Preparation method of synergistically modified concrete-basalt fiber high-corrosion-resistance composite pipeline
By lining the concrete pipe with a composite structure of basalt fiber felt and external protective PE fiberboard, combined with magnesium-based compounds and calcium aluminate modifiers, the structural and corrosion resistance problems of the concrete pipe are solved, and the preparation of a highly corrosion-resistant, anti-seepage and anti-cracking composite pipe is achieved.
Patent Information
- Application Number
- CN202510932469.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-07
- Publication Date
- 2025-09-09
AI Technical Summary
Existing concrete pipes have structural defects such as misalignment, undulation, and cracking in industrial applications, and have poor acid and alkali resistance, corrosion resistance, and high temperature resistance. Existing improvement solutions are costly or complex in process and have poor environmental performance.
A composite structure with basalt fiber felt as inner lining and PE fiberboard as outer protection is adopted, combined with magnesium-based compounds and calcium aluminate modifiers to form a high-strength concrete layer, which forms a corrosion-resistant composite pipe through synergistic reaction.
It significantly improves the corrosion resistance of the pipeline, extends its service life, enhances its compressive strength, is suitable for acid, sulfate or chloride environments, and has anti-seepage and anti-cracking properties.
Smart Images
Figure CN120606541A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of industrial transportation pipelines, and in particular to a method for preparing a synergistically modified concrete-basalt fiber high-corrosion-resistant composite pipeline. Background Art
[0002] Concrete pipes are a common form of drainage pipes due to their simplicity, low cost, ease of installation, and high load-bearing capacity, making them widely used worldwide. However, concrete pipes exhibit several drawbacks in practical use. Major structural defects include misalignment, undulations, cracks, and leakage. Key performance deficiencies include limited acid and alkali resistance, poor corrosion resistance, and poor high-temperature performance. Existing improvement solutions (such as steel reinforcement and polymer coatings) suffer from high costs, complex processes, and poor environmental performance. Basalt fiber is a fiber and composite material made from volcanic basalt through a specific process. It exhibits high tensile strength and excellent mechanical properties; low thermal conductivity, excellent flame retardancy, and both high and low-temperature resistance; acid and alkali resistance, excellent chemical stability, and strong corrosion resistance; as well as excellent compatibility with cement and strong bonding strength, offering irreplaceable advantages for reinforcing cement concrete structures. Chopped basalt fiber is an inorganic mineral fiber made from a corresponding continuous basalt fiber matrix, chopped to lengths less than 50 mm, that can be evenly distributed throughout cement concrete. Adding chopped basalt fibers to concrete creates a uniform, randomly distributed support system within the concrete, effectively creating a secondary reinforcement effect. The randomly distributed basalt fibers can reduce the concrete's plastic shrinkage, dispersing the shrinkage energy across countless fibers. This effectively enhances the concrete's toughness and reduces cracks and fissures caused by shrinkage during initial setting. However, simultaneous bonding of basalt fibers to the interior and exterior walls of concrete pipes has yet to be seen.
[0003] Concrete is a heterogeneous, multi-component, porous composite material composed of three phases: solid, liquid, and gas. Certain corrosive media in the concrete structure's environment enter through the concrete's pores, where they react with the Ca(OH)2 solution and cement hydration products present in the pores, resulting in chemical reactions and a series of physical and chemical destructive effects, known as concrete corrosion. In industrial applications, corrosion of concrete structures primarily falls into three categories: decomposition, crystallization, and a combination of crystallization and decomposition. Modifiers are chemical substances introduced into cement to improve the concrete's internal structure, increase its density, enhance its impermeability, and thereby enhance its corrosion resistance. Different modifiers have varying properties and chemical reactions. For industrial applications, optimizing the modifier formulation and selecting materials that dynamically respond to corrosive environments can be considered. By sacrificing the decomposition products of certain components and reacting with other components, a more stable anti-corrosion phase can be formed, thereby triggering localized self-repair or enhancing corrosion protection. Summary of the Invention
[0004] To address the above problems, the present invention provides a method for preparing a synergistically modified concrete-basalt fiber high-corrosion-resistant composite pipe. The composite pipe of the present invention comprises, from the inside to the outside, an inner lining layer, a high-strength concrete layer, and an outer protective layer. The preparation method comprises the following steps: 1) Spray epoxy resin on the outer wall of the inner mold of the annular mold for pre-curing; 2) Lay basalt fiber felt on the pre-cured epoxy resin and heat to cure; 3) Pour high-strength concrete slurry on the heated and cured epoxy resin and the inner wall of the annular mold outer mold, and vibrate to compact it; 4) Remove the inner mold and lay the outer protective layer on the outside of the poured high-strength concrete slurry; 5) Coat fluorocarbon resin on the outer protective layer, steam cure it after curing, and then remove the inner mold of the mold to obtain it.
