Interface-reinforced high-durability offshore structural concrete and preparation method thereof
By pretreating manufactured sand with nano-silica and treating coarse aggregate with silane coupling agent, the density of the interfacial transition zone is improved, which solves the problem of insufficient durability of near-shore structural concrete and achieves a combination of high durability and economy.
Patent Information
- Application Number
- CN202511073328.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-01
- Publication Date
- 2025-11-14
AI Technical Summary
The durability of concrete structures in offshore engineering projects deteriorates severely in environments with high salt spray, wet-dry cycles, and chemical corrosion. Existing technologies struggle to balance high durability, economy, and ease of construction.
Manufactured sand pretreated with nano-silica was used to replace natural river sand, and coarse aggregate was treated with silane coupling agent to improve the density of the interface transition zone and form a multi-layer barrier to block chloride ion intrusion.
It significantly improves the durability of concrete, reduces production costs, enhances construction convenience and concrete density, and meets the needs of green transformation.
Smart Images
Figure CN120943584A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of concrete technology, and specifically relates to an interface-strengthened, high-durability nearshore structural concrete and its preparation method. Background Technology
[0002] Offshore engineering structures made of concrete (such as cross-sea bridges, port terminals, offshore wind power foundations, and basements of coastal buildings) are exposed to complex environments including high salt spray, wet-dry cycles, and chemical corrosion, resulting in a significantly higher rate of concrete durability degradation compared to inland buildings. Statistics show that maintenance costs due to concrete durability issues account for over 60% of the total life-cycle cost of offshore concrete structures globally. Domestic and international research indicates that the main forms of damage to offshore concrete include chloride ion attack, sulfate attack, carbonation, steel reinforcement corrosion, and freeze-thaw damage. Chloride ion attack is the primary cause of steel reinforcement corrosion and expansion, while sulfate attack leads to concrete expansion and cracking, further accelerating structural deterioration. Domestic research indicates that in environments dominated by chloride ion attack, the service life of ordinary C40 concrete is typically less than 30 years.
[0003] Currently, the main technical approaches adopted domestically and internationally to improve the durability of concrete in nearshore structures are as follows: (1) optimizing the concrete mix proportion and reducing the water-cement ratio to improve concrete density; (2) incorporating mineral admixtures (such as fly ash, slag, silica fume, etc.) to improve the microstructure of concrete; (3) using concrete anti-corrosion coatings or surface treatment technologies; and (4) developing new corrosion-resistant steel bars or non-metallic reinforcing materials. However, these methods still have some limitations: for example, excessive amounts of mineral admixtures may lead to insufficient early strength and affect construction progress; the long-term effects of surface treatment technologies are difficult to guarantee; and the cost of new reinforcing materials is high and the construction process is complex.
[0004] Therefore, it is of great significance to develop a near-shore structural concrete that combines high durability, economy and ease of construction. Summary of the Invention
[0005] This invention proposes an interface-reinforced, high-durability nearshore structural concrete and its preparation method. The high-durability nearshore structural concrete is prepared by using manufactured sand pretreated with nano-silica as a substitute for natural river sand. After pretreatment, the density of the manufactured sand-slurry interface transition zone is effectively improved, sealing the chloride ion intrusion channels. Furthermore, the application of a silane coupling agent to pretreat the coarse aggregate further improves the coarse aggregate-slurry interface transition zone and enhances the aggregate-slurry interface bonding quality. Through the combined effect, the intrusion channels of chloride ions through the interface transition zone are effectively sealed, thus improving the overall durability of the coastal structural concrete. This technology has the advantages of simple processing and a wide range of reinforcing agent sources. The application of manufactured sand promotes the green transformation of traditional high-durability concrete.
