Concrete curing methods

Abstract

This invention discloses a concrete curing method, belonging to the field of building construction technology, aiming to solve the problems of concrete cracking and insufficient strength caused by inaccurate humidity control in existing concrete curing processes. The method includes: laying a permeable geotextile after the concrete has set, setting up an arched plastic frame and covering it with a heat-insulating plastic film with permeable holes to form an air layer; installing humidity sensors within the air layer to monitor humidity; and activating a spray system according to the temperature gradient when the humidity of the air layer is below 40%. The spray interval and duration are adjusted according to the temperature, with evaporation inhibitors added at high temperatures and the spray water heated at low temperatures. This method, through precise control of humidity and temperature, significantly improves the strength and durability of concrete, reduces cracking, and is suitable for concrete curing operations in building construction.

Description

Technical Field

[0001] This invention relates to the field of building construction technology. More specifically, this invention relates to a method for curing concrete. Background Technology

[0002] Concrete curing is a crucial step in ensuring its strength development and durability, but existing methods have significant shortcomings in terms of humidity control precision. Traditional curing mainly relies on manual watering or fixed-interval spraying, which is difficult to respond to real-time changes in the humidity of the concrete surface. When the ambient humidity is below 40%, the rate of water evaporation from the concrete surface is much higher than the rate of internal replenishment, easily leading to plastic shrinkage cracks and a decrease in structural strength. In addition, temperature fluctuations further exacerbate the difficulty of humidity control: in high-temperature environments, water evaporates too quickly, and conventional spraying cannot compensate in time; in low-temperature environments, sprayed water is prone to freezing, which not only reduces the curing effect but may also damage the internal structure of the concrete due to the expansion of ice crystals.

[0003] Existing covering materials (such as single plastic films or permeable geotextiles) also have limitations. While plastic films can provide insulation, condensation can easily lead to localized over-wetting or uneven wetting; permeable geotextiles, while allowing water to pass through, lack active humidity regulation capabilities. If the gap between the covering layer and the concrete surface is not properly designed, it can easily create differences in humidity distribution, with some areas remaining in a low-humidity state for extended periods. These problems stem from two main difficulties: first, the lack of high-density, non-intrusive humidity monitoring methods (improper sensor placement is easily affected by covering materials or fails to reflect overall humidity); second, the disconnect between spraying strategies and dynamic changes in temperature and humidity, requiring additional measures (such as anti-evaporation or anti-freezing) under extreme temperatures, which are difficult to integrate with existing technologies.

[0004] These defects lead to increased dispersion in concrete strength (the standard deviation of 28-day compressive strength often exceeds 15%) and an increased cracking rate, especially in large-volume concrete or construction in high-temperature / cold regions. Although attempts have been made to improve the spraying system or covering materials, the complexity of temperature and humidity coupling control and the high requirements for ease of construction have made it difficult to balance accuracy and engineering practicality. Summary of the Invention

[0005] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0006] Another objective of this invention is to provide a concrete curing method that addresses the problems of uneven humidity distribution, delayed monitoring response, and poor adaptability to temperature and humidity coupling control in traditional concrete curing methods.

[0007] To achieve these objectives and other advantages according to the present invention, a concrete curing method is provided, comprising the following steps: S1. After the concrete pouring surface has set, a permeable geotextile with a mesh size of 2 cm × 2 cm is laid. Above the permeable geotextile, a plastic arch frame is laid with a mesh size of 1 m × 1 m to 2 m × 2 m. The arch frame has an arched structure with the arch apex facing upwards and an arch height of 5 cm to 10 cm. A heat-insulating plastic film is laid on top of the arch frame, and multiple micro-concave water collection areas are formed on the heat-insulating plastic film by heat pressing. Each water collection area has a diameter of 3 cm and a depth of 0.5 mm. A seepage hole with a diameter of 3.0 mm ± 0.2 mm and a hole spacing of 8 cm to 12 cm is opened in the center of the micro-concave water collection area. In the concrete edge area, the permeable geotextile and heat-insulating plastic film are extended outwards to cover 50 cm to 100 cm, and the edges are compacted with soil bags. An air layer is formed between the heat-insulating plastic film and the permeable geotextile by the support of the arch frame. S2. Within the air layer, at every 20 m 2 up to 50 m 2 Install humidity sensors, which are fixed to the side of the arch frame, with the sensing part of the humidity sensor 3 cm to 5 cm away from the upper surface of the permeable geotextile. S3. When the humidity sensor detects that the relative humidity of the air layer is <40%, the spray system is activated to spray water onto the film micro-concave water collection area. During spraying, when the ambient temperature is ≥30℃, an evaporation inhibitor is added to the spray water; when the ambient temperature is <30℃, no evaporation inhibitor is added to the spray water. The specific spraying operation is as follows: When the ambient temperature is >40℃, the spraying interval is 8 to 15 minutes, and each spraying lasts 1.5 to 2.5 minutes. When 30℃≤Ambient temperature<40℃, spraying interval is 20 min to 40 min, each lasting 2 min to 3 min; When 20℃≤Ambient temperature<30℃, the spraying interval is 1 h to 2 h, and each spraying lasts 1.5 min to 2.5 min. When 10℃≤Ambient temperature<20℃, the spraying interval is 3 h to 5 h, and each spraying lasts 1.5 min to 2.5 min. When the ambient temperature is <10℃, the spraying interval is 6 h to 8 h, each spraying lasts 1.0 min to 1.5 min, and the spraying water temperature is heated to 25℃±2℃. Maintenance lasts 7 to 14 days.

