Stable and controllable precast concrete member surface quality improving method

Abstract

The invention relates to the technical field of green buildings, in particular to a stable and controllable precast concrete member surface quality improving method. The process comprises the steps of steel mold table polishing and cleaning, long-acting release agent brushing, mold assembling, steel skeleton implanting, pouring and maintaining, demolding and surface protecting. The outer side of the component is a clear water veneer with a mirror surface effect, and a protective film is arranged on the outer surface of the clear water veneer. According to the method, double-stage grinding is matched with the long-acting release agent, the roughness Ra of the ground surface of the steel mold table is smaller than or equal to 1.6 microns, and the surface smoothness of a component achieves the mirror surface effect; the slurry leakage rate is reduced to 5% or below through the treatment of the chamfering strips at the die combination position, and the defects of concrete surface honeycombs, pitted surfaces and the like caused by slurry leakage are effectively avoided; by optimizing the vibrating process and controlling the quality of raw materials, the bubble rate on the surface of the component is smaller than or equal to 0.5%, the bubble diameter is smaller than or equal to 2 mm, the distance is larger than or equal to 50 mm, the surface of the component is smoother, the overall quality and attractiveness of the component are greatly improved, and the rate of finished products exceeds 95%.

Description

Technical Field

[0001] This invention relates to the field of green building technology, specifically to a stable and controllable method for improving the surface quality of precast concrete components. Background Technology

[0002] In the current architectural field, exposed concrete architecture has gained increasing attention and favor in recent years due to its unique aesthetic effect. It presents the raw texture of concrete without additional decoration, showcasing a natural and rustic beauty. However, in actual construction, exposed concrete architecture faces many insurmountable challenges.

[0003] Traditional construction techniques have serious shortcomings in controlling concrete surface quality, with prominent issues of grout leakage and water loss. Grout leakage leads to defects such as honeycomb and pitting on the concrete surface, severely affecting the appearance and texture of the components; water loss can cause surface cracking and sanding, reducing the durability of the components. These problems not only significantly detract from the appearance of the components but may also pose a potential threat to the structural safety. These issues are even more pronounced for components with high surface quality requirements. After demolding, components are prone to chipped edges and corners, which not only affects the integrity of the components' appearance but may also weaken their structural performance; the appearance of rust spots also damages the aesthetics of the component's surface and reduces its durability. Pollution during construction is also a significant concern; contaminants such as dust and oil adhere to the component surface and are difficult to clean, severely impacting the natural beauty of fair-faced concrete.

[0004] Existing methods lack systematic control over aspects such as mold handling, reinforcement installation, concrete forming, and post-construction protection. These stages operate independently, failing to form an organic whole. This makes it impossible to fundamentally solve surface quality problems and achieve consistent improvements in surface quality during actual construction. Summary of the Invention

[0005] The purpose of this invention is to provide a stable and controllable method for improving the surface quality of precast concrete components, so as to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A method for improving the surface quality of stable and controllable precast concrete components, the method employing a horizontal mold production method, comprising the following steps: S1. Grinding and cleaning of steel formwork: Use a large floor grinder with a wire brush to grind the steel formwork in a cross pattern until the surface is bright and has a uniform metallic luster. Then, switch to a 50-grit diamond grinding head for two-stage cross grinding. The grinding speed should be controlled at 1.5-2m / min. After grinding, wipe the steel formwork with a lint-free cloth dampened with industrial alcohol to achieve a mirror finish and remove any oil residue. Furthermore, the flatness error of the template surface after grinding is ≤0.5mm, the surface roughness Ra≤1.6μm, the rust removal rate is 100%, and the reflectivity is ≥85%.

