Self-insulating mold-free prefabricated board and preparation method thereof

Abstract

The present invention discloses a self-insulating, mold-free prefabricated board and a preparation method thereof. The self-insulating, mold-free prefabricated board comprises a prefabricated board body, the prefabricated board body comprising a steel mesh and concrete, wherein a plurality of mold-free boxes made of pre-cured and solidified foamed geopolymer are encapsulated within the concrete, a plurality of insulation cavities are provided within the mold-free boxes, and the insulation cavities are filled with a fireproof and heat-insulating slurry made from a biomass base. The prefabricated board body, the mold-free boxes, and the fireproof and heat-insulating slurry are cured and formed in an autoclave. The present invention facilitates the foaming and molding of the fireproof and heat-insulating slurry, achieving self-insulation, resulting in a high energy-saving rate for the entire board, good sealing performance, and excellent thermal insulation and mechanical properties. This improves the complex steam curing process of traditional processes, thereby saving the curing process and time costs.

Description

Technical Field

[0001] The present invention relates to the technical field of self-insulating prefabricated panels, and in particular to a self-insulating, mold-free prefabricated panel and a preparation method thereof. Background Art

[0002] In recent years, with China's increasing emphasis on energy conservation and environmental protection, prefabricated buildings have rapidly developed. This, coupled with rising public expectations for quality of life and living environment, has also accelerated the pace of prefabricated building development. While prefabricated buildings offer ease and speed, they face a significant challenge: insulation. Current insulation technologies primarily include external insulation, internal insulation, sandwich insulation, and self-insulation. Self-insulating prefabricated panels are particularly well-suited to the efficient and green design of prefabricated buildings, and therefore are widely used.

[0003] However, traditional self-insulating prefabricated panels often suffer from the following issues: poor fireproofing and thermal insulation, a need for improved airtightness, difficulty disassembling the self-insulating molds, and multiple steaming cycles, resulting in a cumbersome process and high energy consumption. Therefore, improving traditional self-insulating prefabricated panels to overcome these shortcomings is a critical issue in this field. Summary of the Invention

[0004] The purpose of the present invention is to address the deficiencies of the prior art and provide a self-insulating, mold-free prefabricated board with a simple steaming process, good airtightness, and excellent fireproof and heat-insulating properties, and a preparation method thereof.

[0005] The self-insulating, formwork-free prefabricated board provided by the present invention comprises a prefabricated board body, which comprises a steel mesh and concrete. A plurality of formwork-free boxes made of pre-cured and solidified foamed geopolymer are encapsulated in the concrete. A plurality of insulation cavities are provided in the formwork-free boxes, which are filled with a fireproof and heat-insulating slurry made from a biomass base. The prefabricated board body, the formwork-free boxes and the fireproof and heat-insulating slurry are cured and formed in an autoclave.

[0006] The steel mesh is formed by binding and fixing a number of steel bars arranged in a crisscross pattern. The formwork-free box includes a bottom box and a cover plate. The cover plate is tightly covered on the bottom box. The insulation cavity is enclosed by the bottom box and the cover plate. A number of positioning holes corresponding to the corresponding steel bars are opened on the side wall of the bottom box. The formwork-free box is clamped on the steel mesh by steel bars passing through the positioning holes and is cast into a whole by concrete.

[0007] In order to make the mold-free box have high porosity, high mechanical strength, strong bonding properties, good durability, fire resistance, high temperature resistance, acid and alkali resistance, and ensure that its preparation process has low energy consumption, small CO2 emissions, no pollution, abundant raw material sources, simple preparation process, and low cost, the mold-free box is prepared by polymerization reaction of an alkali activator, a foaming agent and a foam stabilizer, the alkali activator is mixed with kaolin, NaOH particles and industrial water glass, the foaming agent is hydrogen peroxide with a mass concentration of 30%, and the foam stabilizer is soap.