[0008] Preferably, in step S1, the heat-insulating plastic film laid on the top of the arch frame comprises multiple film panels, each panel being 4 m to 8 m wide and 0.12 mm ± 0.02 mm thick; adjacent panels overlap along the length direction, with an overlap width of 2 cm to 5 cm, the overlap seam being located directly above the arch top of the arch frame, and the overlap is fixed by pressing the edges with soil bags, the soil bags weighing 1 kg to 2 kg and spaced 1 m to 1.5 m apart.

[0009] Preferably, the inner wall of the perforation hole has a nano-silica hydrophobic layer with a contact angle with water ≥150°; the perforation area is ≥2 m from the edge of the film plate and ≥50 cm from the overlap seam.

[0010] Preferably, the evaporation inhibitor in step S3 is polyethylene glycol 400; wherein: When the ambient temperature is >40℃, the mass-volume percentage concentration of the polyethylene glycol 400 in the spray water is 0.3% (w / v). When 30℃≤Ambient temperature<40℃, the mass-volume percentage concentration of the polyethylene glycol 400 in the spray water is 0.2% (w / v). The polyethylene glycol 400 forms a nanoscale hydrophilic film layer in the sprayed water, which is used to inhibit water evaporation and enhance the spreading and penetration of water molecules on the concrete surface.

[0011] Preferably, when the ambient temperature is <5℃, the sprinkler system should be paused and the following steps should be taken: A1. Remove the heat-insulating plastic film panels from the areas to be coated in sections, and make temporary reset marks at the overlap joints; remove the arches and permeable geotextiles in the corresponding areas to expose the concrete surface. A2. Apply a curing agent to the exposed concrete surface at a rate of 150–200 g / m². 2 Apply two coats, with an interval of 30±5 min, to form a film thickness of 80–100 μm. A3. After the curing agent has dried to the surface, re-lay the permeable geotextile, arch frame and film plate according to the reset mark position, and fix the soil bag at the edge.

[0012] Preferably, the curing agent is formulated from the following components in weight percentage: 60%~70% polyurethane resin base liquid, 5%~8% nano zinc oxide, 2%~3% polyether modified silicone oil, and the balance being solvent oil; the nano zinc oxide has a particle size of 20~30nm.

[0013] Preferably, the heat-insulating plastic film has a three-layer co-extruded structure; The outer layer comprises a low-density polyethylene matrix with a density of 0.915–0.925 g / cm³. 3The low-density polyethylene matrix is ​​doped with nano-ceramic particles with a particle size of 20 nm–40 nm, and the nano-ceramic particles account for 8%–12% of the total mass. The nano-ceramic particles are a mixture of antimony-doped tin oxide and indium tin oxide in a mass ratio of 3:1. The outer layer thickness accounts for 25%–30% of the total film thickness. The middle layer comprises a polyolefin elastomer, and the thickness of the middle layer accounts for 40%–45% of the total film thickness; The inner layer comprises a low-density polyethylene matrix with a density of 0.918–0.928 g / cm³. 3 The low-density polyethylene matrix is ​​incorporating hydrophobic nano-silica with a particle size of 30 nm–50 nm and a mass percentage of 5%–8%.

[0014] Preferably, the plastic arch frame is injection molded from a blend of polypropylene and 30% glass fiber. The cross-section of the arch frame is a pentagonal honeycomb structure with a wall thickness of 1.5 mm ± 0.2 mm and a single arch frame load capacity of ≥ 50 kg. The bottom of the arch frame is provided with L-shaped buckles that are embedded in the permeable geotextile mesh. The buckle spacing is consistent with the mesh spacing of the arch frame.

[0015] The present invention has at least the following beneficial effects: This invention utilizes an arched support to form a uniform air layer (arch height 5 cm to 10 cm), the synergistic effect of permeable geotextile and porous insulating film, and edge extension covering of 50 cm to 100 cm followed by compaction. This effectively eliminates uneven humidity, reducing the standard deviation of humidity distribution to below 5% and decreasing the cracking rate by 40%. (Based on a 20 m...) 2 up to 50 m 2 Density sensors are deployed on the sides of the arch frame (sensor ends 3 cm to 5 cm from the geotextile) to achieve real-time monitoring across the entire area. When humidity is <40%, the sprinkler system responds within 2 minutes, and the evaporation rate in high-temperature zones is reduced by 35%. Sprinkler parameters are dynamically adjusted based on temperature gradients: in high-temperature zones, polyethylene glycol 400 (0.1%-0.3%) is added, shortening the interval to 8 minutes; in low-temperature zones, the water temperature is heated to 25℃±2℃, extending the interval to 6 hours. This dynamic adaptation of temperature and humidity ensures that the concrete strength compliance rate increases to 98% after 7 to 14 days of curing, while reducing energy consumption by 20%.

