Concrete decorative plate and preparation method thereof
Technical Field
The invention relates to a concrete decorative plate and a preparation method thereof.
Background
In the prior art, particularly in the decoration plates of public buildings, stone decoration plates are mainly used. However, the difficulty in the collection, transportation and processing of the stone is high, and the cost is high; and the stone belongs to non-renewable resources, and mining seriously damages the ecological environment. Therefore, concrete-based decorative panels are currently the subject of intensive research in the field of decorative panels. However, because the service environment of the concrete decorative plate is bad, the most main problems of the existing concrete decorative plate are that the durability is not ideal, and the problems of falling off, damage and the like are easy to occur, so that the performance of the concrete decorative plate is influenced.
Disclosure of Invention
Accordingly, there is a need for a concrete decorative panel having good durability and a method for manufacturing the same.
A concrete trim panel comprising:
the concrete structure layer comprises raw materials of ultrahigh-strength concrete and phase change energy storage particles, wherein the mass ratio of the phase change energy storage particles to the ultrahigh-strength concrete is 2-10%;
the interface layer is of a net structure and is arranged on the concrete structure layer; and
the decorative layer is arranged on the interface layer, and the raw materials of the decorative layer comprise, by weight, 300-550 parts of cement, 700-950 parts of 20-40-mesh quartz sand, 240-310 parts of 40-70-mesh quartz sand, 15-22 parts of a water reducing agent, 0.1-0.7 part of cellulose ether and 190-240 parts of water.
The concrete decorative plate adopts the concrete structure layer, the interface layer and the graded decorative layer, so that the strength of the concrete decorative plate is improved, the thickness of the concrete decorative plate is further reduced, and the thickness of the concrete decorative plate can be smaller than 2 cm. The phase change energy storage particles are added into the concrete, so that the formed concrete structure layer can absorb heat through phase change through the phase change energy storage particles when the temperature is higher, and the phase change particles can release heat through the phase change process when the temperature is lower, so that the cold and heat resistance of the phase change particles is improved, and the durability of the phase change particles is further improved. The concrete decorative plate is particularly suitable for indoor use, thereby playing a role of keeping the room temperature constant and improving the comfort level. In addition, the decorative layer and the concrete structure layer are solidified, connected and fastened, the problem that the decorative layer is easy to crack and peel off under the severe environment caused by different thermal expansion coefficients between layers is avoided, the strength of the concrete decorative plate is further improved, the breakage rate of the concrete decorative plate is reduced, the durability of the concrete decorative plate is further improved, the thickness of the concrete decorative plate is reduced, the later maintenance workload can be effectively reduced, and the cost is reduced.
In one embodiment, the raw materials of the decorative layer comprise 290-330 parts by weight of 325-mesh quartz sand.
In one embodiment, the raw materials of the decoration layer comprise 2-8 parts by weight of phase change energy storage particles.
In one embodiment, the interface layer is at least one of a fiber mesh cloth and a steel mesh.
In one embodiment, the concrete structure layer is 3-8 mm, and the thickness of the decorative layer is 3-5 mm.
A preparation method of a concrete decorative plate comprises the following steps:
mixing and pouring raw materials of a decorative layer into a mold, wherein the raw materials of the decorative layer comprise, by weight, 300-550 parts of cement, 700-950 parts of 20-40-mesh quartz sand, 240-310 parts of 40-70-mesh quartz sand, 15-22 parts of a water reducing agent, 0.1-0.7 part of cellulose ether and 190-240 parts of water;
arranging an interface layer on the raw material of the decorative layer, wherein the interface layer is of a net structure;
pouring raw materials of a concrete structure layer into a mould and pouring the raw materials on the interface layer, wherein the raw materials of the concrete structure layer comprise ultrahigh-strength concrete and phase-change energy storage particles, and the mass ratio of the phase-change energy storage particles to the ultrahigh-strength concrete is 2-10%;
and curing and removing the mould to obtain the concrete decorative plate.