[0005] The composite pipe produced by this invention features an outer protective layer made of PE fiberboard to enhance the pipe's impact resistance. The PE fiberboard is bonded to the high-strength concrete layer with a special adhesive, ensuring a tight bond between the two layers and preventing the infiltration of moisture and corrosive media, thereby improving the pipe's corrosion resistance. Furthermore, the PE fiberboard exhibits excellent toughness and wear resistance, effectively resisting scratches and abrasion from external objects and extending the pipe's service life.
[0006] The specific composition of each layer of the composite pipeline structure is as follows: ① Inner lining layer: basalt fiber felt or woven cloth, which is pre-cured with epoxy resin and then adhered to the inner wall of the mold; ② High-strength concrete layer: High-strength concrete poured on the outside of the inner lining layer, with short-cut basalt fiber and modifier added, and vibrated to compact; ③ Outer protective layer: The outer layer of basalt fiber mesh cloth is coated with fluorocarbon resin material and cured to wrap the concrete layer.
[0007] The modifier formula and modification mechanism of the present invention are as follows: 1. Modifier formula ①Magnesium-based compound (MgO / Mg(OH)2) modifier Add 3~5% of magnesium-based compounds (MgO / Mg(OH)2) as sacrificial components. When in an acidic environment, they are consumed first. The chemical reaction formula is as follows: MgO + H2O → Mg(OH)2 (Formula 1); Mg(OH)2 + 2H + → Mg 2+ + 2H2O (Formula 2); Released Mg 2+ It reacts with the active SiO2 in silica fume / slag to form low-solubility acid-resistant magnesium silicate gel (MSH). The chemical reaction formula is as follows: Mg 2+ + SiO2 + H2O → MSH (Formula 3); ②Calcium aluminate (CaAl2O4) modifier Add 5~8% calcium aluminate (CaAl2O4) as a sacrificial component. When in a sulfate corrosion environment, CaAl2O4 will trigger a secondary phase with sulfate, preferentially reacting to form ettringite (AFt) and aluminum gel, filling the pores caused by local corrosion. The chemical reaction formula is as follows: CaAl2O4 + 3CaSO4 + 16H2O→3CaO·Al2O3·3CaSO4·(30~32)H2O (Formula 4); Al 3+ + 3OH - → Al(OH)3 (Formula 5); 2. Synergistic mechanism between the two modifiers a. In an acidic environment, the preferential reaction of magnesium-based compounds (MgO / Mg(OH)2) can delay the sudden drop in the pH of the system and protect calcium aluminate (CaAl2O4) and cement hydration products (such as CSH) from rapid dissolution; Mg 2+ Al released from CaAl2O4 3+ , SiO2 in silica fume / slag reacts to form magnesium aluminum silicate gel (MASH), which can bind harmful ions (such as Cl⁻, SO4 2- ), the chemical reaction formula is as follows: Mg 2+ + Al 3+ + SiO2 + H2O → MASH (Eq. 6); b. Under sulfate environment, Mg 2+ With SO4 2- Prioritizes the generation of magnesium sulfate (MgSO4) to reduce SO4 2- Risk of forming expansive ettringite by reaction with CaAl2O4; Al(OH)3 gel generated by the reaction of CaAl2O4 and the decomposition products of Mg(OH)2 fill pores / cracks together, reducing the sulfate penetration rate.
[0008] Mg 2+ + SO4 2- → MgSO4 (Formula 7); c. In a chloride salt environment, the Mg(OH)2 layered structure can physically adsorb Cl - , reducing free Cl - Corrosion of concrete; CaAl2O4 and Cl -The reaction generates Friedel salt (3CaO·Al2O3·CaCl2·10H2O), which solidifies chloride ions.
[0009] C3A + CaCl2 + 10H2O → 3CaO·Al2O3·CaCl2·10H2O (Formula 8).
[0010] The present invention utilizes the excellent properties of basalt fiber materials and the synergistic enhancement mechanism of the modifier and the corrosive components or concrete ingredients, so that the basalt fiber-concrete composite pipeline structure with the added modifier has the advantages of anti-seepage and crack prevention, long service life, and high compressive strength. At the same time, it significantly improves the corrosion resistance in acid, sulfate or chloride environments, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 Schematic diagram of the synergistic enhancement mechanism of magnesium-based compounds (MgO / Mg(OH)2) and calcium aluminate (CaAl2O4). DETAILED DESCRIPTION
[0012] The present invention is described below with reference to examples, which are only used to explain the present invention and are not used to limit the scope of the present invention.
[0013] The present invention adopts synergistic modified concrete-basalt fiber to prepare a high corrosion-resistant composite pipe. The high corrosion-resistant composite pipe comprises an inner lining layer, a high-strength concrete layer and an outer protective layer from the inside to the outside.
[0014] The preparation method is as follows: 1. Use a sprayer to spray epoxy resin on the inner wall of the mold: the binder of basalt fiber felt has good compatibility with the resin, which can improve the formability of special-shaped composite materials. Therefore, epoxy resin is selected as a thermosetting polymer synthetic material for bonding between the basalt fiber felt lining layer and the high-strength concrete layer.
