Acid and alkali resistant corrosion resistant high-strength composite drainage pipe and preparation method thereof

Abstract

The application relates to the technical field of building materials, in particular to an acid-alkali-resistant and corrosion-resistant high-strength composite drainage pipe and a preparation method thereof. The pipe comprises the following raw materials in parts by weight: 260-350 parts of sulphoaluminate cement, 40-80 parts of fly ash, 60-90 parts of solid waste-based micro-nano composite, 600-760 parts of river sand, 950-1200 parts of gravel, 110-150 parts of water, 12-18 parts of microcapsule repair agent, 5-10 parts of microbial mineralization repair agent, 6-8 parts of additive, and 0.8-1.0 parts of polypropylene fiber. The corrosion-resistant cementitious material and the double-mechanism self-repairing system are synergistically integrated, so that the drainage pipe has high strength, realizes intelligent sensing, rapid sealing and permanent healing of microcracks, and the durability and service life of the pipe in a corrosive environment are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to an acid and alkali resistant and corrosion-resistant high-strength composite drainage pipe and its preparation method. Background Technology

[0002] Concrete drainage pipes, as core components of urban infrastructure, are widely used in municipal drainage, industrial wastewater transportation, and highway culverts. They are constantly exposed to complex soil and fluid environments, frequently subjected to corrosive media such as acids, sulfates, and chloride ions. Simultaneously, they endure internal water pressure, external loads, and temperature stress, making them highly susceptible to microcracks. These microcracks provide channels for the rapid intrusion of corrosive media, leading to steel reinforcement corrosion, concrete spalling, performance degradation, and ultimately premature structural failure, severely impacting the safety and service life of the drainage system.

[0003] Traditional concrete pipes show signs of corrosion within 2-3 years in acidic environments with a pH < 4 (corrosion rate reaches 1.5 mm / year). HDPE pipes have poor temperature resistance (softening above 60℃) and insufficient UV resistance (strength decreases by 40% after 5 years of outdoor use). Metal pipes suffer from severe electrochemical corrosion (perforation rate exceeds 30% in coastal areas after 3 years). New application scenarios include a 12% annual increase in wastewater treatment volume in chemical industrial parks (containing strong acids / alkalis / organic solvents); marine economic development driving demand for Cl- corrosion resistance (pipeline network lifespan required in seawater intrusion areas ≥ 30 years); and new standards for pressure resistance (≥ 1.6 MPa) being proposed for urban underground utility tunnels.

[0004] Although some technologies have been developed to improve the corrosion resistance of concrete by enhancing its corrosion resistance, applying protective coatings, or introducing a single self-healing mechanism, the inherent chemical nature of concrete, which is not resistant to acids, still requires further improvement; or the coating may fail due to poor adhesion between the coating and the substrate and easy damage; or the self-healing components (such as microorganisms) may not be able to survive and remain effective for a long time due to their limited repair capabilities or incompatibility with the high-alkali and high-temperature curing process environment of concrete. Summary of the Invention

[0005] This invention provides an acid and alkali resistant and corrosion-resistant high-strength composite drainage pipe and its preparation method, in order to solve the problems of existing concrete drainage pipes being prone to cracking and having insufficient durability in harsh corrosive environments such as strong acid and high salt, as well as the limited self-healing capabilities.

[0006] To address the above problems, the present invention provides an acid and alkali resistant, corrosion-resistant, high-strength composite drainage pipe and its preparation method, employing the following technical solution: A high-strength composite drainage pipe with acid and alkali resistance and corrosion resistance comprises the following raw materials in parts by weight: 260-350 parts of sulfoaluminate cement, 40-80 parts of fly ash, 60-90 parts of solid waste-based micro-nano composite, 600-760 parts of river sand, 950-1200 parts of crushed stone, 110-150 parts of water, 12-18 parts of microcapsule repair agent, 5-10 parts of microbial mineralization repair agent, 6-8 parts of additives; and 0.8-1.0 parts of polypropylene fiber.

[0007] Among them, the solid waste-based micro-nano composites include solid waste rich in calcium, silicon and aluminum and mechanical activators, with the amount of mechanical activators added in the solid waste-based micro-nano composites being 0.02%-0.05%.

