A composite multilayer polyurea concrete protective structure resistant to strong impacts

Abstract

The application belongs to the field of protective engineering, and particularly relates to a composite multi-layer polyurea concrete protective structure resisting strong impact. The composite multi-layer polyurea concrete protective structure comprises, in sequence, a concrete I layer, a force bearing plate made of high-strength steel, a concrete II layer and a polyurea coating, wherein the concrete I layer is a blast-facing surface; a W-shaped array support made of steel is cast in the concrete I layer; a plurality of bonding holes are arranged in the force bearing plate; the two inflection points at the bottom of each W-shaped unit of the W-shaped array support are arranged outside the bonding holes of the force bearing plate; a composite reinforcing rib frame is cast in the concrete II layer; the composite reinforcing rib constituting the composite reinforcing rib frame is composed of a metal circular tube, a glass fiber rod arranged in the metal circular tube and a metal circular sheet at the two ends of the metal circular tube; and the composite reinforcing ribs are connected by spot welding at the intersection points. The application can effectively resist the fire attack of the enemy and effectively prevent the secondary damage caused by the scattering of concrete and gravel; the modular design facilitates replacement and easy repair after strong impact damage.

Description

Technical Field

[0001] This invention belongs to the field of protective engineering, specifically relating to a composite multilayer polyurea concrete protective structure resistant to strong impacts. Background Technology

[0002] To withstand enemy fire and protect facilities and personnel, fortifications play a crucial role, and most modern fortifications are constructed of concrete. The powerful impacts from artillery shells and rockets are the primary means of attacking fortifications. These impacts not only consist of high-temperature, high-pressure shockwaves but also fragmentation and other blast products. The resulting high-speed concrete fragments can damage equipment and personnel inside the fortifications. Therefore, a highly protective and effective fortification resistant to strong impacts can significantly reduce the lethality of enemy fire and enhance our sustained combat capability.

[0003] Currently, the concrete structures of protective fortifications adopt the structural designs of civilian houses and bridges, and are constructed through the matching of steel bars and concrete. This protective structure has the following defects:

[0004] (1) Low protective capability. Reinforced concrete has low design strength and is difficult to withstand enemy fire. Increasing the size and thickness will greatly increase the difficulty, time and cost of construction;

[0005] (2) Destruction produces gravel. Concrete is a brittle material. After being damaged by fire, it produces high-speed gravel, causing secondary damage to equipment and personnel inside the fortifications;

[0006] (3) Difficult to repair after damage. Due to the large weight of concrete and its integral casting, it is difficult to achieve rapid and effective repair.

[0007] In summary, existing reinforced concrete defensive fortifications have drawbacks such as low protective capacity, secondary debris generation, and difficulty in repair, and cannot effectively protect the safety of our facilities and personnel. Summary of the Invention

[0008] The purpose of this invention is to provide a composite multilayer polyurea concrete protective structure that is resistant to strong impacts.

[0009] The technical solution to achieve the purpose of this invention is: a composite multilayer polyurea concrete protective structure resistant to strong impact, comprising a concrete layer I, a load-bearing plate made of high-strength steel, a concrete layer II, and a polyurea coating arranged sequentially, wherein the concrete layer I is the blast-facing surface;

[0010] The concrete layer I contains a W-shaped array support made of steel reinforcement. Multiple bonding holes are arrayed on the load-bearing plate. The bottom two inflection points of each W-shaped unit of the W-shaped array support abut against the bonding holes of the load-bearing plate. The concrete layer II contains a composite reinforcing frame. The composite reinforcing ribs that make up the composite reinforcing frame are composed of metal round tubes, glass fiber rods set inside the metal round tubes, and metal round plates at both ends of the metal round tubes. The intersections of the composite reinforcing ribs are connected by spot welding.

[0011] Furthermore, the W-shaped array support is composed of multiple sets of reinforcing ribs arranged in a crisscross pattern. Each set of reinforcing ribs includes multiple W-shaped units extending in one direction. Each W-shaped unit has outwardly extending extensions at both ends of its top. Two adjacent W-shaped units are welded together through the extensions, and the connection of the extensions is welded to the connection of the extensions of another set of reinforcing ribs arranged orthogonally. Orthogonally arranged connecting steel bars are welded to the middle inflection point of the W-shaped unit.

