44 results about "Sulphate attack" patented technology

The invention discloses sulfate-erosion-resistant metakaolin-slag-based geopolymer concrete, belongs to the technical field of concrete, and aims to solve the problems that the corrosion resistance of traditional silicate concrete is ineffective and the adaptability of conventional alkali-activated concrete is insufficient in a special environment. The concrete comprises the following components in parts by weight: 60-90 parts of a cementing material, 120-170 parts of aggregate, 15-30 parts of a composite activator, 2-8 parts of a function regulator and the like, the cementing material is prepared from nano TiO2 / KH-550 composite modified metakaolin, slag and silica fume-coal gangue powder-HAP composite powder; the aggregate comprises modified limestone macadam (soaked and dried by a sodium dihydrogen phosphate solution) and river sand; the composite exciting agent comprises water glass, sodium hydroxide, sodium pyrophosphate, propylene glycol and the like; the function regulator comprises superfine fly ash, a naphthalene water reducer, HPMC (Hydroxy Propyl Methyl Cellulose) and boric acid. Through the synergistic effect of the components, the sulfate corrosion resistance, the mechanical property and the environmental adaptation performance of the concrete are improved, and the concrete is suitable for engineering construction under the service environment of high-concentration sulfate and the like.

The invention belongs to the technical field of building material and solid waste resource utilization, and relates to a high-durability and high-toughness slag powder-steel slag powder quaternary synergistic excitation-reinforcing agent and a preparation method of gel system mortar. The quaternary synergistic excitation-reinforcing agent comprises the following raw materials in parts by mass: 4-16 parts of sodium hydroxide, 79 parts of sodium silicate, 4-16 parts of aluminum sulfate and 60 parts of metakaolin, and the sum of the mass parts of the sodium hydroxide and the aluminum sulfate is 20. According to the quaternary synergistic excitation-reinforcing agent, sodium hydroxide and sodium silicate are used as main excitants, and aluminum sulfate serving as a function regulator and metakaolin serving as a high-activity aluminum-silicon source and a micro aggregate are introduced to serve as synergistic reinforcing components; the four components cooperate to jointly form an excitation-reinforcement composite system with high durability and high toughness; the sulfate erosion resistance, the chloride ion penetration resistance, the carbonization resistance, the toughness and the impact resistance of the slag powder-steel slag powder cementing system mortar are improved.

The present application belongs to the technical field of concrete, and discloses a method for evaluating the degradation grade of concrete aggregate caused by sulphate attack. The method comprises the following steps: first, preparing fine aggregate samples from the sulphur-containing aggregate to be evaluated; then, mixing the samples with cement and water to prepare mortar expansion rate test pieces and mortar flexural strength test pieces; next, testing the 84d expansion rate of the mortar expansion rate test pieces and the 84d flexural strength retention rate of the mortar flexural strength test pieces; finally, evaluating the grade according to the test results: if the 84d expansion rate is greater than 0.2%, the sulphate attack is determined to be strong; if the 84d expansion rate is less than or equal to 0.2% and the flexural strength retention rate is less than 80%, the sulphate attack is determined to be moderate; if the 84d expansion rate is less than or equal to 0.2% and the flexural strength retention rate is greater than or equal to 80%, the sulphate attack is determined to be weak. The present application solves the problem of the lack of a unified test method standard for sulphate attack on concrete aggregate, provides a complete test method, establishes an evaluation system for the damage grade of sulphate attack, and promotes the use of aggregate with excessive sulphur content.