[0008] The microcapsule repair agent has a capsule wall made of urea-formaldehyde resin-nano silica composite material and a core made of a mixture of vinyl ester resin and latent curing agent.

[0009] Among them, the microbial mineralization remediation agent includes alkali-resistant Bacillus licheniformis, nutrients, and a porous modified desulfurized gypsum carrier loaded with the bacteria and nutrients.

[0010] Furthermore, the mechanical activator is one or a mixture of triethanolamine, triisopropanolamine, diethanolamine, sodium hexametaphosphate, ethylene glycol, and polyethylene glycol.

[0011] Furthermore, the solid waste includes one or more of the following: power plant fly ash, desulfurization gypsum, slag, mineral slag, and tailings.

[0012] Furthermore, in the urea-formaldehyde resin-nano silica composite material, the mass of nano silica accounts for 3%-15% of the solid mass of urea-formaldehyde resin, and the thickness of the capsule wall is 3-5 μm.

[0013] Furthermore, in the core, the mass of the latent curing agent is 1%-5% of the mass of the vinyl ester resin.

[0014] The latent curing agent is at least one of dicumyl oxide and benzoyl peroxide.

[0015] Furthermore, the core also includes an accelerator, and the mass of the accelerator is 1% of the mass of the vinyl ester resin.

[0016] The accelerator is cobalt naphthenate.

[0017] Furthermore, the additive is a polycarboxylate high-performance water-reducing agent.

[0018] The above-mentioned method for preparing an acid and alkali resistant and corrosion-resistant high-strength composite drainage pipe includes the following steps: S1. Dry mixing treatment: Take an appropriate amount of sulfoaluminate cement, fly ash, solid waste-based micro-nano composite, river sand, and crushed stone, and put them into a mixer to mix the dry materials evenly.

[0019] S2. Take 80% water and all the additives and premix them to form a water-based agent. Then add the water-based agent to the dry material being mixed at a uniform speed and continue mixing to form mortar.

[0020] S3. Add all the polypropylene fibers, microcapsule repair agent, microbial mineralization repair agent, and the remaining 20% ​​water to the mortar in sequence, and stir gently at low speed until evenly mixed.

[0021] S4. Feed the mixture formed in S3 into the tube mold for molding, then let it stand for 1-2 hours, slowly raise the temperature and cure it at a certain temperature for 3-4 hours, and then let it cool naturally to room temperature.

[0022] S5. Demold the tube and transfer it to a water curing tank for at least one week.

[0023] Furthermore, in S4, the heating rate is 15-20℃ / h, and the temperature rise does not exceed 55℃.

[0024] Furthermore, in S4, the temperature is raised to 55°C and maintained at a constant temperature of 55°C.

[0025] The beneficial effects of the acid and alkali resistant, corrosion-resistant, high-strength composite drainage pipe and its preparation method provided by this invention are: 1. This invention employs a dual-repair synergistic mechanism. The microcapsule repair agent achieves rapid physical sealing; when a crack occurs, stress concentration causes the microcapsule to rupture, releasing the core and rapidly forming a waterproof sealing layer within days. This process effectively prevents the rapid intrusion of moisture and harmful ions. Additionally, the microbial mineralization repair agent allows moisture and air to penetrate along the microcracks, activating the microbial carrier. Alkali-resistant Bacillus licheniformis metabolizes nutrients to generate carbonate ions, which combine with calcium ions to form calcium carbonate crystals. These crystals continuously grow and intertwine, permanently filling and healing the crack within weeks.

[0026] The synergistic effect of microcapsule repair agents and microbial mineralization repair agents results in a flexible polymer sealing layer formed by the microcapsules, while the calcium carbonate produced by the microorganisms is a rigid mineral. The combination of these two agents creates a composite repair material with good compatibility with the concrete matrix and high strength.

[0027] Based on this, polypropylene fibers disperse macroscopic wide cracks into a large number of microcracks, which greatly increases the probability of contact with microcapsules and microorganisms, thereby improving the triggering efficiency and repair success rate of the repair system.

[0028] 2. In this invention, the hydration products of sulfoaluminate cement are mainly high-sulfur hydrated calcium sulfoaluminate (AFt) and low-alkalinity CSH gel, with almost no formation of the "weak phase" Ca(OH)2, which is susceptible to acid and sulfate corrosion. Furthermore, the solid waste micro / nano composite further consumes the remaining small amount of Ca(OH)2 in the system through the "volcanic ash effect," generating more stable CSH gel. Its micro / nano particles effectively fill the voids between cement particles, significantly reducing porosity and physically blocking corrosion pathways.

