Basic magnesium sulfate cement concrete civil air defense door leaf and preparation method

Abstract

The invention provides a basic magnesium sulfate cement concrete civil air defense door leaf which comprises a door leaf body, the door leaf body comprises a steel plate outer frame and a door leaf inner layer structure, the door leaf inner layer structure comprises fiber nets and a reinforcing mesh, the fiber nets are attached to the inner wall of the steel plate outer frame, the reinforcing mesh is arranged between the inner fiber net and the outer fiber net, and a concrete filling layer is poured in the reinforcing mesh. The concrete filling layer comprises a basalt rock particle layer and a basic magnesium sulfate cement concrete layer; a reserved operation hole is formed in the outer side face of the door leaf, and a plugging cover is arranged on the reserved operation hole. The basic magnesium sulfate cement concrete comprises magnesium oxide, an additive, 0.5-8 whiskers, magnesium sulfate, a filler, sand and water. The invention further provides a preparation method of the basic magnesium sulfate cement concrete civil air defense door leaf. The prepared basic magnesium sulfate cement concrete civil air defense door leaf is good in corrosion resistance, long in service life and high in impact resistance, and the door leaf can be rapidly repaired through grouting after being impacted and damaged.

Description

Technical Field

[0001] The invention belongs to the technical field of civil air defense doors, and relates to a basic magnesium sulfate cement concrete civil air defense door leaf and a preparation method thereof. Background Art

[0002] The structural strength and resistance performance of civil air defense doors are mainly determined by the design strength and reliability of components such as door leaves, locking mechanisms, hinge mechanisms and door frames, among which the material selection and structural form of the door leaves play a major decisive role.

[0003] When the door leaf is damaged, the blast wave impact of nuclear weapons or conventional weapons is usually an extremely short-term ultra-high pressure process. As the main wave-facing component, the structural design of the door leaf of the civil air defense door needs to make the internal stress of the door leaf evenly distributed, avoid the dangerous points of excessive local stress, and maximize the mechanical properties of the material, so as to ensure that the civil air defense door has a high impact resistance. Civil air defense door leaves are usually made of high-strength steel to withstand shock waves and explosion pressure.

[0004] Civil defense doors are doors for the entrance and exit of protective projects, and belong to civil defense protection equipment. The door leaves of existing civil defense doors are usually made of ordinary concrete or a combination of ordinary concrete and steel structure. The disadvantages of such civil defense doors are also obvious, with poor impact resistance and short service life. Therefore, the present invention proposes a basic magnesium sulfate cement concrete civil defense door leaf and a preparation method to solve the above problems. Summary of the invention

[0005] In order to overcome the problems existing in the prior art, the present invention provides a basic magnesium sulfate cement concrete civil air defense door leaf and a preparation method, which is simple to manufacture and has strong impact resistance. After being impacted by a shock wave, the door leaf can absorb energy through the crushing of concrete blocks. After being damaged, the door leaf can be quickly repaired by grouting, which can effectively solve the problems in the background technology.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] (1) The present invention provides a basic magnesium sulfate cement concrete civil air defense door leaf, characterized in that it comprises a door leaf, the door leaf comprises a hollow steel plate outer frame and a door leaf inner layer structure; the door leaf inner layer structure is arranged inside the steel plate outer frame, and comprises a fiber mesh and a steel mesh, the fiber mesh is attached to the inner wall of the steel plate outer frame, the steel mesh is arranged between the inner and outer fiber meshes, and a concrete filling layer is cast in the steel mesh; the concrete filling layer comprises a basalt rock particle layer and a basic magnesium sulfate cement concrete layer.

