High-content yellow river silt c50 high-performance concrete and preparation method thereof

Abstract

The application discloses high-content Yellow River silt C50 high-performance concrete and a preparation method thereof, which comprises the following components in parts by mass: cement: 300-450 parts, fly ash: 50-100 parts, Yellow River silt: 50% of the total mass of fine aggregate, gravel: 1000-1200 parts, multi-component composite silicon reinforcing agent: 10-30 parts, special soil dispersant: 5-15 parts, and water: 140-180 parts. The dispersant and the reinforcing agent are deeply synergized in function, and the problems of dispersion and activity excitation of the Yellow River silt under high content are effectively solved. The formula can be adjusted according to the silt characteristics of different river sections, and the stability and industrial reproducibility of the concrete performance are significantly improved by combining with the twice stirring process. The technical scheme realizes high-content and high-value utilization of the Yellow River silt, meets the high-performance concrete standard, and achieves high unification of technical, environmental protection and economic benefits.

Description

Technical Field

[0001] This invention belongs to the field of waste recycling technology, specifically a high-performance C50 concrete with high Yellow River sediment content and its preparation method. Background Technology

[0002] Yellow River sediment is a major solid waste generated during the comprehensive management of the Yellow River Basin, with a huge annual accumulation. For a long time, its disposal has mainly relied on dredging and subsequent stockpiling, which not only occupies a large amount of land resources but also puts continuous pressure on the ecological environment. With the ecological protection and high-quality development of the Yellow River Basin rising to a national strategy, how to transform Yellow River sediment into usable resources has become an urgent technical challenge. Currently, the use of Yellow River sediment in building materials faces the following main technical shortcomings:

[0003] First, current technologies for the resource utilization of Yellow River sediment mostly focus on low-value-added approaches, such as using it for dam backfilling, low-grade masonry mortar, or as an inert admixture in cement production. Large-scale production of high-grade concrete, especially C50 and above high-performance concrete, has not yet been achieved, thus failing to fully realize its potential value. Second, due to the small particle size, large specific surface area, and high content of clay minerals in Yellow River sediment, its surface exhibits strong negative charge, making it prone to agglomeration in cement-based systems. This results in poor workability and high water demand in the mixture. Traditional admixtures are insufficient to effectively address the dispersion problem of sediment particles, leading to severe degradation of concrete strength development and durability. Third, current technologies do not adequately activate the activity of Yellow River sediment. Most methods only use sediment as an inert filler, failing to effectively utilize its potential pozzolanic activity or interface optimization effects. The lack of systematic synergistic design between reinforcing agents and dispersants makes it difficult to achieve stable performance even with high-cost admixtures at large dosages. Fourth, existing preparation processes mostly follow the traditional one-time mixing method for concrete, failing to match the process to the differences in physical properties between mud and sand particles and cement particles. The mixing parameters lack targeted optimization, making it difficult to fully utilize the actual effectiveness of reinforcing agents and dispersants, and making it difficult to stably reproduce laboratory formulas in industrial production.

[0004] In summary, existing technologies for preparing high-performance concrete with high Yellow River sediment content suffer from prominent problems such as difficulty in dispersion, insufficient activity, poor process matching, and low added value from resource utilization. An innovative solution that can systematically solve these technical challenges is urgently needed. Summary of the Invention

[0005] The technical solution adopted in this invention is as follows: A high-performance C50 concrete with high Yellow River sediment content, comprising the following components by mass:

[0006] Cement: 300-450 parts;

[0007] Fly ash: 50-100 parts;

[0008] Yellow River sediment: accounts for 50% of the total mass of fine aggregate;

[0009] Crushed stone: 1000-1200 parts;

[0010] Multi-component composite silicon reinforcing agent: 10-30 parts;

[0011] Special soil dispersant: 5-15 parts;

[0012] Water: 140–180 parts;

[0013] The multi-component composite silicon reinforcing agent comprises, by mass percentage, 30%–50% sodium silicate, 10%–30% potassium silicate, 5%–15% nano-silica, 5%–15% aluminum sulfate, and 1%–5% triethanolamine;

[0014] The special soil dispersant contains, by mass percentage, 40%–60% polycarboxylate superplasticizer, 10%–20% sodium lignosulfonate, 5%–15% sodium polyacrylate, 1%–5% sodium dodecyl sulfate, and 1%–3% pH adjuster.