[0008] In order to make the fireproof and thermal insulation slurry have high porosity, excellent thermal insulation performance and mechanical properties, the fireproof grade can reach Class A non-combustible, and its raw material source is abundant, the preparation process is simple, and the cost is low, the fireproof and thermal insulation slurry is prepared by polymerization reaction of carbonized biomass, inorganic binder, foaming agent and foam stabilizer, the inorganic binder is a metakaolin-based geopolymer, the foaming agent is hydrogen peroxide with a mass concentration of 30%, and the foam stabilizer is soap.

[0009] In order to ensure that the entire board has a high energy saving rate, good sealing performance, and excellent thermal insulation and mechanical properties, the bottom box and the cover plate are connected by mortise and tenon joints.

[0010] The method for preparing the self-insulating, mold-free prefabricated plate provided by the present invention comprises the following steps:

[0011] S1. Make a mold-free box

[0012] S11, making a first mold and a second mold that are consistent with the appearance of the bottom box and the cover plate;

[0013] S12, pouring the geopolymer slurry to be foamed into the first mold and the second mold evenly coated with the release agent;

[0014] S12, placing the first mold and the second mold filled with the geopolymer slurry into a pre-curing autoclave for pre-curing, wherein the temperature of the pre-curing steam is 65° C.-80° C. and the curing time is 3 h-5 h, so that the mold-free box is initially cured and has a certain strength;

[0015] S2. Make a third mold that is consistent with the shape of the prefabricated panel body, provide reserved holes on the side walls of the third mold to facilitate the insertion of steel bars into the mold, and evenly apply a release agent on the inner wall of the third mold;

[0016] S3, taking the bottom box out of the first mold and placing it in the third mold;

[0017] S4, passing the crisscrossed steel bars through the bottom box and the third mold and tying them together to form a steel mesh;

[0018] S5. Prepare fireproof and thermal insulation slurry and pour it into the insulation cavity of the mold-free box, ensuring that the filling amount of the fireproof and thermal insulation slurry is 86%-88% of the insulation cavity to achieve self-insulation. At the same time, make three groups of test blocks with the same conditions for thermal insulation, mechanical and fire performance testing at different times.

[0019] S6. Put on the cover;

[0020] S7. Pour the mixed concrete slurry horizontally into a third mold equipped with a steel mesh at a pouring temperature of 25°C-35°C. Simultaneously, prepare three groups of test blocks under the same conditions from the concrete slurry for compressive strength testing and demolding strength testing at different times.

[0021] S8, vibrating

[0022] Use mechanical vibration to tamp the concrete slurry in the third mold, and use a vibrating rod as an auxiliary to eliminate bubbles in the concrete slurry, so that the concrete slurry is densely combined and the concrete strength is guaranteed;

[0023] S9, steaming

[0024] After vibrating, the plate is sent to the autoclave for steam curing. The pressure rise time of the autoclave is 100-120 minutes. The pressure in the autoclave rises to 1.1MPa-1.2MPa. The temperature in the autoclave is maintained at 180℃-200℃. After the autoclave is kept at constant temperature and pressure for 8h-12h, the pressure is reduced. The pressure reduction time is 100-120 minutes to cure the plate and achieve higher strength.

[0025] S10, demoulding finished product

[0026] After steam curing, cool to room temperature and take out, and perform standard curing for 28 days. After demoulding, self-insulating and mold-free prefabricated panels can be obtained.

[0027] In step S2 , a magnetic box for fixing the third mold is bolted to the third mold.

[0028] In order to facilitate separation of the concrete from the third mold and to ensure a smooth and clean surface of the concrete, in step S2 , the release agent is silicone oil.

[0029] In step S5, the configuration process of the fireproof and thermal insulation slurry is as follows: carbonized biomass is used as raw material, kaolin-based geopolymer is used as inorganic binder, hydrogen peroxide with a mass concentration of 30% is used as foaming agent, and soap is used as foam stabilizer for stirring and mixing. After stirring and mixing, let it stand for 5-10 minutes, and mix again to obtain the fireproof and thermal insulation slurry.