[0008] Furthermore, the basic magnesium sulfate cement concrete in the basic magnesium sulfate cement concrete layer is composed of the following components in parts by weight: 20-22 parts of magnesium oxide, 2-3 parts of admixture, 1-5 parts of 5.1.8 whiskers, 10-12 parts of magnesium sulfate, 5-8 parts of filler, 30-35 parts of sand, and 30-40 parts of water; wherein the admixture is a mixture of one or more of sodium dihydrogen phosphate, sodium monohydrogen phosphate, and trisodium phosphate, and the 5.1.8 whiskers are 5Mg(OH) 2 MgCl 2 8H 2 O, with an aspect ratio of 42-120 and a purity of not less than 95%.

[0009] Furthermore, in the basic magnesium sulfate cement concrete, the weight percentage of 5·1·8 whiskers is preferably 2-5 parts.

[0010] Furthermore, the preparation method of the 5·1·8 whisker is: MgO, MgCl 2 6H 2 O and water are mixed evenly, MgO, MgCl 2 6H 2 The molar ratio of O and water was 0.1:1:13; KH 2 PO 4 , KH 2 PO 4 The added mass is 2-4% of the added mass of MgO, and the mixture is mixed evenly; the mixture is encapsulated in a reaction container, and the reaction container is placed in a 30°C constant temperature water bath shaker and shaken for 12 hours. After the reaction is completed, the product is rinsed with deionized water, dispersed in anhydrous ethanol, and naturally dried to obtain 5·1·8 whiskers.

[0011] Furthermore, the preparation method of the basic magnesium sulfate cement concrete is: pour magnesium sulfate heptahydrate into water to fully dissolve it to obtain a magnesium sulfate solution, then dissolve the weighed admixture in the magnesium sulfate solution, then add 5·1·8 whiskers, fillers and sand, and finally add magnesium oxide to the solution, stir evenly to obtain basic magnesium sulfate cement mortar.

[0012] Furthermore, the magnesium oxide is one or both of calcined magnesite powder and calcined dolomite powder; the magnesium sulfate is magnesium sulfate heptahydrate; the filler is one or both of fly ash, silica ash, slag, sawdust, gypsum powder, dolomite powder and shale powder; the sand is one or both of river sand, lake sand, mountain sand, desalinated sea sand, machine-made sand and mixed sand.

[0013] Furthermore, the outer side surface of the door leaf is provided with at least one reserved operating hole, the reserved operating hole is connected with the gap between the steel plate outer frame and the inner structure of the door leaf, and a blocking cover is provided outside the reserved operating hole, and the blocking cover is threadedly connected to the door leaf.

[0014] Furthermore, an anti-accidental opening device is provided on one side of the door leaf; the anti-accidental opening device includes a handle, a turntable and a pointer; the damping shaft is vertically arranged on one side surface of the door leaf, the turntable and the handle are fixedly connected to the damping shaft, and the handle is distributed on the outside of the turntable; the pointer is fixed on the turntable, and a digital number is provided on the surface of the door leaf, and the pointer can be made to correspond to the position of the digital number by rotating the turntable; the turntable is a circular disk with a notch on one side, and the distance between the handle and the edge of the door leaf is less than the diameter of the circular disk; when the turntable is rotated so that its notch is rotated to near the edge of the door leaf, the turntable does not extend beyond the edge of the door leaf, and the door leaf can be opened, and when the turntable is rotated so that its non-notch is rotated to near the edge of the door leaf, the turntable extends beyond the edge of the door leaf, is fixedly connected to the card slot on the other door leaf, and the door leaf is closed.

[0015] Furthermore, the fiber mesh is a 3D woven fiber mesh, woven with basalt fibers; the thickness range of the 3D woven fiber mesh is 15-45 mm, and the spatial grid size of the 3D woven fiber mesh is 4-8 mm×4-8 mm.

[0016] Furthermore, a door shaft installation groove is provided on one side of the door leaf; and a plurality of annular reinforcing rib plates and radial reinforcing rib plates are provided on both side surfaces of the door leaf.