The invention discloses low-heat slag cement and a preparation method thereof. The cement is prepared from the following components in percentage by weight: 50%-70% of high belite Portland cement clinker, 20%-50% of active slag micropowder, 4%-6% of gypsum, 1%-5% of composite functional filler, 0.1%-1.0% of a construction performance regulator and 0.01%-0.1% of a grinding aid. The preparation method comprises the following steps: preparing the rapidly cooled high belite clinker; the slag and the sodium sulfate-triethanolamine composite exciting agent are jointly ground to prepare high-activity slag micro powder; all the components are jointly ground in proportion until the specific surface area is 300-400 m / kg, and the proportion of particles with the particle size of 3-30 microns is controlled to be larger than 70%. Through the synergistic effect of multiple components, low hydration heat (less than or equal to 230kJ / kg in 7 days), high early strength (more than or equal to 12MPa in 7 days) and high later strength (more than or equal to 32.5 MPa in 28 days) are realized at the same time, and the concrete has excellent chloride ion permeation resistance and sulfate attack resistance, is excellent in construction performance, and is particularly suitable for engineering construction of mass concrete and in a severe environment.

This invention discloses a method for predicting concrete strength based on surface color changes under sulfate attack. The steps are as follows: preparing several sets of standard concrete specimens; conducting sulfate attack experiments on the standard concrete specimens for different numbers of attacks; testing the compressive strength of the standard concrete specimens under different numbers of attacks; measuring the surface color of the standard concrete specimens after testing the compressive strength under different numbers of attacks and creating a standard color chart for concrete sulfate attack; establishing the correspondence between the content of corrosion products and the number of cycles; establishing a curve showing the relationship between surface color and total content of corrosion products; establishing a curve showing the relationship between corrosion products and compressive strength; and predicting the compressive strength of concrete in the field. This invention provides a short evaluation cycle, high accuracy, and avoids damage to the concrete structure.

The present application relates to the technical field of concrete, in particular to a high-performance concrete mixture for power plants and a construction method thereof. The interface-hydration synergistic regulation technology is adopted, in which cementitious materials, water, river sand and continuously graded gravel are used as the matrix, and poly-carboxylic acid water reducing agent, crystal nucleus slurry A / B and zwitterionic-hydrophobic copolymer brush modified silica particle B are alternately added in stages to pre-coat and synchronously disperse the coarse aggregate, so that the concrete with long-time slump retention, low bleeding, high early and long-term strength, significantly reduced electric flux and chloride ion permeability, improved sulfate erosion resistance and volume stability is obtained under the conventional mixing and pumping conditions. The in-mold temperature, layered pouring thickness, vibration frequency and curing time limit are specified to ensure the engineering implementability and durability, and the concrete is suitable for power plant structures in high-temperature, high-humidity and chlorine-containing environments, and the construction is reliable and the maintenance is convenient.

The invention discloses a preparation method of an all-solid-waste building material, which comprises the following steps: S1, raw materials of the all-solid-waste building material comprise steel slag, lithium slag, carbide slag and water according to a mass ratio of (11-13): (4-6): 1: (2-4); s2, uniformly mixing and stirring the raw materials in the S1, casting and molding, curing for 2-3 days in an environment with the temperature of 15-25 DEG C and the humidity of 45-55%, and demolding; and S3, after demolding, carrying out carbonization maintenance in an environment with the temperature of 15-25 DEG C and the humidity of 45-55% to obtain the all-solid waste building material. According to the all-solid-waste building material and the preparation method thereof, the steel slag, the lithium slag and the carbide slag are adopted as raw materials, the building material with the strength reaching up to 30 Mpa is prepared, it is guaranteed that the compressive strength is not smaller than 24.3 Mpa, meanwhile, it is guaranteed that the drying shrinkage rate is smaller than 0.29%, the sulfate erosion resistance expansion rate is smaller than 0.07%, and the all-solid-waste building material can replace baking-free bricks to be used in buildings.