[0012] Furthermore, the thickness of the concrete protective structure is H0, and its length and width are both L0. The thickness of concrete layer I is H1, the height of concrete layer II is H1, the height of the W-shaped array support (i.e., the height of the W-shaped unit) is h1, the bending height of the W-shaped unit is h2, the bending angle of the W-shaped unit's bending position is 60°, the length of the W-shaped unit is 2b1, and the length of the W-shaped unit from the outermost end of one side extension to the corresponding side inflection point at the bottom is b2. The dimensions of the W-shaped unit satisfy the following formula:

[0013]

[0014] b2 = tan 30° * h1

[0015] b1-b2=tan 30°*(h1-h2)

[0016]

[0017] The thickness H1 of concrete layer I satisfies the following formula:

[0018] H1≥h1+20mm

[0019]

[0020] Furthermore, the steel bars used in the W-type array support have a yield strength of not less than 500 MPa and a tensile strength of not less than 630 MPa.

[0021] Furthermore, the composite reinforcing frame has two layers of composite reinforcing ribs, each layer arranged in a crisscross pattern. The two layers of composite reinforcing ribs are connected by composite reinforcing ribs, and welded at the intersections. The height of the composite reinforcing rib frame is f1, and the distribution width is f2, satisfying the following requirements:

[0022] f1 = (H2 - 20) / 2

[0023] f2 = (L0 - 40) / 9.

[0024] Furthermore, the diameter of the glass fiber rod is equal to the inner diameter of the metal tube and not less than 6 mm; the glass fiber rod is made of 60±10 fiber bundles wound and woven together, and the density of each fiber bundle is not less than 2.45 g / cm³. 3 The tensile strength is not less than 919 MPa, the Young's modulus is not less than 113 MPa, and the elongation is not less than 1.5%; the metal round tube is made of Q235, with an outer diameter of 8 mm-10 mm and a wall thickness of not less than 1 mm.

[0025] Furthermore, the load-bearing plate is made of Q960E with a yield strength of not less than 960MPa and a thickness of not less than 5mm. The diameter of the bonding holes in the load-bearing plate is not less than 140mm. The distance from the center of the outermost bonding hole to the edge of the load-bearing plate is c1 and d1, and the spacing between the longitudinal and transverse holes is c2 and d2, respectively. It also meets the following requirements:

[0026] c1 = d1

[0027] c2 = d2 = (L0 - 2c1 - r - 40) / 8.

[0028] Furthermore, the polyurea coating is applied to the concrete surface using static mixing spraying equipment, with a thickness of not less than 5 mm, a yield strength of not less than 17.8 MPa, a tensile strength of not less than 36 MPa, and an elongation of not less than 340%.

[0029] Furthermore, the concrete grade of the first concrete layer used in both concrete layer I and concrete layer II shall not be lower than C40, the cement strength grade shall not be lower than 42.5, and the coarse sand ratio shall not be lower than 37%.

[0030] Furthermore, nuts are pre-embedded within the concrete protective structure for bolt connection with the defensive fortification frame.

[0031] Compared with the prior art, the significant advantages of this invention are:

[0032] 1. The present invention provides a composite multilayer polyurea concrete protective structure that is resistant to strong impacts and can effectively resist enemy fire. It comprises two layers: the first layer is used to disperse strong impacts, and the second layer is used to resist strong impacts.

[0033] 2. The present invention provides a composite multilayer polyurea concrete protective structure resistant to strong impact, which has a load-bearing plate in the middle and a polyurea coating on the back. The load-bearing plate disperses the impact force and enhances the overall rigidity, and the polyurea coating strengthens the flexibility, which can effectively prevent secondary damage caused by the scattering of concrete debris.

[0034] 3. The present invention provides a composite multilayer polyurea concrete protective structure that is resistant to strong impacts. The whole structure is a flat plate structure with a modular design, which can be easily replaced and repaired after strong impact damage. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the composite multilayer polyurea concrete protective structure of the present invention; wherein (a) is a three-dimensional view, (b) is a front view, and (c) is a schematic diagram of the frame.

[0036] Figure 2 This is a schematic diagram of the W-type array support of the present invention; wherein (a) is a three-dimensional view, (b) is a schematic diagram of the W-type unit, and (c) is a front view.

[0037] Figure 3 This is a schematic diagram of the load-bearing plate of the present invention.