[0015] Furthermore, in the special soil dispersant, the pH adjuster is one or more of sodium hydroxide, sodium carbonate, or sodium silicate, used to adjust the pH value of the aqueous solution of the special soil dispersant to 9-11.

[0016] Furthermore, in the multi-component composite silicon reinforcing agent, the average particle size of the nano-silica is 20-50 nanometers, the aluminum sulfate is industrial-grade aluminum sulfate, and the triethanolamine is triethanolamine with a purity greater than 98%.

[0017] A method for preparing high-performance C50 concrete with high Yellow River sediment content as described in any one of the above-mentioned methods, characterized by comprising the following steps:

[0018] Step 1, First mixing: Put all the Yellow River silt and the special soil dispersant into the mixer, add the first part of water which accounts for 40% to 60% of the total water mass, and add a pH adjuster to maintain the pH value of the system at 9 to 11. Stir at a shear rate of 500 to 1000 rpm for 2 to 5 minutes. At the same time, during the stirring process, perform ultrasonic dispersion treatment at a frequency of 20 to 40 kHz for 1 to 3 minutes to obtain a silt slurry with uniformly dispersed silt particles.

[0019] Step 2, Second mixing: Add cement, fly ash, crushed stone and the multi-component composite silicon reinforcing agent to the mud and sand slurry obtained in Step 1, add the remaining water, control the mixing temperature to 15-35 degrees Celsius, and mix for 3-6 minutes with a mixing energy input of 20-40 kWh / m³ to obtain a concrete mixture with good workability and uniform distribution of each component.

[0020] Step 3: The concrete mixture obtained in Step 2 is shaped and cured for 28 days under standard curing conditions of temperature 20±2 degrees Celsius and relative humidity above 95%, or cured for 12 to 24 hours under steam curing conditions of 60 to 80 degrees Celsius, to obtain the high-content Yellow River sediment C50 high-performance concrete.

[0021] Furthermore, in step one, the pH adjuster is one or more of sodium hydroxide, sodium carbonate, or sodium silicate.

[0022] Furthermore, in step one, the shear rate is controlled by the rotation speed and blade shape of the mixer, and the ultrasonic dispersion treatment is carried out simultaneously with the mechanical stirring.

[0023] Furthermore, in step two, the stirring input is controlled by the integral of the stirring power and stirring time of the mixer, and the mixer used is a planetary mixer or a twin-shaft forced mixer.

[0024] Furthermore, in step two, the stirring temperature is controlled by cooling water in the mixer jacket or by a heating device. When the stirring temperature exceeds 35 degrees Celsius, the cooling system is activated; when the stirring temperature is below 15 degrees Celsius, the heating system is activated.

[0025] Furthermore, in step three, when standard curing is used, the curing period is 28 days; when steam curing is used, the curing temperature is 60–80 degrees Celsius and the curing time is 12–24 hours.

[0026] Furthermore, the Yellow River sediment undergoes pretreatment before use. The pretreatment includes air-drying or baking the Yellow River sediment until the moisture content is less than 1%, and then screening it to make the fineness modulus of the Yellow River sediment 1.6 to 2.2.

[0027] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0028] (1) This invention achieves deep synergy between the two additives by constructing an "integrated reinforcement-dispersion system" composed of a multi-component composite silicon reinforcing agent and a special soil dispersant: the special soil dispersant utilizes the compounding effect of polycarboxylate superplasticizer, sodium lignosulfonate, sodium polyacrylate and sodium dodecyl sulfate to significantly increase the negative charge on the surface of Yellow River sediment particles and form steric hindrance, raising the absolute value of the zeta potential of the sediment slurry to above 45mV, thereby enabling the clay particles to be fully deflocculated and uniformly dispersed during the first stirring process, which is conducive to subsequent water... The chemical reaction creates a highly active sediment substrate; the multi-component composite silicon reinforcing agent provides an alkaline activation environment with sodium silicate and potassium silicate, while nano-silica plays a dual role in filling micro-aggregates and activating volcanic ash. Aluminum sulfate and triethanolamine synergistically promote the formation of ettringite and optimize the interfacial transition zone. The two promote each other in the uniform system created by the dispersant, which increases the 28-day compressive strength by more than 16.5% compared with ordinary reinforcing agents and reduces the chloride ion diffusion coefficient by 43%, thus completely solving the core technical problem of "difficult to handle and poor performance" of Yellow River sediment due to particle agglomeration and low activity.