[0007] During the grinding process, the wire brush makes full contact with the surface of the steel mold, utilizing the rigidity and friction of the wire to powerfully remove concrete residue, rust, and other adhering impurities until the mold surface is bright, indicating that most of the impurities have been removed. Emery, with its high hardness and excellent grinding performance, further refines the surface roughness of the steel mold. At this stage, the grinding speed is strictly controlled to ensure uniform and stable grinding action of the grinding head on the steel mold surface, avoiding uneven grinding or scratches caused by excessively fast grinding speeds. Industrial alcohol, with its good solubility and volatility, effectively dissolves and removes residual oil and metal shavings from the grinding process, providing a clean and uncontaminated base for the subsequent application of the release agent, ensuring uniform adhesion and maximizing its performance.

[0008] The "two-stage cross-grinding method" is adopted to remove impurities, rust, and unevenness from the surface of the steel formwork through two different stages and different grinding tools, so that the steel formwork can reach a surface condition suitable for subsequent construction.

[0009] S2. Applying long-lasting release agent: After cleaning the side mold, apply the long-lasting release agent to the steel mold platform and the side mold. Apply the long-lasting release agent in sections along the long direction of the steel mold platform, with each section being 1 to 1.5 meters long. Keep the brushing direction consistent within each section. Proceed to the coating area along the short direction of the steel mold platform. Repeat the application 3 to 5 times, with an interval of 24 to 48 hours between each application. Cover with plastic film after each application.

[0010] Furthermore, when the side mold is made of steel, it undergoes the same grinding and cleaning process as the steel mold table in S1; when the side mold is made of wood in S2, the moisture content of the wood mold is ≤12%. If there are doors or windows, the side mold is joined at a 45° bevel at the corners corresponding to the doors or windows. Furthermore, a wool brush is used for unidirectional and uniform application. The soft bristles of the wool brush can ensure that the release agent is evenly applied to the mold surface. During the application process, uneven application or missed areas are avoided. The overlapping area at the joint of the segments is minimized, thereby ensuring that the long-lasting release agent can form a uniform and dense release agent layer on the surface of the steel mold. Furthermore, the long-lasting release agent is a nano-silane modified long-lasting release agent, comprising a base emulsion, a nano-silane coupling agent, a film-forming aid, and deionized water, with a mass ratio of 60:5:3:32. The long-lasting release agent can be reused 5-6 times; its adhesion to concrete is ≤1.3 g / m³. 2It can significantly improve the smoothness of the steel formwork surface, facilitate the demolding of precast concrete components, avoid the defects such as chipped edges and corners caused by demolding, and make the surface of the components reflective, greatly enhancing the surface texture of the components. Furthermore, the long-lasting release agent is applied to the center of the steel formwork surface, which is the core load-bearing area of ​​the concrete, with a thickness of 0.1~0.12mm, and to the edge areas of the formwork surface prone to leakage with a thickness of 0.15~0.18mm. This thickness ensures sufficient adhesion and release performance of the release agent without causing excessive drying time or sagging due to excessive thickness. After the first application, allow it to fully cure, allowing the release agent to initially harden and form a stable base film. After the first coat of release agent has completely hardened, subsequent coats are applied, following the same direction as the first coat, to ensure the consistency and stability of the release agent film.

[0011] To prevent the release agent from being contaminated by dust, impurities, etc. after application, a plastic film is used to cover it after each coat to block external pollutants and ensure the cleanliness of the release agent surface, thereby guaranteeing its release effect and improving the surface texture of the component.

[0012] S3. Mold assembly: Chamfer strips pre-coated with long-lasting release agent are pasted at the junction of the side mold and the steel mold base. Glass glue is used to fill the gaps where the width of the side mold joint exceeds 1mm. Rubber plugs are used to seal the tie bolt holes. Furthermore, the chamfer strip is a right triangle with a right angle side length of 5~15 mm, and the chamfer strip is made of PVC / rubber composite material with a 3mm thick rubber layer embedded in the PVC matrix; the chamfer strip is bonded to the mold with neutral glass glue, and the excess edge of the glass glue is scraped flat, and the thickness of the glass glue at the gap between the chamfer strip and the side mold or steel mold table is ≤1mm.