[0017] (II) The present invention also provides a method for preparing a basic magnesium sulfate cement concrete civil air defense door leaf, comprising the following steps:

[0018] Step S1, placing the door leaf template;

[0019] Step S2, applying lubricant to the bottom surface of the door leaf template;

[0020] Step S3, laying the fiber mesh in the area surrounded by the door leaf template;

[0021] Step S4, preparing basic magnesium sulfate cement concrete;

[0022] Step S5, pouring basic magnesium sulfate cement concrete, vibrating continuously to expel bubbles, and pouring until the bottom fiber mesh is covered;

[0023] Step S6, laying the steel mesh on the mesh layer of the bottom fiber mesh, and continuing to pour basic magnesium sulfate cement concrete to 2 / 3 of the height of the steel mesh;

[0024] Step S7, pre-filling 20-50 mm basalt rock particle coarse aggregate on the mortar surface at 2 / 3 of the height of the steel mesh, laying the top fiber mesh on the steel mesh, and continuing to pour basic magnesium sulfate cement concrete until the top fiber mesh is covered, and continuously vibrating to expel bubbles;

[0025] Step S8, smoothing, standing for 24 hours to allow the concrete to solidify, removing it from the door leaf template after solidification, and then sprinkling water on the door leaf for natural curing for 28 days to obtain the inner layer of the civil air defense door leaf;

[0026] Step S9, place the steel plate outer frame on the ground, open the cover plate on the outer side of the steel plate outer frame, then put the inner layer of the civil air defense door leaf into the steel plate outer frame, and then weld the cover plate to the steel plate outer frame;

[0027] Step S10, open the reserved operation hole, and pour the basic magnesium sulfate cement concrete into the inner part of the steel plate outer frame by a grouting machine, and the air inside the steel plate outer frame is discharged through another reserved operation hole. After the pouring is completed, let it stand for 24 hours, and then use a blocking cover to close the reserved operation hole;

[0028] Step S11: If the inner layer of the civil air defense door leaf is shattered after absorbing the shock wave, repeat step 10 when repairing it after the damage.

[0029] The beneficial effects of the present invention are:

[0030] 1. The basic magnesium sulfate cement concrete civil air defense door leaf prepared by the present invention has good corrosion resistance, long service life, strong impact resistance, and can absorb energy through the crushing of concrete blocks after being impacted by shock waves. After the door leaf is damaged, it can be quickly repaired by grouting;

[0031] 2. The basic magnesium sulfate cement concrete in the present invention is a new type of concrete material, which has the advantages of fast setting, early strength, high strength, high bending resistance, high toughness, etc.; the present invention adopts 3D woven basalt fiber, and uses 3D woven basalt fiber as a pulling and connecting component, which has the function of three-dimensional directional continuous constraint, aggregates and fixes the filler, makes the filler dense inside, and has the effect of strengthening and toughening the bending and tensile resistance of the basic magnesium sulfate cement mortar;

[0032] 3. In the present invention, a 3D woven basalt fiber reinforced magnesium sulfate cement mortar structure is used on the wave-facing surface of the door leaf, which can significantly improve the anti-penetration protection of the door body and reduce the additional damage caused by penetration of the engineering structure; the back wave surface also adopts a 3D woven basalt fiber and magnesium sulfate cement mortar structure to reduce the damage caused by earthquake collapse and inhibit the crushing and spalling of the civil air defense door concrete during explosion; in the present invention, 20-50mm basalt rock particles are pre-filled when casting the steel mesh, which can enhance the explosion resistance of the civil air defense door.

