Mechanical guniting and plastering gypsum construction method

Abstract

The invention relates to the technical field of building construction, in particular to a mechanical guniting plastering gypsum construction method which comprises the following steps: base layer treatment: cleaning a wall surface, spraying water to the depth of 8-10mm, paving a reinforcing net with the total width of more than or equal to 300mm at the joint of different materials, and lapping with the lapping width of more than or equal to 150mm; a room cross control line and an in-wall datum line are arranged in an elastic mode, screeding is conducted after a mortar cake is manufactured, and screeding is conducted forcibly within 20 cm of the side edge of a door and window opening; layered spraying is conducted, specifically, bottom ash is vertically sprayed till the thickness is 5-8 mm, and the distance between a spray gun and the wall is 100-200 mm; after the bottom ash is initially set, surface ash is sprayed until the total thickness is 15-20 mm; dynamic slurry regulation and control: the consistency is reduced by 10-15% when the water-cement ratio reference value of the slurry is 0.29 and the environment temperature is higher than 30 DEG C; leveling and calendaring: immediately leveling along the ribs by using a floating rule after the surface ash is sprayed, wetting by using clear water before final setting, and polishing and calendaring; door and window openings are closed up through galvanized L-shaped stopping edge closing strips, and the steel nails are fixed at the interval smaller than or equal to 200 mm. The method has the effect of reducing the possibility of falling and cracking during single-time plastering.

Description

Technical Field

[0001] The present application relates to the technical field of building construction, and in particular to a mechanical spraying plastering gypsum construction method. Background Art

[0002] Currently, interior plastering generally relies on manual application of cement mortar, which presents challenges such as cumbersome processes (requiring interface preparation, layered painting, and puttying), long curing cycles (preventing construction at low temperatures), high rates of hollowing and cracking, and labor-intensiveness. While plastering gypsum is gradually replacing traditional materials due to its strong adhesion and low shrinkage, existing mechanical spraying processes still cannot address core drawbacks such as flow and cracking during thick layer application and poor compatibility at the interface of dissimilar materials.

[0003] Existing mechanical spraying technology has limitations: For example, patent CN107035085A proposes a "one-shot" machine-sprayed gypsum mortar process, which includes meshing the base layer, punching reinforcement, mixing mortar corners, and spraying and leveling in a single pass. While this method improves efficiency, it also has significant drawbacks: The thickness of a single shot is limited; spraying thicknesses greater than 20mm is prone to dripping and cracking. Summary of the Invention

[0004] The present application provides a mechanical spraying plastering gypsum construction method, which can at least partially solve the above technical problems.

[0005] This application provides a mechanical spraying plastering gypsum construction method, which adopts the following technical solutions: A mechanical spraying plastering gypsum construction method comprises the following steps: Base treatment: clean the wall surface and sprinkle water to a depth of 8-10mm, lay a reinforcing mesh with a total width of ≥300mm at the junction of different materials, and overlap them with an overlap width of ≥150mm; Precision positioning: Draw the cross control line of the room and the reference line inside the wall, make the mortar cake and then punch the reinforcement, and compulsorily punch the reinforcement within 20cm on the side of the door and window openings; Layered spraying: First spray the base ash vertically to a thickness of 5-8mm, with the spray gun 100-200mm away from the wall; after the base ash initially solidifies, spray the surface ash to a total thickness of 15-20mm; Dynamic slurry control: The base value of the slurry water-cement ratio is 0.29, and the consistency decreases by 10%-15% when the ambient temperature is greater than 30°C; Leveling and finishing: Immediately after spraying the surface ash, use a scraper to level along the reinforcement, moisten with water and polish before final setting; Node reinforcement: Door and window openings are closed with galvanized L-shaped stop strips, and fixed with steel nails at a spacing of ≤200mm.