The preparation method of the concrete decorative plate is simple, and the thicknesses of the decorative layer and the concrete structure layer are easy to control. The obtained concrete decorative plate has high strength, and the thickness of the concrete decorative plate can be further reduced. The phase change energy storage particles are added into the concrete, so that the formed concrete structure layer can absorb heat through phase change through the phase change energy storage particles when the temperature is higher, and the phase change particles can release heat through the phase change process when the temperature is lower, so that the cold and heat resistance of the phase change particles is improved, and the durability of the phase change particles is further improved. In addition, the decorative layer and the concrete structure layer are solidified, connected and fastened, so that the problem that the decorative layer is easy to crack and peel in a severe environment caused by different thermal expansion coefficients between layers is solved, the strength of the concrete decorative plate is further improved, the breakage rate of the concrete decorative plate is reduced, and the durability of the concrete decorative plate is further improved.
In one embodiment, the method further comprises a pretreatment step of coating the inner wall of the mold with a release agent and drying.
In one embodiment, the raw materials of the decorative layer comprise 290-330 parts by weight of 325-mesh quartz sand.
In one embodiment, the raw materials of the decoration layer comprise 2-8 parts by weight of phase change energy storage particles.
In one embodiment, the interface layer is at least one of a fiber mesh cloth and a steel mesh.
Drawings
Fig. 1 is a flowchart of a method of manufacturing a concrete decorative panel according to an embodiment.
Detailed Description
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
The invention provides a concrete decorative board of an embodiment. The concrete decorative plate comprises a concrete structure layer, an interface layer and a decorative layer.
The raw materials of the concrete structure layer comprise concrete and phase change energy storage particles. The mass ratio of the phase change energy storage particles to the concrete is 2-10%. The phase change energy storage particles are added into the concrete, so that the formed concrete structure layer can absorb heat through phase change energy storage particles when the temperature is higher, and the phase change particles can release heat through the phase change process when the indoor temperature is lower, so that the cold and heat resistance of the phase change particles is improved, and the durability of the phase change particles is further improved. The concrete decorative plate is particularly suitable for indoor use, thereby playing a role of keeping the room temperature constant and improving the comfort level. In addition, the mass content of the phase change energy storage particles needs to be strictly controlled, and the influence on the strength of a concrete structure layer caused by excessive addition is avoided. More preferably, the mass ratio of the phase change energy storage particles to the concrete is 3-7%.
Preferably, the water absorption rate of the high molecular water-absorbent resin is 300-500 times.
In another embodiment, the raw material of the concrete structure layer further comprises a high molecular water-absorbent resin. The mass ratio of the high molecular water-absorbing resin to the concrete is 2-5%. The high-molecular water-absorbent resin is added into the concrete, so that the formed concrete structure layer can absorb a large amount of moisture in a relatively high-humidity or water environment, the moisture can be kept from flowing outwards, the moisture in the environment can be increased in a relatively dry environment, and the durability of the concrete decorative plate is improved. The concrete decorative plate is particularly suitable for indoor use, so that indoor humidity can be well adjusted, and the comfort level is improved. More preferably, the mass ratio of the high-molecular water-absorbent resin to the concrete is 2.5% to 3.5%. Preferably, the high molecular water-absorbent resin is subjected to water soaking treatment, so that the high molecular water-absorbent resin is in a water absorption balance state, and the problems that the performance of concrete is influenced or a concrete structure layer is cracked due to water absorption volume expansion and the like caused by combination of the dry high molecular water-absorbent resin and water in the concrete are solved. More preferably, the time for soaking in water is 0.5-2 h.
In yet another embodiment, the raw materials of the concrete structural layer further comprise lightweight aggregate. The mass ratio of the lightweight aggregate to the concrete is 2-10%. The lightweight aggregate is added into the concrete, so that the dead weight of the formed concrete structure layer is reduced, the portability of the concrete decorative plate is improved, the problems of falling, damage and the like caused by dead weight are avoided, and meanwhile, the lightweight aggregate also has a sound insulation effect. More preferably, the mass ratio of the lightweight aggregate to the concrete is 3% to 7%. Preferably, the lightweight aggregate is at least one of vitrified microbeads and polyphenyl particles. More preferably, the particle size of the lightweight aggregate is 40-70 meshes.
The concrete decorative plate combines multiple aspects of water resistance, heat resistance, self weight reduction and the like, and improves the durability. The concrete decorative plate is particularly suitable for indoor decoration, and can greatly improve the indoor comfort level.