[0029] Furthermore, the inherently low alkalinity of the matrix provides a relatively mild survival environment for the alkali-resistant Bacillus licheniformis in the microbial remediation agent, a prerequisite for its long-term survival and maintenance of activity. Simultaneously, this environment also reduces the risk of alkaline hydrolysis of the microcapsule core-vinyl ester resin, ensuring the long-term stability of the remediation agent. Detailed Implementation

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Those skilled in the art should understand that the embodiments described below are only some, not all, of the embodiments disclosed. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0031] The principles and spirit of the present invention will be explained in detail below with reference to several representative embodiments.

[0032] Example 1 of an acid and alkali resistant and corrosion-resistant high-strength composite drainage pipe provided by the present invention: The raw materials include the following parts by weight: 300 parts of sulfoaluminate cement, 60 parts of fly ash, 75 parts of solid waste-based micro-nano composite, 680 parts of river sand, 1075 parts of crushed stone, 130 parts of water, 15 parts of microcapsule repair agent, 8 parts of microbial mineralization repair agent, 7 parts of additives, and 0.9 parts of polypropylene fiber.

[0033] The additive is a polycarboxylate high-performance water-reducing agent.

[0034] The polypropylene fiber is 19 mm in length.

[0035] Among them, the solid waste-based micro-nano composite is a solid waste rich in calcium, silicon and aluminum and a mechanical activator, and the amount of mechanical activator added in the solid waste-based micro-nano composite is 0.03%.

[0036] Specifically, the solid waste is a mixture of power plant fly ash, desulfurization gypsum, slag, mineral slag, and tailings. The maximum particle size of the solid waste is controlled to be no greater than 5 mm before use. After high-energy ball milling with a mechanical activator, a solid waste-based nano-mixture is obtained, with a surface area ≥600 m² / kg and a median particle size D50 ≤15 μm.

[0037] In this embodiment, the mechanical activator is triethanolamine.

[0038] In this embodiment, the capsule wall of the microcapsule repair agent is a urea-formaldehyde resin-nano silica composite material, and the core is a mixture of vinyl ester resin and latent curing agent.

[0039] Specifically, in the urea-formaldehyde resin-nano silica composite material, the mass of nano silica accounts for 9% of the solid mass of urea-formaldehyde resin, and the thickness of the capsule wall is 5 μm.

[0040] In the core, the mass of the latent curing agent is 3% of the mass of the vinyl ester resin.

[0041] The latent curing agent is dicumyl oxide. The core also includes an accelerator, and the mass of the accelerator is 1% of the mass of the vinyl ester resin.

[0042] The accelerator is cobalt naphthenate.

[0043] In this embodiment, the microcapsule repair agent is prepared as follows: Aqueous phase preparation: 1. In a three-necked flask, dissolve 4g of film-forming agent polyvinyl alcohol in 200g of deionized water and stir at 60℃ with medium speed until clear.

[0044] 2. Add 10g of urea and 20g of 37% formaldehyde solution, and stir well.

[0045] 3. Adjust the pH of the mixture to 8.5-9.0 using triethanolamine, a pH adjuster. This slightly alkaline environment is a necessary condition for the subsequent formation of urea-formaldehyde resin prepolymer.

[0046] 4. Add 1.57g of nano silica, increase the stirring speed, and continue stirring for 30 minutes to ensure it is fully dispersed and uniform.

[0047] Core preparation: In a beaker, mix 40g of vinyl ester resin, 1.2g of dicumyl peroxide and 0.4g of cobalt naphthenate.

[0048] Stir at low speed until the solids are completely dissolved and well mixed. Avoid vigorous stirring to prevent introducing too many air bubbles.

[0049] Capsule forming: 1. Stabilize the temperature of the aqueous system at 55℃ and maintain medium-speed stirring (approximately 400-600 rpm).

[0050] 2. The capsule core mixture is slowly and dropwise added to the aqueous phase using a dropping funnel.

