CN-122010512-A - Cold region hydraulic self-repairing concrete based on geopolymer and preparation method

Abstract

The invention discloses a geopolymer-based hydraulic self-repairing concrete for a cold region and a preparation method thereof, and belongs to the technical field of self-repairing concrete. The concrete is prepared from slag powder, retired fan blade micropowder, fly ash and nano silicon dioxide as an excessive composite precursor, a composite alkali-exciting agent, calcium fluoride, polyvinyl alcohol, retired fan blade fibers, aggregate and water according to a specific proportion. The preparation method comprises the steps of pre-mixing material preparation, slurry preparation, pouring molding, surface spraying and 7-14 days of water spraying maintenance. The concrete strength recovery rate of the invention exceeds 100%, the freezing cycle time reaches 350-400 times, the mechanical property is excellent, the recycling of solid waste can be realized, the environment is protected, the energy is saved, and the concrete is suitable for hydraulic buildings such as cold region underground tunnels, water level change regions and the like. Aims at solving the technical problems of poor freezing resistance, no self-repairing capability, insufficient environmental protection and the like of the existing hydraulic concrete in cold areas.

Inventors

• YUAN JINFENG
• CHEN YONGMING
• SONG YANG
• GU XIAOXI
• WANG XULI
• Hu zibo
• ZHANG LIMEI
• ZHANG YU
• DONG GUANGHAO
• ZHOU QINGWEI
• RU SHIRONG
• WANG YANG
• WANG FEI
• LI JIAN

Assignees

• 吉林省水利科学研究院(吉林省水利科技推广总站、吉林省水利水电工程质量检测中心、吉林省灌溉试验中心站)

Dates

Publication Date

20260512

Application Date

20260330

Claims (2)

1. 1. The cold region hydraulic self-repairing concrete based on the geopolymer is characterized by comprising, by weight, 325-365 parts of slag powder, 65-90 parts of retired fan blade micropowder, 33-52 parts of fly ash, 8-13 parts of nano silicon dioxide, 48-55 parts of instant potassium silicate, 20 parts of anhydrous sodium metasilicate, 12-17 parts of sodium metasilicate pentahydrate, 1-2 parts of retired fan blade fiber, 1-3 parts of calcium fluoride, 3-9 parts of polyvinyl alcohol, 850-905 parts of machine-made sand, 696-740 parts of crushed stone and 180-200 parts of water; Wherein, the slag powder, the retired fan blade micropowder, the fly ash and the nano silicon dioxide form an excessive composite precursor, and the total dosage of the excessive composite precursor is 1.3 times of the dosage of the standard precursor; The instant potassium silicate and sodium metasilicate pentahydrate form a composite alkali-activated agent; The anhydrous sodium metasilicate solution is used for spraying the cured concrete surface; The slag powder is of grade S95, the specific surface area is not lower than 400 m <2 >/kg, the fineness of the micro powder of the retired fan blade is not lower than 200 meshes, the diameter of a monofilament of the fiber of the retired fan blade is 5 mu m, the length of the monofilament is 3-5 mm, the fly ash is of grade I or grade II, the nano silicon dioxide is white powder with the particle size of 5-100 nm, the modulus of the instant potassium silicate is 2.3-2.5, the anhydrous sodium metasilicate is industrial grade white powder, the density is 2.4 g/cm < 3 >, the fineness of the sodium metasilicate pentahydrate is 60 meshes, the fineness of the calcium fluoride is 100 meshes, the loss on ignition is not more than 0.6%, the polyvinyl alcohol is a dry powder mixture type, the fineness of 160 meshes, the fineness modulus of the machine-made sand is 2.4-2.8, and the particle size of the broken stone is 5-20 mm.
2. 2. A method for preparing the geopolymer-based cold region hydraulic self-repairing concrete according to claim 1, which is characterized by comprising the following steps: step S1, preparing ready-mixed materials, namely mixing slag powder, retired fan blade micropowder, fly ash, nano silicon dioxide, retired fan blade fiber, calcium fluoride, polyvinyl alcohol, machine-made sand and crushed stone according to the weight part of the raw materials in claim 1, and stirring the mixture for 2 minutes by adopting forced stirring to obtain a dry material mixture; S2, preparing slurry, namely dissolving the instant potassium silicate and the sodium metasilicate pentahydrate in the water in the weight part of the water in the claim 1, adding the fully dissolved water into a stirrer, and adopting forced stirring for 3min; S3, pouring and forming, namely leveling and vibrating the concrete to be placed in the warehouse in time, wherein water cannot be added into the warehouse in the pouring process; S4, surface spraying treatment, namely after pouring and molding for 12 hours, dissolving the anhydrous sodium metasilicate with the weight part as defined in claim 1 into 100 parts of water to prepare a solution, spraying the solution on the surface of the cured geopolymer concrete, and after 1 hour, spraying for 1 time when the surface is dry, and spraying for 3 times, wherein the surface non-drying spraying time can be prolonged properly; and S5, curing, namely performing water spraying curing for 7-14 days after the surface spraying treatment is completed.

