent dosage is 1.7% (the mass ratio of the solid content of the water reducing agent to the cementitious material), and the steel fiber dosage (volume dosage) is 2%;

[0106] The silane content in step (2) is 1% of the mass of the silicon ash in step (1), and the mixing ratio (mass ratio) of hydrolyzed silane is m1 (KH550): m2 (tap water): m3 (anhydrous ethanol) = 1:3:2.5;

[0107] In step (2), the components are mixed according to the mixing ratio, stirred with a glass rod for 3 minutes, and then allowed to stand for more than 2 hours (hydrolysis for 2 hours) to obtain a hydrolyzed silane solution;

[0108] In step (4), the curing temperature is 20°C ± 2°C, and the relative humidity is > 95%.

[0109] Example 4

[0110] The present invention provides a method for preparing low-viscosity UHPC by first mixing hydrolyzed silane with silica fume, which specifically comprises:

[0111] (1) Prepare raw materials: including water, cement, mineral powder, silica fume, quartz sand, steel fiber, water reducer, defoamer, γ-aminopropyltriethoxysilane (KH550) and anhydrous ethanol, and weigh the raw materials according to the required proportion;

[0112] (2) Preparation of hydrolyzed silane: silane, tap water and anhydrous ethanol are uniformly mixed to form a hydrolyzed silane solution;

[0113] (3) Preparation of silane-modified UHPC: first, hydrolyzed silane, silica fume and water were poured into a mixer and stirred for 5 min. Then, a water reducer was added and stirred for 2 min. Then, cement, quartz sand and mineral powder were added and stirred for 3 min to obtain a homogeneous slurry. Then, steel fiber was added and stirred for another 3 min to form a modified UHPC mixture.

[0114] (4) The UHPC mixture prepared in step (3) is molded, demolded after standard curing for 72 hours, and placed in a high-temperature steam environment at 90° C. for steam curing for 48 hours to obtain the silane-modified UHPC.

[0115] The mixing water in step (1) is city tap water; the cement is ordinary Portland cement with a P·O 52.5 and a specific surface area of ​​0.445 m2 / g; the mineral powder is S95 premium product; the silica ash is light grey in appearance, the main component is SiO2, and the specific surface area is 21.8m 2 / g; the quartz sand particle size is 26-40 mesh (0.7mm-0.425mm) refined quartz sand; the steel fiber is copper-plated straight steel fiber, with a length of 13mm and a diameter of 0.20mm; the water reducer is a CM6 polycarboxylic acid high-performance water reducer produced by a certain company, with a light yellow viscous liquid appearance, a solid content of 40%, and a water reduction rate of 30%; the KH550 is alkaline, with an appearance of colorless transparent liquid and a density of 0.946g / cm 3 , molecular weight 221.4, content ≥97%; anhydrous ethanol is a colorless liquid, density: 0.79g / cm 3 , molecular weight 46.07, ethanol content ≥ 99.7%, water content ≤ 0.3%;

[0116] The mass ratio of cement, silica fume, quartz sand and mineral powder in step (1) is 1:0.42:1:0.27, the water-cement ratio is 0.17 (the water consumption includes the water consumption for hydrolyzing silane), the water reducing agent dosage is 1.7% (the mass ratio of the solid content of the water reducing agent to the cementitious material), and the steel fiber dosage (volume dosage) is 2%;

[0117] The silane content in step (2) is 1% of the mass of the silicon ash in step (1), and the mixing ratio (mass ratio) of hydrolyzed silane is m1 (KH550): m2 (tap water): m3 (anhydrous ethanol) = 1:3:5;

[0118] In step (2), the components are mixed according to the mixing ratio, stirred with a glass rod for 3 minutes, and then allowed to stand for more than 2 hours (hydrolysis for 2 hours) to obtain a hydrolyzed silane solution;

[0119] In step (4), the curing temperature is 20°C ± 2°C, and the relative humidity is > 95%.

