Construction method for improving the strength of fiber reinforced cementitious panels

Abstract

The application discloses a construction method for improving the strength of fiber reinforced cement boards and relates to the field of building construction; the construction method for improving the strength of fiber reinforced cement boards effectively solves the problems of easy loosening, edge warping and deformation of the board under the traditional single-board fixing mode, significantly improves the overall connectivity of the board and the keel and the anti-deformation capacity of the wall, and forms a double-board cooperative stress structure by connecting long U-shaped steel to the inner side of the fiber reinforced cement board joint and by jointly restraining the edges of the adjacent boards on the keel; meanwhile, the water-resistant flexible putty is filled and pressed into the glass fiber mesh belt at the joint of the outer board, which not only can offset the joint stress of the fiber reinforced cement board caused by dry shrinkage, wet expansion and temperature change, prevent the putty layer from cracking and rainwater leakage, but also avoids forming a rigid filling layer to hinder the normal pressure relief of the wall.

Description

Technical Field

[0001] This invention relates to building construction technology, specifically to a construction method for improving the strength of fiber-reinforced cement boards. Background Technology

[0002] Fiber-reinforced cement board, as a lightweight, high-strength, and brittle composite material, has been widely used in pressure relief wall systems for modern factory buildings. Its core design concept is that, in the event of an explosion, the wall can precisely fracture or detach at a predetermined location within milliseconds, rapidly forming a pressure relief channel to release the instantaneous overpressure generated by the explosion to the outside, thus effectively preventing the main building structure from collapsing due to the rapid accumulation of internal pressure. This material not only possesses excellent pressure relief performance but also, due to its lightweight nature, significantly reduces the load requirements on the main structure, making it the preferred surface material for pressure relief wall systems. However, in practical engineering applications, the construction quality of fiber-reinforced cement board directly determines the long-term stability and functionality of the pressure relief wall system. Because fiber-reinforced cement board itself is a brittle material, its impact resistance and deformation resistance are relatively limited. Even slight external impacts or uneven deformation can cause the board to crack, affecting the overall appearance and structural integrity of the wall.

[0003] More importantly, in the complex environment of a chemical plant, fiber-reinforced cement boards are constantly affected by multiple factors, including temperature changes, humidity fluctuations, and structural settlement. The boards experience shrinkage and expansion in alternating wet and dry environments, and thermal expansion and contraction due to temperature differences. These inherent material properties cause volume changes that accumulate continuous stress at the board joints. Currently, conventional construction methods typically use simple putty to fill the joints between inner and outer layers of fiber-reinforced cement boards, lacking an effective coordinating stress mechanism between boards and between boards and the joists. Over time, the putty layer at the joints becomes unable to effectively buffer and dissipate the stress generated by board deformation, making it prone to cracking and peeling. This not only compromises the airtightness and waterproofing of the wall, leading to safety hazards such as rainwater leakage and gas leaks, but more seriously, the loosening at the board joints can gradually spread to the entire board, causing warping, deformation, and even detachment. If the fixing of the panels and the keel fails, it will not only affect the normal use of the wall, but may also fail to rupture and release pressure in the intended manner during an explosion, thus losing the core protective function of the pressure relief wall.

[0004] Therefore, how to effectively improve the connection strength between boards, enhance the integrity of boards and keel, and suppress joint cracking and board loosening while maintaining the pressure relief performance of fiber reinforced cement boards has become a key technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a construction method to improve the strength of fiber-reinforced cement boards, so as to solve the problem that the existing fiber-reinforced boards are only fixed by screws, lack a coordinated force-bearing mechanism, are prone to deformation and loosening, and affect the pressure relief effect and service life.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a construction method for improving the strength of fiber-reinforced cement boards, comprising:

[0007] Construction preparation;

[0008] Before construction begins, the work area should be thoroughly cleaned.