[0033] 4. The present invention adopts 5·1·8 whiskers as a basic magnesium sulfate cement mortar made of an admixture. The whiskers can not only provide in-situ growth points and induce crystal nucleus hydration, but also have mechanical strength and good toughness. In the cement slurry, they can better contact with the raw materials, react more fully, and connect more tightly, which plays a role in strengthening and toughening. It will increase the heat release rate of basic magnesium sulfate cement hydration, shorten its induction period, and have a significant improvement effect on the early compressive strength and water resistance of cement, further improving its early strength. At the same time, adding whiskers can improve its internal structure, generate more main strength phases, and make the internal structure have higher mechanical strength and compactness. The compact internal structure is more resistant to the erosion of external water, and the water resistance is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of the structure of the basic magnesium sulfate cement concrete civil air defense door leaf of the present invention;

[0035] Figure 2 A top view of the door leaf of a basic magnesium sulfate cement concrete civil air defense door;

[0036] Figure 3 for Figure 2 A partial enlarged schematic diagram in the middle;

[0037] Figure 4 is a schematic diagram of the structure of the fiber web;

[0038] Figure 5 The present invention is a flow chart of the method for preparing the basic magnesium sulfate cement concrete civil air defense door leaf;

[0039] Figure 6 This is the SEM image of the 5·1·8 whisker prepared in Example 1;

[0040] Figure 7 The compressive strength test results of the inner layer structure of the door leaf prepared in Examples 1 to 4;

[0041] Figure 8 The softening coefficient test results of the inner layer structure of the door leaf prepared in Examples 1 to 4;

[0042] Fig. 9 Schematic diagram of the device for preventing accidental opening of the present invention.

[0043] The symbols in the accompanying drawings are:

[0044] 1. Door axis installation groove; 2. Reserved operation hole; 3. Door leaf; 31. Steel plate frame; 32. Fiber mesh; 33. Steel mesh; 34. Concrete filling layer; 4. Annular reinforcing rib plate; 5. Radial reinforcing rib plate; 6. Digital label; 7. Turntable; 8. Handle; 9. Pointer; 10. Damping shaft. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0046] Example 1

[0047] like Figures 1 to 3 As shown, the present invention provides a basic magnesium sulfate cement concrete civil air defense door leaf, including a door leaf 3, wherein the door leaf 3 includes a hollow steel plate outer frame 31 and a door leaf inner layer structure; the door leaf inner layer structure is arranged inside the steel plate outer frame 31, including a fiber mesh 32 and a steel mesh 33, the fiber mesh 32 is attached to the inner wall of the steel plate outer frame 31, the steel mesh 33 is arranged between the inner and outer fiber meshes 32, and a concrete filling layer 34 is cast in the steel mesh 33; the concrete filling layer 34 includes a basalt rock particle layer and a basic magnesium sulfate cement concrete layer.

[0048] like Figure 1 As shown, two reserved operation holes 2 are provided on the upper part of the outer side of the door leaf 3, the reserved operation holes 2 are connected to the gap between the steel plate outer frame 31 and the inner layer structure of the door leaf, and a blocking cover is provided outside the reserved operation hole 2, and the blocking cover is threadedly connected to the door leaf 3. Basic magnesium sulfate cement concrete can be poured into the door leaf 3 through one reserved operation hole 2, and the air inside the steel plate outer frame 31 is discharged through the other reserved operation hole 2, thereby increasing the strength of the door leaf 3.

[0049] like Figure 4 As shown, the fiber mesh 32 is a 3D woven fiber mesh, woven with basalt fibers, the thickness range of the 3D woven fiber mesh is 45 mm, and the spatial grid size of the 3D woven fiber mesh is 8 mm×8 mm. Figure 1 As shown, a door shaft installation groove 1 is provided on one side of the door leaf 3, and the door leaf 3 can be hinged to the door frame structure through the door shaft installation groove 1. A plurality of annular reinforcing ribs 4 and radial reinforcing ribs 5 are provided on both sides of the door leaf 3. The plurality of annular reinforcing ribs 4 are concentrically distributed, and the radial reinforcing ribs 5 are connected to each annular reinforcing rib 4 at the same time.