[0029] (2) In view of the differences in mineral composition and ionic environment of different sections of the Yellow River sediment, the present invention makes the special soil dispersant formula adjustable. The pH value of the dispersant aqueous solution is precisely controlled at 9-11 by pH adjusters such as sodium hydroxide, sodium carbonate or sodium silicate, so that the dispersant can adapt to the surface charge characteristics of upstream quartz-feldspar type, midstream montmorillonite-illite type and downstream fine-particle salt-rich sediment. At the same time, the introduction of aluminum sulfate and triethanolamine in the multi-component composite silicon reinforcing agent can effectively stimulate the potential activity of clay minerals. Experiments show that the concrete prepared by the technology of the present invention has a stable strength of more than 60 MPa under the sediment conditions of the upper, middle and lower reaches, and the electrical flux is less than 1000C at 56 days. After 300 freeze-thaw cycles, the relative dynamic elastic modulus is still maintained at more than 85%, which realizes good universality of sediment raw materials in the whole Yellow River basin and breaks through the constraints of geographical limitations on resource utilization.

[0030] (3) This invention establishes a two-stage mixing process flow that matches the "integrated reinforcement-dispersion system" and precisely defines key parameters such as the shear rate, pH environment, ultrasonic assistance, and mixing energy input and temperature control of the first mixing. The first mixing uses a high shear rate of 500-1000 rpm combined with ultrasonic treatment to enable the dispersant to be rapidly adsorbed on the surface of the mud and sand particles and achieve uniform dispersion. The second mixing uses a mixing energy input of 20-40 kWh / m³ and a temperature control of 15-35 degrees Celsius to ensure that the reinforcement participates in the hydration reaction uniformly and fully activates the mud and sand activity. This process reduces the thickness of the interface transition zone from 42.3 μm in traditional one-stage mixing to 18.5 μm, the concrete porosity from 16.7% to 8.2%, and the strength standard deviation from 4.5 MPa to 1.5 MPa, significantly improving the performance stability and reproducibility in industrial production and ensuring that the laboratory formula can be stably reproduced in large-scale engineering applications.

[0031] (4) This invention increases the amount of Yellow River sediment to 50% of the total mass of fine aggregate and successfully prepares high-performance concrete of grade C50 or above. When the sediment content is 50%, the 28-day compressive strength still reaches 61.5 MPa, the flexural strength is 6.7 MPa, the slump is 210 mm with a loss of only 12 mm in 1 hour, and the drying shrinkage rate is 330 × 10⁻⁶. -6 All performance indicators meet the requirements of high-grade concrete engineering. At the same time, it realizes an innovative resource utilization path that transforms the huge amount of Yellow River sediment from an environmental governance burden into a high-value-added building material raw material. Compared with traditional manufactured sand concrete, each cubic meter of concrete can replace about 480 kg of fine aggregate, which greatly reduces the damage to the ecological environment caused by river sand mining. Furthermore, due to the reduction in cement usage and full utilization of the potential activity of sediment, it significantly reduces carbon emissions in the concrete production process, forming an innovative solution that unifies technical performance, environmental protection, and economic benefits.

[0032] (5) Comparative experimental data confirms that the present invention has significant performance advantages over the prior art in key aspects such as the optimization of reinforcing agent dosage, dispersion effect of dispersant, matching of mixing process parameters, determination of maximum sediment dosage, and adaptability to sediment in different river sections. In particular, under the condition of 50% high dosage, the 28-day compressive strength of the concrete of the present invention is 28.4% higher than that of the control group with ordinary reinforcing agent and one-time mixing process, the freeze-thaw cycle resistance is increased by 42%, and the chloride ion permeability is reduced by 57%. The above data fully demonstrate that the technical solution of the "integrated reinforcement-dispersion system" and the two-time mixing process proposed in the present invention not only solves the core technical obstacle of Yellow River sediment resource utilization in principle, but also has reliability, economy and wide adaptability in practical engineering applications, providing practical technical support for ecological protection and high-quality development of the Yellow River Basin. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the process of the present invention;

[0034] Figure 2 This is a schematic diagram illustrating the effect of the dosage of the multi-component composite silicon reinforcing agent of the present invention on the strength of concrete.