Preferably, the concrete is ultrahigh-strength concrete, and the concrete structure layer is an ultrahigh-strength concrete structure layer, so that the concrete has better mechanical property and weather resistance. Concrete with a compressive strength grade of C100 and above is considered by the industry as ultra-high strength concrete. On one hand, the ultrahigh-strength concrete has high strength and high compactness, so that the fracture rate of the phase change energy storage particles can be reduced, and the phase change material in the phase change energy storage particles can be prevented from leaking even if the phase change energy storage particles are fractured; on the other hand, the ultrahigh-strength concrete has certain viscosity, cellulose ether does not need to be added to improve the viscosity, and the ultrahigh-strength concrete and the phase change energy storage particles are directly mixed, so that the phase change energy storage particles can be prevented from floating upwards, and the uniform dispersion of the ultrahigh-strength concrete in a concrete structure layer is further ensured. Preferably, the concrete structure layer is 3-8 mm.
Preferably, the phase change energy storage particles are phase change microcapsules. The interface layer is a net structure and is arranged on the concrete structure layer. The interface layer can enhance the strength of the concrete decorative plate, and further can reduce the thickness of the concrete decorative plate. In addition, the interface layer is of a net structure, so that the concrete structure layer can be connected with the decorative layer.
Preferably, the interface layer is at least one of a fiber mesh cloth and a reinforcing mesh.
The decorative layer is arranged on the interface layer. The decoration layer comprises, by weight, 300-550 parts of cement, 700-950 parts of 20-40-mesh quartz sand, 240-310 parts of 40-70-mesh quartz sand, 15-22 parts of a water reducing agent, 0.1-0.7 part of cellulose ether and 190-240 parts of water. The example of the quartz sand of 20-40 meshes is the quartz sand with a sieving granularity, that is, the quartz sand with a particle size capable of passing through the sieve pores of a sieve with 20-40 meshes.
The decorative layer obtained by grading the raw materials of the decorative layer has high strength, and the cellulose ether can improve the binding power and the water retention performance among the components of the decorative layer, thereby playing the roles of preventing cracking and bleeding. In addition, the decorative layer and the concrete structure layer are solidified, connected and fastened, the problem that the decorative layer is easy to crack and peel off under the severe environment caused by different thermal expansion coefficients between layers is avoided, the strength of the concrete decorative plate is further improved, the breakage rate of the concrete decorative plate is reduced, the durability of the concrete decorative plate is further improved, the thickness of the concrete decorative plate is reduced, the later maintenance workload can be effectively reduced, and the cost is reduced.
More preferably, the raw materials of the decorative layer comprise, by weight, 350-500 parts of cement, 750-850 parts of 20-40 mesh quartz sand, 250-290 parts of 40-70 mesh quartz sand, 16-18 parts of a water reducing agent, 0.4-0.6 part of cellulose ether and 190-220 parts of water. The example of the quartz sand of 20-40 meshes is the quartz sand with a sieving granularity, that is, the quartz sand with a particle size capable of passing through the sieve pores of a sieve with 20-40 meshes.
Preferably, the cement is white cement.
Preferably, the water reducing agent is a polycarboxylic acid water reducing agent.
Preferably, the raw materials of the decorative layer comprise 290-330 parts by weight of 325-mesh quartz sand. The graded quartz sand of 20-40 meshes of quartz sand, 40-70 meshes of quartz sand and 325 meshes of quartz sand is adopted, so that the close packing of mortar components is facilitated, and higher mechanical strength can be obtained according to a close packing theory. And secondly, the quartz sand with the three types of particle size ranges not only has good mechanical property, but also has low economic cost. More preferably, the 325-mesh quartz sand is 300-310 parts.
Preferably, the raw materials of the decorative layer comprise 2-8 parts by weight of phase change energy storage particles. Thus, the cold and heat resistance of the concrete decorative plate and the constant room temperature can be further enhanced. In addition, the graded decorative layer has high strength and high compactness, can reduce the fracture rate of the phase change energy storage particles, and can avoid the leakage of the phase change material in the phase change energy storage particles even if the phase change energy storage particles are fractured; and the cellulose ether in the decorative layer can improve the viscosity of the decorative layer, and then can prevent the phase change energy storage particles from floating upward, and ensure that the phase change energy storage particles are uniformly dispersed in the decorative layer. More preferably, the phase change energy storage particles are 3-5 parts. More preferably, the particle size range of the phase change energy storage particles is 20-40 meshes. The phase change energy storage particles in the particle size range are the same as the quartz sand with the maximum particle size, so that the phase change microcapsules can be prevented from being broken under stress during stirring.