[0006] By adopting the above technical solution, the permeability of the base layer is controlled (watering to a depth of 8-10mm), followed by interface anti-cracking treatment (reinforcement mesh 300mm wide + 150mm overlap), then spatial positioning (cross line + ash cake + forced ribs at the opening), and then layered spraying (bottom ash 5-8mm → surface ash to 15-20mm). The slurry temperature is controlled during spraying (base water-cement ratio 0.29, >30℃ reduce viscosity by 10%-15%), and then the surface is leveled (scraper leveling + water grinding and calendering before final setting). Finally, the nodes are reinforced (L-shaped strip closing, steel nails ≤200mm); precise watering depth avoids hollowing rate caused by uneven water absorption of the base layer, and the crack resistance of layered construction is improved, reducing the occurrence of dripping; the overlap width of the reinforcement mesh ≥150mm blocks the expansion of cracks at the junction of materials; forced ribs at the opening eliminate weak areas at corners; dynamic water-cement ratio control ensures high-temperature spraying leveling, and the L-shaped edge strip steel nails are fixed at a close distance to inhibit stress cracking at the corners of doors and windows, thereby improving structural durability.

[0007] Optionally, in the layered spraying step, when the total thickness of the plaster is greater than 35 mm, a hot-dip galvanized steel wire mesh is added between the base plaster and the surface plaster.

[0008] By adopting the above technical solution, when the total thickness of the plaster is greater than 35mm, a hot-dip galvanized steel wire mesh is laid between the base plaster and the surface plaster; the steel wire mesh forms a three-dimensional skeleton to withstand the shear stress generated by the deadweight of the thick plaster layer (>35mm), reducing the risk of sagging and cracking, and improving the crack resistance; together with the base reinforcement mesh, it forms a "surface + layer" dual anti-cracking system.

[0009] Optionally, in the leveling and finishing step, micro-cracks appearing before final setting are repaired with a thin layer of surface gypsum slurry, and the dry surface is sprinkled with water to moisten it and then calendered a second time.

[0010] By adopting the above technical solution, a thin layer of gypsum slurry is applied to the micro-cracks before final setting, sprinkled with water to moisten it, and then calendered twice; the surface micro-cracks are repaired by utilizing the activity of gypsum before final setting to improve the repair rate, reduce the need for later scraping and redoing, and calender twice to eliminate the repair joints; and the dynamic water-cement ratio is coordinated to ensure the bonding strength of the repair slurry.

[0011] Optionally, after punching the reinforcement, a joint is set up, with a joint set up every ≤13m² of the wall surface, and the length-to-width ratio of the joint is ≤2.5:1.

[0012] By adopting the above technical solution, partition strips are installed after punching reinforcement, with one strip installed every ≤13m², and the length-to-width ratio of the partition joint is ≤2.5:1; the partition density (≤13m² / strip) accurately matches the plaster shrinkage rate, and the joint length-to-width ratio is ≤2.5:1 to prevent stress concentration and reduce shrinkage cracks; a directional stress release channel is provided for thick plaster layers (>35mm), which works together with the wire mesh to resist cracking.

[0013] Optionally, in the layered spraying step, the initial setting of the base ash is determined by finger pressure, and grooves with a depth of 2-3 mm and a spacing of 20 mm are scraped on the surface of the base ash with a toothed scraper before spraying the surface ash.

[0014] By adopting the above technical solution, the finger pressure method is used to judge the initial setting of the base ash, and the toothed scraper is used to scrape grooves (depth 2-3mm / spacing 20mm); the finger pressure method avoids premature construction and damage to the base ash structure; the grooves increase the contact area between layers, and the slurry is embedded to form a "mortise and tenon effect" to improve the bonding strength; the joints release macroscopic stress + the grooves enhance microscopic bonding, doubly controlling the interlayer peeling.

[0015] Optionally, when repairing, longitudinal scratches are made at the cracked position, and the repair is performed by spraying and then plastering.

[0016] By adopting the above technical solution, the cracks are scratched longitudinally, sprayed, and plastered to repair them; the scratches increase the roughness of the repair interface and improve the density of anchor points; the spraying penetrates the base layer before plastering to eliminate false adhesion and improve the stability of the repair; the split joints reduce the generation of new cracks. This process is specifically designed to treat residual cracks.

[0017] Optionally, a stress buffer layer is added between the layers of layered spraying: after the bottom ash is initially set, a gypsum-based penetrating crystallization material is sprayed, dried to form a porous membrane, and then the surface ash is sprayed.

