A lightweight fire-retardant multi-layer structural panel material and a method of making the same

Abstract

The application discloses a kind of lightweight fire-retardant multilayer structure wallboard material and preparation method thereof, specifically related to the field of new wall material for insulation or surface protection, wallboard material includes by mass fraction: silicate clinker 30~40 parts;Granulated blast furnace slag powder 8~14 parts;Silica fume 2~6 parts;Magnesium oxide 12~20 parts;Potassium dihydrogen phosphate 8~14 parts;Borate retarder 0.3~0.8 parts;Delayed hydration particles 8~16 parts;Zeolite 4~8 parts.Formation of magnesium potassium phosphate network and calcium silicate hydrate network in time sequence interpenetration under 20 degrees Celsius condition after mixing, and by surface coating inorganic hydrophobic coating Delayed hydration particles form banded porous structure zone along the thickness direction within 12~72 hours, so that the surface crack generated by quenching is deflected in the structure zone and dissipates energy without penetrating to the interface, so as to avoid systematic peeling.

Description

Technical Field

[0001] This invention relates to the field of novel wall materials for insulation or surface protection, and more specifically, to a lightweight, flame-retardant, multi-layered wall panel material and its preparation method. Background Technology

[0002] In real building fire scenarios, when thick-coated inorganic fire-retardant wall panels are subjected to the sudden change in temperature from high to low by fire-fighting water, the thermal expansion stress formed on the coating surface due to the previous high temperature of the flame is suddenly released, causing the surface layer to shrink rapidly. This almost instantaneous temperature gradient causes the formation of a dense network of brittle cracks on the surface. The cracks propagate deep along the coating thickness at an extremely high speed. Because the coating usually has a brittle structure mainly composed of cement matrix and lightweight aggregate, this network lacks a mechanism to absorb the energy at the crack tip, causing the cracks to penetrate almost unimpeded to the interface between the coating and the old wall surface, forming a peeling channel with almost no adhesion resistance. Once the entire coating peels off, the fire-retardant protection function fails instantly, and the fire resistance system of the wall panel is completely destroyed.

[0003] In this process, the key problem is not insufficient adhesion in the traditional sense, nor is it the failure of bonding caused by construction defects. Rather, it is that the thick coating itself exhibits brittle fracture characteristics under extreme heat and humidity alternating stress. In addition, there is no mechanism in the structure that can force the cracks to deviate, dissipate, or delay their propagation, which is almost a "mechanical short circuit". This chain propagation of cracks from the surface to the interface, from the minute to the severe, is a very easy-to-overlook but extremely destructive weak link in the design of thick flame retardant coatings.

[0004] Therefore, the core problem of novel wall materials in the prior art can be summarized as follows: the thick-film inorganic flame-retardant coating lacks an internal crack deflection or energy dissipation mechanism under the rapid cooling impact of a fire, which leads to the brittle network directly penetrating to the interface and causing the entire coating to peel off systematically. Summary of the Invention

[0005] To overcome the aforementioned deficiencies of the prior art, embodiments of the present invention provide a lightweight flame-retardant multi-layer structure wall panel material and its preparation method. This material involves the sequential interpenetration of a magnesium potassium phosphate network and a hydrated calcium silicate network at 20 degrees Celsius after mixing. Delayed hydration particles coated with an inorganic hydrophobic coating form a banded porous structure region along the thickness direction within 12 to 72 hours. This allows surface cracks generated by rapid cooling to deflect and dissipate energy within this structural region, preventing them from penetrating to the interface and thus avoiding systematic peeling. This addresses the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a lightweight, flame-retardant, multi-layered wall panel material:

[0007] The wall panel material, by weight, comprises: 30-40 parts silicate clinker; 8-14 parts granulated blast furnace slag powder; 2-6 parts silica fume; 12-20 parts magnesium oxide; 8-14 parts potassium dihydrogen phosphate; 0.3-0.8 parts borate retarder; 8-16 parts delayed hydration particles; 4-8 parts zeolite; 8-12 parts magnesium hydroxide; 4-8 parts hollow mullite microspheres; 2-5 parts quicklime; 0.2-0.6 parts water-reducing agent; and water.

[0008] The mass fraction ratio of water to cementitious material is 0.25 to 0.32, wherein the cementitious material comprises a composition of the silicate clinker, the granulated blast furnace slag powder, the silica fume and the magnesium oxide;

[0009] The delayed hydration particles consist of a core of sulfoaluminate clinker particles or potassium dihydrogen phosphate particles, with an inorganic hydrophobic coating on the outer surface of the particle core. The particle size is 0.5–1.5 mm and the coating thickness is 5–15 micrometers.

[0010] The zeolite is of type 13X or Y, with a particle size of 0.5–1.0 mm;

[0011] The hollow mullite microspheres have a particle size of 0.3 to 1.5 mm and are coated with an aluminum phosphate coating with a thickness of 3 to 8 micrometers.

[0012] After mixing, the wall panel material forms a time-interpenetrating structure of potassium magnesium phosphate network and calcium silicate hydrate network in sequence at 20 degrees Celsius, and generates a banded porous structure region in the thickness direction through delayed hydration particles within 12 to 72 hours.

[0013] In a preferred embodiment, the inorganic hydrophobic coating is composed of zirconium phosphate and silicon dioxide in a mass ratio of 1:1 to 1:3. The coating is formed on the surface of the particle core by a sol-gel method to delay the contact time between the particle core and water, thereby achieving a delayed hydration effect in the thickness direction.

[0014] In a preferred embodiment, the aluminum phosphate coating is formed by uniformly spraying a mixed coating containing ammonium aluminate and aluminum dihydrogen phosphate onto the outer surface of hollow mullite microspheres and curing it at 150–200 degrees Celsius, thereby improving the structural stability of the hollow mullite microspheres under high-temperature conditions and the interfacial bonding force with the cementitious material.

[0015] In a preferred embodiment, during the formation of the strip-shaped porous structure region, the aluminate or phosphate ions released by the delayed hydration particles react with the surrounding incompletely hydrated cementitious material to generate a locally brittle phase. This improves the thermal resistance path inside the thick coating through the alternating distribution of pores and solid phases, and reduces the thermal conductivity to no more than 0.08 W / (m·K).

[0016] A method for preparing a lightweight, flame-retardant, multi-layered wall panel material:

[0017] S1 raw material pretreatment includes:

[0018] S1.1 Dry silicate clinker, granulated blast furnace slag powder, silica fume, magnesium oxide, potassium dihydrogen phosphate, borate retarder, zeolite, magnesium hydroxide, and quicklime in an oven at 105°C for 2 hours, and then cool to 20°C.

[0019] S1.2 The powder in S1.1 is sieved to a sieve aperture of less than 150 micrometers, and the sieved portion is collected. The silica fume is used in its original state and is not sieved again.