This invention proposes a sulfate-resistant silicate cement composite cementitious material based on cement clinker from decommissioned wind turbine blades, its preparation method, and its application. By mass percentage, the raw materials of this cementitious material include 32-40% cement clinker from decommissioned wind turbine blades, 42-50% granulated blast furnace slag powder, 5-9% silica fume, 3-5% gypsum, and 5-8% fly ash. By mass percentage, the mineral composition of the cement clinker from decommissioned wind turbine blades includes 72.0-80.0% C3S, 6.0-14.8% C2S, ≤3.6% C3A, and 9.9-10.7% C4AF, with the total amount of C3S and C2S ≥85%. The technical problem to be solved is how to achieve high-value resource utilization of retired wind turbine blades in a coordinated manner, and to prepare silicate cement composite cementitious materials with both high early strength and excellent resistance to sulfate attack, so that their 3d compressive strength is ≥15MPa, 28-day compressive strength is ≥52MPa, and 28-day corrosion resistance coefficient K is ≥1.1, thus making them more suitable for practical use.

The invention belongs to the technical field of concrete materials, and particularly relates to corrosion-resistant concrete for shield tunnel segments and a preparation method of the corrosion-resistant concrete. The concrete comprises sulphoaluminate cement, fly ash, slag powder, machine-made sand, gravel, a polycarboxylate superplasticizer, a defoaming agent, water and two key modified components, wherein the two key modified components comprise a layered double hydroxide-aluminum silicate nanosheet compound and a phosphate radical intercalation modified strontium molybdate slow-release corrosion inhibitor. During preparation, firstly, all the dry materials are put into a stirrer for dry mixing, then water and the additive are added for stirring to obtain mixed slurry, and a finished product is obtained after pouring, vibrating and steam curing. Wherein the two modified compounds are synthesized through a specific process, the former can adsorb corrosive ions and refine pores, and the latter can slowly release corrosion-inhibiting ions to protect reinforcing steel bars. The prepared concrete has excellent chloride ion penetration resistance, sulfate erosion resistance and carbonization resistance, the durability is remarkably improved, and the concrete is particularly suitable for shield tunnel segments in the severe corrosion environment.

The present application belongs to a kind of anti-corrosion, anti-crack concrete material for mass concrete engineering;Components and mass fraction are as follows: high iron phase cement 225-378 parts;Fluoroaluminate cement 5-12 parts;Ternary component admixture 158-215 parts;Three-level coarse aggregate 936-1077 parts;Two-level fine aggregate 630-837 parts;The initial slump of prepared concrete material is 180-210mm, 56d compressive strength is 10%-15% more, 7d hydration heat is between 170-210kJ / kg, adiabatic temperature rise is less than 50℃, electric flux is between 600-700C, chloride ion diffusion coefficient is less than 1.8*10 ‑12 m 2 / s, sulphate attack resistance grade is higher than KS90, shrinkage value is less than 300μm / m, which improves the durability and service life of C45-C80 mass concrete structure under high corrosion environment.

This invention provides a method for quantitatively assessing the degree of sulfate attack on concrete, relating to concrete attack assessment technology, including: plotting SO4... 2‑ Concentration standard curve; determination of free SO4 in the sample. 2‑ Content, denoted as C （游离） Determine the total SO4 content of the same mass of test samples from the same source. 2‑ Content, denoted as C （总） C （总） With C （游离） The difference is the content of bound sulfate ions in the sample to be tested, denoted as C. （AFt，AFm） ; Calculate the bound sulfate content C per gram of the sample to be tested. 1 （AFt，AFm） :;C 1 （AFt，AFm） The value represents the amount of ettringite and monosulfide-type hydrated calcium sulfoaluminate formed. Using the formation of ettringite and monosulfide-type hydrated calcium sulfoaluminate as an evaluation index, the degree of sulfate attack on concrete is assessed. This method achieves a quantitative assessment of the degree of sulfate attack on concrete from the perspective of the chemical nature of the attack, and features accurate quantification, simple operation, and the ability to distinguish SO4. 2‑ Advantages such as shape.