[0051] 3. After the capsule core is added, increase the stirring speed to 1500-2000 rpm and continue emulsifying for 20-30 minutes to form a stable oil / water emulsion. At this time, under the action of shear force, the capsule core is dispersed into tiny droplets, while PVA and nano-SiO2 are distributed on the surface of the droplets, initially stabilizing the emulsion.

[0052] 4. Heat the reaction system to 60-65℃.

[0053] 5. At this temperature, urea and formaldehyde begin to undergo hydroxymethylation under weakly alkaline conditions, generating a transparent urea-formaldehyde resin prepolymer.

[0054] 6. As the reaction proceeds, the water-soluble urea-formaldehyde prepolymer begins to deposit in the aqueous phase onto the interface of the oil droplets because the interfacial energy is lowest. Simultaneously, nano-silica particles are also encapsulated and embedded into the forming wall material.

[0055] 7. Slowly add 2g of ammonium chloride (dissolved in a small amount of water) dropwise into the reaction system to achieve acidic curing.

[0056] 8. After cooling, filtering, and drying, a free-flowing white or off-white powdery microcapsule repair agent is obtained.

[0057] It should be noted that, in this embodiment, the fracture toughness of the matrix material formed after removing the microcapsule repair agent and the microbial mineralization repair agent in the acid and alkali resistant and corrosion-resistant high-strength composite drainage pipe is greater than that of the capsule wall.

[0058] In this embodiment, the microbial mineralization remediation agent includes alkali-resistant Bacillus licheniformis, nutrients, and a porous modified desulfurized gypsum carrier loaded with the bacteria and nutrients.

[0059] In this embodiment, the spore concentration of alkali-resistant Bacillus licheniformis is ≥10. 10 CFU / g.

[0060] The porous modified desulfurized gypsum carrier has a particle size range of 150-300μm and a porosity of >40%.

[0061] The weight ratio of alkali-resistant Bacillus licheniformis spores to porous modified desulfurized gypsum carrier and nutrient solution is 4:42:100.

[0062] The nutrients include urea, calcium lactate, and yeast extract. In this embodiment, trehalose is added to enhance the activity of alkali-resistant Bacillus licheniformis. The weight ratio of urea, calcium lactate, yeast extract, and trehalose is (10:10:1:2.5).

[0063] The acid- and alkali-resistant, corrosion-resistant, high-strength composite drainage pipe is prepared using the materials described in this embodiment according to the following steps.

[0064] S1. Dry mixing treatment: Take the corresponding amounts of sulfoaluminate cement, fly ash, solid waste-based micro-nano composite, river sand, and crushed stone, and put them into the mixer to make the dry materials mix evenly.

[0065] S2. Take 80% water and all the additives and premix them to form a water-based agent. Then add the water-based agent to the dry material being mixed at a uniform speed and continue mixing to form mortar.

[0066] S3. Add all the polypropylene fibers, microcapsule repair agent, microbial mineralization repair agent, and the remaining 20% ​​water to the mortar in sequence, and stir gently at low speed until evenly mixed.

[0067] Specifically, stir gently at a low speed of 15-30 revolutions per minute for 5-8 minutes.

[0068] To minimize damage to microcapsule repair agents and microbial mineralization repair agents. S4. Feed the mixture formed in S3 into the tube mold for molding, then let it stand for 1-2 hours, slowly raise the temperature and cure it at a certain temperature for 3-4 hours, and then let it cool naturally to room temperature.

[0069] S5. Demold the tube and transfer it to a water curing tank for one week.

[0070] In S4, the heating rate is 15-20℃ / h, and the temperature rise does not exceed 55℃.

[0071] In S4, the temperature is raised to 55℃ and maintained at a constant temperature of 55℃.

[0072] Example 2 of an acid and alkali resistant and corrosion-resistant high-strength composite drainage pipe provided by the present invention: The raw materials include the following parts by weight: 260 parts of sulfoaluminate cement, 40 parts of fly ash, 60 parts of solid waste-based micro-nano composite, 600 parts of river sand, 950 parts of crushed stone, 110 parts of water, 12 parts of microcapsule repair agent, 5 parts of microbial mineralization repair agent, 6 parts of additives, and 0.8 parts of polypropylene fiber.

[0073] The additive is a polycarboxylate high-performance water-reducing agent.

[0074] The polypropylene fiber is 19 mm in length.