[0006] To solve the above technical problems, the present invention includes the following technical solutions:
[0007] An interface-reinforced, high-durability nearshore structural concrete, wherein the components of the concrete are in the following mass ratio (kg / m³). 3 ):
[0008] Granulated blast furnace slag powder 100-150, fly ash 50-100, cement 200-250, pretreated manufactured sand 200-300, pretreated coarse aggregate 900-1100, high-efficiency water-reducing agent 3-4, natural sand 400-500, and water 160-180.
[0009] This invention also provides a method for preparing interface-reinforced high-durability nearshore structural concrete, used to formulate the interface-reinforced high-durability nearshore structural concrete, the method comprising the following steps:
[0010] Step S1: Add cement, natural sand, granulated blast furnace slag powder, fly ash, pretreated coarse aggregate and pretreated manufactured sand into the mixer and mix for 60-120 seconds.
[0011] Step S2: Add high-efficiency water-reducing agent and water, and stir for 240-360 seconds.
[0012] Furthermore, the pretreatment method for coarse aggregate is as follows: commercially available KH-550 silane coupling agent is mixed with anhydrous ethanol at a volume ratio of 1:19 to prepare a 5% solution, and an appropriate amount of deionized water is added to promote the hydrolysis reaction. After standing and maturing, it is used for aggregate surface treatment; crushed stone is soaked in a 5% silane coupling agent for 2 hours and then spread flat on the ground in a dry and ventilated place to air dry.
[0013] Furthermore, the pre-treatment method for manufactured sand is as follows: the manufactured sand is sieved using a 600μm square hole sieve to obtain inert micro powder after sieving, the remaining manufactured sand is placed in a dry place to dry, and nano-SiO2 sol is prepared in an alkaline environment using the sol-gel method.
[0014] Further, the preparation method of the nano-SiO2 sol includes: adding 100 mL of anhydrous ethanol to a beaker as a solvent; adding 10 mL of tetraethyl orthosilicate and stirring evenly; slowly adding ammonia water to adjust the pH of the solution to 9-10; placing the beaker in a constant temperature water bath at 60-70°C; under stirring conditions, slowly adding 10 mL of deionized water to initiate the hydrolysis reaction of tetraethyl orthosilicate; continuing to stir for 2-3 hours until the solution gradually becomes a transparent or translucent sol state; uniformly spraying the nano-SiO2 sol onto the surface of the sieved inert micro powder using a spray bottle, and then mixing the treated inert micro powder with the sieved residue of the machine sand evenly at a weight ratio of 0.1-0.2:1.
[0015] Further, the method for preparing nano-SiO2 sol using the sol-gel method includes: adding 100 mL of anhydrous ethanol to a beaker as a solvent; adding 10 mL of tetraethyl orthosilicate and stirring until homogeneous; slowly adding ammonia water to adjust the pH of the solution to 9-10; placing the beaker in a constant temperature water bath at 60-70°C; under stirring conditions, slowly adding 10 mL of deionized water to initiate the hydrolysis reaction of tetraethyl orthosilicate; continuing to stir for 2-3 hours until the solution gradually becomes a transparent or translucent sol state; uniformly spraying the nano-SiO2 sol onto the surface of the sieved inert micro powder using a spray bottle; and then mixing the treated inert micro powder with the sieved residue of the machine sand until homogeneous, with a mixing weight ratio of 0.1-0.2:1.
[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects:
[0017] This invention provides an interface-reinforced, high-durability nearshore structural concrete and its preparation method. Through the synergistic modification of the coarse aggregate-slurry interface and the manufactured sand-slurry interface in the manufactured sand high-durability concrete, the interconnecting gaps at the aggregate-slurry interface are effectively reduced, and the density at the interface is improved. The coarse aggregate-slurry interface, the transition slurry, and the manufactured sand-slurry interface form a multi-layered barrier and an overall effect, further blocking the diffusion of environmental chloride ions into the concrete interior, successfully improving the durability of the nearshore structural concrete. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the sieved manufactured sand in the preparation method of interface-reinforced high-durability near-shore structural concrete in one embodiment of the present invention.