[0018] By adopting the above technical solution, after the initial setting of the base ash, the gypsum-based penetrating crystallization material is sprayed, dried into a porous film, and then sprayed with surface ash; the penetrating crystallization material fills the pores of the base ash to form a porous buffer layer to dissipate shrinkage stress and improve bending strength; a buffer film is constructed on the scraper groove interface to form a double composite of "mechanical interlocking + chemical bonding"; the notches in the repair area and the buffer layer work together to improve the resistance to re-cracking.

[0019] Optionally, during the construction of the buffer layer, after the bottom ash has initially set, a needle roller is used to roll the surface to form a micropore array, and then when the top ash is sprayed, the slurry penetrates into the micropores to form mechanical anchoring.

[0020] By adopting the above technical solution, the needle roller rolls the bottom ash → forms a micropore array → the surface ash slurry penetrates into the micropores for anchoring; the micropores (depth 0.5-1mm) make the surface ash slurry form a "barb structure", which improves the tensile strength; the buffer layer porous membrane (right 7) + micropore mechanical anchoring realizes the "elastic buffer-rigid anchoring" gradient transition.

[0021] Optionally, during the construction of the hot-dip galvanized steel wire mesh, U-shaped nails are used to fix it to the base in both directions, and the overlap of the steel wire mesh is tightened with double-strand galvanized iron wire, and the overlap width is ≥150mm.

[0022] By adopting the above technical solution, the wire mesh is fixed with U-shaped nails, and the double-strand iron wire is twisted tightly at the overlap. The U-shaped nails constrain the displacement of the mesh in both directions to improve the pull-out resistance; the twisted double-strand iron wire ensures the continuity of force transmission in the overlap area and improves the integrity of the mesh; it provides a rigid skeleton support for the thick plaster layer (>35mm), forming a "rigid and flexible" system with the joints.

[0023] Optionally, the layered spraying step also includes anti-cracking construction of internal and external corners. For external corner treatment: install galvanized external corner strips with chamfers before spraying, and spray the spray gun back and forth within a range of ±30° along the angle line direction, and then switch the fan-shaped nozzle to perform 45° oblique cross-spraying within a range of 200mm on both sides of the external corner; for internal corner treatment: embed polypropylene fiber bundles impregnated with gypsum slurry before final setting.

[0024] By adopting the above technical solution, the chamfered external corner strips are pre-installed, ±30° angle line sweeping, and 45° oblique cross spraying are performed; for the internal corners: impregnated polypropylene fiber bundles are embedded before final setting; the external corner strips are anti-collision, ±30° sweeping covers dead corners and reduces the hollowing rate; 45° oblique spraying eliminates interface seams; the internal corner fiber bundles (50mm long) bridge the shrinkage cracks and reduce the possibility of cracking in the internal corners; the buffer layer suppresses stress concentration at the corners and forms a three-dimensional node reinforcement with the fiber bundles / directional spraying.

[0025] In summary, this application includes at least one of the following beneficial technical effects: 1. Precise watering depth prevents hollowing caused by uneven water absorption in the base layer, and layered construction improves crack resistance and reduces the occurrence of dripping. A reinforced mesh overlap width of ≥150mm prevents crack propagation at material interfaces. Forced ribs at openings eliminate weak corners. Dynamic water-cement ratio control ensures leveling during high-temperature spraying. Closely spaced L-shaped edge strips with steel nails suppress stress cracking at door and window corners, improving structural durability. 2. After the initial setting of the base ash, a gypsum-based infiltrative crystalline material is sprayed, dried into a porous film, and then sprayed with surface ash. The infiltrative crystalline material fills the pores of the base ash, forming a porous buffer layer to dissipate shrinkage stress and improve bending strength. A buffer film is constructed on the scraping groove interface, forming a dual composite of "mechanical interlocking + chemical bonding". The incisions in the repair area and the buffer layer synergistically improve the resistance to re-cracking. 3. External corner strips are protected from collisions, with ±30° sweeping to cover blind spots and reduce hollowing rates; 45° oblique spraying eliminates interface seams; fiber bundles (50mm long) at internal corners bridge shrinkage cracks, reducing the possibility of cracking; the buffer layer suppresses stress concentration at the corners and forms a three-dimensional node reinforcement with the fiber bundles / directional spraying. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flow chart of the mechanical spraying plastering gypsum construction method in the embodiment of the present application. DETAILED DESCRIPTION

[0027] The following combination Figure 1This application is described in further detail.