[0075] Among them, the solid waste-based micro-nano composite is a solid waste rich in calcium, silicon and aluminum and a mechanical activator, and the amount of mechanical activator added in the solid waste-based micro-nano composite is 0.02%.

[0076] Specifically, the solid waste is a mixture of power plant fly ash, desulfurization gypsum, slag, mineral slag, and tailings. The maximum particle size of the solid waste is controlled to be no greater than 5 mm before use. After high-energy ball milling with a mechanical activator, a solid waste-based nano-mixture is obtained, with a surface area ≥600 m² / kg and a median particle size D50 ≤15 μm.

[0077] In this embodiment, the mechanical activator is triethanolamine.

[0078] In this embodiment, the capsule wall of the microcapsule repair agent is a urea-formaldehyde resin-nano silica composite material, and the core is a mixture of vinyl ester resin and latent curing agent.

[0079] Specifically, in the urea-formaldehyde resin-nano silica composite material, the mass of nano silica accounts for 3% of the solid mass of urea-formaldehyde resin, and the thickness of the capsule wall is 3μm.

[0080] In the core, the mass of the latent curing agent is 1% of the mass of the vinyl ester resin.

[0081] The latent curing agent is dicumyl oxide. The core also includes an accelerator, and the mass of the accelerator is 1% of the mass of the vinyl ester resin.

[0082] The accelerator is cobalt naphthenate.

[0083] In this embodiment, the microbial mineralization remediation agent includes alkali-resistant Bacillus licheniformis, nutrients, and a porous modified desulfurized gypsum carrier loaded with the bacteria and nutrients.

[0084] In this embodiment, the spore concentration of alkali-resistant Bacillus licheniformis is ≥10. 10 CFU / g.

[0085] The porous modified desulfurized gypsum carrier has a particle size range of 150-300μm and a porosity of >40%.

[0086] The weight ratio of alkali-resistant Bacillus licheniformis spores to porous modified desulfurized gypsum carrier and nutrient solution is 4:42:100.

[0087] The nutrients include urea, calcium lactate, and yeast extract. In this embodiment, trehalose is added to enhance the activity of alkali-resistant Bacillus licheniformis. The weight ratio of urea, calcium lactate, yeast extract, and trehalose is (10:10:1:2.5).

[0088] Example 3 of an acid and alkali resistant and corrosion-resistant high-strength composite drainage pipe provided by the present invention: The raw materials include the following parts by weight: 350 parts of sulfoaluminate cement, 80 parts of fly ash, 90 parts of solid waste-based micro-nano composite, 760 parts of river sand, 1200 parts of crushed stone, 150 parts of water, 18 parts of microcapsule repair agent, 10 parts of microbial mineralization repair agent, 8 parts of additives; and 1.0 part of polypropylene fiber.

[0089] The additive is a polycarboxylate high-performance water-reducing agent.

[0090] The polypropylene fiber is 19 mm in length.

[0091] Among them, the solid waste-based micro-nano composite is a solid waste rich in calcium, silicon and aluminum and a mechanical activator, and the amount of mechanical activator added in the solid waste-based micro-nano composite is 0.05%.

[0092] Specifically, the solid waste is a mixture of power plant fly ash, desulfurization gypsum, slag, mineral slag, and tailings. The maximum particle size of the solid waste is controlled to be no greater than 5 mm before use. After high-energy ball milling with a mechanical activator, a solid waste-based nano-mixture is obtained, with a surface area ≥600 m² / kg and a median particle size D50 ≤15 μm.

[0093] In this embodiment, the mechanical activator is triethanolamine.

[0094] In this embodiment, the capsule wall of the microcapsule repair agent is a urea-formaldehyde resin-nano silica composite material, and the core is a mixture of vinyl ester resin and latent curing agent.

[0095] Specifically, in the urea-formaldehyde resin-nano silica composite material, the mass of nano silica accounts for 15% of the solid mass of urea-formaldehyde resin, and the thickness of the capsule wall is 4μm.

[0096] In the core, the mass of the latent curing agent is 1% of the mass of the vinyl ester resin.

[0097] The latent curing agent is dicumyl oxide. The core also includes an accelerator, and the mass of the accelerator is 1% of the mass of the vinyl ester resin.

[0098] The accelerator is cobalt naphthenate.