[0035] Figure 3 This is a schematic diagram illustrating the effect of different dispersants on the workability of concrete according to the present invention;

[0036] Figure 4 This is a schematic diagram illustrating the effects of different stirring processes on strength and microstructure according to the present invention;

[0037] Figure 5 This is a schematic diagram illustrating the effect of Yellow River sediment content on concrete strength according to the present invention.

[0038] Figure 6 This is a schematic diagram comparing the effects of sediment in different river sections on concrete performance according to the present invention.

[0039] Figure 7 This is a schematic diagram illustrating the effect of different multi-component composite silicon reinforcing agent preparation processes on concrete performance according to the present invention; Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0041] Example 1, please refer to Figure 1 - Figure 7 Comparative Experiment on the Effect of Multi-component Composite Silicon Reinforcing Agent Dosage on Concrete Performance

[0042] 1. Experimental Objective

[0043] The reinforcing effect of different dosages of "multi-component composite silicon reinforcing agent" in high-performance C50 concrete with high dosage of Yellow River sediment was investigated to determine the optimal dosage range and to compare it with commercially available ordinary silicon reinforcing agent.

[0044] 2. Experimental materials and proportions (parts by mass)

[0045] Cement: P·O 42.5, 380 parts

[0046] Fly ash: Grade I, 70 parts

[0047] Yellow River silt (50% of fine aggregate mass): dried and sieved (fineness modulus 1.8), 480 parts

[0048] Crushed stone: 5-25mm continuous gradation, 1100 parts

[0049] Special soil dispersant: 10 parts

[0050] Water: 160 servings

[0051] Multi-component composite silicon reinforcing agent: Variables (0 parts, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts)

[0052] Comparative group: Commercially available ordinary silicon reinforcing agent (main component is sodium silicate), dosage 15 parts

[0053] 3. Preparation process (according to claims 4-10)

[0054] First mixing: Yellow River silt + special soil dispersant + first batch of water (50% of total water volume, pH=10), shear and mix at 800r / min for 3 minutes, supplemented by 30kHz ultrasound for 2 minutes.

[0055] Second mixing: Add cement, fly ash, crushed stone, reinforcing agent and remaining water, mix at 25℃, mix energy input of 30kWh / m³, mix for 5 minutes.

[0056] Maintenance: Standard maintenance for 28 days.

[0057] 4. Experimental Results and Data

[0058] No enhancer 0 185 48.2 5.1 8.5 Multi-component composite silicon reinforcing agent 5 190 52.3 5.6 7.2 Multi-component composite silicon reinforcing agent 10 195 56.8 6.1 6.1 Multi-component composite silicon reinforcing agent 15 200 61.5 6.7 5.0 Multi-component composite silicon reinforcing agent 20 198 63.2 6.9 4.8 Multi-component composite silicon reinforcing agent 25 195 63.0 6.8 4.9 Multi-component composite silicon reinforcing agent 30 190 62.5 6.7 5.1 Commercially available common silicon reinforcing agents 15 175 52.8 5.5 8.8

[0059] 5. Results Analysis

[0060] As the dosage of "multi-component composite silicon reinforcing agent" increases, the compressive strength of concrete first rises and then stabilizes, reaching a peak of 63.2 MPa at a dosage of 20 parts, meeting the C50 requirement (≥50 MPa) and possessing a high margin coefficient.

[0061] Compared to commercially available ordinary silicon reinforcing agents, the reinforcing agent of this invention improves strength by about 16.5% and resistance to chloride ion penetration by about 43% at the same dosage (15 parts), indicating that it significantly optimizes the interfacial transition zone through the synergistic effect of nano-silica filling and aluminum sulfate activation.

[0062] Example 2, please refer to Figure 1 - Figure 7 The effect of special soil dispersant on the dispersion effect of Yellow River sediment and the workability of concrete.

[0063] 1. Experimental Objective

[0064] To verify the effectiveness of the "special soil dispersant" designed for the surface characteristics of Yellow River sediment, and to compare the effect of ordinary polycarboxylate superplasticizer on the dispersion performance of sediment-cement system.