[0038] Figure 4 This is a schematic diagram of the composite reinforcing frame of the present invention; wherein (a) is a three-dimensional view, (b) is a top view, (c) is a cross-sectional view of the reinforcing rib, and (d) is a front view.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1-Concrete Layer I, 2-W-type array support, 3-Bearing plate, 4-Concrete Layer II, 5-Composite reinforcing frame, 6-Polyurea coating, 7-Fiberglass rod, 8-Metal round tube. Detailed Implementation

[0041] The present invention will now be described in further detail with reference to the accompanying drawings.

[0042] like Figure 1-4 As shown, the present invention provides a composite multilayer polyurea concrete protective structure resistant to strong impact, comprising a protective matrix and a functional layer;

[0043] The protective substrate includes a concrete layer I 1 for direct resistance to fire strikes and a concrete layer II 4 for strength support and protection against crushed stone.

[0044] The functional layer includes a W-shaped array support 2, a load-bearing plate 3, a composite reinforcing frame 5, and a polyurea coating 6.

[0045] The thickness of the concrete protective structure is H0, and its length and width are both L0.

[0046] The concrete layer I is integrally cast with the concrete and the W-shaped array support 2, and the thickness of the concrete above and below the W-shaped array support 2 is not less than 10mm.

[0047] The W-shaped array support 2 serves to reinforce the first layer of the substrate and disperse force. The reinforcing steel bars are bent into a "W" shape, allowing the impact force to be evenly distributed throughout the first layer via the "W" structure. The W-shaped array support 2 is made of reinforcing steel, preferably HRB500, with a yield strength of not less than 500 MPa and a tensile strength of not less than 630 MPa. Figure 2 As shown, the height is h1 and the length is 2b1. The bending angles at bending positions b, c, and d are all 60°, achieving effective and stable transmission of impact force. Nine "M"-shaped supports are set in the longitudinal and transverse directions of the concrete. The length L0 of the concrete indicates that:

[0048]

[0049] The bending height relationship for the "W" shape is set as follows:

[0050]

[0051] Calculation yields:

[0052] b2 = tan 30° * h1

[0053] b1-b2=tan 30°*(h1-h2)

[0054]

[0055] It can be seen that the total height of the W-shaped array bracket is h1, and the distance from the middle corner to the bottom is 2 / 3h1.

[0056] The thickness H1 of concrete layer I is known to be:

[0057] H1≥h1+20mm

[0058]

[0059] The concrete grade used for the first concrete layer shall be no less than C40, the cement strength grade shall be no less than 42.5, and the coarse sand ratio shall be no less than 37%.

[0060] The second concrete layer is integrally cast with concrete and composite reinforcing bars, and its thickness is H2.

[0061] H2 = H0 - H1

[0062]

[0063] The composite reinforcing rib of the composite reinforcing frame 5 is composed of fiberglass rods 7 and metal tubes 8, possessing the hardness and brittleness of fiberglass and the flexibility of metal tubes. The cylindrical fiberglass rods 7 are placed inside the metal tubes 8, and both ends are sealed by welding with metal discs. The diameter of the fiberglass rods 7 is not less than 6mm; the fiberglass rods 7 are made of 60 fiber bundles wound and woven together, and the density of each fiber bundle is not less than 2.45g / cm³. 3 The tensile strength is not less than 919MPa, the Young's modulus is not less than 113MPa, and the elongation is not less than 1.5%; the metal round tube 8 is made of Q235, with an outer diameter of 8mm-10mm and a wall thickness of not less than 1mm.

[0064] The composite reinforcing ribs are configured in two layers, with longitudinal composite reinforcing ribs between the two layers. The ribs are spot-welded at the intersections, with a height of f1 and a distribution width of f2, meeting the following requirements:

[0065] f1 = (H2 - 20) / 2

[0066] f2 = (L0 - 40) / 9

[0067] The concrete requirements for the second concrete layer are the same as those for the first concrete layer.

[0068] The load-bearing plate 3 is made of Q960E with a yield strength of not less than 960MPa and a thickness of not less than 5mm. It has bonding holes with a diameter of r and a minimum of 140mm, evenly distributed throughout the load-bearing plate. The load-bearing plate 3 can disperse the impact force transmitted from the first layer, evenly transferring it to the second layer of concrete, preventing the splashing of aggregate from the first layer, increasing the bond strength between the first and second layers of concrete, and reducing the weight of the load-bearing plate.