[0030] To ensure the strength of the concrete and prevent it from deformation and cracking, in step S7, the concrete slurry is prepared as follows: the concrete is prepared according to a concrete mix ratio with a strength grade of not less than C25, mixed using a forced mixer, allowed to stand for 5-10 minutes after mixing, and mixed again to obtain concrete slurry.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] 1. By setting a mold-free box with an insulation cavity inside the main body of the prefabricated board, it is easy to pour the fireproof and thermal insulation slurry, and the poured biomass-based fireproof and thermal insulation slurry is separated from the poured concrete, which is convenient for the fireproof and thermal insulation slurry to foam and form, realize self-insulation, and make the whole board have high energy saving rate, good sealing performance, and excellent thermal insulation and mechanical properties.

[0033] 2. A combined steam-curing method is adopted. The mold-free box is pre-cured to solidify and shape it. During the production, the biomass-based fireproof and thermal insulation slurry is first poured, and the mold-free box is sealed before pouring concrete to form a whole. Finally, the whole is sent into the autoclave for curing and shaping. This improves the complicated steam-curing process of the traditional process, thereby saving the curing process and time cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a partial cross-sectional structural schematic diagram of the self-insulating and mold-free prefabricated plate in the present invention.

[0035] Figure 2 It is a schematic diagram of the explosion structure of the mold-free box in the present invention.

[0036] Figure 3 Process flow chart of the preparation method of the present invention.

[0037] Figure 4 Schematic diagram of the structure of step S3 in the preparation method of the present invention.

[0038] The symbols and corresponding component names shown in the figure are:

[0039] 1. Precast panel body; 11. Steel mesh; 12. Concrete;

[0040] 2. No-mold-removal box; 21. Insulation cavity; 22. Bottom box; 221. Positioning hole; 23. Cover plate;

[0041] 3. Fireproof and thermal insulation slurry;

[0042] 4. Third mold; 41. Reserved hole; 42. Magnetic box. DETAILED DESCRIPTION

[0043] from Figure 1It can be seen that the self-insulating, mold-free prefabricated board of the present invention comprises a prefabricated board body 1 integrally cured and formed by an autoclave, a mold-free box 2 and a fireproof and thermal insulation slurry 3. The mold-free box 2 is made of foamed geopolymer pre-cured and solidified and encapsulated in the prefabricated board body 1. A plurality of thermal insulation cavities 21 are provided in the mold-free box 2. The fireproof and thermal insulation slurry 3 is made of biomass and filled in the thermal insulation cavity 21. The filling amount of the fireproof and thermal insulation slurry 3 is 88% of the thermal insulation cavity 21, and a part of the foaming space is reserved to achieve self-insulation.

[0044] from Figures 1 to 2 It can be seen that the precast panel body 1 of the present invention includes a steel mesh 11 and concrete 12. The steel mesh 11 is formed by binding and fixing a plurality of steel bars arranged in a crisscross pattern. Its main function is to improve the transverse and longitudinal bending strength of the precast panel.

[0045] The formwork-free box 2 includes a base box 22 and a cover plate 23. A number of positioning holes 221 corresponding to the corresponding steel bars are opened on the side wall of the base box 22. The cover plate 23 is connected to the base box 22 by mortise and tenon joints, so that the entire board has a high energy saving rate, good sealing performance, and excellent thermal insulation performance and mechanical properties; the insulation cavity 21 is formed by the base box 22 and the cover plate 23, and the volume of the insulation cavity 21 accounts for 30%-35% of the volume of the entire self-insulating formwork-free prefabricated board, so that the fireproof insulation slurry 3 is separated from the concrete 12, which is convenient for foaming and improves the insulation effect; the formwork-free box 2 is clamped on the steel mesh 11 by the steel bars passing through the positioning holes 221 and is cast into a whole by the concrete 12.