[0065] 2. Experimental Design

[0066] The dosage of multi-component composite silicon reinforcing agent was fixed at 15 parts, and the content of Yellow River sediment accounted for 50% of the fine aggregate. A special soil dispersant dosage gradient was set (0, 5, 8, 10, 12, 15 parts), and a commercially available ordinary polycarboxylate superplasticizer (10 parts) was used as a control group.

[0067] 3. Experimental Results and Data

[0068] No dispersant 0 120 45 -8.2 42.5 Special soil dispersant 5 175 25 -35.6 55.2 Special soil dispersant 8 195 18 -42.1 58.9 Special soil dispersant 10 210 12 -48.5 61.5 Special soil dispersant 12 215 10 -50.2 61.8 Special soil dispersant 15 215 10 -51.0 61.3 Commercially available polycarboxylate superplasticizers 10 180 45 -22.3 53.1

[0069] 4. Results Analysis

[0070] The specialized soil dispersant significantly improves the surface negative charge of silt particles (absolute value of Zeta potential > 45mV) through the synergistic effect of sodium lignosulfonate and sodium polyacrylate, achieving efficient electrostatic-steric dual stabilization.

[0071] At a dosage of 10 parts, the initial slump reached 210 mm, with a loss of only 12 mm in 1 hour, far superior to ordinary water-reducing agents. Meanwhile, the uniformly dispersed silt provided a better reaction substrate for the reinforcing agent, resulting in a 44.7% increase in 28-day strength compared to the group without a dispersant.

[0072] Example 3, please refer to Figure 1 - Figure 7 Comparative Experiment on Optimization of Two Stirring Process Parameters

[0073] 1. Experimental Objective

[0074] The invention verifies the decisive role of the "two-stage mixing process" and its key parameters (first mixing shear rate, second mixing energy input) on the microstructure and macroscopic properties of concrete, and compares it with the traditional one-stage mixing process.

[0075] 2. Experimental Grouping

[0076] Group A (Optimized Group of this Invention): First stirring shear rate 800 r / min, second stirring energy input 35 kWh / m³, temperature 25℃.

[0077] Group B (low shear group): The first stirring shear rate was 200 r / min, and the rest were the same as Group A.

[0078] Group C (Low Energy Input Group): The energy input for the second stirring is 15 kWh / m³, and the rest is the same as Group A.

[0079] Group D (Traditional One-Time Mixing): All raw materials are added at once, mixing time is 8 minutes, and mixing energy input is 30kWh / m³.

[0080] 3. Experimental Results and Data

[0081] A (This invention) 62.8 18.5 8.2 1.5 B (Low Shear) 54.2 32.0 12.5 3.2 C (Low-energy input) 51.5 35.6 14.1 3.8 D (One-time mixing) 48.9 42.3 16.7 4.5

[0082] 4. Results Analysis

[0083] The optimized two-stage mixing process (Group A) of this invention achieves full dispersion of mud and sand particles by prioritizing high shear rate, and then ensures that the reinforcing agent participates in the hydration reaction uniformly by high mixing energy input, thereby reducing the thickness of the interface transition zone to 18.5 μm, which is 56% less than the traditional one-stage mixing.

[0084] In terms of macroscopic performance, the strength increased by 28.4%, and the strength standard deviation decreased significantly, indicating that the stability of industrial production has been greatly improved.

[0085] Example 4, please refer to Figure 1 - Figure 7 Experiments on the optimization of sediment content in the Yellow River and its comparison with ordinary manufactured sand

[0086] 1. Experimental Objective

[0087] This study verifies the maximum allowable amount of Yellow River sediment as fine aggregate under the technical system of this invention and its impact on concrete performance, and compares its performance with that of ordinary manufactured sand concrete.

[0088] 2. Experimental Design

[0089] The proportions of Yellow River sediment in the total mass of fine aggregate were 30%, 40%, 50%, 60%, and 70%, respectively. The mixture consisted of 15 parts fixed reinforcing agent, 10 parts dispersant, and a two-stage mixing process. The control group consisted of manufactured sand concrete with the same gradation (without sediment).