[0120] Comparative Example 5

[0121] A method for preparing UHPC, specifically comprising:

[0122] (1) Prepare raw materials: including water, cement, mineral powder, silica fume, quartz sand, steel fiber, water reducer and defoamer, and weigh the raw materials according to the required proportion;

[0123] (2) Preparation of UHPC: Dissolve the water reducer in water; pour it into a mixer together with silica fume and stir for 5 minutes; then add cement, quartz sand, and mineral powder and stir for 3 minutes to obtain a homogeneous slurry; add steel fiber and stir for another 3 minutes to form a UHPC mixture;

[0124] (3) The UHPC mixture prepared in step (2) is molded, demolded after standard curing for 72 hours, and placed in a high-temperature steam environment at 90° C. for steam curing for 48 hours to obtain the UHPC.

[0125] The mixing water in step (1) is city tap water; the cement is ordinary Portland cement with a P·O 52.5 and a specific surface area of ​​0.445 m 2 / g; the mineral powder is S95 premium product; the silica ash is light grey in appearance, the main component is SiO2, and the specific surface area is 21.8m 2 / g; the quartz sand particle size is 26-40 mesh (0.7mm-0.425mm) refined quartz sand; the steel fiber is copper-plated straight steel fiber, with a length of 13mm and a diameter of 0.20mm; the water reducer is a CM6 polycarboxylic acid high-performance water reducer produced by a certain company, with a light yellow viscous liquid appearance, a solid content of 40%, and a water reduction rate of 30%;

[0126] The mass ratio of cement, silica fume, quartz sand and mineral powder in step (1) is 1:0.42:1:0.27, the water-cement ratio is 0.17 (the water consumption includes the water consumption for hydrolyzing silane), the water reducing agent dosage is 1.7% (the mass ratio of the solid content of the water reducing agent to the cementitious material), and the steel fiber dosage (volume dosage) is 2%;

[0127] In step (3), the curing temperature is 20°C ± 2°C and the relative humidity is > 95%.

[0128] Example 5

[0129] The present invention provides a method for preparing low-viscosity UHPC by directly mixing hydrolyzed silane with a UHPC mixture, which specifically comprises:

[0130] (1) Prepare raw materials: including water, cement, mineral powder, silica fume, quartz sand, steel fiber, water reducer, defoamer, γ-aminopropyltriethoxysilane (KH550) and anhydrous ethanol, and weigh the raw materials according to the required proportion;

[0131] (2) Preparation of hydrolyzed silane: silane, tap water and anhydrous ethanol are uniformly mixed to form a hydrolyzed silane solution;

[0132] (3) Preparation of silane-modified UHPC: Cement, silica fume, mineral powder and quartz sand were first mixed and dry-mixed for 2 min; hydrolyzed silane, water reducer and water were then added to the dry mix and stirred for 6 min to obtain a homogeneous slurry; steel fiber was added and stirred for another 3 min to form a modified UHPC mixture;

[0133] (4) The UHPC mixture prepared in step (3) is molded, demolded after standard curing for 72 hours, and placed in a high-temperature steam environment at 90° C. for steam curing for 48 hours to obtain the silane-modified UHPC.

[0134] The mixing water in step (1) is city tap water; the cement is ordinary Portland cement with a P·O 52.5 and a specific surface area of ​​0.445 m 2 / g; the mineral powder is S95 premium product; the silica ash is light grey in appearance, the main component is SiO2, and the specific surface area is 21.8m 2 / g; the quartz sand particle size is 26-40 mesh (0.7mm-0.425mm) refined quartz sand; the steel fiber is copper-plated straight steel fiber, with a length of 13mm and a diameter of 0.20mm; the water reducer is a CM6 polycarboxylic acid high-performance water reducer produced by a certain company, with a light yellow viscous liquid appearance, a solid content of 40%, and a water reduction rate of 30%; the KH550 is alkaline, with an appearance of colorless transparent liquid and a density of 0.946g / cm 3 , molecular weight 221.4, content ≥97%; anhydrous ethanol is a colorless liquid, density: 0.79g / cm 3 , molecular weight 46.07, ethanol content ≥ 99.7%, water content ≤ 0.3%;