[0019] Figure 2 This is a schematic diagram of the inert micro powder after sieving in the preparation method of interface-reinforced high-durability near-shore structural concrete in one embodiment of the present invention.
[0020] Figure 3 This is a schematic diagram illustrating the synergistic interaction between the coarse aggregate-slurry interface and the manufactured sand-slurry interface in the preparation method of interface-reinforced high-durability nearshore structural concrete according to an embodiment of the present invention. Detailed Implementation
[0021] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides an interface-reinforced, high-durability nearshore structural concrete and its preparation method, based on the present invention. The advantages and features of the present invention will become clearer from the following description.
[0022] Example 1
[0023] The following is combined with Figures 1 to 3 This invention provides a detailed description of the interface-reinforced, high-durability nearshore structural concrete and its preparation method.
[0024] An interface-reinforced, high-durability nearshore structural concrete, wherein the components of the concrete are in the following mass ratio (kg / m³). 3 ):
[0025] Granulated blast furnace slag powder 100-150, fly ash 50-100, cement 200-250, pretreated manufactured sand 200-300, pretreated coarse aggregate 900-1100, high-efficiency water-reducing agent 3-4, natural sand 400-500, and water 160-180.
[0026] The cement is generally P.O42.5 ordinary Portland cement or P.II 52.5 Portland cement; the coarse aggregate is 5-25 continuous particle size stone; the granulated blast furnace slag powder is S95 grade mineral powder; the fly ash is Grade II fly ash; the manufactured sand and natural sand are generally medium sand with a fineness modulus of 2.3-3.0; the high-efficiency water-reducing agent is polycarboxylate high-efficiency water-reducing agent with a water reduction rate of ≥30%; the water is ordinary tap water; the coarse aggregate pretreatment agent is silane coupling agent; the manufactured sand pretreatment agent is nano SiO2 sol.
[0027] This invention also provides a method for preparing interface-reinforced high-durability nearshore structural concrete, used to formulate the interface-reinforced high-durability nearshore structural concrete, the method comprising the following steps:
[0028] Step S1: Add cement, natural sand, granulated blast furnace slag powder, fly ash, pretreated coarse aggregate and pretreated manufactured sand into the mixer and mix for 60-120 seconds.
[0029] Step S2: Add high-efficiency water-reducing agent and water, and stir for 240-360 seconds.
[0030] In this embodiment, more preferably, the pretreatment method for coarse aggregate is as follows: commercially available KH-550 silane coupling agent and anhydrous ethanol are mixed at a volume ratio of 1:19 to prepare a 5% solution, and an appropriate amount of deionized water is added to promote the hydrolysis reaction. After standing and aging, it is used for aggregate surface treatment; the crushed stone is soaked in a 5% silane coupling agent for 2 hours and then spread flat on the ground in a dry and ventilated place to air dry.
[0031] In this embodiment, more preferably, the pretreatment method for manufactured sand is as follows: the manufactured sand is sieved using a 600μm square hole sieve to obtain inert micro powder after sieving, the remaining manufactured sand is placed in a dry place to dry, and nano-SiO2 sol is prepared in an alkaline environment using the sol-gel method.
[0032] In this embodiment, more preferably, the preparation method of nano-SiO2 sol includes: adding 100 mL of anhydrous ethanol to a beaker as a solvent; adding 10 mL of tetraethyl orthosilicate and stirring evenly; slowly adding ammonia water to adjust the pH of the solution to 9-10; placing the beaker in a constant temperature water bath at a temperature of 60-70°C; slowly adding 10 mL of deionized water under stirring to initiate the hydrolysis reaction of tetraethyl orthosilicate; continuing to stir for 2-3 hours until the solution gradually becomes a transparent or translucent sol state; uniformly spraying the nano-SiO2 sol onto the surface of the sieved inert micro powder using a spray bottle; and then mixing the treated inert micro powder with the sieved residue of the machine sand evenly at a weight ratio of 0.1-0.2:1.