[0090] 4. Experimental Results and Data

[0091] Yellow River silt 30 64.5 1.2 285 220 Yellow River silt 40 63.2 1.4 305 215 Yellow River silt 50 61.5 1.8 330 210 Yellow River silt 60 55.8 2.8 385 195 Yellow River silt 70 48.2 4.2 445 170 Manufactured sand 0 65.2 1.1 260 225

[0092] 4. Results Analysis

[0093] When the Yellow River sediment content is ≤50%, the 28-day strength of the concrete of this invention is higher than 60MPa, and its freeze-thaw resistance and drying shrinkage performance are close to those of manufactured sand concrete.

[0094] When the dosage reaches 60%, the performance begins to decline significantly. Therefore, 50% is determined to be the optimal high dosage boundary, within which the best balance between performance and resource utilization can be achieved.

[0095] Example 5, please refer to Figure 1 - Figure 7 A comprehensive comparison of the adaptability and durability of sediment in different sections of the Yellow River.

[0096] 1. Experimental Objective

[0097] The adaptability of this invention to sediment (differences in mineral composition and salinity) in different sections of the upper, middle and lower reaches of the Yellow River was investigated, and the durability index of the concrete was comprehensively evaluated.

[0098] 2. Experimental Materials

[0099] Sediment A: Upper Yellow River, mainly composed of quartz and feldspar, with low mud content.

[0100] Sediment B: The middle reaches of the Yellow River have a high content of clay minerals (montmorillonite and illite).

[0101] Sediment C: Lower Yellow River, mostly fine particles, containing a small amount of soluble salts.

[0102] 3. Experimental formulation and process

[0103] The following formula is used uniformly: 15 parts reinforcing agent, 10 parts dispersant (the pH value of the dispersant is finely adjusted to the optimal range by pH adjuster for different river sections), and the sediment accounts for 50% of the fine aggregate.

[0104] 4. Experimental Results and Data

[0105] Upstream A 63.5 850 92.5 310 Midstream B 61.2 920 88.3 345 Downstream C 60.8 980 85.6 370 Comparison of ordinary river sand 65.0 780 94.0 290

[0106] 5. Results Analysis

[0107] Despite the differences in sediment properties across different river sections, the adaptive adjustments made to the "enhanced-dispersion integrated system" of this invention (especially pH adjustment of the dispersant) ensure that the concrete strength of sediment in each river section remains stable above 60 MPa, the electrical flux is below 1000°C, and the freeze-thaw resistance is excellent.

[0108] This demonstrates that the present invention has good universality for sediment in the entire Yellow River basin, breaks through the geographical limitations of raw materials, and provides technical support for large-scale engineering applications.

[0109] Example 6, please refer to Figure 1 - Figure 7 Comparative Experiment on the Preparation Process and Implementation Effect of Multi-component Composite Silicon Reinforcement Agent

[0110] 1. Experimental Objective

[0111] The "multi-component composite silicon reinforcing agent" described in this invention is not a simple physical mixture, but a composite activation-filling system prepared through a specific sequence and process. This embodiment aims to disclose its detailed preparation method and verify the advancement and necessity of the reinforcing agent preparation process of this invention by comparing the effects of different preparation methods (simple dry mixing, wet ball milling, and the stepwise composite process optimized by this invention) on concrete performance.

[0112] 2. Preparation method of multi-component composite silicon reinforcing agent (according to the optimized process of this invention)

[0113] Raw material ratio (by mass percentage):

[0114] Sodium silicate: 45%

[0115] Potassium silicate: 25%

[0116] Nano-silica: 12% (average particle size 20nm)

[0117] Aluminum sulfate: 10% (industrial grade)

[0118] Triethanolamine: 8% (purity >98%)

[0119] Preparation steps:

[0120] Premixing: Sodium silicate and potassium silicate powders are added to a high-speed mixer at room temperature and mixed at 200 rpm for 5 minutes to obtain an alkaline silicate base.

[0121] Nano silica dispersion: Slowly add nano silica to the above mixture, and simultaneously turn on ultrasonic-assisted dispersion (frequency 30kHz, power 500W) for 10 minutes to prevent nanoparticles from agglomerating.

[0122] Aluminum sulfate incorporation: While maintaining stirring, add aluminum sulfate in batches, increase the stirring speed to 400 rpm, and mix for 8 minutes to ensure that aluminum sulfate is evenly distributed in the silicate network.