Description

Cold region hydraulic self-repairing concrete based on geopolymer and preparation method Technical Field The invention belongs to the technical field of self-repairing concrete, and particularly relates to a geopolymer-based hydraulic self-repairing concrete for a cold region and a preparation method thereof. Background Concrete is the most widely used building material in hydraulic engineering construction. However, hydraulic concrete buildings in cold areas (such as northern China and high-altitude areas) are subjected to coupling effects of extremely severe environments such as ultra-large day and night temperature differences, high-frequency freeze thawing cycles, strong ultraviolet radiation, water flow flushing and grinding for a long time. The complex and severe working condition is extremely easy to cause microcracks in the concrete structure, and is continuously expanded and communicated, and finally causes degradation diseases such as cracking, denudation, rapid decline of strength and durability and the like, so that the engineering life is seriously shortened, the flood control safety is threatened, and the later maintenance and reinforcement are difficult and the cost is high. To address the above challenges, concrete with self-repairing function is becoming a research hotspot. The self-repairing concrete can automatically repair cracks through a built-in or exogenous mechanism when micro damage is generated, and partial or full performance is recovered. At present, the main self-repairing technology mainly depends on built-in capsules, microorganism mineralization or shape memory alloy and the like, but the methods often have the problems of large packaging difficulty of repairing agents, high cost, poor compatibility with concrete, limited repairing efficiency or single repairing. On the other hand, the traditional silicate cement production process has high energy consumption and large carbon emission, and is contrary to the requirement of sustainable development of the environment. The geopolymer is an inorganic polymer cementing material polymerized by aluminosilicate raw materials under alkaline conditions, has the advantages of high early strength, high temperature resistance, corrosion resistance, low permeability, environmental friendliness (industrial solid waste can be utilized) and the like, and is considered as a potential silicate cement substitute. However, common polymer concrete still has a shortage in freezing resistance and toughness, and has no active self-repairing capability yet. Therefore, development of a new material for hydraulic concrete in cold areas, which comprehensively utilizes solid wastes, is environment-friendly, has excellent anti-freezing and wear-resisting properties and high-efficiency self-repairing capability, is needed. Disclosure of Invention Aiming at the technical problems that the existing cold region hydraulic concrete has poor freezing resistance, no self-repairing capability and insufficient environmental protection, the existing geopolymer concrete is difficult to adapt to the cold region hydraulic extreme environment and the like, the primary aim of the invention is to provide the cold region hydraulic self-repairing concrete based on the geopolymer. Another object of the present invention is to provide a method for preparing the self-repairing concrete described above, which is simple in process, easy to implement and capable of ensuring that the concrete achieves the excellent properties. Technical proposal In order to achieve the above purpose, the invention adopts the following technical scheme: in a first aspect, the invention provides a geopolymer-based cold region hydraulic self-repairing concrete, which is characterized in that main materials consist of the following raw materials in parts by weight: 325-365 parts of slag powder, 65-90 Parts of retired fan blade micro powder, 33-52 Parts of fly ash, 8-13 Parts of nano silicon dioxide, 48-55 Parts of instant potassium silicate, 20 Parts of anhydrous sodium metasilicate, 12-17 Parts of sodium metasilicate pentahydrate, 1-2 Parts of retired fan blade fiber, 1-3 Parts of calcium fluoride, 3-9 Parts of polyvinyl alcohol, 850-905 Parts of machine-made sand, 696-740 Parts of broken stone, 180-200 Parts of water. Wherein the slag powder, the retired fan blade micropowder, the fly ash and the nano silicon dioxide jointly form a composite precursor. One of the core ideas of the invention is that the total dosage of the compound precursor is designed to be 'excessive', which is 1.3 times of the dosage of the conventional precursor, and the dosage of the compound alkali-activator consisting of instant potassium silicate and sodium metasilicate pentahydrate is kept unchanged. The matching design of the excessive precursor and the constant quantity of the exciting agent aims at retaining part of the unreacted active precursor particles in the concrete after the geopolymer is cured for the first time.