The invention provides a concrete compressive strength prediction method based on the combined action of fatigue load and sulfate, which comprises the following steps: firstly, dividing concrete into a degraded area, an enhanced area and an intact area, establishing a compressive strength prediction model only considering sulfate erosion, and then, describing the time-varying diffusion depth of sulfate ions by introducing a power function, so as to predict the compressive strength of the concrete. And correcting key parameters of the diffusion model by using fatigue damage parameters, and finally, coupling to construct a compressive strength model capable of accurately reflecting the combined action of fatigue load and sulfate. According to the method, the technical problem that an existing model cannot accurately describe non-uniformity of an erosion space and a multi-factor coupling effect is effectively solved, a model prediction value is well matched with an experimental value, and a reliable basis is provided for durability design and service life prediction of a concrete structure in a complex environment.

The invention discloses a preparation method of anti-corrosion concrete for a saline soil area based on lithium slag, and belongs to the technical field of building materials. According to the method, the lithium slag is used as an admixture to be applied to concrete preparation, and the impermeability, chloride ion permeability resistance and sulfate erosion resistance of the concrete are improved by utilizing active ingredients and a micro-aggregate effect of the lithium slag, so that the corrosion resistance of the concrete in a saline soil region is remarkably enhanced. According to the invention, the resource utilization of the industrial solid waste lithium slag is realized, the production cost of the concrete is reduced, the service life of the concrete structure in the saline soil region can be effectively prolonged, and the method has remarkable economic benefits and environmental benefits.

This invention discloses a method for sulfate erosion protection and repair of slope drainage facilities, comprising: setting up retaining walls at both ends of the drainage ditch on the slope to be repaired; removing debris from the drainage ditch; chiseling away the concrete structure at the eroded part; and repairing the base layer of the drainage ditch; laying grouting pipes along the drainage ditch and injecting grouting material into the contact surface between the bottom of the slope drainage facility and the soil through the grouting pipes; the grouting material hardens to form an impermeable isolation layer; spraying polymer-modified sulfoaluminate cement emulsion onto the surface of the base concrete structure according to the sulfate concentration obtained by testing, or first applying a base treatment agent and then hot-melt laying a waterproof membrane, or hot-melt laying and fixing the waterproof membrane and covering the entire surface; removing the retaining walls to complete the repair. Through the technical solution of this invention, existing defects are eliminated, the resistance to sulfate erosion is enhanced, and the stability and durability of concrete equipment under special geological conditions are greatly improved.

The invention relates to the technical field of building materials, in particular to a geopolymer with a self-enhancement function, a preparation method and application. The geopolymer is prepared by the preparation method. The preparation method comprises the following steps: feeding and uniformly mixing metakaolin and slag according to a mass ratio of 4: 6 to obtain a precursor; uniformly mixing an alkali activator, water and the precursor according to a mass ratio of 4: 35: 100 to obtain a reaction system; and injecting the reaction system into a mold, carrying out first maintenance, demolding, and then carrying out second maintenance to obtain the geopolymer with the self-enhancement function. The application comprises application of the geopolymer in a dry-wet alternating environment and application of the geopolymer in a chemical medium erosion environment. According to the invention, the geopolymer which has high initial strength and shows a reactive self-enhancement function in harsh environments such as dry-wet alternation, chemical medium (such as sulfate) erosion and the like can be prepared at low cost, so that the durability of the geopolymer is improved.

The present application relates to a kind of anti-sulphate erosion preservatives and its preparation method, a kind of anti-sulphate erosion preservatives, preparation raw materials of the anti-sulphate erosion preservatives include: dense component 25-55 parts;Expanding agent 15-40 parts;Ion curing agent 5-10 parts;Preservative adjuvant 10-20 parts;And inhibitor 3-10 parts.The anti-sulphate erosion preservatives prepared in the present application has super strong anti-sulphate erosion performance, after adding the anti-erosion agent in concrete, dense structure can be formed in the interior of concrete, reduce concrete cracking.The present application is lower than traditional method using anti-sulphate cement single concrete cost, anti-sulphate erosion capacity and anti-chloride ion penetration capacity are significantly improved, with higher economic and social benefits.