[0028] This embodiment discloses a mechanical spraying plastering gypsum construction method.

[0029] Reference Figure 1 , a mechanical spraying plastering gypsum construction method, comprising the following steps: Step 1: Base treatment: clean the wall dust and oil stains, and remove the protruding parts of the concrete; Sprinkle water to moisten the base layer until the water penetrates to a depth of 8-10mm, completing it in two steps (12 hours apart); Specifically, clean the wall surface of loose soil and water it several times until it is moist. Use a capillary hose to water the wall surface from top to bottom, generally twice a day, the day before plastering to ensure the plaster layer has good coagulation and hardening conditions. The amount of water should be sufficient to allow water to penetrate the blocks to a depth of 8-10mm, and watering should be done the day before plastering. In dry weather, if the wall surface is still dry during plastering, spray it with water again. However, if the wall surface does not show any signs of floating water during plastering, this will help increase the strength of the mortar and prevent hollows and cracks.

[0030] At the junction of different materials (masonry walls-concrete beams, cable ducts, etc.), lay alkali-resistant glass fiber mesh cloth or galvanized steel wire mesh with a total width of ≥300mm, with an overlap width of ≥150mm, and use U-shaped nails for two-way fixing (nail spacing ≤150mm); install split strips every ≤13m² of wall surface, and the length-to-width ratio of the split joints shall be ≤2.5:1.

[0031] Specifically, the glass fiber mesh cloth adopts alkali-resistant glass fiber mesh cloth with a mesh size of 4mm*4mm, a width of not less than 300mm, a glue coating greater than 20kg / m2, and a unit area mass greater than 130g / m2; the mesh size of the wire mesh should not be greater than 20*20mm, the steel wire diameter should not be less than 0.4mm, and hot-dip galvanizing is preferred.

[0032] Specifically, at the intersections of different material substrates (wall-beam junctions, concrete components and masonry walls, including structural columns, plumbing slots and plastering seals, lintel-masonry wall junctions, capping-masonry wall junctions, and around openings), an alkali-resistant fiberglass mesh or galvanized steel mesh with a total width of at least 300mm should be applied, with an overlap width of at least 150mm with each base layer. The steel mesh should be secured with special anchors arranged in a plum blossom pattern, with anchors spaced 150mm apart. When hanging the mesh, first apply a layer of bonding plaster to the hanging area, compact any gaps, then hang the mesh and apply bonding plaster to secure it firmly before proceeding to the next step.

[0033] Install internal corner strips, external corner strips and stop strips at openings such as windows and door openings. Use a row of steel nails on each side of the line, with a spacing of 200mm between the nails.

[0034] Joint strips must be installed at the junctions between different structures. The distance between joints must not exceed 5.4 meters in any direction, or the aspect ratio must be 2.5:1. Walls and other surfaces must not exceed one joint per 13 square meters, and ceilings must not exceed one joint per 9 square meters.

[0035] Hang a mesh around the cable duct / box for reinforcement, the mesh width = duct width + 200mm.

[0036] Specifically, after the installation of conduit and cable boxes passes inspection, repair work will begin. Fill the gaps with cement mortar, and for pipelines slotted into brick walls, hang galvanized steel mesh. If pipelines are too dense to be laid with masonry, pour fine stone concrete, then hang the steel mesh. The width of the steel mesh should be equal to the slot width + 2 x 100mm. Secure the gaps with a row of steel nails on each side, with a spacing of 200mm between the nails.

[0037] Electrical boxes and junction boxes must be protected with protective covers or foam blocks. Water and electricity lines should be wrapped to prevent mortar contamination during the plastering process. Covers should be used to protect electrical boxes and junction boxes to prevent damage and contamination during the spraying process.