[0016] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to embodiments, so that those skilled in the art can implement it based on the description.

[0018] This invention provides a concrete curing method, comprising the following steps: S1. After the concrete pouring surface has set, lay a permeable geotextile with a mesh size of 2 cm × 2 cm. Above the permeable geotextile, lay a plastic arch frame with a mesh size of 1 m × 1 m to 2 m × 2 m. The arch frame has an arched structure with the top facing upwards and an arch height of 5 cm to 10 cm. Lay a heat-insulating plastic film on top of the arch frame. The heat-insulating plastic film has permeable holes. In the concrete edge area, extend the permeable geotextile and heat-insulating plastic film outwards to cover 50 cm to 100 cm, and compact the edges with soil bags. An air layer is formed between the heat-insulating plastic film and the permeable geotextile through the support of the arch frame. S2. Within the air layer, at every 20 m 2 up to 50 m 2 Install humidity sensors, which are fixed to the side of the arch frame, with the sensing part of the humidity sensor 3 cm to 5 cm away from the upper surface of the permeable geotextile. S3. When the humidity sensor detects that the relative humidity of the air layer is <40%, the spray system is activated to spray water onto the film micro-concave water collection area. During spraying, when the ambient temperature is ≥30℃, an evaporation inhibitor is added to the spray water; when the ambient temperature is <30℃, no evaporation inhibitor is added to the spray water. The specific spraying operation is as follows: When the ambient temperature is >40℃, the spraying interval is 8 to 15 minutes, and each spraying lasts 1.5 to 2.5 minutes. When 30℃≤Ambient temperature<40℃, spraying interval is 20 min to 40 min, each lasting 2 min to 3 min; When 20℃≤Ambient temperature<30℃, the spraying interval is 1 h to 2 h, and each spraying lasts 1.5 min to 2.5 min. When 10℃≤Ambient temperature<20℃, the spraying interval is 3 h to 5 h, and each spraying lasts 1.5 min to 2.5 min. When the ambient temperature is <10℃, the spraying interval is 6 h to 8 h, each spraying lasts 1.0 min to 1.5 min, and the spraying water temperature is heated to 25℃±2℃. Maintenance lasts 7 to 14 days; In the above technical solution, after the concrete surface has fully set, a permeable geotextile with a mesh size of 2cm square is immediately laid. Then, plastic arches are installed on top of the geotextile at 1m to 2m intervals. The arches are arched with the apex facing upwards, and the arch height is controlled between 5cm and 10cm. A specially made heat-insulating plastic film is covered on the top of the arches, with evenly distributed perforations on its surface. The geotextile and film at the concrete edge areas need to extend outwards by 50cm to 100cm and be compacted at the boundaries with soil bags. The air layer formed by the arch support is located between the film and the geotextile, with a thickness consistent with the arch height.

[0019] Air layer at 20m 2 up to 50 m 2 A humidity sensor is installed, fixed to the side of the arch frame, with the sensing end 3cm to 5cm away from the top surface of the geotextile. When the sensor detects that the relative humidity of the air layer is below 40%, the sprinkler system is automatically activated. Spray water infiltrates through the micro-concave water collection area of ​​the membrane. Specific parameters are dynamically adjusted according to the ambient temperature: When the temperature is above 40℃, an evaporation inhibitor is added to the spray water, and the spray interval is shortened to 8-15 minutes, with each spray lasting 1.5-2.5 minutes; when the temperature is between 30-40℃, an evaporation inhibitor is added to the spray water, and the interval is extended to 20-40 minutes, with each spray lasting 2-3 minutes; when the temperature is between 20-30℃, no evaporation inhibitor is added to the spray water, and the interval is adjusted to 1-2 hours, with each spray lasting 1.5-2.5 minutes; when the temperature is between 10-20℃, no evaporation inhibitor is added to the spray water, and the interval is set to 3-5 hours, with each spray lasting 1.5-2.5 minutes; when the temperature is below 10℃, no evaporation inhibitor is added to the spray water, and the interval is extended to 6-8 hours, with each spray lasting 1.0-1.5 minutes. The spray water must be heated to approximately 25℃. The curing cycle lasts 7-14 days.

[0020] Traditional curing methods have significant drawbacks. Conventional operations rely on manual watering or fixed-time spraying, which cannot respond in real-time to changes in concrete humidity, leading to an imbalance in surface moisture evaporation rates. Especially in high-temperature environments, rapid evaporation coupled with delayed replenishment can easily trigger plastic shrinkage cracks; at low temperatures, sprayed water freezes, and the expanding ice crystals damage the internal structure of the concrete. Existing covering materials, such as single plastic films, easily accumulate condensation, causing uneven wetting and drying, while permeable geotextiles lack active moisture regulation capabilities. Humidity monitoring typically relies on sparse point placement or manual spot checks, making it difficult to capture the overall humidity distribution, and response delays often exceed 30 minutes.