[0050] like Fig. 9As shown, an anti-accidental opening device is provided on one side of the door leaf 3, and the anti-accidental opening device includes a handle 8, a turntable 7 and a pointer 9. A damping shaft 10 is vertically arranged on the surface of one side of the door leaf 3. The turntable 7 and the handle 8 are both fixedly connected to the damping shaft 10, and the handle 8 is distributed on the outside of the turntable 7. The pointer 9 is fixed on the turntable 7. A number mark 6 is provided on the surface of the door leaf 3 (the turntable 7 can be made of a transparent material). The pointer 9 can be made to correspond to the position of the number mark 6 by rotating the turntable 7. The turntable 7 is a circular disk with a notch on one side, and the distance between the handle 8 and the edge of the door leaf 3 is less than the diameter of the circular disk. The turntable 7 can be driven to rotate by the handle 8. When the turntable 7 is rotated so that the notch is rotated to the edge of the door leaf 3, the turntable 7 does not exceed the edge of the door leaf 3, that is, at this time, the turntable 7 will not hinder the rotation of the door leaf 3, and the door leaf 3 can be opened. When the rotating disk 7 is rotated so that the non-notch portion is rotated to the edge of the door leaf 3, the rotating disk 7 exceeds the edge of the door leaf 3 and is fixedly engaged with the card slot on the other door leaf 3, that is, the rotating disk 7 hinders the rotation of the door leaf 3 and the door leaf 3 is closed. Only when the pointer 9 is aligned with the set digital mark 6, the notch on the circular rotating disk 7 is flush with the edge of the door leaf 3, and the door leaf 3 can be opened.

[0051] In this embodiment, the basic magnesium sulfate cement concrete in the basic magnesium sulfate cement concrete layer is composed of the following components in parts by weight: 20 parts of magnesium oxide (light-burned magnesia ore), 2 parts of admixture (sodium dihydrogen phosphate), 5 parts of 5.1.8 whiskers, 10 parts of magnesium sulfate heptahydrate, 5 parts of filler (fly ash and silica fume), 30 parts of sand (machine-made sand) and 33 parts of water.

[0052] Among them, 5·1·8 whiskers are 5Mg(OH) 2 MgCl 2 8H 2 O, the purity of which is 95%, is prepared by: mixing MgO, MgCl 2 6H 2 O and water are mixed evenly, MgO, MgCl 2 6H 2 The molar ratio of O and water was 0.1:1:13; KH 2 PO 4 , KH 2 PO 4 The added mass is 2% of the added mass of MgO, and the mixture is mixed evenly; the mixture is sealed in a reaction container, and the reaction container is placed in a 30°C constant temperature water bath shaker and shaken for 12 hours. After the reaction is completed, the product is rinsed with deionized water, dispersed in anhydrous ethanol, and dried naturally to obtain 5·1·8 whiskers, see Figure 6 .

[0053] The preparation method of basic magnesium sulfate cement concrete is as follows: pour magnesium sulfate heptahydrate into water to fully dissolve it to obtain a magnesium sulfate solution, then dissolve the weighed admixture in the magnesium sulfate solution, then add 5·1·8 whiskers, fillers and sand, and finally add magnesium oxide into the solution, stir evenly to obtain basic magnesium sulfate cement mortar.

[0054] The preparation method of the above-mentioned basic magnesium sulfate cement concrete civil air defense door leaf is as follows: Figure 5 As shown, the following steps are included:

[0055] Step S1, placing the door leaf template;

[0056] Step S2, applying lubricant to the bottom surface of the door leaf template;

[0057] Step S3, laying the fiber mesh 32 in the area surrounded by the door leaf template;

[0058] Step S4, preparing basic magnesium sulfate cement concrete;

[0059] Step S5, pouring basic magnesium sulfate cement concrete, during which the concrete is continuously vibrated to expel air bubbles, and pouring the concrete until the bottom fiber mesh 32 is covered;

[0060] Step S6, laying the steel mesh 33 on the mesh layer of the bottom fiber mesh 32, and continuing to pour basic magnesium sulfate cement concrete to 2 / 3 of the height of the steel mesh 33;