[0069] like Figure 3 As shown, the distances from the center of the first hole to the edge of the load-bearing plate are c1 and d1, and the spacing between the longitudinal and transverse holes is c2 and d2, respectively, and the following requirements are met:

[0070] c1 = d1

[0071] c2 = d2 = (L0 - 2c1 - r - 40) / 8

[0072] The polyurea coating is an explosion-proof coating with a yield strength of not less than 17.8 MPa, a tensile strength of not less than 36 MPa, and an elongation of not less than 340%. It is applied to the concrete surface using static mixing spraying equipment with a thickness of not less than 5 mm.

[0073] Ensure that the load-bearing plate 3 is placed in the center; steam-cur the poured concrete structure, spray water to keep it moist after demolding, and allow it to cure naturally.

[0074] Example

[0075] like Figure 1-4As shown, a composite multilayer polyurea concrete protective structure resistant to strong impact includes a protective substrate and functional layers. The protective substrate includes concrete layer I and concrete layer II. Concrete layer I 1 is cast integrally with W-shaped array support 2. The thickness of concrete layer I 1 is 125mm. It serves as the front layer of the entire protective structure, directly resisting strong impact and dispersing the impact force. Concrete layer II 4 is cast integrally with composite reinforcing frame 5. The thickness of concrete layer II 4 is 100mm. It serves as the back layer of the entire protective structure, indirectly resisting strong impact, reducing deformation, and preventing the impact of gravel.

[0076] The functional layer includes a W-shaped array support 2, a load-bearing plate 3, a composite reinforcing frame 5, and a polyurea coating 6. The W-shaped array support 2 enhances the strength of the concrete layer I 1, with the top of the W-shaped array support 2 facing the blast-facing surface. The W-shaped array support 2 is arranged in a crisscross pattern with a uniform spacing of 181.69 mm, with 9 supports in each direction, and the intersections are spot-welded. A connecting steel bar with a diameter of 5 mm is installed at the bending angle c of the W-shaped array support 2 and spot-welded to the W-shaped array support to improve the overall rigidity of the W-shaped array support 2 and to disperse the impact force. The load-bearing plate 3 is 5mm thick with a yield strength of 960MPa. It is equipped with bonding holes with a diameter of 140mm to ensure the connection strength between concrete layer I 1 and concrete layer II 4. The load-bearing plate 3 cooperates with the W-shaped array bracket 2. The b, c, and d bends of the W-shaped array bracket 2 are located outside the bonding holes. The impact force is transmitted to the load-bearing plate 3 through the W-shaped array bracket 2 to disperse the impact force. At the same time, the load-bearing plate 3 is made of high-strength steel, which improves the overall rigidity of the concrete protective structure and reduces the amount of deformation. The composite reinforcing frame 5 consists of fiberglass rods 7 and metal tubes 8. The fiberglass rods 7 have a diameter of 6mm, and the metal tubes 8 are made of Q235 steel with an outer diameter of 8mm and a wall thickness of 1mm. The fiberglass rods 7 are placed inside the metal tubes 8, and both ends are sealed by welding with metal discs with a diameter of 8mm and a thickness of 1mm. The composite reinforcing frame 5 has two layers, with the composite reinforcing bars in each layer crisscrossing at a spacing of 180mm and spot-welded at the intersections. The two layers of composite reinforcing bars are connected by composite reinforcing bars with a length of 75mm, evenly distributed at each intersection and spot-welded at the intersections. The composite reinforcing bars have the strength of fiberglass rods 7 and the toughness of metal tubes 8, and are used to enhance the stiffness and toughness of concrete layer II 4, thereby improving the protective capacity of the concrete protective structure. The polyurea coating 6 has a thickness of 5mm and is sprayed onto the back of the concrete protective structure. The grade is NL-40, with a yield strength of 17.8MPa, a tensile strength of 36MPa, and an elongation of 340%. It can effectively prevent the flying of gravel caused by impact and avoid secondary damage to equipment and personnel inside the fortification.

[0077] The concrete protective structure of this invention is used in conjunction with the defensive fortification frame. The defensive fortification frame is "L" shaped and nuts can be pre-embedded in the concrete protective structure. It is bolted to the defensive fortification frame to achieve modularity of the defensive fortification. It can effectively resist strong impacts and secondary impacts from gravel, and is easy to replace and repair after being damaged by strong impacts.