[0020] S1.3 The hollow mullite microspheres were dried in a 60℃ oven for 2 hours and then cooled to 20℃ for later use.

[0021] Preparation of S2 functional components, including S2.1 and S2.2:

[0022] S2.1 Preparation of aluminum phosphate coating on the outer surface of hollow mullite microspheres, including:

[0023] S2.1.1 Preparation of spray solution containing ammonium aluminate and aluminum dihydrogen phosphate: Mix them at a mass ratio of 1:1, use deionized water as solvent, and set the solid content to 10% by mass.

[0024] S2.1.2 Place the dried hollow mullite microspheres into a roller sprayer and spray the spray liquid obtained in 2.1.1 at a uniform speed. The amount of spraying is controlled according to the increase of mass by 2% to 6% after coating.

[0025] After spraying S2.1.3, the mixture is cured for 30 to 60 minutes under hot air circulation at 150℃ to 200℃ to obtain hollow mullite microspheres with an aluminum phosphate coating thickness of 3 to 8 micrometers on the outer surface. The microspheres are then cooled to 20℃ and sealed for storage.

[0026] S2.2 Preparation of delayed hydration particles includes preparation via route A or route B:

[0027] Route A (granular core composed of sulfoaluminate clinker particles) includes:

[0028] S2.2.1 Select sulfoaluminate clinker particles with a particle size of 0.5 mm to 1.5 mm as the particle core;

[0029] S2.2.2 Preparation of inorganic hydrophobic coating sol: Mix zirconium phosphate sol and silica sol at a mass ratio of 1:1 to 1:3, and set the solid content to 8% to 12% by mass.

[0030] S2.2.3 Place the particle core in a roller coating equipment, spray the sol obtained in 2.2.2 and continuously roll coat, controlling the drying-spraying cycle until the coating thickness is 5 micrometers to 15 micrometers;

[0031] S2.2.4 is dried at 60℃ for 2 hours, cooled to 20℃ and sieved to remove agglomerates, yielding delayed hydration particles;

[0032] Route B (the particle core composed of potassium dihydrogen phosphate particles) includes:

[0033] S2.2.5 Potassium dihydrogen phosphate and deionized water are mixed at a mass ratio of 9:1 to form plastic granules. The granules are then sphericalized to obtain potassium dihydrogen phosphate granules with a particle size of 0.5 mm to 1.5 mm. The granules are then dried with hot air at 40°C for 1 hour.

[0034] S2.2.6 The same steps as in 2.2.2 to 2.2.4 are used to coat and dry the inorganic hydrophobic coating to obtain delayed hydration particles;

[0035] S3 mixing liquid and dry material premixing includes:

[0036] S3.1 Preparation of mixing solution: Weigh 8 to 14 parts of potassium dihydrogen phosphate according to the formula and dissolve it in the measured water. Add 0.3 to 0.8 parts of borate retarder and 0.2 to 0.6 parts of water-reducing agent. Stir magnetically for 5 minutes to obtain a homogeneous solution.

[0037] S3.2 Preparation of dry premix: Add 30-40 parts of silicate clinker, 8-14 parts of granulated blast furnace slag powder, 2-6 parts of silica fume, 12-20 parts of magnesium oxide, 4-8 parts of zeolite, 8-12 parts of magnesium hydroxide, 2-5 parts of quicklime, and 4-8 parts of hollow mullite microspheres obtained in step S2.1 to a closed mixer. Dry mix at a speed of 20-30 rpm for 3 minutes, and then dry mix at a speed of 60-80 rpm for 2 minutes.

[0038] S4 final mixing and delayed hydration particle addition, including:

[0039] S4.1 Add the mixing liquid prepared in S3.1 to the mortar mixer and start mixing at a speed of 20-30 rpm;

[0040] S4.2 Add the dry premix prepared in S3.2 evenly while stirring at a speed of 20-30 rpm, dry mix at a speed of 20-30 rpm for 2 minutes, then dry mix at a speed of 60-80 rpm for 3 minutes, and let stand for 1 minute to degas.

[0041] S4.3 Reduce the rotation speed to 20-30 rpm, and sprinkle 8-16 parts of the delayed hydration particles obtained in S2.2 onto the surface of the slurry. Stir at 20-30 rpm for 30 seconds to ensure that the particles are evenly dispersed and the coating layer is intact.

[0042] S5 molding and thick coating application include:

[0043] S5.1 Substrate preparation: Remove the powdery and loose layers from the surface of the wall panel to be coated. The surface should be clean and free of standing water. The moisture content of the substrate should not exceed 8% by weight.

[0044] S5.2 Thick Coating Application: At 20℃, the slurry obtained in S4 is applied in a single coat by spraying or troweling, with a thickness of 10 mm to 20 mm; compact from the surface to the interior by vibration and smooth the surface.

[0045] S5.3 Settling: After construction, let stand for 30 minutes without any secondary disturbance or watering.

[0046] S6 maintenance and structural formation include:

[0047] S6.1 Maintenance conditions: Ambient temperature 18℃~22℃, relative humidity 50%~70%, cover with film or place in a windless environment for the first 24 hours to prevent moisture loss;

[0048] S6.2 Sequential Formation: Within 0 to 1 hour after mixing, magnesium oxide reacts with potassium dihydrogen phosphate to form a magnesium potassium phosphate network; within 4 to 48 hours after mixing, silicate clinker, granulated blast furnace slag powder and silica fume hydrate to form a hydrated calcium silicate network; within 12 to 72 hours after mixing, delayed hydration particles gradually initiate hydration, forming a banded porous structure zone in the thickness direction;

[0049] After the S6.3 curing period is over, remove the covering and continue natural curing under normal temperature and ventilation conditions until the 7th day;

[0050] S7 inspection and recording, including:

[0051] S7.1 Thickness inspection: Take three points at any location to measure the thickness. The thickness should be within the range of 10 mm to 20 mm.

[0052] S7.2 Structural Inspection: Drill a Φ25 mm core in a non-load-bearing area, observe and record the location and width of the banded porous structure area caused by delayed hydration particles along the thickness direction; record whether the pore structure is continuous;

[0053] S7.3 Performance Samples: Three 40 mm × 40 mm × 160 mm test strips were prepared, and their flexural strength, compressive strength, and thermal conductivity were tested at 24 hours, 72 hours, and 7 days of age, respectively; the thermal conductivity test was conducted under a temperature difference maintained at 20 K.

[0054] S8 metering and water-to-binder ratio control, including:

[0055] S8.1 The mass fraction ratio of water to cementitious material is controlled at 0.25 to 0.32, wherein the cementitious material is a composition of silicate clinker, granulated blast furnace slag powder, silica fume and magnesium oxide;

[0056] S8.2 If the fluidity decreases due to evaporation of the mixing liquid during the mixing process, add water to maintain the water-cement ratio within the range of 0.25 to 0.32, and mix the water and slurry again for 30 seconds to complete the homogenization.