[0021] This invention achieves uniform humidity diffusion through an air layer in the arch frame, and eliminates localized dry zones by combining the synergistic effect of permeable geotextile and a perforated membrane. Humidity sensors are densely distributed along the sides of the arch frame, ensuring a constant distance from the concrete surface and reducing the monitoring response time to within 2 minutes. The spraying system dynamically adjusts parameters based on temperature gradients: evaporation inhibitors are added at high temperatures to suppress moisture loss, while the sprayed water is heated at low temperatures to prevent freezing. This temperature and humidity coupling mechanism reduces the standard deviation of concrete surface humidity to less than 5%, improves the 28-day compressive strength compliance rate, reduces cracking incidence, and simultaneously lowers energy consumption.

[0022] In another technical solution, in step S1, the heat-insulating plastic film laid on the top of the arch frame comprises multiple film panels, each panel being 4 m to 8 m wide and 0.12 mm ± 0.02 mm thick; adjacent panels overlap along the length direction, with an overlap width of 2 cm to 5 cm, and the overlap seam is located directly above the arch top of the arch frame. The overlap is fixed with soil bags, each weighing 1 kg to 2 kg, spaced 1 m to 1.5 m apart, without adhesive sealing.

[0023] In the above technical solution, the membrane is laid in sections, with the width of each section controlled between 4m and 8m and the thickness maintained at approximately 0.12 mm. Adjacent sections overlap by 2cm to 5cm along their length, with the overlap seams strictly aligned with the highest point of the arch. The fixing method uses soil bags to press the edges instead of traditional adhesive. Each soil bag weighs 1kg to 2kg and is evenly placed on the overlap seams at intervals of 1m to 1.5m. The membrane sections are not sealed with adhesive; they are held together solely by the weight of the soil bags.

[0024] Traditional construction methods typically involve laying the membrane continuously in rolls, which is prone to being overturned in strong winds; or using tape to seal the seams, which easily tears the membrane during removal, resulting in waste. The overlapping positions are highly arbitrary; if off-center from the support points, the membrane will sag and accumulate water, subsequently compressing the concrete surface below. Existing fixing methods mostly rely on covering the membrane with sand or piercing it with U-shaped nails. The former increases the load and affects the stability of the arch, while the latter damages the membrane's integrity, leading to wider leaks.

[0025] This invention reduces the wind-exposed area of ​​individual membrane sections through a segmented design, significantly improving wind resistance. The overlapping at the top of the arch allows water to slide off along the curved surface, preventing localized overpressure. The soil bags at the edges provide adjustable pressure without damaging the membrane, increasing dismantling efficiency by 50%. In particular, the non-adhesive open overlap allows the membrane to expand and contract freely with temperature changes, eliminating stress wrinkles caused by thermal expansion and contraction. It is important to ensure that the soil bags are evenly distributed during implementation to avoid excessive localized pressure that could collapse the arch; the membrane expansion allowance should be maintained at the non-overlapping edges to prevent temperature deformation from stretching the seams.

[0026] In another technical solution, multiple micro-concave water collection areas are formed on the heat-insulating plastic film by hot pressing. Each water collection area has a diameter of 3 cm and a depth of 0.5 mm. Water seepage holes are opened in the center of the micro-concave water collection areas. The hole diameter is 3.0 mm ± 0.2 mm and the hole spacing is 8 cm to 12 cm. The inner wall of the water seepage hole has a nano-silica hydrophobic layer with a contact angle with water ≥ 150°. The opening area is ≥ 2 m away from the edge of the film plate and ≥ 50 cm away from the overlap seam.

[0027] In the above technical solution, uniformly distributed micro-concave water collection areas are formed by hot pressing on the surface of the heat-insulating plastic film. The diameter of each water collection area is strictly controlled to be 3cm and the depth to be 0.5mm. A seepage hole with a diameter of 3.0±0.2mm is opened in the center of each micro-concave area, and the holes are arranged in a matrix of 8-12cm. The inner wall of the seepage hole is modified with nano-silica, and the contact angle with water is ≥150°. The opening area is ≥2m away from the edge of the film plate and ≥50cm away from the overlap seam.

[0028] Directly punching holes in ordinary membranes easily produces burrs, and the hydrophilicity around the holes hinders water diffusion. Randomly distributed holes can easily create localized water accumulation or dry areas. Condensate flows randomly on the membrane surface, with only about 30% effectively penetrating into the concrete. More seriously, the traditional excessively large pore size (often reaching 5-8mm) accelerates water evaporation, resulting in a water utilization rate of less than 40% under high-temperature conditions.

[0029] The micro-concave water collection area of ​​this invention guides water flow to converge, and the hot-pressed bowl-shaped structure directs the sprayed water into the central hole, avoiding runoff loss and achieving a water collection efficiency of 98%. The superhydrophobic coating on the inner wall of the hole prevents water from adhering to the hole wall, ensuring 100% vertical dripping and increasing the seepage rate to 0.5 mL / s. The opening area is located at least 2 meters away from plate joints and edges, eliminating seepage deviation caused by film deformation. It is important to note that high-precision hot-pressing molds must be used during production, with hole diameter tolerance controlled within ±0.05 mm. The nano-coating uses a vapor deposition process to ensure a 100% compliance rate for contact angles ≥150°.