[0099] In this embodiment, the microbial mineralization remediation agent includes alkali-resistant Bacillus licheniformis, nutrients, and a porous modified desulfurized gypsum carrier loaded with the bacteria and nutrients.

[0100] In this embodiment, the spore concentration of alkali-resistant Bacillus licheniformis is ≥10. 10 CFU / g.

[0101] The porous modified desulfurized gypsum carrier has a particle size range of 150-300μm and a porosity of >40%.

[0102] The weight ratio of alkali-resistant Bacillus licheniformis spores to porous modified desulfurized gypsum carrier and nutrient solution is 4:42:100.

[0103] The nutrients include urea, calcium lactate, and yeast extract. In this embodiment, trehalose is added to enhance the activity of alkali-resistant Bacillus licheniformis. The weight ratio of urea, calcium lactate, yeast extract, and trehalose is (10:10:1:2.5).

[0104] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that no microcapsule repair agent and microbial mineralization repair agent were added.

[0105] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that no microcapsule repair agent was added.

[0106] Comparative Example 3 The difference between Comparative Example 2 and Example 1 is that no microbial mineralization repair agent was added.

[0107] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that no nano-silica is added to the microcapsule repair agent.

[0108] Experimental Example 1 Mechanical performance testing. The 28-day compressive strength of concrete is tested in accordance with national standards, the core of which is GB / T50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete".

[0109] Impermeability test: The impermeability grade is tested according to the standard GB / T50082-2009 "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete" in the "Water Permeability Test" section. Repair test: A 0.3mm wide crack is prefabricated, and after 28 days of curing, the recovery of its impermeability is tested.

[0110] Corrosion resistance: The specimens were immersed in a 5% sodium sulfate solution and a dilute sulfuric acid solution with pH=3. After 60 days, the strength loss rate and mass loss rate were measured.

[0111] The test data is shown in Table 1 below: Table 1 As can be seen from Table 1, all examples exhibit high strength and high impermeability, indicating that the addition of the repair agent did not weaken the basic properties of the matrix. Combined with Comparative Example 4, the addition of the repair agent brought about a positive filling effect.

[0112] Experimental Example 2 Test of self-healing efficacy: A 0.3 mm wide crack was prefabricated and cured under standard conditions for 28 days. The change in crack width was observed under a microscope, and the compressive strength recovery rate (strength after repair / strength before damage) was calculated.

[0113] Microbial activity: The number of viable spores in the cured concrete powder was determined by plate counting.

[0114] The test data is shown in Table 2 below: Table 2 As shown in Table 2, Examples 1, 2, and 3 demonstrated highly efficient dual-mechanism repair capabilities. The cracks were almost completely healed, with the highest recovery rates in strength and impermeability, proving the highly efficient synergy between microcapsules (rapid sealing) and microorganisms (permanent mineralization).

[0115] In Comparative Example 2, only the microbial mineralization repair agent showed slow repair speed and poor early sealing, resulting in low strength and impermeability recovery rate.

[0116] In Comparative Example 3, only microcapsule repair agents were present, which could achieve good surface sealing. However, the repair material was an organic polymer, and its compatibility and strength with the matrix were not as good as those of minerals.

[0117] In Comparative Example 4, the repair effect was average, proving that the wall material modified with nano-SiO2 can be triggered more effectively, thereby releasing more repair agents and improving repair efficiency.

[0118] Test Example 4 Corrosion resistance: The specimens were immersed in a 5% sodium sulfate solution and a dilute sulfuric acid solution with pH=3. After 60 days, the strength loss rate and mass loss rate were measured.

[0119] The test data is shown in Table 3 below: Note: A negative strength loss rate indicates a decrease in strength; a positive mass loss rate indicates an increase in mass (accumulation of sulfate corrosion products), and a negative mass loss rate indicates a decrease in mass (acid dissolution).

[0120] Table 3 It should be noted that the standard cement is specifically defined as follows: compared with the example, no solid waste-based micro-nano composites and remediation agents are added, and sulfoaluminate cement is replaced with ordinary silicate cement.

[0121] As shown in Table 3, Example 1 exhibits better durability, lower strength, and lower loss rate under both corrosive environments.