[0057] S9 storage and usage periods include:

[0058] S9.1 The time interval between the completion of mixing and the start of construction shall not exceed 20 minutes;

[0059] S9.2 Unused mixed slurry should not be left to stand at 20℃ for more than 40 minutes. If the time limit is exceeded, water should not be added for reuse.

[0060] The technical effects and advantages of this invention are as follows:

[0061] 1. By coating delayed hydration particles to form a strip-shaped porous structure region in the thickness direction, the surface cracks generated under rapid cooling conditions are deflected and decomposed in this structural region, the energy at the crack tip is dissipated, and the penetration from the surface to the interior and the interface peeling are blocked.

[0062] 2. After mixing, a magnesium potassium phosphate network is first formed to create early bridging, followed by a calcium silicate hydrate network to form a dense skeleton. The two networks interpenetrate in time and space and deform synchronously, reducing stress concentration caused by rapid cooling and shrinkage mismatch.

[0063] 3. Zeolite adsorbs and slowly releases free water during the hardening and service stages, stabilizes the interfacial water content gradient, reduces the peak steam pressure during the water spraying stage, weakens the damage of the internal pressure source to the interface, and maintains pull-out strength and bond integrity.

[0064] 4. Hollow mullite microspheres and ribbon-like porous structures together extend the heat path and disperse the heat flow, reduce the effective thermal conductivity, slow down the temperature rise and temperature gradient on the unexposed surface, and reduce the propagation rate of thermally driven cracks.

[0065] 5. The particle size and coating thickness of the delayed hydration particles are matched with the rheology of the slurry. After a single thick coat, it stabilizes into a band at about one-third and two-thirds of the thickness, eliminating the need for multiple coats and facilitating on-site replication and quality control.

[0066] 6. Magnesium hydroxide absorbs heat and releases water at high temperatures, forming a stable inorganic phase with the phosphate system, which inhibits flame intrusion and smoke release, and improves the protection duration of the thick coating in fire-water quenching cycles. Attached Figure Description

[0067] Figure 1 This is a flowchart of the preparation method of the present invention. Detailed Implementation

[0068] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0069] Refer to the instruction manual appendix Figure 1 An embodiment of the present invention provides a lightweight, flame-retardant, multi-layered wall panel material:

[0070] The wall panel material, by weight, comprises: 30-40 parts silicate clinker; 8-14 parts granulated blast furnace slag powder; 2-6 parts silica fume; 12-20 parts magnesium oxide; 8-14 parts potassium dihydrogen phosphate; 0.3-0.8 parts borate retarder; 8-16 parts delayed hydration particles; 4-8 parts zeolite; 8-12 parts magnesium hydroxide; 4-8 parts hollow mullite microspheres; 2-5 parts quicklime; 0.2-0.6 parts water-reducing agent; and water.

[0071] The mass fraction ratio of water to cementitious material is 0.25 to 0.32, wherein the cementitious material comprises a composition of the silicate clinker, the granulated blast furnace slag powder, the silica fume and the magnesium oxide;

[0072] The delayed hydration particles consist of a core of sulfoaluminate clinker particles or potassium dihydrogen phosphate particles, with an inorganic hydrophobic coating on the outer surface of the particle core. The particle size is 0.5–1.5 mm and the coating thickness is 5–15 micrometers.

[0073] The zeolite is of type 13X or Y, with a particle size of 0.5–1.0 mm;

[0074] The hollow mullite microspheres have a particle size of 0.3 to 1.5 mm and are coated with an aluminum phosphate coating with a thickness of 3 to 8 micrometers.

[0075] After mixing, the wall panel material forms a time-interpenetrating structure of potassium magnesium phosphate network and calcium silicate hydrate network in sequence at 20 degrees Celsius, and generates a banded porous structure region in the thickness direction through delayed hydration particles within 12 to 72 hours.

[0076] The inorganic hydrophobic coating is composed of zirconium phosphate and silicon dioxide in a mass ratio of 1:1 to 1:3. A dense coating layer is formed on the surface of the particle core by the sol-gel method to delay the contact time between the particle core and water, thereby achieving a delayed hydration effect in the thickness direction.

[0077] The aluminum phosphate coating is formed by uniformly spraying a mixed coating containing ammonium aluminate and aluminum dihydrogen phosphate onto the outer surface of hollow mullite microspheres and curing it at 150–200 degrees Celsius, thereby improving the structural stability of the hollow mullite microspheres under high-temperature conditions and the interfacial bonding force with the cementitious material.

[0078] During the formation of the strip-shaped porous structure region, the aluminate or phosphate ions released by the delayed hydration particles react with the surrounding incompletely hydrated cementitious material to generate a locally brittle phase. The alternating distribution of pores and solid phases enhances the thermal resistance path inside the thick coating and reduces the thermal conductivity to no more than 0.08 W / (m·K).

[0079] A method for preparing a lightweight, flame-retardant, multi-layered wall panel material:

[0080] S1 raw material pretreatment includes:

[0081] S1.1 Dry silicate clinker, granulated blast furnace slag powder, silica fume, magnesium oxide, potassium dihydrogen phosphate, borate retarder, zeolite, magnesium hydroxide, and quicklime in an oven at 105°C for 2 hours, and then cool to 20°C.

[0082] S1.2 The powder in S1.1 is sieved to a sieve aperture of less than 150 micrometers, and the sieved portion is collected. The silica fume is used in its original state and is not sieved again.

[0083] S1.3 The hollow mullite microspheres were dried in a 60℃ oven for 2 hours and then cooled to 20℃ for later use.

[0084] Preparation of S2 functional components, including S2.1 and S2.2:

[0085] S2.1 Preparation of aluminum phosphate coating on the outer surface of hollow mullite microspheres, including:

[0086] S2.1.1 Preparation of spray solution containing ammonium aluminate and aluminum dihydrogen phosphate: Mix them at a mass ratio of 1:1, use deionized water as solvent, and set the solid content to 10% by mass.

[0087] S2.1.2 Place the dried hollow mullite microspheres into a roller sprayer and spray the spray liquid obtained in 2.1.1 at a uniform speed. The amount of spraying is controlled according to the increase of mass by 2% to 6% after coating.

[0088] After spraying S2.1.3, the mixture is cured for 30 to 60 minutes under hot air circulation at 150℃ to 200℃ to obtain hollow mullite microspheres with an aluminum phosphate coating thickness of 3 to 8 micrometers on the outer surface. The microspheres are then cooled to 20℃ and sealed for storage.