[0123] Triethanolamine post-treatment: Finally, triethanolamine is added in the form of a spray and stirred for another 5 minutes to obtain a uniform, lumpy gray powder of multi-component composite silicon reinforcing agent.

[0124] Sieving and Packaging: Pass through a 0.3mm square hole sieve and seal in a moisture-proof package.

[0125] Comparison of the preparation methods of the reinforcing agent:

[0126] Group A (simple dry mix): All components were added to the mixer at the same ratio and dry-mixed for 10 minutes. The order of addition and ultrasonic treatment were not controlled.

[0127] Group B (wet ball milling): Add water to each component to make a slurry, ball mill for 2 hours and then spray dry.

[0128] Group C (Optimized process of this invention): Prepared according to the stepwise composite process described above.

[0129] 3. Concrete mix design and preparation

[0130] The optimized mix proportions from Example 1 were used: 380 parts cement, 70 parts fly ash, 480 parts Yellow River silt, 1100 parts crushed stone, 10 parts special soil dispersant, and 160 parts water. A multi-component composite silicon reinforcing agent prepared using processes A, B, and C was added at a dosage of 15 parts for each. The concrete preparation method followed the two-stage mixing process described in claim 4.

[0131] 4. Experimental Results and Data

[0132] Group A (Simple Dry Mixing) 54.6 0.65 320 (Serious Family Reunification) 1120 Group B (Wet Ball Milling) 58.2 0.78 95 890 Group C (Optimized process of this invention) 62.8 0.92 45 680

[0133] Microstructure analysis:

[0134] In Group A, the nano-silica in the reinforcing agent was not effectively dispersed, forming weak areas in the concrete and causing microcracks in the interfacial transition zone.

[0135] The components of Group C reinforcing agent work synergistically and uniformly to form a dense network in the cement paste, reducing the thickness of the interfacial transition zone to 18.2 μm.

[0136] 5. Results Analysis

[0137] The optimized stepwise composite preparation process of this invention achieves uniform distribution of each component at the microscale through the sequence of "alkaline silicate substrate premixing → ultrasonic-assisted nano-dispersion → aluminum sulfate gradient incorporation → triethanolamine spray post-treatment," which effectively inhibits the self-aggregation of nano-silica, allowing it to fully exert its filling and pozzolanic effects in concrete. Compared to simple dry mixing, the strength is increased by 15.0%, and the electrical flux is reduced by 39.3%; compared to wet ball milling, the strength is increased by 7.9%, and the process is simpler, consumes less energy, and produces no wastewater.

[0138] 7. Conclusion

[0139] This embodiment demonstrates the significant technical advantages of the stepwise composite preparation process of the multi-component composite silicon reinforcing agent used in this invention: through sequential feeding and ultrasonic-assisted dispersion, efficient dispersion of nano-components and uniform composite of each active component are achieved, thereby exerting optimal reinforcing effect in concrete. This preparation method is simple, environmentally friendly, and industrially feasible, and is an important component of the "integrated reinforcement-dispersion system" of this invention.

[0140] Overall Conclusion

[0141] Through the comparative experiments of the above six embodiments, the following conclusions can be clearly drawn:

[0142] Creativity: The "integrated reinforcement-dispersion system" composed of the "multi-component composite silicon reinforcing agent" and the "special soil dispersant" proposed in this invention has clear novelty in its component design. Experiments have shown that the synergistic effect of the two on improving the strength, workability, and durability of Yellow River silt concrete far exceeds that of simply adding ordinary admixtures.

[0143] Novelty: The molecular structure designed for the characteristics of Yellow River sediment (charge regulation of dispersant and activation of enhancer) and the precisely matched two-stage stirring process parameters are not publicly reported in existing patent literature.

[0144] Practicality: The technical system of this invention shows good adaptability to sediment in different river sections and can stably achieve the preparation of high-performance concrete with C50 and above, providing a practical, economical and environmentally friendly industrial path for the resource utilization of Yellow River sediment with a large amount (50%).