[0038] The protruding parts of the surfaces of concrete lintels, structural columns, ring beams, etc. should be chipped down to the solid surface, and then smoothed and repaired with mortar.

[0039] The dust, dirt and oil stains on the surface of the plaster foundation should be brushed clean thoroughly. The cleaning of the base layer should prevent the impurities on the concrete surface from affecting the adhesion of the mortar.

[0040] Step 2: Precise positioning: Draw the cross control line of the room and the 200mm reference line inside the wall; Specifically, before plastering, draw a cross-shaped positioning line for the room. Extend the four sides of the cross-shaped positioning line to the wall. Using the cross-shaped positioning line and a tape measure, draw a line 200mm from the inner edge of the wall. Draw a diagonal line to check that the room is square and that the diagonals are of equal length.

[0041] Make plaster cakes (side length 20-50mm, spacing ≤1.5m), and calibrate verticality with a laser positioning device; Specifically, hang vertically: hang vertically at the corners of doors and windows, walls, etc., and the horizontal line is controlled by the floor as the horizontal baseline or the +50cm elevation line, and then put on the square plaster cake, and use the plaster cake as the basis for punching ribs.

[0042] Suite squareness: A squareness control reference line must be set up in each suite on the same floor. It should be set as long as possible to reduce measurement errors. Each room in the same suite on the same floor must use this squareness control reference line, and then use it as a reference to measure each room. The squareness control line should be popped up within 30-60cm from the wall and clearly marked and protected.

[0043] When applying plaster cakes, determine the correct position of the plaster cakes according to the requirements of indoor plastering. The upper plaster cake should be applied first, then the lower plaster cake, and then the flatness should be checked vertically with a laser positioning device. The plaster cakes should be applied with plastering plaster and be square with a side length of 20-50mm. The distance between each plaster cake should not exceed 1.5m.

[0044] Punching reinforcement (rib width ≥ 20mm, spacing ≤ 1.5m), mandatory reinforcement within 20cm of the side of door and window openings; Specifically, after the ash cake hardens, it should be punched with plaster plaster. The distance between the two bars should not be greater than 1.5m, the bar width should not be less than 20mm, and a 3m ruler should be used to check the verticality and flatness. Positioning strips can also be installed instead of punching bars. The distance between the two positioning strips should not be greater than 1.5m. The positioning strips can be pasted with plaster plaster, and the distance between two adjacent pasting points of each positioning strip should not be greater than 900mm.

[0045] Corners, the sides of door and window openings, and the intersections of masonry walls and concrete components must be reinforced. Special areas: Openings wider than 1.2 meters must have reinforcement at the top and bottom. The walls on both sides of door and window openings must be reinforced within 20 cm.

[0046] Step 3: Layered spraying: Slurry configuration: The water-cement ratio is 0.29 (25 kg gypsum with 7.25 kg water). When the ambient temperature is > 30 ° C, the consistency decreases by 10%-15%; Specifically, before spraying, the mechanical spray equipment should be inspected by running it dry. The continuous test run time should be no less than 2 minutes. The feed pipe, air pipe, equipment, and spray gun should be connected and their sealing should be checked. The appropriate nozzle diameter should be selected based on the pumping capacity. If any abnormality is found, the equipment should not be used.

[0047] Add the plastering gypsum to the hopper, connect a clean water hose to the extrusion mortar pump, start the machine, and adjust the water-cement ratio until the mixed slurry has the desired consistency (water-cement ratio W / C per unit of premixed plastering is 25 kg, and the unit water consumption is 7.25 kg). Continuous feeding can then be initiated. The slurry should not remain in the equipment or delivery piping for more than 20 minutes. After spraying, the equipment, delivery pipe, and spray gun should be cleaned promptly.

[0048] Do not re-add water to hardened gypsum, overnight gypsum, or floor gypsum after initial setting. In hot summer weather, the consistency of the plaster slurry should be thinner than normal. When the ambient temperature is >30°C, the consistency will decrease by 10%-15%.