[0030] In another technical solution, the evaporation inhibitor in step S3 is polyethylene glycol 400; wherein: When the ambient temperature is >40℃, the concentration of polyethylene glycol 400 is 0.3%; When 30℃ ≤ ambient temperature < 40℃, the concentration of polyethylene glycol 400 is 0.2%; The polyethylene glycol 400 forms a nanoscale hydrophilic film layer in the sprayed water, with a film thickness of 5–10 nm and a contact angle ≤30°, which is used to inhibit water evaporation and enhance the spreading and penetration of water molecules on the concrete surface.

[0031] In the above technical solution, the spraying system is equipped with an automatic liquid preparation module. When the ambient temperature is >40℃, 0.3% w / v polyethylene glycol 400 is injected into the spraying water; when the temperature is 30-40℃, 0.2% is injected. This inhibitor forms a 5-10 nm continuous hydrophilic film on the concrete surface with a contact angle ≤30°.

[0032] Traditional inhibitors such as fatty acid salts (e.g., calcium stearate) require a concentration greater than 1% to be effective, but they can clog spray nozzles and have a high failure rate. Traditional alcohol inhibitors (e.g., isopropanol) evaporate too quickly, with an effective time of less than 10 minutes in high-temperature environments and a water evaporation inhibition rate of only 40%. The conventional concentration strategy for traditional inhibitors remains unchanged, and excessive residue at low temperatures can cause cracking of the film on the concrete surface.

[0033] This invention utilizes polyethylene glycol 400, whose ethoxy chain length is precisely designed to form a monolayer hydrated film, achieving dual optimization of evaporation inhibition and permeation enhancement. A high-temperature concentration of 0.3% significantly accelerates water molecule spreading. The hydrophilic film binds water molecules through a hydrogen bond network, greatly reducing surface tension and promoting increased water infiltration depth along concrete pores. It is important to note that the polyethylene glycol solution must be prepared and used immediately, with a storage time ≤4 hours; the error of the solution preparation system must be controlled within ±0.02%.

[0034] In another technical solution, when the ambient temperature is <5℃, the sprinkler system is paused, and the following steps are performed: A1. Remove the heat-insulating plastic film panels from the areas to be coated in sections, and make temporary reset marks at the overlap joints; remove the arches and permeable geotextiles in the corresponding areas to expose the concrete surface. A2. Apply curing agent to the exposed concrete surface at a rate of 150–200 g / m²; apply in two coats with an interval of 30±5 min, resulting in a film thickness of 80–100 μm. A3. After the curing agent has dried to the surface, re-lay the permeable geotextile, arch frame and film plate according to the reset mark position, and fix the soil bag at the edge.

[0035] In the above technical solution, when the ambient temperature is <5℃, the sprinkler system should be immediately stopped and operated according to zone, as follows: A1. Zoned exposure of concrete: Remove the film panels of the area to be coated, and spray fluorescent markers at the overlap joints as reset reference points; remove the arch frame and geotextile to expose the concrete surface. A2. Apply curing agent: Use airless spray equipment at a concentration of 150-200 g / m². 2 The total amount is applied in two coats, with a 30-minute interval; the first coat is 80 g / m². 2 A base film is formed, and a second layer is applied to bring the thickness to the target thickness of 80-100μm. A3. Restoration Covering System: After the curing agent is surface dry (not sticky to the touch), back-lay geotextile, arch frame and film according to the marked position, and compact the boundary with soil bags.

[0036] Traditional low-temperature curing requires the removal of the entire insulation layer, resulting in prolonged exposure of the concrete and an increased risk of frost damage. In addition, the traditional method of spraying curing agent in a single thick coat (>150 μm) is prone to sagging during the surface drying process, resulting in poor film uniformity. The partitioned progressive operation of this invention reduces the single exposure area and greatly shortens the low-temperature exposure time of concrete; the first thin coat quickly forms a film and locks in water, and the second coat precisely controls the thickness, greatly improving the uniformity of film thickness; the overlap joint marking error is <2 mm, which helps to improve construction accuracy.

[0037] It should be noted that the standard for determining the surface dryness of the curing agent is a contact angle > 90°; in low-temperature environments, it is preferable to apply the curing agent during the midday period, and the concrete surface temperature must be > 0℃.

[0038] In another technical solution, the curing agent is compounded from the following components by weight percentage: 60%~70% polyurethane resin base liquid, 5%~8% nano zinc oxide, 2%~3% polyether modified silicone oil, and the balance being solvent oil; the nano zinc oxide has a particle size of 20~30 nm.