[0033] In this embodiment, more preferably, the method for preparing nano-SiO2 sol using the sol-gel method includes: adding 100 mL of anhydrous ethanol to a beaker as a solvent; adding 10 mL of tetraethyl orthosilicate and stirring until homogeneous; slowly adding ammonia water to adjust the pH of the solution to 9-10; placing the beaker in a constant temperature water bath at 60-70°C; under stirring conditions, slowly adding 10 mL of deionized water to initiate the hydrolysis reaction of tetraethyl orthosilicate; continuing to stir for 2-3 hours until the solution gradually becomes a transparent or translucent sol state; uniformly spraying the nano-SiO2 sol onto the surface of the sieved inert micro powder using a spray bottle; and then mixing the treated inert micro powder with the sieved residue of the machine sand until homogeneous, with a mixing weight ratio of 0.1-0.2:1.
[0034] The aggregate-paste interface in concrete contains numerous interconnected pores. Therefore, in addition to the existing interconnected pores in the concrete serving as the primary pathway for chloride ion diffusion, the porous aggregate-paste interface also represents a major route for environmental chloride ions to penetrate the concrete. Thus, strengthening the aggregate-paste interface to block chloride ion diffusion pathways can effectively improve the durability of concrete in nearshore structures.
[0035] As a major type of artificial sand, manufactured sand has largely replaced natural sand in concrete engineering. The main problem with manufactured sand is its high content of fine powder and high initial water absorption. Indiscriminate use can easily lead to segregation in the concrete, resulting in honeycomb, pitted surfaces, and low density after pouring. Therefore, it is difficult to use in concrete projects with high durability requirements.
[0036] The powders contained in manufactured sand are mostly inert micro-powders, which do not possess hydration reactivity or the conditions to undergo secondary hydration reactions with the hydration product calcium hydroxide. Therefore, pretreatment is required to activate their reactivity. Furthermore, inert micro-powders (below 600μm) typically constitute a high percentage (25%–35% by mass) in manufactured sand. Higher content results in a larger specific surface area and higher water absorption, drawing away lubricating moisture from the concrete, leading to segregation, poor fluidity, and difficulty in compaction. This is the main reason why manufactured sand cannot be used on a large scale in high-durability concrete projects.
[0037] The nano-SiO2 particles in the nano-SiO2 sol act as nucleating seeds, accelerating the hydration reaction of cement around the manufactured sand particles and inert micro-powder. Simultaneously, their inherent pozzolanic activity generates more CSH gel, filling the pores within the concrete, especially capillary pores, and blocking chloride ion migration pathways. Furthermore, the nano-sized SiO2 particles improve the surface smoothness of the manufactured sand, reduce interparticle friction, effectively improve the fluidity of the concrete, and enhance its workability. They also increase the density of the concrete.
[0038] Silane coupling agents are commonly used for the repair and reinforcement of concrete structures, effectively improving the interfacial bond strength between new and old concrete. Their unique chemical properties improve the interfacial performance between aggregate and cement paste, easily forming a chemically bonded layer on the aggregate surface, significantly enhancing the interfacial bond strength and thus improving the overall performance of the concrete. Furthermore, silane coupling agents form a hydrophobic layer on the aggregate surface, reducing the penetration of moisture and corrosive agents (chloride ions).
[0039] The present invention relates to a synergistic modification of the coarse aggregate-slurry interface and the manufactured sand-slurry interface in interface-reinforced high-durability nearshore structural concrete. This modification effectively reduces the interconnecting gaps at the aggregate-slurry interface and improves the density at the interface. The coarse aggregate-slurry interface, the transition slurry, and the manufactured sand-slurry interface form a multi-layered barrier and an overall effect, further blocking the diffusion of environmental chloride ions into the concrete interior, thus successfully improving the durability of nearshore structural concrete.