[0049] Bottom ash spraying: The spray gun is vertical to the wall (distance 100-200mm), and sprays horizontally and reciprocatingly; Specifically, the nozzle should be perpendicular to the base wall and at a distance of 100-200mm from the base wall during spraying. No material should splash on the working surface. The spraying sequence should be horizontal reciprocating, spraying evenly from top to bottom.

[0050] After the masonry base is prepared before spraying, the base coat can be sprayed two hours after the reinforcement is filled. The thickness is 15mm. When spraying the base coat, first scrape a thin layer. The cement slurry is soft and rough. Then, fill and level according to the required thickness. Then use a large bar to scrape vertically and horizontally, and use a wooden trowel to rub the roughness. After the single base coat is smoothed, a dedicated person should be assigned to remove the remaining gypsum mortar around the reserved holes and smooth it out.

[0051] The thickness is 5-8mm, and there is no mark when pressing with fingers after initial setting. During initial setting, use a toothed scraper to scrape out grooves with a depth of 2-3mm and a spacing of 20mm. Surface ash spraying: After the base ash has initially solidified, spray it to a total thickness of 15-20mm; when the total thickness of the plaster is >35mm, add a hot-dip galvanized steel wire mesh (mesh size ≤20×20mm), fix it with U-shaped nails, and tighten the double-strand wire at the overlap; Specifically, when spraying the base coat and topcoat, the interval between each spraying should be sufficient to ensure no marks remain on the surface of the previous spraying by lightly touching it with your hand. This interval should be kept within 2 hours. When constructing the interior and exterior walls in layers, allow at least 5mm of surface thickness. After spraying the base coat, check for areas that exceed the reserved surface thickness. If so, apply a coating immediately.

[0052] The thickness of the plaster layer should be controlled at 15-20mm, and the thickness of the plaster layer should be consistent for the same apartment type. After spraying a certain area, use a scraper to initially level the sprayed surface. Any leaks should be sprayed and leveled immediately, and then the sprayed surface should be leveled again with a scraper.

[0053] For areas exceeding 35 mm, add a wire mesh in the middle. The slurry should be sprayed perpendicular to the wall surface. The distance between the spray gun and the wall should be controlled to ensure that the slurry moves in a straight line. After finishing the plaster, actual measurements and corrections must be completed before the plaster has dried.

[0054] Strengthening of internal and external corners: pre-install galvanized strips with chamfers on the external corners, spray the spray gun along the corner line at ±30°, then switch to the fan-shaped nozzle to spray at a 45° angle; before the final setting of the internal corners, embed polypropylene fiber bundles (50mm long) impregnated with gypsum slurry.

[0055] Specifically, after large-surface plastering and door and window frame installation, use the control lines along the door and window openings to apply plaster and finish the edges. After the base coat is smoothed, a dedicated person should be assigned to square, smooth, and level the edges of the reserved holes, electrical boxes, slots, and boxes. Use a trowel to square and straighten the external / internal corners. It is not advisable to use a long aluminum alloy ruler to close the internal and external corners; pre-install galvanized strips with chamfers on the external corners, and spray the gun along the angle line at ±30°, then switch to a fan-shaped nozzle to spray at a 45° angle; embed polypropylene fiber bundles (50mm long) impregnated with gypsum slurry before final setting in the internal corners; Step 4: Dynamic leveling and finishing: Immediately after spraying the surface mortar, use a scraper to level along the reinforcement and repair any leaks; Specifically, if micro cracks appear during the final setting of the plaster, apply a thin layer of surface plaster or similar material within 24 hours, with a thickness not exceeding 1mm; if the surface is dry, sprinkle water to moisten it and then apply a thin layer of surface plaster or similar material.

[0056] Before final setting (the surface is slightly dry and not sticky): moisten the surface with clean water, and polish to a smooth finish; Specifically, after the initial setting and before the final setting of the plaster layer, when the surface is slightly dry and not sticky, the surface should be wetted with clean water and polished to remove the slurry and finish it.

[0057] The wall surface after plastering and gypsum construction should be protected from bumps and water soaking, and the room should be kept well ventilated.

[0058] When micro cracks appear, apply a thin layer of gypsum slurry (thickness ≤ 1mm), sprinkle water to moisten it and then calender it twice; The door and window openings are closed with galvanized L-shaped stop strips and fixed with steel nails at a spacing of ≤200mm.