[0039] In the above technical solution, the curing agent is prepared as follows: The curing agent is prepared by weight percentage as follows: 60%-70% polyurethane resin base liquid is used as the film-forming carrier, 5%-8% nano-zinc oxide with a particle size of 20-30 nm is added, and 2%-3% polyether-modified silicone oil is incorporated as a leveling agent. The remaining amount is made up to 100% with solvent oil with a distillation range of 180-220℃. A high-speed shear emulsifier is used to disperse the mixture at 8000 rpm for 30 min to ensure that the agglomeration rate of the nano-zinc oxide is <1%.

[0040] Traditional curing agents, such as epoxy resin-based formulations, require the addition of 15%-20% plasticizer to maintain low-temperature flexibility, but this leads to a loss of 28-day strength. Traditional curing agents, such as silane-based curing agents, have a nano zinc oxide loading of only 2%-3%, a photothermal conversion efficiency of ≤40%, and a film temperature rise of less than 3°C in a -5°C environment. Traditional physical mixing processes result in a nanoparticle settling rate >5 mm / h, and a difference of >30% between the upper and lower components of the film after spraying.

[0041] The nano zinc oxide of this invention generates a surface plasmon resonance effect in the 20-30 nm particle size range, converting most of the sunlight into heat energy and raising the temperature of the film layer; the polyether-modified silicone oil reduces the surface tension of the curing agent and increases the penetration depth; the narrow distribution solvent oil optimizes the polyurethane crosslinking density gradient, and the film layer can still maintain a good elongation at break at -20℃.

[0042] It should be noted that the emulsification temperature should be kept constant at 50±2℃; the nano zinc oxide pre-dispersion is treated with silane coupling agent KH-550; and the viscosity of the finished product is controlled at 350±50 mPa·s (25℃).

[0043] In another technical solution, the heat-insulating plastic film has a three-layer co-extruded structure; The outer layer consists of a low-density polyethylene matrix with a density of 0.915-0.925 g / cm³. 3 The low-density polyethylene matrix is ​​doped with nano-ceramic particles with a particle size of 20 nm-40 nm and a mass ratio of 8%-12%. The nano-ceramic particles are a mixture of antimony-doped tin oxide and indium tin oxide in a mass ratio of 3:1. The outer layer thickness accounts for 25%-30% of the total film thickness. The middle layer comprises a polyolefin elastomer, the thickness of which accounts for 40%-45% of the total film thickness, and the light transmittance is ≥90%. The inner layer consists of a low-density polyethylene matrix with a density of 0.918-0.928 g / cm³. 3 The low-density polyethylene matrix is ​​blended with hydrophobic nano-silica with a particle size of 30 nm-50 nm and a mass ratio of 5%-8% for the nano-silica.

[0044] In the above technical solution, the heat insulation film is manufactured as follows: the film is produced using a three-layer co-extrusion process: Outer layer: Low-density polyethylene matrix (density 0.915-0.925 g / cm³) 3 The film is composed of 8%–12% nano-ceramic particles (20–40 nm in diameter), with antimony-doped tin oxide and indium tin oxide blended in a 3:1 mass ratio, accounting for 25%–30% of the total film thickness; the middle layer is a polyolefin elastomer layer accounting for 40%–45% of the total thickness, with a light transmittance ≥90%; the inner layer is a low-density polyethylene matrix (density 0.918–0.928 g / cm³). 3 ) Blend 5%–8% hydrophobic nano silica (particle size 30-50 nm) to make up the margin for the layer thickness.

[0045] Traditional films with a single-layer structure (such as ordinary PE film) have low infrared blocking rate, and the surface temperature of concrete exceeds the ambient temperature by 15°C in summer; traditional films with added light-blocking agents such as calcium carbonate greatly reduce light transmittance, hindering the photothermal curing of concrete; the hydrophilic inner layer of traditional films results in a condensate film coverage rate of up to 80%, blocking the water infiltration channels.

[0046] The nano-ceramic composite (ATO:ITO=3:1) of this invention increases the reflectivity of the solar infrared band (800-2500 nm) to 92%, and controls the temperature rise of the air layer under the film to within 3°C; the visible light transmittance of the POE middle layer is ≥90% and the haze is <5%, ensuring that the concrete absorbs 60% of the effective light energy to promote hydration; the inner nano-silica layer enables a contact angle of 115° and increases the condensate coalescence rate to 0.2 g / (min·m 2 This, combined with the micro-concave water collection area, enables directional transmission of dripping water.

[0047] In actual production, the following production specifications can be followed: the co-extrusion die temperature is set to 210℃ / 195℃ / 200℃ for the outer / middle / inner layers respectively; the nano-ceramic pre-dispersion uses titanate coupling agent NDZ-201, with an addition amount of 1.5%.

[0048] In another technical solution, the plastic arch frame is injection molded from a blend of polypropylene and 30% glass fiber. The cross-section of the arch frame is a pentagonal honeycomb structure with a wall thickness of 1.5 mm ± 0.2 mm and a single arch frame load capacity of ≥ 50 kg. The bottom of the arch frame is provided with L-shaped buckles that are embedded in the permeable geotextile mesh. The buckle spacing is consistent with the mesh spacing of the arch frame.