Claims

1. A composite multi-layer polyurea concrete armor resistant structure against high impact, characterized by, The concrete protective structure comprises, in sequence, a concrete I layer (1), a high-strength steel bearing plate (3), a concrete II layer (4) and a polyurea coating (6), wherein the concrete I layer (1) is a blast-facing surface. The W-shaped array support (2) with steel material is poured in the concrete I layer (1), the bearing plate (3) is provided with a plurality of sticking holes, the two inflection points of the bottom of each W-shaped unit of the W-shaped array support (2) are located outside the sticking holes of the bearing plate (3); the composite reinforcing rib frame (5) is poured in the concrete II layer (4), the composite reinforcing rib of the composite reinforcing rib frame (5) is composed of a metal round pipe (8), a glass fiber rod (7) arranged in the metal round pipe (8) and a metal round plate at the two ends of the metal round pipe (8); the intersection of the composite reinforcing rib is connected by spot welding; the W-shaped array support (2) is composed of a plurality of groups of reinforcing ribs arranged in a longitudinal and transverse intersecting manner, each group of reinforcing ribs comprises a plurality of W-shaped units extending in one direction, the two ends of the top of each W-shaped unit are provided with an extension part extending outward, the two W-shaped units adjacent to each other are welded into one by the extension part, and the connection part of the extension part is welded with the connection part of the extension part of another group of reinforcing ribs arranged orthogonally, the middle inflection point of the W-shaped unit is welded with the connecting reinforcing rib arranged orthogonally; the height of the W-shaped array support (2) is h1, the bending height of the W-shaped unit is h2, the bending angle of the bending position of the W-shaped unit is 60°, wherein, .

2. The composite multi-layer polyurea concrete armor structure of claim 1, wherein, The thickness of the concrete protective structure is , the length and width are , the thickness of the concrete I layer is H1, the thickness of the concrete II layer is H2, the length of the W-shaped unit is 2b1, and the length from the outermost end of the one-side extension to the corresponding side inflection point at the bottom is b2; the size of the W-shaped unit satisfies the following formula: ， ， The thickness H1 of the concrete I layer satisfies the following formula: 。 3. The composite multi-layer polyurea concrete armor structure of claim 2, wherein, The yield strength of the steel used in the W-shaped array support (2) is not less than 500 MPa, and the tensile strength is not less than 630 MPa.

4. The composite multi-layer polyurea concrete armor structure of claim 3, wherein, The composite reinforcing rib of the composite reinforcing rib frame (5) is arranged in two layers, each layer being arranged in a longitudinal and transverse interlaced manner, the composite reinforcing ribs between the two layers being connected by composite reinforcing ribs, and the intersection points being spot welded; the height of the composite reinforcing rib frame (5) is , the distribution width is , and the following requirements are met: ， 。 5. The composite multi-layer polyurea concrete armor structure of claim 4, wherein, The diameter of the glass fiber rod (7) is equal to the inner diameter of the metal circular tube (8) and not less than 6 mm; the glass fiber rod (7) is made of 60±10 fiber bundles, and the density of each fiber bundle is not less than 2.45 g / cm 3 The tensile strength is not less than 919 MPa, the Young's modulus is not less than 113 MPa, and the elongation rate is not less than 1.5%; the metal circular tube (8) is made of Q235, the outer diameter is 8 mm-10 mm, and the wall thickness is not less than 1 mm.

6. The composite multi-layer polyurea concrete armor structure of claim 5, wherein, The material of the bearing plate (3) is Q960E, the yield strength is not less than 960 MPa, the thickness is not less than 5 mm, the diameter of the bonding hole of the bearing plate (3) is not less than 140 mm, the distance from the center of the bonding hole at the edge to the edge of the bearing plate is and , the vertical and horizontal hole spacing is and , r is the diameter of the bonding hole, and the following requirements are met: ， 。 7. The composite multi-layer polyurea concrete armor structure of claim 6, wherein, The polyurea coating is applied to the back of the concrete protective structure by using a static mixing spraying device, and has a thickness of not less than 5 mm, a yield strength of not less than 17.8 MPa, a breaking strength of not less than 36 MPa and an elongation of not less than 340%.

8. The composite multi-layer polyurea concrete armor structure of claim 7, wherein, The concrete I layer (1) and the concrete II layer (4) are made of concrete with a grade of not less than C40 and a cement strength grade of not less than 42.5, and the coarse sand sand rate is not less than 37%.

9. The composite multi-layer polyurea concrete armor structure of claim 8, wherein, A nut is embedded in the concrete protective structure and used for bolt connection with a defense work skeleton.

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