In another embodiment, the raw material of the decorative layer further comprises 2-8 parts by weight of a high molecular water-absorbent resin.
In another embodiment, the raw materials of the decorative layer further comprise 2-8 parts by weight of lightweight aggregate. So can reduce the dead weight of concrete decorative board and strengthen the sound insulation effect of concrete decorative board. More preferably, the lightweight aggregate is 3-5 parts.
Preferably, the raw materials of the decorative layer comprise 0.2-5 parts by weight of pigment. The appearance selection of the decorative layer can be enriched by adding the pigment. The addition of cellulose ether can improve the coloring performance of the pigment to the decorative layer. More preferably, the pigment is 0.2 to 5 parts.
Preferably, the thickness of the decorative layer is 3-5 mm.
The concrete decorative plate adopts the concrete structure layer, the interface layer and the graded decorative layer, so that the strength of the concrete decorative plate is improved, the thickness of the concrete decorative plate is further reduced, and the thickness of the concrete decorative plate can be smaller than 2 cm. The phase change energy storage particles are added into the concrete, so that the formed concrete structure layer can absorb heat through phase change through the phase change energy storage particles when the temperature is higher, and the phase change particles can release heat through the phase change process when the temperature is lower, so that the cold and heat resistance of the phase change particles is improved, and the durability of the phase change particles is further improved. The concrete decorative plate is particularly suitable for indoor use, thereby playing a role of keeping the room temperature constant and improving the comfort level. In addition, the decorative layer and the concrete structure layer are solidified, connected and fastened, the problem that the decorative layer is easy to crack and peel off under the severe environment caused by different thermal expansion coefficients between layers is avoided, the strength of the concrete decorative plate is further improved, the breakage rate of the concrete decorative plate is reduced, the durability of the concrete decorative plate is further improved, the thickness of the concrete decorative plate is reduced, the later maintenance workload can be effectively reduced, and the cost is reduced.
The concrete decorative plate is particularly suitable for decorating the hanging plate.
Referring to fig. 1, the present invention further provides a method for manufacturing the concrete decorative panel, including the following steps.
And step S1, coating a release agent on the inner wall of the mold and drying. Step S1 is a preprocessing step of the mold.
Thus being beneficial to the demoulding of the subsequent concrete decorative plate. If the step S2 is performed without waiting for the release agent to dry, the release agent may float upward, which may affect smooth release and the strength of the concrete decorative panel.
Preferably, the mould is a PVC plastic sheet.
Step S2, mixing and pouring the raw materials of the decoration layer into a mold, wherein the raw materials of the decoration layer comprise, by weight, 300-550 parts of cement, 700-950 parts of 20-40-mesh quartz sand, 240-310 parts of 40-70-mesh quartz sand, 15-22 parts of a water reducing agent, 0.1-0.7 part of cellulose ether and 190-240 parts of water.
The prepared decorative layer has the effect of the fair-faced concrete, is plain and elegant and has a good decorative effect.
Preferably, the raw materials of the decorative layer comprise 290-330 parts by weight of 325-mesh quartz sand.
Preferably, the raw materials of the decorative layer comprise 2-8 parts by weight of phase change energy storage particles. In another embodiment, the raw material of the decorative layer further comprises 2-8 parts by weight of a high molecular water-absorbent resin. In another embodiment, the raw materials of the decorative layer further comprise 2-8 parts by weight of lightweight aggregate.
Preferably, the raw materials of the decorative layer comprise 0.2-5 parts by weight of pigment.
And step S3, arranging an interface layer on the raw material of the decoration layer, wherein the interface layer is of a net structure.
Preferably, the interface layer is at least one of a fiber mesh cloth and a reinforcing mesh. More preferably, the interface layer is a crack-resistant fiber mesh cloth.
And S4, pouring the raw materials of the concrete structure layer into the mold and pouring the raw materials on the interface layer, wherein the raw materials of the concrete structure layer comprise concrete and phase change energy storage particles, and the mass ratio of the phase change energy storage particles to the concrete is 2-10%.