[0135] The mass ratio of cement, silica fume, quartz sand and mineral powder in step (1) is 1:0.42:1:0.27, the water-cement ratio is 0.17 (the water consumption includes the water consumption for hydrolyzing silane), the water reducing agent dosage is 1.7% (the mass ratio of the solid content of the water reducing agent to the cementitious material), and the steel fiber dosage (volume dosage) is 2%;

[0136] The silane content in step (2) is 1% of the mass of the silicon ash in step (1), and the mixing ratio (mass ratio) of hydrolyzed silane is m1 (KH550): m2 (tap water): m3 (anhydrous ethanol) = 1:3:2.5;

[0137] In step (2), the components are mixed according to the mixing ratio, stirred with a glass rod for 3 minutes, and then allowed to stand for more than 2 hours (hydrolysis for 2 hours) to obtain a hydrolyzed silane solution;

[0138] In step (4), the curing temperature is 20°C ± 2°C, and the relative humidity is > 95%.

[0139] Example 6

[0140] The present invention provides a method for preparing low-viscosity UHPC by directly mixing hydrolyzed silane with a UHPC mixture, which specifically comprises:

[0141] (1) Prepare raw materials: including water, cement, mineral powder, silica fume, quartz sand, steel fiber, water reducer, defoamer, γ-aminopropyltriethoxysilane (KH550) and anhydrous ethanol, and weigh the raw materials according to the required proportion;

[0142] (2) Preparation of hydrolyzed silane: silane, tap water and anhydrous ethanol are uniformly mixed to form a hydrolyzed silane solution;

[0143] (3) Preparation of silane-modified UHPC: Cement, silica fume, mineral powder and quartz sand were first mixed and dry-mixed for 2 min; hydrolyzed silane, water reducer and water were then added to the dry mix and stirred for 6 min to obtain a homogeneous slurry; steel fiber was added and stirred for another 3 min to form a modified UHPC mixture;

[0144] (4) The UHPC mixture prepared in step (3) is molded, demolded after standard curing for 72 hours, and placed in a high-temperature steam environment at 90° C. for steam curing for 48 hours to obtain the silane-modified UHPC.

[0145] The mixing water in step (1) is city tap water; the cement is ordinary Portland cement with a P·O 52.5 and a specific surface area of ​​0.445 m 2 / g; the mineral powder is S95 premium product; the silica ash is light grey in appearance, the main component is SiO2, and the specific surface area is 21.8m 2 / g; the quartz sand particle size is 26-40 mesh (0.7mm-0.425mm) refined quartz sand; the steel fiber is copper-plated straight steel fiber, with a length of 13mm and a diameter of 0.20mm; the water reducer is a CM6 polycarboxylic acid high-performance water reducer produced by a certain company, with a light yellow viscous liquid appearance, a solid content of 40%, and a water reduction rate of 30%; the KH550 is alkaline, with an appearance of colorless transparent liquid and a density of 0.946g / cm 3 , molecular weight 221.4, content ≥97%; anhydrous ethanol is a colorless liquid, density: 0.79g / cm 3 , molecular weight 46.07, ethanol content ≥ 99.7%, water content ≤ 0.3%;

[0146] The mass ratio of cement, silica fume, quartz sand and mineral powder in step (1) is 1:0.42:1:0.27, the water-cement ratio is 0.17 (the water consumption includes the water consumption for hydrolyzing silane), the water reducing agent dosage is 1.7% (the mass ratio of the solid content of the water reducing agent to the cementitious material), and the steel fiber dosage (volume dosage) is 2%;

[0147] The silane content in step (2) is 1% of the mass of the silicon ash in step (1), and the mixing ratio (mass ratio) of hydrolyzed silane is m1 (KH550): m2 (tap water): m3 (anhydrous ethanol) = 1:3:5;

[0148] In step (2), the components are mixed according to the mixing ratio, stirred with a glass rod for 3 minutes, and then allowed to stand for more than 2 hours (hydrolysis for 2 hours) to obtain a hydrolyzed silane solution;

[0149] In step (4), the curing temperature is 20°C ± 2°C, and the relative humidity is > 95%.