[0046] In the present invention, the prefabricated panel body 1 has a length of 4300 mm, a width of 2300 mm, and a thickness of 60 mm.

[0047] In the present invention, the mold-free box 2 has a length of 1710 mm, a width of 1710 mm, an overall height of 40 mm, and a thickness of 5 mm for the bottom box 22 and the cover plate 23 .

[0048] In the present invention, the fireproof and heat-insulating slurry 3 has a length of 1700 mm, a width of 1700 mm, and a thickness of 30 mm.

[0049] In the present invention, the mold-free box 2 is prepared by polymerization reaction of an alkali activator, a foaming agent, and a foam stabilizer. The alkali activator is a mixture of metakaolin, industrial water glass, and NaOH particles in a mass ratio of 8:7.3:1, respectively. The foaming agent is hydrogen peroxide with a mass concentration of 30%, and the foam stabilizer is soap. This makes the mold-free box 2 have the advantages of high porosity, high mechanical strength, strong bonding properties, good durability, fire resistance, high temperature resistance, acid and alkali resistance, etc., and its preparation process has low energy consumption, low CO2 emissions, no pollution, abundant raw material sources, simple preparation process, and low cost. The foaming agent is added to 0.4kg-0.6kg of foaming agent per cubic meter based on the volume of the blank.

[0050] like Figures 3 and 4 As shown, the method for preparing the self-insulating mold-free prefabricated plate of the present invention comprises the following steps:

[0051] S1, making mold-free box 2

[0052] S11, making a first mold and a second mold that are consistent with the appearance of the bottom box 22 and the cover plate 23;

[0053] S12, pouring the geopolymer slurry to be foamed into the first mold and the second mold evenly coated with the release agent;

[0054] S12, placing the first mold and the second mold filled with the geopolymer slurry into a pre-curing autoclave for pre-curing, wherein the temperature of the pre-curing steam is 65°C-80°C (preferably 70°C) and the curing time is 3h-5h, the main function of which is to allow the foamed geopolymer to be initially cured without demolding and have a certain strength;

[0055] S2. Make a third mold 4 that is consistent with the shape of the prefabricated panel body 1, provide a reserved hole 41 on the side wall of the third mold 4 to facilitate the insertion of the steel bars 111, and evenly apply a release agent on the inner wall of the third mold 4;

[0056] S3, taking the bottom box 22 out of the first mold and placing it in the third mold 4;

[0057] S4, passing the crisscrossed steel bars through the bottom box 22 and the third mold 4 and then tying them together to form a steel mesh 11;

[0058] S5. Prepare fireproof and thermal insulation slurry 3, pour a portion of the fireproof and thermal insulation slurry 3 into the thermal insulation cavity 21 of the mold-free box 2, and ensure that the filling amount of the fireproof and thermal insulation slurry 3 is 86%-88% of the thermal insulation cavity, reserving a portion of foaming space to achieve self-insulation of the prefabricated board; at the same time, prepare a portion of the fireproof and thermal insulation slurry 3 into 3 groups of test blocks with the same conditions, and use them for thermal insulation, mechanical, and fire performance testing at different times;

[0059] S6. Cover the cover plate 23 and ensure that the volume of the insulation cavity 21 accounts for 30%-35% of the volume of the entire self-insulating, mold-free prefabricated plate;

[0060] S7. Pour a portion of the mixed concrete slurry horizontally into the third mold 4 equipped with the steel mesh 11. The concrete pouring temperature is 25°C-35°C (preferably 30°C). At the same time, prepare three groups of test blocks with the same conditions from a portion of the concrete slurry for compressive strength testing and demolding strength testing at different times.

[0061] S8, vibrating

[0062] The concrete slurry in the third mold 4 is mechanically vibrated, and a vibrating rod can be used as an auxiliary to remove bubbles in the concrete, so that the concrete is densely combined and the concrete strength is ensured;

[0063] S9, steaming

[0064] After vibrating, the mixture is sent to the autoclave for steam curing. The pressure rise time of the autoclave is 100-120 minutes. The pressure in the autoclave rises to 1.1MPa-1.2MPa. The temperature in the autoclave is maintained at 180℃-200℃. After the autoclave is kept at constant temperature and pressure for 8h-12h (preferably 10h), the pressure begins to decrease. The pressure reduction time is 100-120min.