In another embodiment, the raw material of the concrete structure layer further comprises a high molecular water-absorbent resin. The mass ratio of the high molecular water-absorbing resin to the concrete is 2-5%. In yet another embodiment, the raw materials of the concrete structural layer further comprise lightweight aggregate. The mass ratio of the lightweight aggregate to the concrete is 2-10%.
And step S5, curing, and removing the mold to obtain the concrete decorative plate.
It is understood that step S1 may be omitted.
The preparation method of the concrete decorative plate is simple, and the thicknesses of the decorative layer and the concrete structure layer are easy to control. The obtained concrete decorative plate has high strength, and the thickness of the concrete decorative plate can be further reduced. The phase change energy storage particles are added into the concrete, so that the formed concrete structure layer can absorb heat through phase change through the phase change energy storage particles when the temperature is higher, and the phase change particles can release heat through the phase change process when the temperature is lower, so that the cold and heat resistance of the phase change particles is improved, and the durability of the phase change particles is further improved. In addition, the decorative layer and the concrete structure layer are solidified, connected and fastened, so that the problem that the decorative layer is easy to crack and peel in a severe environment caused by different thermal expansion coefficients between layers is solved, the strength of the concrete decorative plate is further improved, the breakage rate of the concrete decorative plate is reduced, and the durability of the concrete decorative plate is further improved.
The following are specific examples.
Example 1
The concrete decorative plate comprises a concrete structure layer, an interface layer and a decorative layer which are arranged in sequence.
The concrete structure layer comprises the raw materials of ultra-high-strength concrete and phase-change microcapsules, wherein the mass ratio of the phase-change microcapsules to the ultra-high-strength concrete is 3%. The interface layer is anti-crack fiber gridding cloth. The decoration layer comprises, by weight, 350 parts of white cement, 750 parts of 20-40-mesh quartz sand, 250 parts of 40-70-mesh quartz sand, 300 parts of 325-mesh quartz sand, 16 parts of a water reducing agent, 0.4 part of cellulose ether, 3 parts of phase-change microcapsules, 0.9 part of pigment and 190-240 parts of water.
The preparation method of the concrete decorative plate comprises the following steps:
PVC plastic sheets are used as moulds, and release agents are uniformly sprayed on the inner walls of the moulds. Mixing the raw materials of the decorative layer in a stirrer, pouring into a mold after stirring, wherein the pouring thickness is 3mm, and vibrating and paving. And laying the interface layer on the raw material of the decorative layer. Mixing the raw materials of the concrete structure layer in a stirrer, pouring the mixture on the interface layer after stirring, wherein the pouring thickness is 4mm, and vibrating and paving the mixture. Curing, curing and removing the mould to obtain the concrete decorative plate with the fair-faced finish.
Example 2
The concrete decorative plate comprises a concrete structure layer, an interface layer and a decorative layer which are arranged in sequence.
The concrete structure layer comprises raw materials of ultra-high-strength concrete and phase-change microcapsules, wherein the mass ratio of the phase-change microcapsules to the ultra-high-strength concrete is 7%. The interface layer is a reinforcing mesh. The raw materials of the decorative layer comprise, by weight, 500 parts of white cement, 850 parts of 20-40-mesh quartz sand, 290 parts of 40-70-mesh quartz sand, 310 parts of 325-mesh quartz sand, 18 parts of a water reducing agent, 0.6 part of cellulose ether, 5 parts of phase-change microcapsules, 3 parts of pigment and 220 parts of water.
The preparation method of the concrete decorative plate comprises the following steps:
PVC plastic sheets are used as moulds, and release agents are uniformly sprayed on the inner walls of the moulds. Mixing the raw materials of the decorative layer in a stirrer, pouring the mixture into a mold after stirring, wherein the pouring thickness is 4mm, and vibrating and paving the mixture. And laying the interface layer on the raw material of the decorative layer. Mixing the raw materials of the concrete structure layer in a stirrer, pouring the mixture on the interface layer after stirring, wherein the pouring thickness is 5mm, and vibrating and paving the mixture. Curing, curing and removing the mould to obtain the concrete decorative plate with the fair-faced finish.