[0150] Comparative Example 6

[0151] A method for preparing UHPC, specifically comprising:

[0152] (1) Prepare raw materials: including water, cement, mineral powder, silica fume, quartz sand, steel fiber, water reducer and defoamer, and weigh the raw materials according to the required proportion;

[0153] (2) Preparation of UHPC: First, cement, silica fume, mineral powder, and quartz sand were mixed and dry-mixed for 2 minutes; then, water reducer and water were added to the dry mix and stirred for 6 minutes to obtain a homogeneous slurry; steel fiber was added and stirred for another 3 minutes to form a UHPC mixture;

[0154] (3) The UHPC mixture prepared in step (2) is molded, demolded after standard curing for 72 hours, and placed in a high-temperature steam environment at 90° C. for steam curing for 48 hours to obtain the UHPC.

[0155] The mixing water in step (1) is city tap water; the cement is ordinary Portland cement with a P·O 52.5 and a specific surface area of ​​0.445 m 2 / g; the mineral powder is S95 premium product; the silica ash is light grey in appearance, the main component is SiO2, and the specific surface area is 21.8m 2 / g; the quartz sand particle size is 26-40 mesh (0.7mm-0.425mm) refined quartz sand; the steel fiber is copper-plated straight steel fiber, with a length of 13mm and a diameter of 0.20mm; the water reducer is a CM6 polycarboxylic acid high-performance water reducer produced by a certain company, with a light yellow viscous liquid appearance, a solid content of 40%, and a water reduction rate of 30%;

[0156] The mass ratio of cement, silica fume, quartz sand and mineral powder in step (1) is 1:0.42:1:0.27, the water-cement ratio is 0.17 (the water consumption includes the water consumption for hydrolyzing silane), the water reducing agent dosage is 1.7% (the mass ratio of the solid content of the water reducing agent to the cementitious material), and the steel fiber dosage (volume dosage) is 2%;

[0157] In step (3), the curing temperature is 20°C ± 2°C and the relative humidity is > 95%.

[0158] Table 1 Ratios and preparation methods of silane, silane and anhydrous ethanol in various embodiments and comparative examples

[0159]

[0160] Performance Testing

[0161] The expansion degree of each embodiment and comparative example was measured according to the "Standard for Test Methods for Performance of Ordinary Concrete Mixtures" (GB / T 50080-2016).

[0162] The rheological parameters of the freshly mixed UHPC slurry of each embodiment and comparative example were measured using a concrete rheometer from Tianjin Gangyuan Testing Instrument Factory. Since the addition of fibers may cause instrument failure, the rheological parameters were only measured for the freshly mixed UHPC slurry without fibers.

[0163] The compressive and flexural strengths of each embodiment and comparative example were measured according to the Standard for Test Methods for Physical and Mechanical Properties of Concrete (GB / T 50081-2019). Three specimens were tested in each group, and the results were averaged from the three test values.

[0164] Table 2 Performance of UHPC prepared in various embodiments and comparative examples

[0165]

[0166] Examples 1 to 4 and Comparative Examples 1 to 5 use the same mixing order, wherein Comparative Examples 1 and 2 are silane hydrolyzed only in deionized water, Comparative Example 3 is silane hydrolyzed only in anhydrous ethanol, Example 1, Example 2, and Comparative Example 4 are silane hydrolyzed in a mixed solvent of deionized water and anhydrous ethanol, Examples 3 and 4 are silane hydrolyzed in tap water and anhydrous ethanol, and no hydrolyzed silane is added in Comparative Example 5. Examples 5 and 6 and Comparative Example 6 use the same mixing order, wherein Examples 5 and 6 are silane hydrolyzed in tap water and anhydrous ethanol.

