Fiber reinforce plastic (FRP) green concrete composite structure based on carbonization curing and preparation process of FRP green concrete composite structure

Abstract

The invention relates to the technical field of building materials, and discloses an FRP green concrete composite structure based on carbonization curing and a preparation technology thereof.The preparation technology comprises the following steps that S1, active magnesium oxide cement paste is prepared, specifically, magnesium oxide and fly ash are mixed according to the mass ratio of 7: 3, water and an additive are added, and the active magnesium oxide cement paste is obtained; s2, a mold and a sleeve are prepared, specifically, the hollow sleeve is defined by a glass fiber reinforced composite material; preparing a hollow mold; the mold is arranged in the sleeve, and a gap is formed between the mold and the sleeve; s3, preparing a concrete mixture: mixing and stirring the active magnesium oxide cement paste, aggregate, an additive and water; s4, concrete pouring is conducted, specifically, a concrete mixture is poured into the gaps; s5, curing and demolding: after the concrete mixture is solidified and hardened, taking out the mold to obtain a hollow concrete sample; and S6, carbonization curing. The concrete provided by the invention not only has excellent mechanical properties and durability, but also is environment-friendly.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, and in particular to a carbonization-cured FRP green concrete composite structure and a preparation process thereof. Background Art

[0002] The rapid economic development has led to an annual increase of 10 billion tons in global concrete consumption. Ordinary Portland cement (OPC) is one of the main materials for ordinary concrete (NC), but its production process is high in carbon emissions. Therefore, there is an urgent need to develop a low-carbon, high-strength specimen. The research and development of low-carbon, high-strength specimens can be achieved by utilizing renewable materials or new material technologies, which not only reduces carbon emissions during material production and use, but also improves the mechanical properties of the materials. Furthermore, low-carbon, high-strength specimens not only help achieve the goals of carbon peak and carbon neutrality and mitigate climate change, but also reduce resource consumption, promote construction projects to develop in a more environmentally friendly and sustainable direction, and promote innovation and progress in the field of engineering materials.

[0003] Carbonation curing is a method of improving the performance and durability of concrete by using carbon dioxide (CO2) to promote the carbonation reaction of calcium compounds in concrete. In this process, concrete specimens are usually exposed to an environment containing high concentrations of CO2, such as a special carbonation chamber or a carbonation chamber simulation device. By being exposed to a high CO2 environment, the free calcium compounds in the concrete react with CO2 to form carbonates, thereby increasing the density and hardness of the concrete. This carbonation process can improve the concrete's impermeability, durability and resistance to chemical attack, extend the service life of concrete structures, and at the same time reduce the demand for high-carbon emission materials such as cement used in traditional concrete, helping to reduce carbon footprint and promote the goals of carbon peak and carbon neutrality.

[0004] FRP (Fiber Reinforced Polymer) sleeves are usually made of a composite material mixed with glass fiber, carbon fiber or other fiber materials and resin (such as epoxy resin, polyester resin, etc.). The preparation process usually includes pre-impregnation of the fiber in the resin, and then forming the desired shape and structure through molding, pultrusion or other molding processes. FRP sleeves are usually lighter than metals, but have higher strength, which makes installation and maintenance easier while reducing transportation costs. In addition, FRP sleeves have strong resistance to a variety of chemicals, corrosive environments and seawater, so they have a long service life in harsh environments.

[0005] The production of traditional OPC brings several problems: 1. It requires high sintering temperatures (~1450℃), which leads to 2-3% of global energy consumption; 2. Its production accounts for 5-10% of global carbon dioxide emissions; 3. The production of OPC consumes a large amount of natural resources (i.e. clay, limestone and iron ore). Carbonation curing can reduce the demand for high carbon emission materials such as cement by utilizing the free calcium ions in traditional concrete to react with CO2, thereby helping to reduce carbon emissions. For traditional concrete specimens, during the carbonation curing process, the intrusion of CO2 mainly penetrates into the interior through the surface of the concrete in gaseous form. For high-strength specimens wrapped in FRP sleeves, this form of intrusion will obviously greatly reduce the reaction rate of CO2 and free calcium ions. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the present invention provides an FRP green concrete composite structure based on carbonation curing and its preparation process, which show significant beneficial effects in low-carbon emission reduction, high strength durability and carbonation curing.