SUMMARY OF THE DESCRIPTION This document describes compositions and formulations of lime-based cement extenders or cement substitutes, as well as associated systems and methods. In some embodiments, a lime-based cement extender or cement substitute composition includes at least 5 wt% lime particles and at least 50 wt% pozzolan particles. In some embodiments, the pozzolan particles include silicon dioxide and aluminum oxide. In some embodiments, the composition may be combined with additives and / or aggregates to produce a formulation. The formulation may have at least 5,000 ppm of soluble sulfate and an alumina:silica ratio of at least 0.2:1.Methods to accelerate the formation of calcium and aluminum sulfates to prevent sulfate attack during critical periods include producing a formulation with a high aluminum oxide content, using additives designed to accelerate certain chemical reactions, and omitting limestone. Methods to delay the formation of calcium and aluminum sulfates to prevent sulfate attack during critical periods include producing a formulation with additives designed to delay certain chemical reactions.

The invention discloses portland cement clinker based on marlstone and a preparation method thereof, and relates to the technical field of cement. The method comprises the following steps: crushing, grinding and drying natural marlstone, spraying and activating by using a mixed steeping liquor containing sodium hydroxide, lanthanum nitrate and cerous nitrate, and drying and roasting at low temperature to obtain modified marlstone powder; mixing the powder with calcium carbonate, quartz powder, ferric oxide, dihydrate gypsum, calcium fluoride and barium carbonate, and pressing into a green body; and finally, sequentially carrying out two-stage mineralization calcination on the green body, introducing oxygen-enriched air in a heat preservation stage, continuously calcining, and cooling to obtain the cement clinker. According to the invention, marlstone is used as a main raw material, and the obtained cement clinker has excellent sulfate corrosion resistance through dipping activation and multi-stage calcination processes.

This invention relates to the field of concrete preparation technology, and more particularly to a sulfate-resistant concrete and its preparation method. By weight, it comprises the following components: 230-310 parts cement, 75-87 parts fly ash, 515-620 parts coarse aggregate, 376-408 parts fine aggregate, 3-5 parts water-reducing agent, 2-3 parts modified basalt fiber, 1-2 parts functional additives, and 143-162 parts water. This invention optimizes the concrete formulation system, introduces modified basalt fiber and functional additives, and constructs a multi-layered protection system combining physical barriers and chemical protection, effectively improving the sulfate resistance of concrete.

This invention belongs to the field of concrete materials technology and provides a high-durability lining concrete suitable for environmental sulfate attack and its preparation method. The lining concrete comprises cementitious materials, aggregates, lightly calcined magnesium oxide, organic microfibers, lithium salts, water-reducing agents, air-entraining agents, and water; wherein the water-cement ratio is 0.39~0.43. The cementitious materials are obtained by mixing cement with a C3A content ≤2% and a C3S content ≤35% with a calcium-silicon ratio ≤15% and an aluminum-silicon ratio ≤95% with low calcium and high silicon content and low aluminum-silicon content. This lining concrete achieves dual chemical inhibition of sulfate attack from the source by using admixtures with both low calcium and high silicon content and low aluminum and high silicon content; simultaneously, through the synergistic effect of low C3A and low C3S cement and various components, a multi-layered defense system is formed, from reducing reactants, passivating active phases, regulating expansion stress, to blocking transmission channels, significantly improving the durability of concrete in sulfate environments.

The application discloses a building foundation pile safety monitoring system, which is characterized by comprising a detection component arranged in parallel with a concrete foundation pile to be monitored, wherein the detection component is made of the same concrete material as the concrete foundation pile, a strain gauge is arranged in a monitoring depth position in the detection component, the strain gauge is connected to the detection component through a connecting line arranged in the detection component and connected to a control device, and the control device is connected to an alarm device. The application has the advantages of simple and feasible implementation, high monitoring reliability, strong practicability and the like, and can better monitor the safety of the building foundation pile in a saline environment under the influence of sulfate erosion.