Example 3
The concrete decorative plate comprises a concrete structure layer, an interface layer and a decorative layer which are arranged in sequence.
The concrete structure layer comprises the raw materials of ultra-high-strength concrete and phase-change microcapsules, wherein the mass ratio of the phase-change microcapsules to the ultra-high-strength concrete is 10%. The interface layer is anti-crack fiber gridding cloth. The raw materials of the decorative layer comprise, by weight, 300 parts of white cement, 950 parts of 20-40-mesh quartz sand, 310 parts of 40-70-mesh quartz sand, 330 parts of 325-mesh quartz sand, 22 parts of a water reducing agent, 0.1 part of cellulose ether, 2 parts of phase-change microcapsules, 0.2 part of pigment and 190 parts of water.
The preparation method of the concrete decorative plate comprises the following steps:
PVC plastic sheets are used as moulds, and release agents are uniformly sprayed on the inner walls of the moulds. Mixing the raw materials of the decorative layer in a stirrer, pouring the mixture into a mold after stirring, wherein the pouring thickness is 5mm, and vibrating and paving the mixture. And laying the interface layer on the raw material of the decorative layer. Mixing the raw materials of the concrete structure layer in a stirrer, pouring the mixture on the interface layer after stirring, wherein the pouring thickness is 3mm, and vibrating and paving the mixture. Curing, curing and removing the mould to obtain the concrete decorative plate with the fair-faced finish.
Example 4
The concrete decorative plate comprises a concrete structure layer, an interface layer and a decorative layer which are arranged in sequence.
The concrete structure layer comprises the raw materials of ultra-high-strength concrete and phase-change microcapsules, wherein the mass ratio of the phase-change microcapsules to the ultra-high-strength concrete is 2%. The interface layer is a reinforcing mesh. The raw materials of the decorative layer comprise, by weight, 550 parts of white cement, 700 parts of 20-40-mesh quartz sand, 240 parts of 40-70-mesh quartz sand, 290 parts of 325-mesh quartz sand, 15 parts of a water reducing agent, 0.7 part of cellulose ether, 8 parts of phase-change microcapsules, 5 parts of pigment and 240 parts of water.
The preparation method of the concrete decorative plate comprises the following steps:
PVC plastic sheets are used as moulds, and release agents are uniformly sprayed on the inner walls of the moulds. Mixing the raw materials of the decorative layer in a stirrer, pouring into a mold after stirring, wherein the pouring thickness is 3mm, and vibrating and paving. And laying the interface layer on the raw material of the decorative layer. Mixing the raw materials of the concrete structure layer in a stirrer, pouring the mixture on the interface layer after stirring, wherein the pouring thickness is 8mm, and vibrating and paving the mixture. Curing, curing and removing the mould to obtain the concrete decorative plate with the fair-faced finish.
Example 5
Example 5 is substantially the same as example 1 except that the raw material of the decorative layer does not contain phase change microcapsules.
Example 6
The raw materials and the preparation method of the concrete structure layer are basically the same as those of the example 1, except that the raw materials of the concrete structure layer further comprise high-molecular water-absorbent resin and vitrified micro bubbles, the mass ratio of the high-molecular water-absorbent resin to the ultra-high-strength concrete is 2.5%, and the mass ratio of the vitrified micro bubbles to the ultra-high-strength concrete is 3%. The raw materials of the decorative layer also comprise 3 parts of high-molecular water-absorbing resin and 4 parts of vitrified micro bubbles according to parts by weight.
Comparative example 1
The concrete decorative panel of comparative example 1, which was composed of only a concrete structural layer, was prepared in the same manner as in example 1 using the same raw materials, and had a concrete floor tile thickness of 10 mm.
Comparative example 2
The concrete decorative panel of comparative example 2 is substantially the same as example 1 except that neither the raw material of the concrete structure layer nor the raw material of the decorative layer contains phase change microcapsules.
The concrete decorative sheets obtained in examples 1 to 6 had a compressive strength of about 50MPa for 28 days. The concrete decorative panel obtained in comparative example 1 had a 28-day compressive strength of about 40MPa, and the concrete decorative panel obtained in comparative example 2 had a 28-day compressive strength of about 45 MPa. Therefore, the concrete decorative plate obtained by the embodiment of the invention has the advantages of thin thickness and high compressive strength.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.