[0059] Step 5: Node reinforcement and repair: Door and window openings are closed with galvanized L-shaped stop strips and fixed with steel nails at a spacing of ≤200mm.

[0060] In other embodiments, in the layered spraying step, an interlayer stress buffer is added: after the bottom ash is initially set, a gypsum-based infiltrative crystallization material is sprayed, dried into a porous film, and then the top ash is sprayed; Micropore anchoring: After the bottom ash is initially set, a needle roller is used to roll it to form a micropore array with a depth of 0.5-1mm. Then, when the top ash is sprayed, the slurry penetrates into the micropores to form a mechanical anchor. Crack repair: make longitudinal scratches → spray grout to penetrate the base layer → cover with plaster.

[0061] Specifically, the formula composition (parts by weight): semi-hydrated gypsum powder: 100 parts, Portland cement: 8-12 parts (triggering crystallization reaction), active silica powder (particle size ≤ 5μm): 3-5 parts (filling capillaries), polycarboxylate water reducer: 0.3-0.5 parts (reducing the water-cement ratio to 0.22), crystallization catalyst (nano-silica): 1-2 parts; Preparation process: ① Dry mix semi-hydrated gypsum powder, Portland cement, and activated silica powder until uniform; ② Dissolve the water reducer in water, add the dry materials and stir for 3 minutes until the slurry fluidity reaches 180±10mm (tested according to GB / T 2419); ③ Add nano-silica and stir at low speed for 1 minute. Let it stand and mature for 5 minutes before use.

[0062] Spraying process: Equipment: airless sprayer (nozzle diameter 1.3mm, pressure 15MPa), construction sequence: initial setting of the base ash (no marks left by finger pressure, about 40-60 minutes after spraying); Spraying parameters: vertical spraying at a distance of 200~300mm from the wall, gun speed 0.5m / s, coating thickness 0.2~0.3mm; Drying and film formation: Allow to stand for 30 minutes at an ambient temperature of 25°C to form a porous crystalline film (porosity ≥35%, pore size 20-50μm); Test standard: The film layer is matte white and does not turn to powder when scratched by fingernails; Mechanism of action: The penetrating crystalline material penetrates the capillary pores of the base ash to generate ettringite crystals and CSH gel, forming an elastic buffer layer that can absorb shrinkage stress up to 0.8MPa (ASTM C1581 test).

[0063] Microporous anchoring construction (needle roller rolling process): Needle roller specifications: roller surface material: 304 stainless steel; needle body size: diameter 0.8mm, length 5mm, needle tip cone angle 30°; needle density: 25 needles / cm² (plum blossom array); Rolling operation: Timing: Initial setting of the bottom ash (surface hardness Shore A 40-50); Process parameters: Rolling pressure: 3-5 kgf, Travel speed: 0.3 m / s; Number of rolling passes: 2 times (cross 90° direction); Hole formation effect: Micropore depth: 0.5-1.0 mm, Hole diameter: 0.8-1.2 mm; Hole density: ≥200 holes / dm²; Anchoring principle: The surface mortar penetrates into the micropores and solidifies to form a barbed structure, which increases the interlayer bond strength to 0.75MPa (compared to 0.45MPa without treatment, according to JC / T 2327 standard).

[0064] Crack repair construction (score-spraying-plastering method): Score treatment: Tools: Diamond cutting blade (thickness 1mm, depth 5mm); Grooving specifications: Score along the longitudinal direction of the crack, groove depth ≥ 1 / 3 of the plaster layer thickness; groove width 3-5mm, groove spacing 20mm (staggered arrangement); groove inner wall chiseling (roughness Ra ≥ 12.5μm); Spraying penetration: Slurry: gypsum-based repair mortar (bonding type, water-cement ratio 0.26); Equipment: handheld pressure spray gun (0.4MPa); spray the tank until saturated (slurry penetration depth ≥8mm); let it stand for 10 minutes to allow the slurry to penetrate into the micro-cracks of the base layer.