[0007] In order to achieve the above-mentioned purpose of the invention, the technical solution adopted by the present invention is: a preparation process of FRP green concrete composite structure based on carbonization curing, comprising the following steps:

[0008] S1, preparing active magnesium oxide cement slurry: mixing magnesium oxide and fly ash in a mass ratio of 7:3, and adding water and an admixture to obtain active magnesium oxide cement slurry;

[0009] S2, preparing a mold and a sleeve: using a glass fiber reinforced composite material to enclose a hollow sleeve, the sleeve including a rectangular sleeve and a cylindrical sleeve; preparing a hollow mold, the mold including a rectangular mold and a cylindrical mold matching the sleeve; setting the mold inside the sleeve to form a gap between the mold and the sleeve;

[0010] S3, preparing a concrete mixture: mixing and stirring the active magnesium oxide cement paste, aggregate, additives and water to obtain a concrete mixture;

[0011] S4, concrete pouring: pouring the concrete mixture into the gap between the mold and the sleeve;

[0012] S5, curing and demoulding: after the concrete mixture solidifies and hardens, the mold is removed to obtain a hollow concrete sample;

[0013] S6, carbonation curing: placing the concrete sample in a carbonation curing environment, introducing carbon dioxide gas for carbonation curing, achieving the carbon fixation effect of green concrete, and obtaining an FRP green concrete composite structure.

[0014] Furthermore, in the above-mentioned preparation process of the FRP green concrete composite structure based on carbonization curing, in S2, before the mold is set inside the sleeve, a layer of oil is applied to the outer surface of the mold.

[0015] Furthermore, in the above-mentioned preparation process of the FRP green concrete composite structure based on carbonization curing, in S2, a wooden board is arranged at the bottom of the mold and the sleeve, and the sleeve and the wooden board are connected with hot melt adhesive.

[0016] Furthermore, in the preparation process of the FRP green concrete composite structure based on carbonization curing, the length of the rectangular sleeve is 160 mm, the width is 160 mm, and the height is 300 mm; the bottom diameter of the cylindrical sleeve is 160 mm and the height is 300 mm; the wall thickness of the rectangular sleeve and the cylindrical sleeve is 5 mm.

[0017] Furthermore, in the preparation process of the FRP green concrete composite structure based on carbonization curing, the length of the rectangular mold is 38 mm, the width is 38 mm, and the height is 350 mm; the bottom diameter of the cylindrical mold is 38 mm and the height is 350 mm.

[0018] Furthermore, a FRP green concrete composite structure based on carbonization curing is prepared by any of the above-mentioned preparation processes.

[0019] The beneficial effects of the present invention are as follows: the present invention has shown significant beneficial effects in terms of low-carbon emission reduction, high-strength durability and carbonization curing. In terms of low-carbon emission reduction, active magnesium oxide cement is a low-carbon material. In its preparation process, not only cement is not used, but also alternative materials such as fly ash are used, which reduces carbon emissions, complies with the national carbon emission reduction policy, and achieves environmental protection goals; in terms of high strength and durability, the hollow sleeve surrounded by glass fiber reinforced plastic on the outside provides high-strength support and protection for the concrete specimen, so that the specimen has high tensile strength and durability, which can meet the needs of engineering structures for high-strength materials, and also extends the service life of the specimen; in terms of carbonization curing, the hollow design inside the concrete specimen not only effectively solves the problem of low carbonization curing efficiency of high-strength specimens prepared by glass fiber reinforced plastic sleeves through internal penetration, but also reduces the weight of the specimen and reduces the structural load, providing new ideas for the structural stress failure mode and stress analysis of the specimen, and providing new possibilities for technological development and application in the field of concrete engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The preparation process flow chart of green concrete;

[0021] Figure 2 It is a schematic diagram of the structure of a rectangular sleeve;

[0022] Figure 3It is a schematic diagram of the structure of a cylindrical sleeve;

[0023] Figure 4 It is a structural schematic diagram of a rectangular parallelepiped mold;

[0024] Figure 5 It is a structural schematic diagram of a cylindrical mold;

[0025] Figure 6 It is a structural schematic diagram of the fitting of a rectangular sleeve and a rectangular mold;

[0026] Figure 7 It is a structural schematic diagram of the cylindrical sleeve and the cylindrical mold fitting together. DETAILED DESCRIPTION

[0027] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0028] like Figures 1 to 7 As shown, this embodiment provides a preparation process of an FRP green concrete composite structure based on carbonization curing, comprising the following steps:

[0029] S1, preparing active magnesium oxide cement slurry: magnesium oxide and fly ash are uniformly mixed in a mass ratio of 7:3. To ensure the uniformity of the mixing, a mechanical stirring device is used. Then, an appropriate amount of water and admixtures are added according to a water-binder ratio of 0.4, and stirring is continued to form an active magnesium oxide cement slurry with good fluidity and adhesion.

[0030] S2, preparation of mold and sleeve: Glass fiber reinforced composite material (GFRP) is used as the sleeve material, which has good strength and durability. The sleeve includes a rectangular sleeve and a cylindrical sleeve, wherein the size of the rectangular sleeve is 160mm×160mm×300mm, the bottom diameter of the cylindrical sleeve is 160mm, the height is 300mm, and the wall thickness is 5mm. Prepare a hollow mold, which includes a rectangular mold and a cylindrical mold matching the sleeve. The size of the rectangular mold is 38mm×38mm×350mm, and the bottom diameter of the cylindrical mold is 38mm and the height is 350mm.