[0049] In the above technical solution, the arch frame is injection molded from a blend of polypropylene and 30% glass fiber, with a pentagonal honeycomb structure in cross-section and a wall thickness of 1.5±0.2 mm. A single arch frame can bear a load of ≥50 kg. The bottom integrates L-shaped buckles, with the buckle spacing strictly consistent with the grid spacing of the arch frame (1 m×1 m to 2 m×2 m). During installation, the buckles are directly embedded into the 2 cm×2 cm grid nodes of the permeable geotextile to achieve instantaneous mechanical locking.

[0050] Traditional metal arch frames are heavy and require welding / bolt fixing for installation, which takes a long time per point; condensation corrosion causes rust spots to contaminate the concrete, resulting in a high corrosion rate; if pure plastic arch frames are used, without reinforcement materials, their load-bearing capacity is small, they are prone to softening and deformation at high temperatures, and there is no positioning structure at the bottom, resulting in large construction offset errors; in addition, the traditional binding and fixing method involves wire binding that penetrates the geotextile, damaging its integrity and increasing leakage points.

[0051] This invention features a composite reinforcement structure for the arch frame: 30% glass fiber significantly increases the flexural modulus; furthermore, the pentagonal cell structure greatly enhances the local buckling critical load; and the L-shaped clips form an interference fit with the geotextile mesh, resulting in an installation error of <2 mm and significantly improved wind uplift resistance. It is important to note that during arch frame production, the injection molding pressure is 80 MPa and the mold temperature is 60℃ to ensure the directional distribution of glass fiber. In actual use, reinforcing ribs can be added at the base of the clips to improve their shear resistance; after installation, the insertion depth of all clips must be checked.

[0052] <Example 1> Concrete curing work on a high-speed railway bridge pier.

[0053] 1. Project Overview: Structure: C50 concrete bridge piers, with a single pouring volume of 320 m³; Weather conditions: In July, daytime temperatures range from 30 to 40°C, nighttime temperatures range from 20 to 29°C, and relative humidity is 35% to 38%. Maintenance cycle: 10 days; Material configuration: permeable geotextile (2 cm × 2 cm mesh), three-layer co-extruded thermal insulation film (6 m wide and 0.12 mm thick per piece, including micro-concave water collection area), GF / PP plastic arch frame (1.5 m × 1.5 m mesh layout, load-bearing capacity 70 kg), polyethylene glycol 400 evaporation inhibitor (molecular weight 400 g / mol), polyurethane-based curing agent (containing 6% nano zinc oxide, particle size 25 nm).

[0054] 2. Implementation steps: 2.1 Installation of the final setting covering system: After final setting test (indentation depth ≤ 0.5 mm), lay permeable geotextile with an 80 cm outer edge; embed L-shaped clips into the geotextile mesh nodes at 1.5 m intervals, with a uniform arch height of 8 cm; lay film panels (6 m wide), aligning the overlap seams with the arch top, with an overlap width of 3 cm; compact soil bags (1.5 kg / bag, spaced 1.2 m apart); install air layer humidity sensors every 40 m. 2 Install one (4 cm from the surface of the geotextile).

[0055] 2.2 Spraying: During the daytime temperature range of 30~40℃, the spray system automatically starts: add 0.3% polyethylene glycol 400, every 12 minutes for 2 minutes; water drips through the micro-concave water collection area of ​​the membrane (contact angle of 152° on the inner wall of the pore); the humidity on the concrete surface rises to 65% within 30 minutes. Nighttime temperature range 20~30℃, spray interval 1.5 hours, each spray lasts 2 minutes; 2.3 Temperature and humidity coupled control: Humidity remains >40% throughout the 10-day curing period; 3. Crack detection: After 10 days of curing, the crack rate on the concrete surface was 0.05%, compared to the crack rate of 0.4-0.8% with traditional curing methods. This invention can significantly reduce the crack rate on the concrete surface and help improve the quality of concrete.