[0089] S2.2 Preparation of delayed hydration particles includes preparation via route A or route B:

[0090] Route A (granular core composed of sulfoaluminate clinker particles) includes:

[0091] S2.2.1 Select sulfoaluminate clinker particles with a particle size of 0.5 mm to 1.5 mm as the particle core;

[0092] S2.2.2 Preparation of inorganic hydrophobic coating sol: Mix zirconium phosphate sol and silica sol at a mass ratio of 1:1 to 1:3, and set the solid content to 8% to 12% by mass.

[0093] S2.2.3 Place the particle core in a roller coating equipment, spray the sol obtained in 2.2.2 and continuously roll coat, controlling the drying-spraying cycle until the coating thickness is 5 micrometers to 15 micrometers;

[0094] S2.2.4 is dried at 60℃ for 2 hours, cooled to 20℃ and sieved to remove agglomerates, yielding delayed hydration particles;

[0095] Route B (the particle core composed of potassium dihydrogen phosphate particles) includes:

[0096] S2.2.5 Potassium dihydrogen phosphate and deionized water are mixed at a mass ratio of 9:1 to form plastic granules. The granules are then sphericalized to obtain potassium dihydrogen phosphate granules with a particle size of 0.5 mm to 1.5 mm. The granules are then dried with hot air at 40°C for 1 hour.

[0097] S2.2.6 The same steps as in 2.2.2 to 2.2.4 are used to coat and dry the inorganic hydrophobic coating to obtain delayed hydration particles;

[0098] S3 mixing liquid and dry material premixing includes:

[0099] S3.1 Preparation of mixing solution: Weigh 8 to 14 parts of potassium dihydrogen phosphate according to the formula and dissolve it in the measured water. Add 0.3 to 0.8 parts of borate retarder and 0.2 to 0.6 parts of water-reducing agent. Stir magnetically for 5 minutes to obtain a homogeneous solution.

[0100] S3.2 Preparation of dry premix: Add 30-40 parts of silicate clinker, 8-14 parts of granulated blast furnace slag powder, 2-6 parts of silica fume, 12-20 parts of magnesium oxide, 4-8 parts of zeolite, 8-12 parts of magnesium hydroxide, 2-5 parts of quicklime, and 4-8 parts of hollow mullite microspheres obtained in step S2.1 to a closed mixer. Dry mix at a speed of 20-30 rpm for 3 minutes, and then dry mix at a speed of 60-80 rpm for 2 minutes.

[0101] S4 final mixing and delayed hydration particle addition, including:

[0102] S4.1 Add the mixing liquid prepared in S3.1 to the forced mortar mixer and start mixing at a speed of 20-30 rpm;

[0103] S4.2 Add the dry premix prepared in S3.2 evenly while stirring at a speed of 20-30 rpm, dry mix at a speed of 20-30 rpm for 2 minutes, then dry mix at a speed of 60-80 rpm for 3 minutes, and let stand for 1 minute to degas.

[0104] S4.3 Reduce the rotation speed to 20-30 rpm, and sprinkle 8-16 parts of the delayed hydration particles obtained in S2.2 onto the surface of the slurry. Stir at 20-30 rpm for 30 seconds to ensure that the particles are evenly dispersed and the coating layer is intact.

[0105] S5 molding and thick coating application include:

[0106] S5.1 Substrate preparation: Remove the powdery and loose layers from the surface of the wall panel to be coated. The surface should be clean and free of standing water. The moisture content of the substrate should not exceed 8% by weight.

[0107] S5.2 Thick Coating Application: At 20℃, the slurry obtained in S4 is applied in a single coat by spraying or troweling, with a thickness of 10 mm to 20 mm; compact from the surface to the interior by vibration and smooth the surface.

[0108] S5.3 Settling: After construction, let stand for 30 minutes without any secondary disturbance or watering.

[0109] S6 maintenance and structural formation include:

[0110] S6.1 Maintenance conditions: Ambient temperature 18℃~22℃, relative humidity 50%~70%, cover with film or place in a windless environment for the first 24 hours to prevent moisture loss;

[0111] S6.2 Sequential Formation: Within 0 to 1 hour after mixing, magnesium oxide reacts with potassium dihydrogen phosphate to form a magnesium potassium phosphate network; within 4 to 48 hours after mixing, silicate clinker, granulated blast furnace slag powder and silica fume hydrate to form a hydrated calcium silicate network; within 12 to 72 hours after mixing, delayed hydration particles gradually initiate hydration, forming a banded porous structure zone in the thickness direction;

[0112] After the S6.3 curing period is over, remove the covering and continue natural curing under normal temperature and ventilation conditions until the 7th day;

[0113] S7 inspection and recording, including:

[0114] S7.1 Thickness inspection: Take three points at any location to measure the thickness. The thickness should be within the range of 10 mm to 20 mm.

[0115] S7.2 Structural Inspection: Drill a Φ25 mm core in a non-load-bearing area, observe and record the location and width of the banded porous structure area caused by delayed hydration particles along the thickness direction; record whether the pore structure is continuous;

[0116] S7.3 Performance Samples: Three 40 mm × 40 mm × 160 mm test strips were prepared, and their flexural strength, compressive strength, and thermal conductivity were tested at 24 hours, 72 hours, and 7 days of age, respectively; the thermal conductivity test was conducted under a temperature difference maintained at 20 K.

[0117] S8 metering and water-to-binder ratio control, including:

[0118] S8.1 The mass fraction ratio of water to cementitious material is controlled at 0.25 to 0.32, wherein the cementitious material is a composition of silicate clinker, granulated blast furnace slag powder, silica fume and magnesium oxide;

[0119] S8.2 If the fluidity decreases due to evaporation of the mixing liquid during the mixing process, add water to maintain the water-cement ratio within the range of 0.25 to 0.32, and mix the water and slurry again for 30 seconds to complete the homogenization.

[0120] S9 storage and usage periods include:

[0121] S9.1 The time interval between the completion of mixing and the start of construction shall not exceed 20 minutes;

[0122] S9.2 Unused mixed slurry should not be left to stand at 20℃ for more than 40 minutes. If the time limit is exceeded, water should not be added for reuse.

[0123] Example 1 (Route A: Particle core composed of sulfoaluminate clinker particles)

[0124] I. Formula (parts by weight)

[0125] Silicate clinker 35; Granulated blast furnace slag powder 12; Silica fume 4; Magnesium oxide 16; Potassium dihydrogen phosphate 12; Borate retarder 0.5; Delayed hydration particles 12; Zeolite 6; Magnesium hydroxide 10; Hollow mullite microspheres 6; Quicklime 3; Water-reducing agent 0.4; Water;

[0126] The mass fraction ratio of water to cementitious material is 0.28 (the cementitious material is a composition of silicate clinker, granulated blast furnace slag powder, silica fume, and magnesium oxide).