[0015] Second, lay basalt fiber felt inside the mold and heat-cure it: Basalt fiber felt is a non-woven basalt fiber felt made from chopped basalt fibers through a wet-molding process. It is a new type of high-performance reinforcement material with excellent properties such as high strength, high modulus, high temperature resistance, corrosion resistance, and insulation. As an inner lining, it can improve the pipeline's anti-leakage and anti-corrosion capabilities.
[0016] Third, pour a C60 concrete slurry containing 1% chopped basalt fiber, 3% magnesium-based compounds (MgO / Mg(OH)2), and 5% calcium aluminate (CaAl2O4). Vibration compaction is then performed to achieve mechanical interlocking and enhanced corrosion resistance. Basalt fiber significantly improves concrete performance, enhancing shear, splitting, and fatigue resistance. It significantly improves concrete's mechanical properties, offering significant advantages in performance and price over steel fiber reinforced concrete, glass fiber reinforced concrete, synthetic fiber reinforced concrete, and carbon fiber reinforced concrete. The simultaneous addition of 3% magnesium-based compounds (MgO / Mg(OH)2) and 5% calcium aluminate (CaAl2O4) creates a synergistic effect in acidic, sulfate, or chloride environments, significantly enhancing corrosion resistance. It's important to note that excessive amounts of modifiers should be avoided, as excessive magnesium-based compounds can reduce strength, while excessive calcium aluminate can cause excessive expansion of the reaction product, ettringite.
[0017] 4. Before the initial setting of concrete, apply basalt fiber mesh cloth on the outside: Basalt fiber mesh cloth is based on basalt fiber woven fabric and is soaked in a high-molecular anti-emulsion coating. As an outer protective layer, it makes the pipeline have good acid and alkali resistance and corrosion / erosion resistance.
[0018] 5. Cover with fluorocarbon resin and steam cure for 72 hours before demoulding: Fluorocarbon coating is a series of coatings with fluorocarbon resin as the main film-forming substance. It shows excellent weather resistance, resistance to chemical corrosion, and can maintain stable performance in a variety of environments.
[0019] Figure 1 It is the synergistic enhancement mechanism of magnesium-based compounds (MgO / Mg(OH)2) and calcium aluminate (CaAl2O4) in three environments: acid, sulfate or chloride.
[0020] 1. Under acidic environment, magnesium-based compound modifier reacts preferentially with H+ to generate Mg 2+ and water; Al2O4 reacts to form 3+ and Al(OH)3 gel; Mg 2+ and Al released by water and calcium aluminate modifier 3+ , SiO2 in silica fume / slag reacts to form magnesium aluminum silicate gel (MASH); magnesium aluminum silicate gel and Al(OH)3 gel together fill the pores produced by local corrosion.
[0021] 2. Under sulfate environment, Mg 2+ With SO4 2- The first step is to generate magnesium sulfate (MgSO4). CaAl2O4 will react with sulfate to generate ettringite (AFt). The generation of magnesium sulfate consumes SO4. 2- , reducing SO4 2-Risk of reacting with CaAl2O4 to form expansive ettringite; magnesia sulfate and ettringite together fill pores / cracks and reduce the sulfate penetration rate.
[0022] 3. In chloride salt environment, Mg(OH)2 layered structure can physically adsorb Cl - , reducing free Cl - Corrosion of concrete; CaAl2O4 and Cl - The reaction forms Friedel salt (3CaO·Al2O3·CaCl2·10H2O), which can solidify chloride ions as a stable phase.
[0023] 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, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.
Claims
1. A method for preparing a synergistic modified concrete-basalt fiber high corrosion resistance composite pipe, characterized in that: The composite pipe comprises, from inside to outside, an inner lining layer, a high-strength concrete layer and an outer protective layer; The preparation method comprises the following steps: 1) Spray epoxy resin on the outer wall of the inner mold of the annular mold for pre-curing; 2) Lay basalt fiber felt on the pre-cured epoxy resin and heat to cure; 3) Pour high-strength concrete slurry on the heated and cured epoxy resin and the inner wall of the annular mold outer mold, and vibrate to compact it; 4) Remove the inner mold and lay the outer protective layer on the outside of the poured high-strength concrete slurry; 5) Coat fluorocarbon resin on the outer protective layer, steam cure it after curing, and then remove the inner mold of the mold to obtain it.
2. The preparation method according to claim 1, characterized in that The high-strength concrete slurry is composed of the following substances in percentage by weight: 1% to 3% of chopped basalt fiber, 3% to 5% of a magnesium-based modifier, 5% to 8% of a calcium-based modifier, and the balance of concrete.
3. The preparation method according to claim 1, characterized in that The outer protective layer is basalt fiber mesh cloth.