[0013] Additionally, to address the risk of grout leakage, a backup plan is provided: 1.5mm thick double-sided adhesive strips can be pre-applied to the joints. If a small amount of grout leakage is found after demolding, it can be cleaned with laser cutting and then smoothed with special repair mortar for fair-faced concrete. This process can reduce the grout leakage rate to below 3%.

[0014] The chamfering strip creates a smooth transition at the joint, preventing grout leakage during concrete pouring due to right-angle gaps. Neutral silicone sealant is used to fill the gaps; it has good adhesion, sealing properties, and weather resistance, effectively filling gaps and preventing grout leakage and water loss. During filling, the sealant layer thickness should be controlled to ≤1mm to ensure filling effectiveness while avoiding excessive thickness that could affect the component's appearance. After filling, use a scraper to remove excess sealant, ensuring a smooth and clean surface at the joint.

[0015] For side formwork joints, when the joint width is greater than 1mm, inject silicone sealant and compact it. Silicone sealant fills the joint gap, forming a sealing barrier to prevent concrete grout from seeping out. After injection, compaction ensures the sealant adheres tightly to both sides of the joint, guaranteeing its airtightness and effectively preventing quality defects such as honeycomb and pitting on the component surface caused by grout leakage and water loss. This ensures the smoothness and integrity of the component surface.

[0016] S4. Steel frame installation: Tie the reinforcing bars into a steel frame with the end of the binding wire facing the inside of the steel frame. Install protective pads at intervals around the outer periphery of the upper and lower chord bars. Hoist the steel frame into the mold. Furthermore, the steel frame assembly is completed in a dedicated binding area. This area provides a relatively independent and clean working environment, effectively preventing scratches, contamination, and other damage to the long-lasting release agent when directly binding reinforcing bars on the steel formwork. During the binding process, the ends of the binding wires are directed towards the inside of the component to prevent them from being exposed and rusting due to contact with the external environment during subsequent construction, which would affect the appearance and durability of the component.

[0017] Furthermore, when hoisting the steel frame, care must be taken to avoid bumping into the steel formwork platform, which could scratch the surface and damage the release agent layer. The binding wire must be ensured not to touch the steel formwork platform or side formwork. When installing the reinforcing bars, operators are required to wear non-woven shoe covers. Non-woven shoe covers are soft, static-free, and do not shed easily, which can effectively reduce contamination of the release agent application area and prevent dust and debris from the soles of the shoes from contaminating the release agent and affecting the molding effect of the fair-faced concrete.

[0018] Furthermore, the protective gasket is a cement-gray plastic gear with a notch. The notch has a certain degree of elasticity, the color difference between the gasket and the fair-faced concrete is ΔE≤3, the compressive strength is ≥C50, and the contact area with the steel formwork is ≤3cm². When the cement-gray protective gasket is exposed on the concrete surface, the color is not too abrupt, and the gear shape minimizes the exposed portion and makes it less noticeable, thereby reducing the impact of the protective gasket on the surface quality of the component.

[0019] S5. Pouring and curing: Pour the proportioned fair-faced concrete into the mold in batches and distribute it evenly. Use an integrated vibrating table for frequency conversion vibration and cover with a film for constant temperature curing for 4-5 days to obtain precast components. Furthermore, the concrete slump is between 150 and 170 mm; this slump range ensures that the concrete has good fluidity, making it easy to distribute evenly by the concrete placing machine, while avoiding problems such as segregation and bleeding caused by excessive slump, which would affect the strength and surface quality of the concrete; the concrete is poured in at least three batches. Furthermore, the concrete is vibrated at 40Hz for 40-50 seconds until the surface is smooth and free of air bubbles. Within this frequency and time range, air bubbles inside the concrete are fully expelled, and particles are tightly packed together, thereby improving the density of the concrete. For complex components, alternating vibration at 30Hz low frequency and 50Hz high frequency for 8 seconds each is used. Low-frequency vibration allows the coarse aggregate inside the concrete to settle fully, filling large voids; high-frequency vibration helps to expel tiny air bubbles, making the surface of the component denser and smoother. Through this multi-frequency synergistic vibration method, it is ensured that the concrete in all parts of the complex component achieves good density; after vibration, the concrete density is ≥98%. S6. Demolding: Remove the side mold and use a special lifting tool to lift the component for demolding. After demolding, transfer it to a rubber pad and flip it over so that the component stands upright against the support frame. Then, tie and fix the steel frame to the support frame. Furthermore, before demolding, check whether the long-lasting release agent is damaged, and apply it locally to the damaged areas. When flipping, use a hook to hook the truss lifting point on the upper part of the steel frame, with the bottom of the component abutting against the rubber pad. The flipping time is ≥60s. Furthermore, the lifting speed is controlled at 0.5m / min, the rubber pad thickness is ≥10mm, and the Shore hardness is 50-60D; the bottom rubber pad can prevent stress concentration and damage to the components, and the truss reinforcement is tied to the support frame with Φ8mm iron wire at the back, with a tying point spacing of ≤600mm, and the anti-tipping stability coefficient is ≥1.5.