[0061] Step S7, pre-fill 20 mm basalt rock particle coarse aggregate on the mortar surface at 2 / 3 of the height of the steel mesh 33, lay the top fiber mesh 32 on the steel mesh 33, and continue to pour basic magnesium sulfate cement concrete until it covers the top fiber mesh 32, and continuously vibrate to expel bubbles during the process;

[0062] Step S8, smoothing, standing for 24 hours to allow the concrete to solidify, removing it from the door leaf template after solidification, and then sprinkling water on the door leaf for natural curing for 28 days to obtain the inner layer structure of the civil air defense door leaf, recorded as JM-5;

[0063] Step S9, place the steel plate outer frame 31 on the ground, open the cover plate on the outer side of the steel plate outer frame 31, then put the inner layer structure of the civil air defense door leaf into the steel plate outer frame 31, and then weld the cover plate to the steel plate outer frame 31;

[0064] Step S10, open the two reserved operating holes 2, and pour the basic magnesium sulfate cement concrete into the interior of the steel plate outer frame 31 through a grouting machine. The air inside the steel plate outer frame 31 is discharged through another reserved operating hole 2. After the pouring is completed, let it stand for 24 hours, and then use a sealing cover to close the reserved operating hole 2, and the basic magnesium sulfate cement concrete civil defense door leaf is prepared.

[0065] When in use, the door leaf 3 is first impacted, and the concrete layer inside it absorbs energy and is shattered, which can effectively weaken the damage of the impact force. If the inner layer of the door leaf of the civil air defense door is shattered after absorbing the shock wave, when repairing after the damage, repeat step 10.

[0066] Example 2

[0067] This embodiment is basically the same as Embodiment 1, except that:

[0068] In this embodiment, the basic magnesium sulfate cement concrete in the basic magnesium sulfate cement concrete layer is composed of the following components in parts by weight: 20 parts of magnesium oxide (light-burned magnesia ore), 2 parts of admixture (sodium dihydrogen phosphate), 1 part of 5.1.8 whiskers, 10 parts of magnesium sulfate heptahydrate, 5 parts of filler (fly ash and silica fume), 30 parts of sand (machine-made sand) and 33 parts of water.

[0069] The inner layer structure of the basic magnesium sulfate cement concrete civil air defense door leaf prepared in this embodiment is denoted as JM-1.

[0070] Example 3

[0071] This embodiment is basically the same as Embodiment 1, except that:

[0072] In this embodiment, the basic magnesium sulfate cement concrete in the basic magnesium sulfate cement concrete layer is composed of the following components in parts by weight: 20 parts of magnesium oxide (light-burned magnesia ore), 2 parts of admixture (sodium dihydrogen phosphate), 3 parts of 5.1.8 whiskers, 10 parts of magnesium sulfate heptahydrate, 5 parts of filler (fly ash and silica fume), 30 parts of sand (machine-made sand) and 33 parts of water.

[0073] The inner layer structure of the basic magnesium sulfate cement concrete civil air defense door leaf prepared in this embodiment is denoted as JM-3.

[0074] Example 4

[0075] This embodiment is basically the same as Embodiment 1, except that:

[0076] In this embodiment, the basic magnesium sulfate cement concrete in the basic magnesium sulfate cement concrete layer is composed of the following components in parts by weight: 20 parts of magnesium oxide (light-burned magnesia ore), 2 parts of admixture (sodium dihydrogen phosphate), 0 parts of 5.1.8 whiskers, 10 parts of magnesium sulfate heptahydrate, 5 parts of filler (fly ash and silica fume), 30 parts of sand (machine-made sand) and 33 parts of water.

[0077] The inner layer structure of the basic magnesium sulfate cement concrete civil air defense door leaf prepared in this embodiment is denoted as JM-0.

[0078] Performance testing:

[0079] The compressive strength and water resistance of the inner layer structures of the basic magnesium sulfate cement concrete civil air defense door leafs JM-0, JM-1, JM-3 and JM-5 prepared in Examples 1 to 4 were tested.