[0127] II. Functional Component Parameters

[0128] Aluminum phosphate coating on the outer surface of hollow mullite microspheres: coating thickness 5 micrometers; curing temperature 150 degrees Celsius; curing time 30 minutes;

[0129] Delayed hydration particles: The particle core is sulfoaluminate clinker particles; the particle size is 0.9 mm (distributed from 0.8 mm to 1.2 mm); the inorganic hydrophobic coating is a zirconium phosphate and silica sol coating; the coating thickness is 10 micrometers;

[0130] III. Mixing and Construction Parameters

[0131] Mixing solution: Dissolve 12 parts of potassium dihydrogen phosphate in metered water, add 0.5 parts of borate retarder and 0.4 parts of water-reducing agent, and stir magnetically for 5 minutes;

[0132] Dry premix: Weigh the powder and hollow mullite microspheres according to the formula, dry mix at 25 rpm for 3 minutes, and dry mix at 70 rpm for 2 minutes;

[0133] Final mixing: Add the mixing liquid to a forced mortar mixer and mix at 25 rpm; add the dry premix and mix at 25 rpm for 2 minutes, then mix at 70 rpm for 3 minutes, and let stand for 1 minute to degas; reduce the speed to 25 rpm and sprinkle in 12 parts of delayed hydration particles at once, and mix at 25 rpm for 30 seconds.

[0134] Thick coating application: ambient temperature 20 degrees Celsius; single coat thickness 15 mm; let stand for 30 minutes after application;

[0135] IV. Maintenance and Structural Formation

[0136] At a temperature of 20 degrees Celsius and a relative humidity of 60%, the film is covered for the first 24 hours; a magnesium potassium phosphate network forms from 0 to 1 hour; a hydrated calcium silicate network forms from 4 to 48 hours; and a strip-shaped porous structure zone is generated along the thickness direction from 12 to 72 hours; natural curing is completed on the 7th day.

[0137] Example 2 (Route B: Particle core composed of potassium dihydrogen phosphate particles)

[0138] I. Formula (parts by weight)

[0139] Silicate clinker 32; Granulated blast furnace slag powder 14; Silica fume 6; Magnesium oxide 20; Potassium dihydrogen phosphate 14; Borate retarder 0.8; Delayed hydration particles 16; Zeolite 8; Magnesium hydroxide 12; Hollow mullite microspheres 8; Quicklime 5; Water-reducing agent 0.6; Water;

[0140] The mass fraction ratio of water to cementitious material is 0.32;

[0141] II. Functional Component Parameters

[0142] Aluminum phosphate coating on the outer surface of hollow mullite microspheres: coating thickness 6 micrometers; curing temperature 180 degrees Celsius; curing time 45 minutes;

[0143] Delayed hydration particles: The particle core is potassium dihydrogen phosphate particles; the particle size is 1.2 mm (distributed from 1.0 mm to 1.5 mm); the inorganic hydrophobic coating is a zirconium phosphate and silica sol coating; the coating thickness is 15 micrometers;

[0144] III. Mixing and Construction Parameters

[0145] Mixing solution: Dissolve 14 parts of potassium dihydrogen phosphate in metered water, add 0.8 parts of borate retarder and 0.6 parts of water-reducing agent, and stir magnetically for 5 minutes;

[0146] Dry premix: dry mix at 25 rpm for 3 minutes, or dry mix at 70 rpm for 2 minutes;

[0147] Final mixing: After the mixture is put into the machine, stir at 25 rpm, add the dry premix and stir at 25 rpm for 2 minutes, stir at 70 rpm for 3 minutes, let stand for 1 minute to degas; reduce to 25 rpm, add 16 parts of delayed hydration granules, and stir at 25 rpm for 30 seconds;

[0148] Thick coating application: ambient temperature 20 degrees Celsius; single coat thickness 20 mm; let stand for 30 minutes after application;

[0149] IV. Maintenance and Structural Formation

[0150] Temperature 20 degrees Celsius, relative humidity 60%; formation sequence is the same as in Example 1; natural curing completed on day 7;

[0151] Example 3 (Route A, Lower Limit Window)

[0152] I. Formula (parts by weight)

[0153] 40g silicate clinker; 8g granulated blast furnace slag powder; 2g silica fume; 12g magnesium oxide; 8g potassium dihydrogen phosphate; 0.3g borate retarder; 8g delayed hydration particles; 4g zeolite; 8g magnesium hydroxide; 4g hollow mullite microspheres; 2g quicklime; 0.2g water-reducing agent; water;

[0154] The mass fraction ratio of water to cementitious material is 0.25;

[0155] II. Functional Component Parameters

[0156] Aluminum phosphate coating on the outer surface of hollow mullite microspheres: coating thickness 3 micrometers; curing temperature 150 degrees Celsius; curing time 30 minutes;

[0157] Delayed hydration particles: The particle core is sulfoaluminate clinker particles; the particle size is 0.6 mm (distributed from 0.5 mm to 0.8 mm); the inorganic hydrophobic coating is a zirconium phosphate and silica sol coating; the coating thickness is 5 micrometers;

[0158] III. Mixing and Construction Parameters

[0159] The steps for mixing liquid, dry premix, final mixing and thick coating are the same as in Example 1; single coat thickness is 10 mm; ambient temperature is 20 degrees Celsius; let stand for 30 minutes after application.

[0160] IV. Maintenance and Structural Formation

[0161] Temperature 20 degrees Celsius, relative humidity 60%; formation sequence is the same as in Example 1; natural curing completed on day 7;

[0162] Example 4 (Route A, the location of the strip-shaped porous structure region is traceable)

[0163] I. Formula (parts by weight)

[0164] Silicate clinker 35; Granulated blast furnace slag powder 10; Silica fume 5; Magnesium oxide 16; Potassium dihydrogen phosphate 12; Borate retarder 0.5; Delayed hydration particles 12; Zeolite 6; Magnesium hydroxide 10; Hollow mullite microspheres 6; Quicklime 3; Water-reducing agent 0.4; Water;

[0165] The mass fraction ratio of water to cementitious material is 0.28;

[0166] II. Functional Component Parameters

[0167] Aluminum phosphate coating on the outer surface of hollow mullite microspheres: coating thickness 8 micrometers; curing temperature 200 degrees Celsius; curing time 60 minutes;

[0168] Delayed hydration particles: The particle core is sulfoaluminate clinker particles; the particle size is 1.0 mm (distributed from 0.5 mm to 1.5 mm); the inorganic hydrophobic coating is a zirconium phosphate and silica sol coating; the coating thickness is 12 micrometers;

[0169] Static positioning: After the thick coating is formed, it is left to stand undisturbed for 30 minutes to stabilize the banded distribution of delayed hydration particles in the thickness direction;

[0170] III. Mixing and Construction Parameters

[0171] The mixing liquid, dry premix, final mixing and thick coating application steps are the same as in Example 1; single coat thickness is 15 mm; ambient temperature is 20 degrees Celsius; let stand for 30 minutes after application;

[0172] IV. Maintenance and Structural Formation

[0173] Temperature 20 degrees Celsius, relative humidity 60%; formation sequence is the same as in Example 1; natural curing is completed on the 7th day; in Example 4, a Φ25 mm core is drilled on the 3rd day and X-ray CT is used to record the position and width of the strip-shaped porous structure area in the thickness direction.