[0065] S10, demoulding finished product

[0066] After steam curing, cool to room temperature and take out, and perform standard curing for 28 days. After demoulding, self-insulating and mold-free prefabricated panels can be obtained.

[0067] In step S2 , a magnetic box 42 for fixing the third mold is bolted to the third mold 4 .

[0068] In step S2, the release agent is silicone oil, which is mainly used to facilitate the separation of the concrete 12 from the third mold 4 and to make the surface of the concrete 2 smooth and clean;

[0069] In step S5, the configuration process of the fireproof and thermal insulation slurry 3 is as follows: carbonized biomass is used as raw material, kaolin-based geopolymer is used as inorganic binder, hydrogen peroxide with a mass concentration of 30% is used as foaming agent, and soap is used as foam stabilizer for stirring and mixing. After stirring and mixing, it is allowed to stand for 5-10 minutes and mixed again to obtain a fireproof and thermal insulation slurry, so that the fireproof and thermal insulation slurry has high porosity, excellent thermal insulation performance and mechanical properties, and the fire protection grade can reach Class A non-combustible, and its raw material source is abundant, the preparation process is simple, and the cost is low.

[0070] In step S7, the concrete slurry is prepared as follows: the concrete is prepared according to a concrete mix ratio with a strength grade of not less than C25, mixed with a forced mixer, allowed to stand for 5-10 minutes after mixing, and mixed again to obtain concrete slurry.

[0071] In the present invention, the force ratio of the steel mesh 11 to the concrete 12 is generally about 2.5:1-3.5:1, which is determined according to specific circumstances, including factors such as load-bearing capacity and service life, thereby having a higher load-bearing capacity and service life.

[0072] In the present invention, the number of the insulation cavities 21 can be two, four or six, which is determined specifically according to the stress conditions of the plate and the insulation volume required by the plate, which is convenient for operation and has good insulation performance.

Claims

1. A self-insulating, formwork-free prefabricated plate, comprising a prefabricated plate body (1), wherein the prefabricated plate body comprises a steel mesh (11) and concrete (12), and is characterized in that: A plurality of formwork-free boxes (2) made of pre-cured and solidified foamed geopolymer are encapsulated in the concrete, a plurality of heat-insulating cavities (21) are provided in the formwork-free boxes, and a fire-proof heat-insulating slurry (3) made of a biomass base is filled in the heat-insulating cavities. The prefabricated panel body, the formwork-free boxes, and the fire-proof heat-insulating slurry are cured and formed in an autoclave.

2. The self-insulating prefabricated board according to claim 1, characterized in that: The steel mesh is formed by binding and fixing a plurality of steel bars arranged in a crisscross pattern. The formwork-free box comprises a bottom box (22) and a cover plate (23). The cover plate is tightly mounted on the bottom box. The heat-insulating cavity is formed by the bottom box and the cover plate. A plurality of positioning holes (221) arranged corresponding to the corresponding steel bars are opened on the side wall of the bottom box. The formwork-free box is mounted on the steel mesh by steel bars passing through the positioning holes and is cast into a whole by concrete.

3. The self-insulating, mold-free prefabricated board according to claim 1, characterized in that: The mold-free box is prepared by polymerization reaction of an alkali activator, a foaming agent and a foam stabilizer, wherein the alkali activator is prepared by mixing metakaolin, NaOH particles and industrial water glass, the foaming agent is hydrogen peroxide with a mass concentration of 30%, and the foam stabilizer is soap.