[0080] Figure 7 , Figure 8 The effect of different whisker content on the compressive strength and water resistance of basic magnesium sulfate cement is shown in the figure. The 5·1·8 whiskers added in the test have a significant improvement on the initial compressive strength and water resistance of cement, and the improvement effect increases with the increase of whisker content. Figure 7 In the 1-day curing period, the compressive strength of JM-0 was 23MPa, while the compressive strength of JM-5 with 5g whisker addition reached 36.5MPa, with a 58.7% increase in compressive strength, a 37.86% increase in 3d strength, and a 16.58% increase in 28d strength. As the age increases, the improvement effect of whiskers gradually weakens. Figure 8 The softening coefficient of the JM-0 specimen at 30d is 0.21, while the softening coefficient of the JM-5 specimen at 28d reaches 0.404, and the softening coefficient increases by 92.38%.

[0081] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A basic magnesium sulfate cement concrete civil air defense door leaf, characterized in that: It comprises a door leaf (3), wherein the door leaf (3) comprises a hollow steel plate outer frame (31) and a door leaf inner layer structure; The inner layer structure of the door leaf is arranged inside the steel plate outer frame (31), and comprises a fiber mesh (32) and a steel mesh (33); the fiber mesh (32) is attached to the inner wall of the steel plate outer frame (31); the steel mesh (33) is arranged between the inner and outer fiber meshes (32); a concrete filling layer (34) is poured in the steel mesh (33); the concrete filling layer (34) comprises a basalt rock particle layer and a basic magnesium sulfate cement concrete layer.

2. The basic magnesium sulfate cement concrete civil air defense door leaf according to claim 1 is characterized in that: The basic magnesium sulfate cement concrete in the basic magnesium sulfate cement concrete layer is composed of the following components in parts by weight: 20-22 parts of magnesium oxide, 2-3 parts of admixture, 1-5 parts of 5.1.8 whiskers, 10-12 parts of magnesium sulfate, 5-8 parts of filler, 30-35 parts of sand, and 30-40 parts of water; Wherein, the additive is one or a mixture of sodium dihydrogen phosphate, sodium monohydrogen phosphate, and trisodium phosphate, and the 5·1·8 whisker is 5Mg(OH)2·MgCl2·8H2O, with an aspect ratio of 42-120 and a purity of not less than 95%.

3. The basic magnesium sulfate cement concrete civil air defense door leaf according to claim 2 is characterized in that: The preparation method of the 5·1·8 whisker is as follows: Mix MgO, MgCl2·6H2O and water evenly, and the molar ratio of MgO, MgCl2·6H2O and water is 0.1:1:13; Add KH2PO4, the added mass of KH2PO4 is 2-4% of the added mass of MgO, and mix well; The mixture was encapsulated in a reaction container, and the reaction container was placed in a 30°C constant temperature water bath shaker and shaken for 12 h. After the reaction was completed, the product was rinsed with deionized water, dispersed in anhydrous ethanol, and dried naturally to obtain 5·1·8 whiskers.

4. The basic magnesium sulfate cement concrete civil air defense door leaf according to claim 2 is characterized in that: The preparation method of the basic magnesium sulfate cement concrete is: Pour magnesium sulfate heptahydrate into water and fully dissolve it to obtain a magnesium sulfate solution, then dissolve the weighed admixture in the magnesium sulfate solution, then add 5.1.8 whiskers, fillers and sand, and finally add magnesium oxide to the solution, stir evenly to obtain basic magnesium sulfate cement mortar.

5. The basic magnesium sulfate cement concrete civil air defense door leaf according to claim 2 is characterized in that: The magnesium oxide is one or both of magnesite light-burned powder and dolomite light-burned powder; The magnesium sulfate is magnesium sulfate heptahydrate; The filler is one or two of fly ash, silica ash, slag, sawdust, gypsum powder, dolomite powder and shale powder; The sand is one or two of river sand, lake sand, mountain sand, desalinated sea sand, machine-made sand and mixed sand.