[0020] S7. Surface protection: After the surface of the component has dried and faded, apply a layer of fair-faced concrete protective agent to the surface of the component multiple times to form a protective film; cover the component with a film.

[0021] Furthermore, the concrete protective agent comprises 35% siloxane, 3% emulsifier, 1% surfactant, 0.1% defoamer, 0.5% bactericide, and 60.4% water. It is applied at least three times, with a 2-hour interval between each application, allowing sufficient drying and penetration time for the protective agent to better bond with the concrete surface and form a stable and effective protective film. The resulting protective film has a thickness of 5-10 μm and an impermeability grade ≥P6. This thickness ensures the protective effect without significantly affecting the natural texture and appearance of the component. The protective film achieves a "lotus effect," making it difficult for water stains to adhere to the component surface, effectively preventing water contamination of the component surface, and the protective duration is ≥10 years. Furthermore, the film is an electrostatically adsorbed plastic film used to protect the surface of the finished component from dust and other contaminants.

[0022] The present invention also provides a precast fair-faced concrete component, which is prepared by the above-mentioned stable and controllable method for improving the surface quality of precast concrete components. The outer side of the component is a mirror-effect fair-faced finish, and the outer surface of the fair-faced finish has a protective film.

[0023] Due to the adoption of the above technical solution, the technical progress achieved by this invention compared to the prior art is as follows: 1. Through a two-stage grinding process combined with a long-lasting release agent, the surface roughness Ra of the steel mold table after grinding is ≤1.6μm, resulting in a surface flatness error of ≤1mm / 2m and a mirror-like smoothness. The treatment of the chamfer strip at the mold assembly reduces the grout leakage rate from 15% in the traditional process to below 5%, effectively avoiding defects such as honeycomb and pitting on the concrete surface caused by grout leakage. By optimizing the vibration process and controlling the quality of raw materials, the surface bubble rate of the component is ≤0.5%, the bubble diameter is ≤2mm, and the spacing is ≥50mm, making the surface of the component smoother and more even, greatly improving the overall quality and aesthetics of the component, with a yield rate of over 95%.

[0024] 2. The long-lasting release agent can be reused more than 5 times with a single application, which is 100% faster than the traditional release agent which only requires 2-3 applications. This reduces the number of applications and improves production efficiency. The protective gasket is combined with the rebar binding process, which avoids the need for later repairs due to rebar displacement or gasket detachment.

[0025] 3. The siloxane protective agent chemically bonds with the concrete, penetrating more than 2mm into the concrete to form a strong protective film. After weather resistance testing, the surface color difference ΔE≤2, which is almost imperceptible to the naked eye, and the water stain pollution rate ≤5%. It can effectively resist the erosion of natural factors such as ultraviolet rays and rainwater, maintain the color and texture of the component surface, extend its service life, and reduce maintenance costs and replacement frequency. Attached Figure Description

[0026] Figure 1 This is a flowchart of the process flow of the present invention; Figure 2 This is a schematic diagram of the structure of the protective gasket of the present invention.