[0167] As can be seen from Table 1, 1) the unmodified UHPC (Comparative Example 5) prepared by mixing silica fume with a water reducer and water has an expansion of 530 mm, a yield stress τ0 of 708.7 / Pa, a plastic viscosity μ of 48.4 / (Pa·s), a compressive strength of 173.2 MPa, and a flexural strength of 47.1 MPa. The silane-modified UHPC (Examples 1, 2, 3, and 4) prepared by the present invention has greatly improved fluidity and rheology, and the change in mechanical properties is negligible. Comparative Examples 1 and 2 have poor modification effects on UHPC, indicating that silane needs to be hydrolyzed in the mixed solvent described in the present invention. Comparative Example 3 causes a significant decrease in the mechanical properties of the modified UHPC, indicating that silane needs to be hydrolyzed in the mixed solvent described in the present invention. In comparative example 4, the silane content is 3% of the mass of silica fume, and the mixing ratio (mass ratio) of hydrolyzed silane is m1 (KH550): m2 (deionized water): m3 (anhydrous ethanol) = 3:9:15. This mixing ratio is outside the recommended mixing ratio range of the present invention, and its mechanical properties are significantly reduced. 2) The unmodified UHPC (Comparative Example 6) prepared by mixing all dry powders with water reducers and water has an expansion of 665 mm, a yield stress τ0 of 406.0 / Pa, a plastic viscosity μ of 36.3 / (Pa·s), a compressive strength of 172.0 MPa, and a flexural strength of 43.1 MPa. The silane-modified UHPC (Examples 5 and 6) prepared by the present invention has greatly improved fluidity and rheology, and the change in mechanical properties is negligible.

[0168] The contents explained in the above embodiments should be understood as these embodiments are only used to more clearly illustrate the present invention, and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

Claims

1. A method for preparing UHPC based on hydrolyzed silane, characterized in that It consists of the following steps: Preparation of hydrolyzed silane: adding silane, water and anhydrous ethanol in a mass ratio of m1 (silane): m2 (water): m3 (anhydrous ethanol) = 1: (2-3): (1-5), mixing evenly and standing for hydrolysis to obtain a hydrolyzed silane solution; The amount of hydrolyzed silane solution added to UHPC is determined according to the mass ratio of silane in the hydrolyzed silane solution to silica fume in UHPC being 1% to 2%. The hydrolyzed silane solution is mixed with various raw materials of UHPC to prepare a silane-modified UHPC mixture. The prepared silane-modified UHPC mixture is molded, cured, demoulded, and steamed to obtain silane-modified UHPC; The hydrolyzed silane solution was allowed to stand for hydrolysis for 2 hours; The preparation method of silane-modified UHPC mixture comprises the following steps: Firstly, dry powder and steel fiber are mixed and dry-mixed, and then the prepared hydrolyzed silane solution, admixture and water are added and stirred evenly to form a silane-modified UHPC mixture; The silane is KH550; The dry powder material includes cement, silica fume, quartz sand, and powder A. The admixture includes a water reducer. The powder A is a combination of quartz powder and mineral powder. The mass ratio of the cement, silica fume, quartz sand, and powder A is 1:0.3-0.5:0.9-1.1:0.15-0.35, the water-cement ratio is 0.1-0.3, the mass ratio of the solid content of the water reducer to the cementitious material is 1.0-2.0%, and the volumetric dosage of the steel fiber is 1.5-2.5%.

2. The method for preparing UHPC based on hydrolyzed silane according to claim 1, characterized in that: The time for mixing the dry powder and steel fiber is 0.5min to 20min.

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