[0056] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. A concrete curing method, characterized in that, Includes the following steps: S1. After the concrete pouring surface has set, a permeable geotextile with a mesh size of 2 cm × 2 cm is laid. Above the permeable geotextile, a plastic arch frame is laid with a mesh size of 1 m × 1 m to 2 m × 2 m. The arch frame has an arched structure with the top facing upwards and an arch height of 5 cm to 10 cm. A heat-insulating plastic film is laid on top of the arch frame, and multiple micro-concave water collection areas are formed on the heat-insulating plastic film by heat pressing. Each water collection area has a diameter of 3 cm and a depth of 0.5 mm. A seepage hole with a diameter of 3.0 mm ± 0.2 mm and a hole spacing of 8 cm to 12 cm is opened in the center of the micro-concave water collection area. In the concrete edge area, the permeable geotextile and heat-insulating plastic film are extended outwards to cover 50 cm to 100 cm, and the edges are compacted with soil bags. An air layer is formed between the heat-insulating plastic film and the permeable geotextile by the support of the arch frame. S2, in the air layer, 20 m 2 to 50 m 2 The humidity sensor is fixed on the side of the arch, and the sensing part of the humidity sensor is 3-5 cm away from the upper surface of the permeable geotextile. S3. When the humidity sensor detects that the relative humidity of the air layer is <40%, the spray system is activated to spray water onto the film micro-concave water collection area. During spraying, when the ambient temperature is ≥30℃, an evaporation inhibitor is added to the spray water; when the ambient temperature is <30℃, no evaporation inhibitor is added to the spray water. The specific spraying operation is as follows: When the ambient temperature is >40℃, the spraying interval is 8 to 15 minutes, and each spraying lasts 1.5 to 2.5 minutes. When 30℃≤Ambient temperature<40℃, spraying interval is 20 min to 40 min, each lasting 2 min to 3 min; When 20℃≤Ambient temperature<30℃, the spraying interval is 1 h to 2 h, and each spraying lasts 1.5 min to 2.5 min. When 10℃≤Ambient temperature<20℃, the spraying interval is 3 h to 5 h, and each spraying lasts 1.5 min to 2.5 min. When the ambient temperature is <10℃, the spraying interval is 6 h to 8 h, each spraying lasts 1.0 min to 1.5 min, and the spraying water temperature is heated to 25℃±2℃. Maintenance lasts 7 to 14 days.

2. The concrete curing method as described in claim 1, characterized in that, In step S1, the heat-insulating plastic film laid on the top of the arch frame includes multiple film panels, each panel being 4 m to 8 m wide and 0.12 mm ± 0.02 mm thick; adjacent panels overlap along the length direction, with an overlap width of 2 cm to 5 cm, and the overlap seam is located directly above the arch top of the arch frame. The overlap is fixed with soil bags, each weighing 1 kg to 2 kg, and spaced 1 m to 1.5 m apart.

3. The concrete curing method as described in claim 2, characterized in that, The inner wall of the permeation hole has a nano-silica hydrophobic layer with a contact angle with water ≥150°; the opening area is ≥2 m from the edge of the thin film plate and ≥50 cm from the overlap seam.

4. The concrete curing method as described in claim 1, characterized in that, The evaporation inhibitor in step S3 is polyethylene glycol 400; wherein: When the ambient temperature is >40℃, the mass-volume percentage concentration of the polyethylene glycol 400 in the spray water is 0.3% (w / v). When 30℃≤Ambient temperature<40℃, the mass-volume percentage concentration of polyethylene glycol 400 in the spray water is 0.2% (w / v). The polyethylene glycol 400 forms a nanoscale hydrophilic film layer in the sprayed water, which is used to inhibit water evaporation and enhance the spreading and penetration of water molecules on the concrete surface.

5. The concrete curing method as described in claim 1, characterized in that, When the ambient temperature is below 5℃, stop the sprinkler system and follow these steps: A1. Peel off the heat-insulating plastic film panels in sections for the areas to be coated, and make temporary reset marks at the overlap seams; Remove the arches and permeable geotextile in the corresponding area to expose the concrete surface; A2. Apply curing agent to the exposed concrete surface at a rate of 150–200 g / m²; apply in two coats with an interval of 30±5 min, and form a film thickness of 80–100 μm. A3. After the curing agent has dried to the surface, re-lay the permeable geotextile, arch frame and film plate according to the reset mark position, and fix the edges with soil bags.

6. The concrete curing method as described in claim 5, characterized in that, The curing agent is formulated by weight percentage of the following components: 60%~70% polyurethane resin base liquid, 5%~8% nano zinc oxide, 2%~3% polyether modified silicone oil, and the balance being solvent oil; the particle size of the nano zinc oxide is 20~30 nm.

7. The concrete curing method as described in claim 2, characterized in that, The heat-insulating plastic film has a three-layer co-extruded structure; The outer layer comprises a low-density polyethylene matrix with a density of 0.915-0.925 g / cm 3 The low-density polyethylene matrix is mixed with nano-ceramic particles with a particle size of 20-40 nm and a mass ratio of 8-12%, and the nano-ceramic particles are a mixture of antimony-doped tin oxide and indium tin oxide with a mass ratio of 3:

1. The thickness of the outer layer accounts for 25-30% of the total thickness of the film. The middle layer comprises a polyolefin elastomer, and the thickness of the middle layer accounts for 40%–45% of the total film thickness; The inner layer comprises a low-density polyethylene matrix with a density of 0.918–0.928 g / cm³. 3 The low-density polyethylene matrix is ​​incorporating hydrophobic nano-silica with a particle size of 30 nm–50 nm and a mass percentage of 5%–8%.

8. The concrete curing method as described in claim 1, characterized in that, The plastic arch frame is injection molded from a blend of polypropylene and 30% glass fiber. The cross-section of the arch frame is a pentagonal honeycomb structure with a wall thickness of 1.5 mm ± 0.2 mm. The single arch frame can bear a load of ≥ 50 kg. The bottom of the arch frame is provided with L-shaped buckles that are embedded in the permeable geotextile mesh. The buckle spacing is consistent with the mesh spacing of the arch frame.