[0122] In Example 1, sulfoaluminate cement and solid waste-based micro / nano composites can form a low-calcium, high-density, corrosion-resistant matrix. Microcracks generated during corrosion are promptly sealed by the self-healing system, blocking the path of corrosive media penetration and forming a dynamic "immune protection".

[0123] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details.

Claims

1. A high-strength composite drainage pipe resistant to acids and alkalis, characterized in that, The raw materials include the following parts by weight: 260-350 parts of sulfoaluminate cement, 40-80 parts of fly ash, 60-90 parts of solid waste-based micro / nano composite, 600-760 parts of river sand, 950-1200 parts of crushed stone, 110-150 parts of water, 12-18 parts of microcapsule repair agent, 5-10 parts of microbial mineralization repair agent, 6-8 parts of additives; and 0.8-1.0 parts of polypropylene fiber. The solid waste-based micro / nano composite includes solid waste rich in calcium, silicon, and aluminum, and a mechanical activator. The amount of mechanical activator added to the solid waste-based micro / nano composite is 0.02%-0.05%. Among them, the wall of the microcapsule repair agent is a urea-formaldehyde resin-nano silica composite material, and the core is a mixture of vinyl ester resin and latent curing agent; Among them, the microbial mineralization remediation agent includes alkali-resistant Bacillus licheniformis, nutrients, and a porous modified desulfurized gypsum carrier loaded with the bacteria and nutrients.

2. The acid and alkali resistant and corrosion-resistant high-strength composite drainage pipe according to claim 1, characterized in that, The mechanical activator is one or a mixture of triethanolamine, triisopropanolamine, diethanolamine, sodium hexametaphosphate, ethylene glycol, and polyethylene glycol.

3. The acid and alkali resistant, corrosion-resistant, high-strength composite drainage pipe according to claim 1, characterized in that, The solid waste includes one or more of the following: power plant fly ash, desulfurization gypsum, slag, mineral slag, and tailings.

4. The acid and alkali resistant and corrosion-resistant high-strength composite drainage pipe according to claim 1, characterized in that, In the urea-formaldehyde resin-nano silica composite material, the mass of nano silica accounts for 3%-15% of the solid mass of urea-formaldehyde resin, and the thickness of the capsule wall is 3-5 μm.

5. The acid and alkali resistant and corrosion-resistant high-strength composite drainage pipe according to claim 1, characterized in that, In the core, the mass of the latent curing agent is 1% - 5% of the mass of the vinyl ester resin; The latent curing agent is at least one of dicumyl oxide and benzoyl peroxide.

6. The acid and alkali resistant and corrosion-resistant high-strength composite drainage pipe according to claim 1, characterized in that, The core also includes an accelerator, and the mass of the accelerator is 1% of the mass of the vinyl ester resin; The accelerator is cobalt naphthenate.

7. The acid and alkali resistant and corrosion-resistant high-strength composite drainage pipe according to claim 1, characterized in that, The additive is a polycarboxylate high-performance water-reducing agent.

8. A method for preparing an acid and alkali resistant, corrosion-resistant, high-strength composite drainage pipe according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Dry mixing treatment: Take an appropriate amount of sulfoaluminate cement, fly ash, solid waste-based micro-nano composite, river sand, and crushed stone, and put them into a mixer to make the dry materials mix evenly. S2. Take 80% water and all the additives and premix them to form an aqueous solution. Then add the aqueous solution to the dry material being mixed at a uniform speed and continue mixing to form mortar. S3. Add all the polypropylene fibers, microcapsule repair agent, microbial mineralization repair agent, and the remaining 20% ​​water to the mortar in sequence, and stir gently at low speed until evenly mixed. S4. Feed the mixture formed in S3 into the tube mold for molding, then let it stand for 1-2 hours, slowly raise the temperature and cure it at a certain temperature for 3-4 hours, and then let it cool naturally to room temperature. S5. Demold the tube and transfer it to a water curing tank for at least one week.

9. The method for preparing the acid and alkali resistant and corrosion-resistant high-strength composite drainage pipe according to claim 8, characterized in that, In S4, the heating rate is 15-20℃ / h, and the temperature rise does not exceed 55℃.

10. The method for preparing the acid and alkali resistant and corrosion-resistant high-strength composite drainage pipe according to claim 9, characterized in that, In S4, the temperature is raised to 55℃ and maintained at a constant temperature of 55℃.

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