[0174] It should be noted that for Examples 1 to 4:

[0175] Example 1: Tests and Results

[0176] After curing for 7 days at 20℃ and 60% relative humidity, five wall panel samples (300 mm × 300 mm, with a 15 mm thick coating) were taken and subjected to two cycles of rapid cooling (650℃ for 10 minutes → 20℃ water spray at 2 bar for 2 minutes). The penetration rate of the through-cracks was obtained using X-ray CT (30 μm voxel size) to acquire three-dimensional volumetric data in the thickness direction. The ratio of the total penetration length of the crack to the total length of the thickness-direction measurement line was calculated using Otsu thresholding and three-dimensional skeletonization; the result was 7.2% ± 1.1%. The spalling area fraction was statistically determined to be 3.1% ± 0.6% using high-definition backlight imaging and pixel counting. The interfacial pull-out strength was determined according to ASTM C1583 method, using a 50 mm pull-out disc, a cutting depth of 2 mm, and a loading rate of 0.05 MPa / s. The initial value was 1.18 MPa ± 0.09 MPa, and after rapid cooling, it was 0.98 MPa ± 0.08 MPa, with a retention rate of 83.1% ± 4.2%.

[0177] The steady-state thermal conductivity, according to GB / T10294, with a sample thickness of 15 mm and a temperature difference of 20 K, was 0.076 W / (m·K) ± 0.003 W / (m·K). CT analysis showed that the banded porous structure region was located at thicknesses of 0.34 and 0.67 mm, with a band position deviation of ±7%, a bandwidth of 1.1 mm ± 0.2 mm, an open porosity of 28% ± 3%, and a connectivity index of 0.78 ± 0.05. The pH of the pore solution, measured with a planar electrode at 0.5 hours and 24 hours, was 9.7 and 11.6, respectively. The DSC / TG of the banded powder showed the first exothermic peak at 28 hours.

[0178] The aforementioned data is used to demonstrate that the time-series interpenetrating structure and the strip-shaped porous structure region have been formed, and that they effectively suppress through cracks and spalling.

[0179] Example 2 Test and Results:

[0180] Under the same curing and quenching conditions, five samples with dimensions of 300 mm × 300 mm were taken (thick coating thickness of 20 mm, delayed hydration particles were potassium dihydrogen phosphate core, dosage of 16 parts, and water to cementitious material mass fraction ratio of 0.32).

[0181] The penetration rate of the through crack measured by CT was 9.4%±1.5%, and the spalling area fraction was 4.6%±0.8%; the initial value of the interfacial pull-out strength was 1.05MPa±0.10MPa, and after rapid cooling it was 0.77MPa±0.09MPa, with a retention rate of 73.3%±5.1%; the steady-state thermal conductivity was 0.079W / (m·K)±0.004W / (m·K).

[0182] CT scans showed that the banded porous structure was located at thicknesses of 0.36 and 0.64 mm, with a band position deviation of ±9%, a bandwidth of 1.3 mm ± 0.2 mm, an open porosity of 31% ± 3%, and a connectivity index of 0.72 ± 0.06. The pH values ​​were 9.4 and 11.3 at 0.5 hours and 24 hours, respectively. The DSC / TG ratio of the banded powder showed its first exothermic peak at 16 hours.

[0183] The results show that under the conditions of 20 mm thickness and 0.32 water to cementitious material mass fraction, the delayed hydration particles of potassium dihydrogen phosphate core can still form a banded porous structure region and achieve crack deflection and interface retention.

[0184] Example 3 Test and Results:

[0185] Under the same process, five samples with a coating thickness of 10 mm were taken (8 parts of delayed hydration particles, sulfoaluminate clinker core, particle size of 0.5-0.8 mm, and water to cementitious material mass ratio of 0.25); the penetration rate of through cracks by CT method was 6.1%±1.0%, and the spalling area fraction was 2.7%±0.5%; the initial value of the interfacial pull-out strength was 1.22 MPa±0.08 MPa, and after rapid cooling it was 1.02 MPa±0.07 MPa, with a retention rate of 83.6%±3.7%;

[0186] The steady-state thermal conductivity was 0.074 W / (m·K) ± 0.003 W / (m·K); CT scans showed that the banded porous structure was located at thicknesses of 0.33 and 0.66 mm, with a band position deviation of ±6%, a bandwidth of 0.9 mm ± 0.1 mm, an open porosity of 27% ± 2%, and a connectivity index of 0.80 ± 0.04; the pH values ​​were 9.9 and 11.8 at 0.5 hours and 24 hours, respectively; the DSC / TG ratio of the banded powder showed its first exothermic peak at 36 hours.

[0187] The results confirmed that a continuous strip-shaped porous structure region and stable resistance to penetration and peeling can still be obtained under the lower limit conditions.

[0188] Example 4: Tests and Results

[0189] According to the formulation system and process of Example 1, band statistics and repeatability verification were added; 5 samples with a thick coating of 15 mm were taken, and the CT voxel size was 30 micrometers. 5 cross sections were cut at equal intervals for each sample, for a total of 25 cross sections for statistics.

[0190] The penetration rate of the through crack was 7.0%±1.2%, and the spalling area fraction was 3.3%±0.7%; the initial interfacial pull-out strength was 1.16MPa±0.09MPa, and after rapid cooling it was 0.96MPa±0.08MPa, with a retention rate of 82.8%±4.0%; the steady-state thermal conductivity was 0.075W / (m·K)±0.003W / (m·K).

[0191] The first zone of the banded porous structure region is concentrated at a thickness of 0.35±0.02 mm, and the second zone is concentrated at a thickness of 0.66±0.02 mm; the width is 1.2 mm±0.2 mm, the open porosity is 29%±3%, and the connectivity index is 0.79±0.05; the pH was measured to be 9.6 and 11.5 at 0.5 hours and 24 hours, respectively; the powder DSC / TG of the banded region showed the first exothermic peak at 30 hours.

[0192] The above statistical results provide repeatability evidence for the location, width, and connectivity of the strip-shaped porous structure region, and establish a causal correspondence with the results of through cracks and spalling.