[0027] In the diagram: 1-protective gasket; 2-notch. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to embodiments: like Figure 1 As shown, a stable and controllable method for improving the surface quality of precast concrete components is employed, using a horizontal mold production method, and includes the following steps: S1. Grinding and cleaning of steel formwork: Use a large floor grinder with a wire brush to grind the steel formwork in a cross pattern until the surface has a uniform metallic luster. Then, switch to a 50-grit diamond grinding head for two-stage cross grinding. The grinding speed should be controlled at 1.5 / min. After grinding, wipe the formwork with a lint-free cloth dampened with industrial alcohol to achieve a mirror finish and remove any oil residue. Furthermore, the flatness error of the template surface after grinding is 0.5mm, the surface roughness Ra is 1.6μm, the rust removal rate is 100%, and the reflectivity is 85%.

[0029] S2. Apply long-lasting release agent: After cleaning the side mold, use a wool brush to apply the long-lasting release agent to the steel mold platform and side mold. Apply the long-lasting release agent in sections along the long direction of the steel mold platform, with each section being 1.5m long. Keep the brushing direction consistent within each section. Proceed to the coating area along the short direction of the steel mold platform. Repeat the coating 3 times, with an interval of 24 hours between each coating. Cover with plastic film after each coating.

[0030] In this embodiment, the side mold is made of wood with a moisture content of 10%. If there are doors or windows, the side mold is joined at a 45° bevel at the corners corresponding to the doors and windows. During the coating process, avoid uneven coating or missed areas, and minimize the overlapping area at the joints between sections; Furthermore, the long-lasting release agent is a nano-silane modified long-lasting release agent, comprising a base emulsion, a nano-silane coupling agent, a film-forming aid, and deionized water, with a mass ratio of 60:5:3:32; the adhesion of the long-lasting release agent to concrete is 1.3 g / m³. 2 ; The long-lasting release agent should be applied to the middle of the steel formwork surface, which is the core load-bearing area of ​​the concrete, with a thickness of 0.1 mm, and to the edge areas of the formwork surface that are prone to grout leakage with a thickness of 0.18 mm. After the first application, allow it to fully cure before applying subsequent applications. Follow the same direction as the first application to ensure the consistency and stability of the release agent film.

[0031] To prevent the release agent from being contaminated by dust, impurities, etc. after application, a plastic film is used to cover it after each coat to block external pollutants and ensure the cleanliness of the release agent surface, thereby guaranteeing its release effect and improving the surface texture of the component.

[0032] S3. Mold assembly: Apply chamfer strips pre-coated with long-lasting release agent to the junction of the side mold and the steel mold base. Use glass glue to fill the gaps where the width of the side mold joint exceeds 1mm. Use rubber plugs to seal the tie bolt holes. The chamfering strip is a right triangle with a right angle side length of 5 mm. The chamfering strip is made of PVC / rubber composite material, with a 3 mm thick rubber layer embedded in the PVC matrix. The chamfering strip is bonded to the mold with neutral glass glue, and the excess glass glue edges are scraped smooth. The thickness of the glass glue at the gap between the chamfering strip and the side mold or steel mold table is 1 mm. Use a scraper to remove excess glue to make the joint surface smooth and clean.

[0033] For side mold joints, when the joint width is greater than 1mm, inject glass glue and compact it.

[0034] S4. Steel frame installation: Tie the steel bars into a steel frame with the end of the tie wire facing the inside of the steel frame. Install protective pads 1 at intervals around the outer periphery of the upper and lower chord bars. Hoist the steel frame into the formwork. First, the steel frame is assembled in the dedicated binding area. During the binding process, the end of the binding wire should face the inside of the component. When hoisting the steel frame, it is necessary to avoid bumping into the steel formwork. The binding wire must ensure that it does not touch the steel formwork or the side formwork. When installing the reinforcing bars, operators are required to wear non-woven shoe covers.

[0035] Protective gasket 1 is a cement gray plastic gear with a notch 2. The notch 2 has a certain degree of elasticity. The color difference between it and the fair-faced concrete is ΔE=3. The compressive strength is C50. The contact area with the steel mold table is 3cm².