4. The self-insulating prefabricated board material according to claim 1, characterized in that: The fireproof and thermal insulation slurry is prepared by polymerization reaction of carbonized biomass, an inorganic binder, a foaming agent and a foam stabilizer, wherein the inorganic binder is a metakaolin-based geopolymer, the foaming agent is hydrogen peroxide with a mass concentration of 30%, and the foam stabilizer is soap.

5. The self-insulating prefabricated board material according to claim 2, characterized in that: The bottom box and the cover plate are connected by mortise and tenon joints.

6. A method for preparing the self-insulating, mold-free prefabricated board according to claim 2, characterized in that: The steps include: S1. Making a mold-free box (2) S11, making a first mold and a second mold that are consistent with the appearance of the bottom box (22) and the cover plate (23); S12, pouring the geopolymer slurry to be foamed into the first mold and the second mold evenly coated with the release agent; S12, placing the first mold and the second mold filled with the geopolymer slurry into a pre-curing autoclave for pre-curing, wherein the temperature of the pre-curing steam is 65° C.-80° C. and the curing time is 3 h-5 h; S2, making a third mold (4) that is consistent with the shape of the prefabricated plate body (1), providing a reserved hole (41) on the side wall of the third mold for facilitating the insertion of steel bars into the mold, and evenly applying a release agent on the inner wall of the third mold; S3, taking the bottom box out of the first mold and placing it in the third mold; S4, passing the crisscrossed steel bars through the bottom box and the third mold and then tying them together to form a steel mesh (11); S5, prepare fireproof thermal insulation slurry (3), pour the fireproof thermal insulation slurry into the thermal insulation cavity of the mold-free box and ensure that the filling amount of the fireproof thermal insulation slurry is 86%-88% of the thermal insulation cavity; at the same time, make the fireproof thermal insulation slurry into 3 groups of test blocks with the same conditions, and use them for thermal insulation, mechanical and fireproof performance testing at different periods; S6. Put on the cover; S7. Pour the mixed concrete slurry horizontally into a third mold equipped with a steel mesh at a pouring temperature of 25°C-35°C. Simultaneously, prepare three groups of test blocks under the same conditions from the concrete slurry for compressive strength testing and demolding strength testing at different times. S8, vibrating The concrete slurry in the third mold is vibrated mechanically, and a vibrating rod is used as an auxiliary; S9, steaming After vibrating, the mixture is sent to the autoclave for steam curing. The pressure rise time of the autoclave is 100-120 minutes. The pressure in the autoclave rises to 1.1MPa-1.2MPa. The temperature in the autoclave is maintained at 180-200°C. After the autoclave is kept at constant temperature and pressure for 8-12 hours, the pressure is reduced. The pressure reduction time is 100-120 minutes. S10, demoulding finished product After steam curing, cool to room temperature and take out, and perform standard curing for 28 days. After demoulding, self-insulating and mold-free prefabricated panels can be obtained.

7. The method for preparing the self-insulating prefabricated board material according to claim 6, characterized in that: In step S2, a magnetic box (42) for fixing the third mold is bolted to the third mold.

8. The method for preparing the self-insulating, mold-free prefabricated board according to claim 6, characterized in that: In step S2, the release agent is silicone oil.

9. The method for preparing the self-insulating, mold-free prefabricated board according to claim 6, characterized in that: In step S5, the configuration process of the fireproof and thermal insulation slurry is as follows: carbonized biomass is used as raw material, kaolin-based geopolymer is used as inorganic binder, hydrogen peroxide with a mass concentration of 30% is used as foaming agent, and soap is used as foam stabilizer for stirring and mixing. After stirring and mixing, let it stand for 5-10 minutes, and mix again to obtain the fireproof and thermal insulation slurry.

10. The method for preparing the self-insulating prefabricated board without demoulding according to claim 6, characterized in that: In step S7, the concrete slurry is prepared as follows: the concrete is prepared according to a concrete mix ratio with a strength grade of not less than C25, mixed with a forced mixer, allowed to stand for 5-10 minutes after mixing, and mixed again to obtain concrete slurry.

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