The application discloses a concrete internal source type sulfate corrosion resisting additive, a preparation method and a quantification method, and belongs to the field of concrete additive materials. 2‑ The application forms stable barium sulfate precipitates, blocks the corrosion from the root, improves the compactness of the concrete by the compact component precursor, and blocks the transmission path of SO4 2‑ The calcium ion complexing agent further inhibits the generation of ettringite and thomsonite by complexing free Ca 2+ The application also provides a concrete internal source type sulfate corrosion resisting additive, a preparation method and a quantification method, and belongs to the field of concrete additive materials. 2‑ The application can make the 180d expansion rate of the concrete be less than 0.1%, and the long-term strength retention rate reach more than 99%, and solves the internal source corrosion damage problem caused by the aggregate containing sulfates.

The invention discloses a barrier material for inhibiting subgrade soil salt from migrating to a road surface and a preparation method thereof. The barrier material comprises the following components in percentage by mass: 20-40% of a surface hydrophobically reinforced nano SiO2 / ZnO composite material, 10-20% of a filler, 10-30% of a filler and 10-30% of a filler, 10%-25% of a functionalized carbon nanotube with the surface grafted with a silane coupling agent; and 35%-60% of polyvinyl alcohol-based hydrogel. Through the synergistic effect of the hydrophobic nano barrier, the carbon tube conductive network and hydrogel adsorption, efficient dispersion of the nano material and multi-scale pore sealing are realized, and migration of subgrade soil salt to the pavement is continuously inhibited. The invention realizes breakthrough improvement of sulfate corrosion resistance, and is suitable for harsh environments such as saline land and the like.

A method for internal and external collaborative integrated protection of concrete is provided. The method has two aspects: first, combining reinforcement with cement and significantly enhancing compactness and strength of the concrete through a special surface treatment process; and second, successively constructing dual rough structures at microscopic and nanoscopic levels on the surface of the concrete through a super-hydrophobic anti-corrosive coating technology to form an efficient super-hydrophobic coating. The method effectively resists the erosion from external environments, solves problems such as carbonation of concrete, sulphate attack and corrosion of steel bar, and provides a high-performance and long-life concrete material solution for the field of civil engineering.

The invention belongs to the technical field of protective coatings of building materials, and provides a nano-modified multi-component hydrophobic polysiloxane coating as well as a preparation method and application thereof. By adopting the preparation method provided by the invention, the cross-linked state and molecular weight distribution state of the hydrophobic polysiloxane component and the cross-linked polysiloxane component can be effectively improved from the nanoscale and the microscale; and the high hydrophobicity of the coating interface of the composite polymer is maintained, and meanwhile, the permeation and adsorption capacity of the polysiloxane emulsion in cement micropores is fully improved. According to the preparation method of the nano-modified composite polysiloxane emulsion, the synergistic compounding effect of multi-component polysiloxane is improved, the rheological property and working performance of the polysiloxane emulsion coating are improved, and a stable hydrophobic protective film and a waterproof impervious layer are formed on the surface of a cementing material; the waterproof performance, the chlorine salt and sulfate corrosion resistance, the carbonization resistance, the freeze thawing resistance and the surface abrasion resistance of the cement-based material are enhanced.

This invention provides a method for preparing sulfate-resistant concrete. The method includes: adding 8% to 12% PBL powder to freshly mixed ordinary Portland cement concrete; wherein the PBL powder is prepared by grinding phosphogypsum, magnesite, and limestone in a dry basis mass ratio of 4:2:1. By adding 8% to 12% PBL powder to ≥C30 ordinary Portland cement concrete, even after the corrosive medium sulfate has penetrated into the concrete, a sulfate attack reaction will not occur. Therefore, even in highly corrosive environments, it is not necessary to adopt engineering measures such as waterproofing layers, reducing the corrosivity of environmental water, drainage, soil replacement, lowering the groundwater level, and setting up protective layers as specified in DL / T5801—2019 "Technical Specification for Application of Sulfate-Resistant Concrete".