[0145] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-performance C50 concrete with high Yellow River sediment content, characterized in that, Includes the following components by mass: Cement: 300-450 parts; Fly ash: 50-100 parts; Yellow River sediment: accounts for 50% of the total mass of fine aggregate; Crushed stone: 1000-1200 parts; Multi-component composite silicon reinforcing agent: 10-30 parts; Special soil dispersant: 5-15 parts; Water: 140–180 parts; The multi-component composite silicon reinforcing agent comprises, by mass percentage, 30%–50% sodium silicate, 10%–30% potassium silicate, 5%–15% nano-silica, 5%–15% aluminum sulfate, and 1%–5% triethanolamine; The special soil dispersant contains, by mass percentage, 40%–60% polycarboxylate superplasticizer, 10%–20% sodium lignosulfonate, 5%–15% sodium polyacrylate, 1%–5% sodium dodecyl sulfate, and 1%–3% pH adjuster.

2. The high-performance C50 concrete with high Yellow River sediment content according to claim 1, characterized in that, In the special soil dispersant, the pH adjuster is one or more of sodium hydroxide, sodium carbonate, or sodium silicate, used to adjust the pH value of the aqueous solution of the special soil dispersant to 9-11.

3. The high-performance C50 concrete with high Yellow River sediment content according to claim 1, characterized in that, In the multi-component composite silicon reinforcing agent, the average particle size of the nano-silica is 20-50 nanometers, the aluminum sulfate is industrial grade aluminum sulfate, and the triethanolamine is triethanolamine with a purity greater than 98%.

4. A method for preparing high-performance C50 concrete with high Yellow River sediment content as described in any one of claims 1 to 3, characterized in that, Includes the following steps: Step 1, First mixing: Put all the Yellow River silt and the special soil dispersant into the mixer, add the first part of water which accounts for 40% to 60% of the total water mass, and add a pH adjuster to maintain the pH value of the system at 9 to 11. Stir at a shear rate of 500 to 1000 rpm for 2 to 5 minutes. At the same time, during the stirring process, perform ultrasonic dispersion treatment at a frequency of 20 to 40 kHz for 1 to 3 minutes to obtain a silt slurry with uniformly dispersed silt particles. Step 2, Second mixing: Add cement, fly ash, crushed stone and the multi-component composite silicon reinforcing agent to the mud and sand slurry obtained in Step 1, add the remaining water, control the mixing temperature to 15-35 degrees Celsius, and mix for 3-6 minutes with a mixing energy input of 20-40 kWh / m³ to obtain a concrete mixture with good workability and uniform distribution of each component. Step 3: The concrete mixture obtained in Step 2 is shaped and cured for 28 days under standard curing conditions of temperature 20±2 degrees Celsius and relative humidity above 95%, or cured for 12 to 24 hours under steam curing conditions of 60 to 80 degrees Celsius, to obtain the high-content Yellow River sediment C50 high-performance concrete.

5. The method for preparing high-performance C50 concrete with high Yellow River sediment content according to claim 4, characterized in that, In step one, the pH adjuster is one or more of sodium hydroxide, sodium carbonate, or sodium silicate.

6. The method for preparing high-performance C50 concrete with high Yellow River sediment content according to claim 4, characterized in that, In step one, the shear rate is controlled by the rotation speed and blade shape of the mixer, and the ultrasonic dispersion treatment is carried out simultaneously with the mechanical stirring.

7. The method for preparing high-performance C50 concrete with high Yellow River sediment content according to claim 4, characterized in that, In step two, the stirring input is controlled by the integral of the stirring power and stirring time of the mixer, and the mixer used is a planetary mixer or a twin-shaft forced mixer.

8. The method for preparing high-performance C50 concrete with high Yellow River sediment content according to claim 4, characterized in that, In step two, the stirring temperature is controlled by cooling water in the mixer jacket or by a heating device. When the stirring temperature exceeds 35 degrees Celsius, the cooling system is activated; when the stirring temperature is below 15 degrees Celsius, the heating system is activated.

9. The method for preparing high-performance C50 concrete with high Yellow River sediment content according to claim 4, characterized in that, In step three, when standard curing is used, the curing period is 28 days; when steam curing is used, the curing temperature is 60-80 degrees Celsius and the curing time is 12-24 hours.

10. The method for preparing high-performance C50 concrete with high Yellow River sediment content according to claim 4, characterized in that, The Yellow River sediment undergoes pretreatment before use. The pretreatment includes air-drying or baking the Yellow River sediment until the moisture content is less than 1%, and then screening it to make the fineness modulus of the Yellow River sediment 1.6 to 2.2.

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