[0040] The optimized application of manufactured sand responds to the national goals of low-carbon and sustainable development. Moreover, manufactured sand costs about 20 yuan less per ton than natural sand. Using manufactured sand to replace natural sand can reduce the cost of concrete production, achieve the goal of cost reduction and efficiency improvement, and also has high social benefits.
[0041] The following are specific examples. The mechanical properties of concrete for nearshore structures are tested in accordance with the standard GB / T 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete"; the electrical conductivity performance of concrete for nearshore structures is tested in accordance with the standard GB / T 50082-2009 "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete".
[0042] Comparative Example 1: Concrete mix design for ordinary near-shore structures is as follows: (kg / m³) 3 )
[0043]
[0044] The mechanical properties and electrical flux of ordinary nearshore structural concrete are tested as follows:
[0045]
[0046] Example 1: The concrete mix design for high-durability nearshore structures is as follows: (kg / m³) 3 )
[0047]
[0048] The mechanical properties and electrical flux of high-durability nearshore structural concrete are tested as follows:
[0049]
[0050] Example 2: The concrete mix design for high-durability nearshore structures is as follows: (kg / m³) 3 )
[0051]
[0052] The mechanical properties and electrical flux of high-durability nearshore structural concrete are tested as follows:
[0053]
[0054] By comparing Examples 1 and 2 with Comparative Example 1, it can be seen that the mechanical properties and chloride ion penetration resistance of the near-shore structural concrete in the embodiments of the present invention are effectively improved.
[0055] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. The above embodiments only illustrate several implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.
Claims
1. An interface-reinforced, high-durability nearshore structural concrete, characterized in that, The components of the concrete are in the following mass ratio (kg / m³) 3 ): Granulated blast furnace slag powder 100-150, fly ash 50-100, cement 200-250, pretreated manufactured sand 200-300, pretreated coarse aggregate 900-1100, high-efficiency water-reducing agent 3-4, natural sand 400-500, and water 160-180.
2. A method for preparing interface-reinforced, high-durability nearshore structural concrete, characterized in that, The method for preparing the interface-reinforced, high-durability near-shore structural concrete of claim 1 includes the following steps: Step S1: Add cement, natural sand, granulated blast furnace slag powder, fly ash, pretreated coarse aggregate and pretreated manufactured sand into the mixer and mix for 60-120 seconds. Step S2: Add high-efficiency water-reducing agent and water, and stir for 240-360 seconds.
3. The preparation method according to claim 2, characterized in that, The pretreatment method for coarse aggregate is as follows: commercially available KH-550 silane coupling agent is mixed with anhydrous ethanol at a volume ratio of 1:19 to prepare a 5% solution, and an appropriate amount of deionized water is added to promote the hydrolysis reaction. After standing and maturing, it is used for aggregate surface treatment; crushed stone is soaked in a 5% silane coupling agent for 2 hours and then spread flat on the ground in a dry and ventilated place to air dry.
4. The preparation method according to claim 2, characterized in that, The pre-treatment method for manufactured sand is as follows: the manufactured sand is sieved using a 600μm square hole sieve to obtain inert micro powder after sieving. The remaining manufactured sand is placed in a dry place to dry, and nano-SiO2 sol is prepared in an alkaline environment using the sol-gel method.
5. The preparation method according to claim 4, characterized in that, The preparation method of the nano-SiO2 sol includes: adding 100 mL of anhydrous ethanol to a beaker as a solvent; adding 10 mL of tetraethyl orthosilicate and stirring evenly; slowly adding ammonia water to adjust the pH of the solution to 9-10; placing the beaker in a constant temperature water bath at 60-70°C; under stirring, slowly adding 10 mL of deionized water to initiate the hydrolysis reaction of tetraethyl orthosilicate; continuing to stir for 2-3 hours until the solution gradually becomes a transparent or translucent sol state; uniformly spraying the nano-SiO2 sol onto the surface of the sieved inert micro powder using a spray bottle; then mixing the treated inert micro powder with the sieved residue of the machine sand evenly at a weight ratio of 0.1-0.2:1.