The invention relates to the technical field of building materials, in particular to a durable building material for resource utilization of solid waste barium slag and a preparation method of the durable building material. The material is composed of Portland cement, mineral powder, fly ash, stabilized barium slag, aggregate, a water reducing agent and the like. The barium slag modifier which is synthesized through three-step reaction and integrates the functions of chelation, permeation and oxidation has a synergistic effect with a sulfate radical slow-release agent and a trapping agent, soluble barium ions and sulfides in barium slag are converted into stable barium sulfate, and free sulfate radicals are removed. The stabilized barium slag serves as inert functional powder, and after the stabilized barium slag is compounded with other raw materials, the effects of micro aggregate filling and interface strengthening are achieved. According to the method, efficient detoxification and bulk digestion of the barium slag are achieved, the obtained material is low in leaching toxicity and good in mechanical property, has excellent sulfate corrosion resistance, volume stability and durability, is adaptive to existing production equipment, does not need to be greatly improved, conforms to the green and low-carbon development concept, and provides a reliable way for solid waste recycling.

The application discloses a kind of high durability concrete suitable for strong corrosion coastal saline soil area, it is related to building material technical field.The durability concrete is prepared from the following weight parts of raw materials: Portland cement 320-380 parts, slag powder 80-120 parts, fly ash 50-80 parts, quartz sand 650-750 parts, broken stone 1100-1300 parts, modified graphene dispersion 15-25 parts, composite rust inhibitor 8-12 parts, high efficiency water reducing agent 6-10 parts, water 140-160 parts, nano silicon dioxide 10-18 parts.The application significantly improves the chloride ion penetration resistance, sulphate attack resistance and freeze-thaw resistance of concrete through the synergistic effect of composite admixture, modified graphene and composite rust inhibitor, reduces the shrinkage of concrete, enhances its long-term durability in strong corrosion saline soil environment;Preparation process is simple, raw material is easy to get, cost is controllable, can be widely used in strong corrosion saline soil area of road, bridge, building foundation and other engineering structures, has good economic benefit and engineering application value.

This invention provides a hydraulic concrete utilizing waste oyster shell powder and its preparation method, belonging to the field of concrete and resource recycling technology. The hydraulic concrete utilizing waste oyster shell powder provided by this invention is prepared from the following raw materials in parts by weight: 100 parts cement, 5-15 parts oyster shell powder, 10-30 parts silica fume, 200-300 parts fine aggregate, 800-1000 parts coarse aggregate, 40-50 parts water, and 0.5-1.5 parts water-reducing agent. The oyster shell powder is ground to a particle size ≤90μm and then calcined at 800-950°C for 1.5 hours. This concrete not only increases the 28-day compressive strength by 12.8% compared to ordinary concrete, but also possesses good resistance to sulfate attack and high impermeability, while efficiently utilizing waste oyster shell powder.

This invention relates to a protective system and its preparation method for enhancing the durability of concrete in coastal bridges. The protective system is applied to concrete containing cementitious materials, aggregates, and water. The cementitious materials include functional admixtures, such as a proprietary composite modified core-shell powder, complexation reaction modified mineral powder, and zeolite powder-supported gypsum whisker composite powder. This invention utilizes a dual-response film-forming mechanism of "secretion-triggered ion complexation." When biological secretions come into contact with the concrete surface, the core-shell powder releases alkaline substances to neutralize organic acids. Simultaneously, the complexation reaction modified mineral powder undergoes a complexation reaction with metal ions in the secretions, forming an organic-inorganic interlocking protective film. This film then fuses with the subsequently grown shellfish shell to construct a dual protective structure. This invention provides stable protection, enhancing the concrete's resistance to chloride ion penetration and sulfate attack, effectively inhibiting steel corrosion, and extending the service life of concrete in coastal bridges.