[0031] During the installation process, a layer of oil is first evenly applied to the outer surface of the mold to facilitate subsequent demoulding. Then, the oiled mold is placed in the GFRP sleeve, and a wooden board is placed at the bottom of the sleeve. The sleeve and the wooden board are firmly bonded with hot melt adhesive to form a stable casting space, which not only ensures the stability of the mold, but also effectively prevents the leakage of concrete slurry.

[0032] S3, prepare concrete mixture: Mix and stir the active magnesium oxide cement paste, aggregate, additives and water to obtain a concrete mixture; the selection of aggregate has a significant impact on the mechanical properties of concrete, and natural sand and gravel with uniform particle size and cleanness are selected. During the mixing process, ensure that all components are fully dispersed and evenly mixed to obtain a concrete mixture with consistent performance.

[0033] S4, Concrete pouring: After the concrete mixture is prepared, it is poured into the gap between the mold and the sleeve. During the pouring process, vibration compaction is performed to eliminate bubbles and ensure the density and uniformity of the concrete. Vibration compaction can be performed using a manual vibrator or a mechanical vibrating table. Through vibration compaction, the voids inside the concrete can be minimized, thereby improving its structural strength.

[0034] S5, curing and demoulding: After the concrete mixture is initially solidified and hardened, demoulding is required. Since the mold surface has been oiled, the demoulding process is relatively easy. After demoulding, the hollow concrete specimen needs to continue wet curing to maintain appropriate humidity and temperature conditions to promote the full progress of the hydration reaction.

[0035] S6, Carbonation Curing: After completing the foundation curing, the concrete specimens are placed in a special carbonation curing environment. Carbonation treatment is carried out by controlling the carbon dioxide concentration, temperature and humidity in the environment. Carbonation refers to the reaction of carbon dioxide with calcium hydroxide in concrete to produce calcium carbonate, thereby improving the strength and durability of concrete. In this process, the GFRP sleeve provides high-strength support and protection for the concrete specimens, making the concrete specimens have high tensile strength and durability. This process not only helps to improve the physical properties of concrete, but also effectively reduces its carbon footprint and achieves the goal of green environmental protection.

[0036] Through the above steps, a carbonization-cured FRP green concrete composite structure is finally obtained, which not only has excellent mechanical properties and durability, but also exhibits good environmental friendliness. The green concrete of the present invention has broad application prospects in construction engineering and infrastructure construction.

Claims

1. A preparation process of FRP green concrete composite structure based on carbonization curing, characterized in that: The following steps are involved: S1, preparing active magnesium oxide cement slurry: mixing magnesium oxide and fly ash in a mass ratio of 7:3, and adding water and an admixture to obtain active magnesium oxide cement slurry; S2, preparing a mold and a sleeve: using a glass fiber reinforced composite material to enclose a hollow sleeve, the sleeve comprising a rectangular sleeve and a cylindrical sleeve; preparing a hollow mold, the mold comprising a rectangular mold and a cylindrical mold matching the sleeve; setting the mold inside the sleeve to form a gap between the mold and the sleeve; S3, preparing a concrete mixture: mixing and stirring the active magnesium oxide cement paste, aggregate, additives and water to obtain a concrete mixture; S4, concrete pouring: pouring the concrete mixture into the gap between the mold and the sleeve; S5, curing and demoulding: after the concrete mixture solidifies and hardens, the mold is removed to obtain a hollow concrete sample; S6, carbonation curing: placing the concrete sample in a carbonation curing environment, introducing carbon dioxide gas for carbonation curing, achieving the carbon fixation effect of green concrete, and obtaining an FRP green concrete composite structure.

2. The preparation process of the FRP green concrete composite structure based on carbonization curing according to claim 1 is characterized in that: In S2, before the mold is placed inside the sleeve, a layer of oil is applied to the outer surface of the mold.

3. The preparation process of the FRP green concrete composite structure based on carbonization curing according to claim 1 is characterized in that: In S2, a wooden board is arranged at the bottom of the mold and the sleeve, and the sleeve and the wooden board are connected with hot melt adhesive.

4. The preparation process of the FRP green concrete composite structure based on carbonization curing according to claim 1 is characterized in that: The length of the rectangular sleeve is 160 mm, the width is 160 mm, and the height is 300 mm; the bottom diameter of the cylindrical sleeve is 160 mm, and the height is 300 mm; the wall thickness of the rectangular sleeve and the cylindrical sleeve are both 5 mm.

5. The preparation process of the FRP green concrete composite structure based on carbonization curing according to claim 1 is characterized in that: The length of the rectangular parallelepiped mold is 38 mm, the width is 38 mm, and the height is 350 mm; the bottom diameter of the cylindrical mold is 38 mm, and the height is 350 mm.

6. A FRP green concrete composite structure based on carbonization curing, characterized in that: Prepared by the preparation process according to any one of claims 1 to 5.

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