[0065] Plaster covering: filling in layers: first layer: fill the slot to 80% full, embed alkali-resistant glass fiber mesh cloth (50mm wide); second layer: smooth and extend 1mm beyond the original wall surface; fine treatment: use a stainless steel spatula dipped in water to press the surface before final setting, and the offset with the original wall surface should be ≤0.5mm; cover with curing film for 24 hours (humidity ≥90%).

[0066] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A mechanical spraying plastering gypsum construction method, characterized in that: The following steps are involved: Base treatment: clean the wall surface and sprinkle water to a depth of 8-10mm, lay a reinforcing mesh with a total width of ≥300mm at the junction of different materials, and overlap them with an overlap width of ≥150mm; Precision positioning: Draw the cross control line of the room and the reference line inside the wall, make the mortar cake and then punch the reinforcement, and compulsorily punch the reinforcement within 20cm on the side of the door and window openings; Layered spraying: First spray the base ash vertically to a thickness of 5-8mm, with the spray gun 100-200mm away from the wall; After the bottom ash has initially solidified, spray the surface ash to a total thickness of 15-20mm; Dynamic slurry control: The base value of the slurry water-cement ratio is 0.29, and the consistency decreases by 10%-15% when the ambient temperature is greater than 30°C; Leveling and finishing: Immediately after spraying the surface ash, use a scraper to level along the reinforcement, moisten with water and polish before final setting; Node reinforcement: Door and window openings are closed with galvanized L-shaped stop strips, and fixed with steel nails at a spacing of ≤200mm.

2. The mechanical spraying plastering gypsum construction method according to claim 1, wherein: In the layered spraying step, when the total thickness of the plaster is greater than 35 mm, a hot-dip galvanized steel wire mesh is added between the base plaster and the surface plaster.

3. The mechanical spraying plastering gypsum construction method according to claim 1, wherein: In the leveling and finishing step, micro cracks appearing before final setting are repaired with a thin layer of surface gypsum slurry, and the dry surface is sprinkled with water to moisten it and then calendered a second time.

4. The mechanical spraying plastering gypsum construction method according to claim 2, characterized in that: After punching the reinforcement, set the partition strips, set a partition every ≤13m² of the wall surface, and the length-to-width ratio of the partition joint is ≤2.5:

1.

5. The mechanical spraying plastering gypsum construction method according to claim 4, characterized in that: In the layered spraying step, the initial setting of the base ash is determined by finger pressure, and grooves with a depth of 2-3 mm and a spacing of 20 mm are scraped on the surface of the base ash with a toothed scraper before spraying the surface ash.

6. The mechanical spraying plastering gypsum construction method according to claim 4, characterized in that: When repairing, make longitudinal scratches at the cracked location and repair it by spraying and then plastering.

7. The mechanical spraying plastering gypsum construction method according to claim 5 or 6, characterized in that: A stress buffer layer is added between the layers of layered spraying: after the base ash is initially set, a gypsum-based penetrating crystallization material is sprayed, dried to form a porous membrane, and then the surface ash is sprayed.

8. The mechanical spraying plastering gypsum construction method according to claim 7, characterized in that: During the construction of the buffer layer, after the bottom ash has initially solidified, a needle roller is used to roll the surface to form a micropore array, and then when the top ash is sprayed, the slurry penetrates into the micropores to form mechanical anchoring.

9. The mechanical spraying plastering gypsum construction method according to claim 2, characterized in that: During the construction of the hot-dip galvanized steel wire mesh, U-shaped nails are used to fix it to the base in two directions. The overlap of the steel wire mesh is tightened with double-strand galvanized iron wire, and the overlap width is ≥150mm.

10. The mechanical spraying plastering gypsum construction method according to claim 7, characterized in that: The layered spraying steps also include anti-cracking construction of internal and external corners. For external corner treatment: install chamfered galvanized external corner strips before spraying, and spray the spray gun back and forth within a range of ±30° along the angle line direction. Then switch the fan-shaped nozzle to make a 45° oblique cross spray within a range of 200mm on both sides of the external corner. For internal corner treatment: embed polypropylene fiber bundles impregnated with gypsum slurry before final setting.

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