[0193] It should be noted that this solution addresses the issue of penetrating cracks and interface peeling in thick-coated inorganic flame-retardant wall panels after rapid cooling with water spraying during a fire. It proposes a method for controlling the path of internal cracks within the material itself. The formula uses silicate clinker, granulated blast furnace slag powder, silica fume, and magnesium oxide as the cementing material, combined with potassium dihydrogen phosphate, borate retarder, delayed hydration particles, zeolite, magnesium hydroxide, hollow mullite microspheres, quicklime, and a water-reducing agent. After mixing, at 20 degrees Celsius, magnesium oxide reacts with potassium dihydrogen phosphate to form a magnesium potassium phosphate network. Subsequently, the cementing material continues to hydrate to form a hydrated calcium silicate network, with the two interpenetrating each other in a chronological order.

[0194] The core of the delayed hydration particles is sulfoaluminate clinker particles or potassium dihydrogen phosphate particles, and the outer surface is coated with an inorganic hydrophobic coating. The particle size and coating thickness are determined according to the application in the example. The particles initiate hydration within twelve to seventy-two hours, forming a porous boundary around the particles and generating a banded porous structure zone along the thickness direction. This causes surface cracks to deflect and attenuate within the structural zone, preventing them from penetrating to the substrate interface. Zeolite is used to regulate free water during the hardening and service periods. The aluminum phosphate coating on the outer surface of the hollow mullite microspheres is used to form a continuous interface with the hydrated calcium silicate network and stabilize the morphology of the microspheres. Magnesium hydroxide provides a heat-absorbing and water-releasing flame-retardant effect. The overall purpose is to establish a stable crack deflection and energy dissipation path within the material.

[0195] The implementation steps are carried out in the order of S1 to S9 in the plan: raw material pretreatment includes drying and sieving; the preparation of functional components is divided into two parts, S2.1 is the preparation of aluminum phosphate coating on the outer surface of hollow mullite microspheres, and S2.2 is the preparation of delayed hydration particles. Route A uses sulfoaluminate clinker particles as the core, and route B uses potassium dihydrogen phosphate particles as the core. After the two parts are completed, they are mixed; the mixing adopts the link of "mixing liquid - dry material premixing - final mixing - low shear incorporation of delayed hydration particles". Dry material premixing is carried out in combination with 20 to 30 revolutions per minute for 3 minutes and 60 to 80 revolutions per minute for 2 minutes. During final mixing, low shear is controlled to add delayed hydration particles and keep the coating layer intact; the construction is a single coat with a thickness of 10 to 20 mm. After completion, it is left to stand for 30 minutes to stabilize the distribution of particles in the thickness direction; the curing stage is carried out under the conditions of 18 to 22 degrees Celsius and 50% to 70% relative humidity, forming a magnesium potassium phosphate network, a hydrated calcium silicate network and a banded porous structure zone according to the time window;

[0196] The inspection included thickness measurement, core drilling and X-ray imaging to observe the location and width of the strip-shaped porous structure area, interface pull-out and steady-state thermal conductivity tests, and recording pH and thermal analysis to confirm the reaction sequence; all terms and parameters were consistent with the claims, and the mass fraction ratio of water to cementitious material, particle size, coating thickness, construction thickness and curing conditions were all performed within the specified range to ensure that the results were reproducible;

[0197] The reason for choosing this design scheme is that crack control is achieved by the material itself, without relying on the addition of structural layers; the time-interpenetration allows the early-formed magnesium potassium phosphate network to undertake bridging, while the later-formed hydrated calcium silicate network undertakes the skeleton, and the two work together in the same coating.

[0198] Delayed hydration particles form a banded porous structure zone within a predetermined time window and depth zone. Combined with the aluminum phosphate coating on the outer surface of zeolite and hollow mullite microspheres, this achieves a combination of functions including thickness-direction crack deflection, interfacial water content stabilization, and thermal shock buffering.

[0199] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lightweight, flame-retardant, multi-layered wall panel material, characterized in that: The wall panel material, by weight, comprises: 30-40 parts silicate clinker; 8-14 parts granulated blast furnace slag powder; 2-6 parts silica fume; 12-20 parts magnesium oxide; 8-14 parts potassium dihydrogen phosphate; 0.3-0.8 parts borate retarder; 8-16 parts delayed hydration particles; 4-8 parts zeolite; 8-12 parts magnesium hydroxide; 4-8 parts hollow mullite microspheres; 2-5 parts quicklime; 0.2-0.6 parts water-reducing agent; and water. The mass fraction ratio of water to cementitious material is 0.25 to 0.32, wherein the cementitious material comprises a composition of the silicate clinker, the granulated blast furnace slag powder, the silica fume and the magnesium oxide; The delayed hydration particles consist of a core of sulfoaluminate clinker particles or potassium dihydrogen phosphate particles, with an inorganic hydrophobic coating on the outer surface of the particle core. The particle size is 0.5–1.5 mm and the coating thickness is 5–15 micrometers. The zeolite is of type 13X or Y, with a particle size of 0.5–1.0 mm; The hollow mullite microspheres have a particle size of 0.3 to 1.5 mm and are coated with an aluminum phosphate coating with a thickness of 3 to 8 micrometers. After mixing, the wall panel material forms a time-interpenetrating structure of potassium magnesium phosphate network and calcium silicate hydrate network in sequence at 20 degrees Celsius, and generates a banded porous structure region in the thickness direction through delayed hydration particles within 12 to 72 hours.

2. The lightweight flame-retardant multi-layer structure wall panel material according to claim 1, characterized in that: The inorganic hydrophobic coating is composed of zirconium phosphate and silicon dioxide in a mass ratio of 1:1 to 1:

3. It forms a coating layer on the surface of the particle core through a sol-gel method to delay the contact time between the particle core and water, thereby achieving a delayed hydration effect in the thickness direction.

3. The lightweight flame-retardant multi-layer structure wall panel material according to claim 1, characterized in that: The aluminum phosphate coating is formed by uniformly spraying a mixed coating containing ammonium aluminate and aluminum dihydrogen phosphate onto the outer surface of hollow mullite microspheres and curing it at 150–200 degrees Celsius, thereby improving the structural stability of the hollow mullite microspheres under high-temperature conditions and the interfacial bonding force with the cementitious material.

4. The lightweight flame-retardant multi-layer structure wall panel material according to claim 1, characterized in that: During the formation of the strip-shaped porous structure region, the aluminate or phosphate ions released by the delayed hydration particles react with the surrounding incompletely hydrated cementitious material to generate a locally brittle phase. The alternating distribution of pores and solid phases enhances the thermal resistance path inside the thick coating and reduces the thermal conductivity to no more than 0.08 W / (m·K).