[0036] S5. Pouring and curing: The proportioned fair-faced concrete is poured into the mold in batches and evenly distributed. The integrated vibrating table is used for frequency conversion vibration, and the precast components are obtained after 45 days of constant temperature curing with a film covering. The concrete slump is 170mm; the concrete is evenly distributed using a concrete placing boom; the concrete is poured in three batches; the concrete is vibrated at 40Hz for 45 seconds until the surface is smooth and free of air bubbles; for complex components, alternating vibrations at 30Hz and 50Hz for 8 seconds each are used. After vibration, the concrete density is 98%. S6. Demolding: Remove the side mold and use a special lifting tool to lift the component for demolding. After demolding, transfer it to a rubber pad and flip it over so that the component stands upright against the support frame. Then, tie and fix the steel frame to the support frame. Furthermore, before demolding, check whether the long-lasting release agent is damaged, and apply it locally to the damaged areas. When flipping, use a hook to hook the truss lifting point on the upper part of the steel frame, and let the bottom of the component rest against the rubber pad. The flipping time is 90 seconds. Furthermore, the lifting speed is controlled at 0.5m / min, the rubber pad thickness is 10mm, and the Shore hardness is 50D; the truss reinforcement is tied to the support frame with Φ8mm iron wire at the back, the tying point spacing is 600mm, and the anti-tipping stability coefficient is 1.5.

[0037] S7. Surface protection: After the surface of the component has dried and faded, apply a layer of fair-faced concrete protective agent to the surface of the component multiple times to form a protective film; cover the component with a film.

[0038] Furthermore, the composition of the fair-faced concrete protective agent is 35% siloxane, 3% emulsifier, 1% surfactant, 0.1% defoamer, 0.5% bactericide and 60.4% water. It is applied 3 times with an interval of 2 hours between each application to allow the protective agent to bond with the concrete surface and form a protective film with a thickness of 6μm, an impermeability grade of P6, and a protection duration of ≥10 years. Furthermore, the film is a plastic film that is electrostatically adsorbed.

[0039] The present invention also provides a precast fair-faced concrete component, which is prepared by the above-mentioned stable and controllable method for improving the surface quality of precast concrete components. The outer side of the component is a mirror-effect fair-faced finish, and the outer surface of the fair-faced finish has a protective film.

[0040] It should be noted that, in the description of this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joint" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0041] The present invention has been described in detail above. However, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, any modifications or improvements that do not depart from the spirit of the present invention are within the scope of protection of the present invention.

Claims

1. A stable and controllable method for improving the surface quality of precast concrete components, characterized in that, The method employs a horizontal mold production process and includes the following steps: S1. Grinding and cleaning of steel formwork: Use a large floor grinder with a wire brush to grind the steel formwork in a cross pattern. After the surface is shiny, replace it with a 50-grit diamond grinding head for two-stage cross grinding. The grinding speed is controlled at 1.5-2m / min. After grinding, wipe the steel formwork with a lint-free cloth dampened with industrial alcohol to achieve a mirror finish and remove any oil residue from the surface. S2. Apply long-lasting release agent: After cleaning the side mold, apply long-lasting release agent to the steel mold platform and the side mold. Apply the long-lasting release agent in sections along the long direction of the steel mold platform, with each section being 1 to 1.5 meters long. Keep the brushing direction consistent within each section. Proceed to the coating area along the short direction of the steel mold platform. Repeat the application 3 to 5 times, with an interval of 24 to 48 hours between each application. Cover with plastic film after each application. S3. Mold assembly: Chamfer strips pre-coated with long-lasting release agent are pasted at the junction of the side mold and the steel mold base. Glass glue is used to fill the gaps where the width of the side mold joint exceeds 1mm. Rubber plugs are used to seal the tie bolt holes. S4. Steel frame installation: Tie the reinforcing bars into a steel frame with the end of the binding wire facing the inside of the steel frame. Install protective pads at intervals around the outer periphery of the upper and lower chord bars. Hoist the steel frame into the mold. S5. Pouring and curing: Pour the proportioned fair-faced concrete into the mold in batches and distribute it evenly. Use an integrated vibrating table for frequency conversion vibration and cover with a film for constant temperature curing for 4-5 days to obtain precast components. S6. Demolding: After removing the side mold, use a special lifting tool to lift the component for demolding. After demolding, transfer it to a rubber pad and flip it over so that the component is placed upright against the support frame. Then, tie and fix the steel frame to the support frame. S7. Surface protection: After the surface of the component has dried and faded, apply a layer of fair-faced concrete protective agent to the surface of the component multiple times to form a protective film; cover the component with a film.