6. The basic magnesium sulfate cement concrete civil air defense door leaf according to claim 1, characterized in that: The outer side surface of the door leaf (3) is provided with at least one reserved operating hole (2), the reserved operating hole (2) is connected to the gap between the steel plate outer frame (31) and the inner layer structure of the door leaf, and a blocking cover is provided outside the reserved operating hole (2), and the blocking cover is threadedly connected to the door leaf (3).

7. The basic magnesium sulfate cement concrete civil air defense door leaf according to claim 1, characterized in that: One side of the door leaf (3) is provided with an anti-accidental opening device; The device for preventing accidental opening comprises a handle (8), a turntable (7) and a pointer (9); the damping shaft (10) is vertically arranged on a side surface of the door leaf (3); the turntable (7) and the handle (8) are both fixedly connected to the damping shaft (10), and the handle (8) is distributed on the outside of the turntable (7); the pointer (9) is fixed on the turntable (7); a numerical mark (6) is arranged on the surface of the door leaf (3), and the pointer (9) can be made to correspond to the position of the numerical mark (6) by rotating the turntable (7); The turntable (7) is a circular disk with a notch on one side, and the distance between the handle (8) and the edge of the door leaf (3) is smaller than the diameter of the circular disk; when the turntable (7) is rotated so that the notch is rotated to the edge of the door leaf (3), the turntable (7) does not extend beyond the edge of the door leaf (3), and the door leaf (3) can be opened; when the turntable (7) is rotated so that the non-notch portion is rotated to the edge of the door leaf (3), the turntable (7) extends beyond the edge of the door leaf (3), is fixedly engaged with a slot on another door leaf (3), and the door leaf (3) is closed.

8. The basic magnesium sulfate cement concrete civil air defense door leaf according to claim 1, characterized in that: The fiber mesh (32) is a 3D woven fiber mesh, woven with basalt fibers; The thickness range of the 3D woven fiber mesh is 15-45 mm, and the spatial grid size of the 3D woven fiber mesh is 4-8 mm×4-8 mm.

9. The basic magnesium sulfate cement concrete civil air defense door leaf according to claim 1, characterized in that: A door shaft mounting groove (1) is provided on one side of the door leaf (3); Both side surfaces of the door leaf (3) are provided with a plurality of annular reinforcing rib plates (4) and radial reinforcing rib plates (5).

10. A method for preparing a basic magnesium sulfate cement concrete civil air defense door leaf, characterized in that: The steps include: Placing a door leaf template and laying the fiber mesh (32) in the area enclosed by the door leaf template; pouring basic magnesium sulfate cement concrete until the concrete covers the bottom fiber mesh (32); Laying the steel mesh (33) on the mesh layer of the bottom fiber mesh (32), and continuing to pour basic magnesium sulfate cement concrete until it reaches a certain height of the steel mesh (33); Pre-filling basalt rock particle coarse aggregate on the concrete mortar surface of the steel mesh (33), laying the top fiber mesh (32) on the steel mesh (33), and continuing to pour basic magnesium sulfate cement concrete until the top fiber mesh (32) is covered; After the concrete solidifies, it is removed from the door leaf template and cured to obtain the inner layer structure of the civil air defense door leaf; The inner layer structure of the civil air defense door leaf is installed inside the steel plate outer frame (31); The reserved operation hole (2) is opened, and the basic magnesium sulfate cement concrete is poured into the interior of the steel plate outer frame (31) by a grouting machine. The air inside the steel plate outer frame (31) is discharged through another reserved operation hole (2). After the pouring is completed, it is left to stand for a period of time, and the reserved operation hole (2) is closed. The basic magnesium sulfate cement concrete civil air defense door leaf is prepared.

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