5. The method for preparing a lightweight flame-retardant multi-layer structure wall panel material according to claim 1, characterized in that, include: S1 raw material pretreatment includes: S1.1 Dry silicate clinker, granulated blast furnace slag powder, silica fume, magnesium oxide, potassium dihydrogen phosphate, borate retarder, zeolite, magnesium hydroxide, and quicklime in an oven at 105°C for 2 hours, and then cool to 20°C. S1.2 The powder in S1.1 is sieved to a sieve aperture of less than 150 micrometers, and the sieved portion is collected. The silica fume is used in its original state and is not sieved again. S1.3 The hollow mullite microspheres were dried in a 60℃ oven for 2 hours and then cooled to 20℃ for later use. Preparation of S2 functional components, including S2.1 and S2.2: S2.1 Preparation of aluminum phosphate coating on the outer surface of hollow mullite microspheres, including: S2.1.1 Preparation of spray solution containing ammonium aluminate and aluminum dihydrogen phosphate: Mix them at a mass ratio of 1:1, use deionized water as solvent, and set the solid content to 10% by mass. S2.1.2 Place the dried hollow mullite microspheres into a roller sprayer and spray the spray liquid obtained in 2.1.1 at a uniform speed. The amount of spraying is controlled according to the increase of mass by 2% to 6% after coating. After spraying S2.1.3, the mixture is cured for 30 to 60 minutes under hot air circulation at 150℃ to 200℃ to obtain hollow mullite microspheres with an aluminum phosphate coating thickness of 3 to 8 micrometers on the outer surface. The microspheres are then cooled to 20℃ and sealed for storage. S2.2 Preparation of delayed hydration particles includes preparation via route A or route B: Route A includes: S2.2.1 Select sulfoaluminate clinker particles with a particle size of 0.5 mm to 1.5 mm as the particle core; S2.2.2 Preparation of inorganic hydrophobic coating sol: Mix zirconium phosphate sol and silica sol at a mass ratio of 1:1 to 1:3, and set the solid content to 8% to 12% by mass. S2.2.3 Place the particle core in a roller coating equipment, spray the sol obtained in 2.2.2 and continuously roll coat, controlling the drying-spraying cycle until the coating thickness is 5 micrometers to 15 micrometers; S2.2.4 is dried at 60℃ for 2 hours, cooled to 20℃ and sieved to remove agglomerates, yielding delayed hydration particles; Route B includes: S2.2.5 Potassium dihydrogen phosphate and deionized water are mixed at a mass ratio of 9:1 to form plastic granules. The granules are then sphericalized to obtain potassium dihydrogen phosphate granules with a particle size of 0.5 mm to 1.5 mm. The granules are then dried with hot air at 40°C for 1 hour. S2.2.6 The same steps as in 2.2.2 to 2.2.4 are used to coat and dry the inorganic hydrophobic coating to obtain delayed hydration particles; S3 mixing liquid and dry material premixing includes: S3.1 Preparation of mixing solution: Weigh 8 to 14 parts of potassium dihydrogen phosphate according to the formula and dissolve it in the measured water. Add 0.3 to 0.8 parts of borate retarder and 0.2 to 0.6 parts of water-reducing agent. Stir magnetically for 5 minutes to obtain a homogeneous solution. S3.2 Preparation of dry premix: Add 30-40 parts of silicate clinker, 8-14 parts of granulated blast furnace slag powder, 2-6 parts of silica fume, 12-20 parts of magnesium oxide, 4-8 parts of zeolite, 8-12 parts of magnesium hydroxide, 2-5 parts of quicklime, and 4-8 parts of hollow mullite microspheres obtained in step S2.1 to a closed mixer. Dry mix at a speed of 20-30 rpm for 3 minutes, and then dry mix at a speed of 60-80 rpm for 2 minutes. S4 final mixing and delayed hydration particle addition, including: S4.1 Add the mixing liquid prepared in S3.1 to the mortar mixer and start mixing at a speed of 20-30 rpm; S4.2 Add the dry premix prepared in S3.2 evenly while stirring at a speed of 20-30 rpm, dry mix at a speed of 20-30 rpm for 2 minutes, then dry mix at a speed of 60-80 rpm for 3 minutes, and let stand for 1 minute to degas. S4.3 Reduce the rotation speed to 20-30 rpm, and sprinkle 8-16 parts of the delayed hydration particles obtained in S2.2 onto the surface of the slurry. Stir at 20-30 rpm for 30 seconds to ensure that the particles are evenly dispersed and the coating layer is intact. S5 molding and thick coating application include: S5.1 Substrate preparation: Remove the powdery and loose layers from the surface of the wall panel to be coated. The surface should be clean and free of standing water. The moisture content of the substrate should not exceed 8% by weight. S5.2 Thick Coating Application: At 20℃, the slurry obtained in S4 is applied in a single coat by spraying or troweling, with a thickness of 10 mm to 20 mm; compact from the surface to the interior by vibration and smooth the surface. S5.3 Settling: After construction, let stand for 30 minutes without any secondary disturbance or watering. S6 maintenance and structural formation include: S6.1 Maintenance conditions: Ambient temperature 18℃~22℃, relative humidity 50%~70%, cover with film or place in a windless environment for the first 24 hours to prevent moisture loss; S6.2 Sequential Formation: Within 0 to 1 hour after mixing, magnesium oxide reacts with potassium dihydrogen phosphate to form a magnesium potassium phosphate network; within 4 to 48 hours after mixing, silicate clinker, granulated blast furnace slag powder and silica fume hydrate to form a hydrated calcium silicate network; within 12 to 72 hours after mixing, delayed hydration particles gradually initiate hydration, forming a banded porous structure zone in the thickness direction; After the S6.3 curing period is over, remove the covering and continue natural curing under normal temperature and ventilation conditions until the 7th day; S7 inspection and recording, including: S7.1 Thickness inspection: Take three points at any location to measure the thickness. The thickness should be within the range of 10 mm to 20 mm. S7.2 Structural Inspection: Drill a Φ25 mm core in a non-load-bearing area, observe and record the location and width of the banded porous structure area caused by delayed hydration particles along the thickness direction; record whether the pore structure is continuous; S7.3 Performance Samples: Three 40 mm × 40 mm × 160 mm test strips were prepared, and their flexural strength, compressive strength, and thermal conductivity were tested at 24 hours, 72 hours, and 7 days of age, respectively; the thermal conductivity test was conducted under a temperature difference maintained at 20 K. S8 metering and water-to-binder ratio control, including: S8.1 The mass fraction ratio of water to cementitious material is controlled at 0.25 to 0.32, wherein the cementitious material is a composition of silicate clinker, granulated blast furnace slag powder, silica fume and magnesium oxide; S8.2 If the fluidity decreases due to evaporation of the mixing liquid during the mixing process, add water to maintain the water-cement ratio within the range of 0.25 to 0.32, and mix the water and slurry again for 30 seconds to complete the homogenization. S9 storage and usage periods include: S9.1 The time interval between the completion of mixing and the start of construction shall not exceed 20 minutes; S9.2 Unused mixed slurry should not be left to stand at 20℃ for more than 40 minutes. If the time limit is exceeded, water should not be added for reuse.

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