2. The method for improving the surface quality of stable and controllable precast concrete components according to claim 1, characterized in that, The flatness error of the template surface after grinding of the steel template table described in S1 is ≤0.5mm, the surface roughness Ra is ≤1.6μm, the rust removal rate is 100%, and the reflectivity is ≥85%.

3. The method for improving the surface quality of stable and controllable precast concrete components according to claim 1, characterized in that, The long-lasting release agent described in S2 is a nano-silane modified long-lasting release agent, comprising a base emulsion, a nano-silane coupling agent, a film-forming aid, and deionized water, with a mass ratio of 60:5:3:

32. The long-lasting release agent is applied to the center of the steel mold base with a thickness of 0.1~0.12 mm, and to the edge areas with a thickness of 0.15~0.18 mm. The adhesion of the long-lasting release agent to concrete is ≤1.3 g / m³. 2 .

4. The method for improving the surface quality of stable and controllable precast concrete components according to claim 1, characterized in that, When the side mold material mentioned in S2 is a steel mold, the same grinding and cleaning process as the steel mold table in S1 shall be performed; when the mold material mentioned in S2 is a wooden mold, the moisture content of the wooden mold shall be ≤12%.

5. The method for improving the surface quality of stable and controllable precast concrete components according to claim 1, characterized in that, The chamfer strip in S3 is a right triangle with a right angle side length of 5~15 mm. The chamfer strip is made of PVC / rubber composite material. The chamfer strip is bonded to the mold with neutral glass glue. The thickness of the glass glue at the gap between the chamfer strip and the side mold or steel mold table is ≤1 mm.

6. The method for improving the surface quality of stable and controllable precast concrete components according to claim 1, characterized in that, The protective pad described in S4 is a cement-gray notched plastic gear with a color difference of ΔE≤3 from fair-faced concrete, a compressive strength ≥C50, and a contact area with the steel formwork ≤3cm².

7. The method for improving the surface quality of stable and controllable precast concrete components according to claim 1, characterized in that, The concrete slump described in S5 is 150~170mm; it is vibrated at a frequency of 40Hz for 40~50s, supplemented by alternating vibration at 30Hz and 50Hz for 8s each, so that the concrete density is ≥98% after vibration.

8. The method for improving the surface quality of stable and controllable precast concrete components according to claim 1, characterized in that, Before demolding in S6, check whether the long-lasting release agent is damaged. Apply local repair coating to the damaged areas. When flipping, hook the truss lifting point on the upper part of the steel frame with a hook, and let the bottom of the component rest against the rubber pad. The flipping time is ≥60s.

9. The method for improving the surface quality of stable and controllable precast concrete components according to claim 1, characterized in that, The concrete protective agent described in S7 consists of 35% siloxane, 3% emulsifier, 1% surfactant, 0.1% defoamer, 0.5% bactericide, and 60.4% water. The resulting protective film has a thickness of 5-10 μm and an impermeability grade ≥ P6. The film is an electrostatically adsorbed plastic film.

10. A precast fair-faced concrete component, characterized in that, The component is prepared by a stable and controllable method for improving the surface quality of precast concrete components according to any one of claims 1-9, and the outer side of the component is a mirror-effect fair-faced finish, the outer surface of which has a protective film.

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