[0009] Measurement and layout;

[0010] Accept and install the main and secondary keels that have been brought to the site, and install the main and secondary keels on the concrete main structure to form a skeleton;

[0011] Acceptance of fiber-reinforced cement boards;

[0012] Install the outer double-layer fiber-reinforced cement board. Arrange the inner and outer fiber-reinforced cement boards according to the wall size and keel spacing. Use countersunk screws to fix the outer inner fiber-reinforced cement board to the U-shaped steel and C-shaped steel that serve as secondary keels. Use countersunk screws to fix the outer outer fiber-reinforced cement board to the square tube that serves as the main keel, and leave the construction joint on the rigid connection of the square tube.

[0013] Install the inner fiber-reinforced cement board, and use countersunk screws to rivet and fix the inner fiber-reinforced cement board to the U-shaped steel and C-shaped steel that serve as secondary keels; use countersunk screws to fix the construction joint of the upper and lower boards to the square tube that serves as the main keel, so that the construction joint is left on the rigid connection of the square tube.

[0014] After installation, conduct an inspection, clean up any debris, and then accept the installation.

[0015] Furthermore, during installation, both the outer double-layer fiber-reinforced cement board and the inner fiber-reinforced cement board are installed one by one starting from one end of the layout position, and the boards are fixed to the keel by gradually tightening from the center of the board outwards.

[0016] Furthermore, the vertical joints of the upper and lower layers of the outer double-layer fiber-reinforced cement board are staggered by ≥300mm; the vertical joints of the upper and lower layers of the inner fiber-reinforced cement board are also staggered by ≥300mm.

[0017] Furthermore, the construction joint between the inner layers of the outer double-layer fiber-reinforced cement board is 3-5mm, and the construction joint between the inner fiber-reinforced cement board panels is 3-5mm.

[0018] Furthermore, the joints between the fiber-reinforced cement boards are filled with water-resistant flexible putty, and fiberglass mesh is attached to the outer fiber-reinforced cement board.

[0019] Furthermore, the countersunk screw head is recessed into the interior of the board surface, below the surface layer of the board.

[0020] Furthermore, the construction process specifically includes completing detailed construction drawings based on the architectural design specifications, preparing a special construction plan for lightweight pressure relief walls, preparing machinery and materials, and determining construction monitoring and testing plans.

[0021] Furthermore, the measurement and layout specifically includes verifying the elevation and cross-sectional dimensions of the main concrete structure, projecting the wall axis and edge lines of the lightweight pressure relief wall, popping up the wall elevation line, laying out the keel and board, and popping up the fixed point layout on the main concrete structure according to the detailed drawings.

[0022] Furthermore, the countersunk screw head is coated with anti-rust paint, and the screw hole is filled with fire-retardant repair paste on the flat surface.

[0023] Furthermore, rock wool blocks are used to fill the spaces between the keel cavities.

[0024] Compared with existing technologies, the construction method for improving the strength of fiber-reinforced cement boards provided by this invention has the following advantages:

[0025] 1. This application utilizes a continuous U-shaped steel bar to attach to the joints of the inner fiber-reinforced cement boards, thereby binding the edges of adjacent boards together to the keel and forming a double-board cooperative load-bearing structure. This effectively solves the problems of easy loosening, warping, and deformation of boards under traditional single-board fixing methods, and significantly improves the overall connection between the boards and the keel and the deformation resistance of the wall.

[0026] 2. This application uses water-resistant flexible putty to fill the joints of the outer panel and presses in fiberglass mesh, which can not only offset the joint stress caused by the shrinkage and expansion of the fiber reinforced cement board due to dryness and wetness and temperature changes, and prevent the putty layer from cracking and rainwater leakage, but also avoids the formation of a rigid filling layer that hinders the normal pressure relief of the wall.

[0027] 3. The U-shaped steel in this application can effectively buffer and disperse the impact of external forces and the energy of local damage, reduce the non-explosive damage rate of the plate due to accidental collision or vibration, and extend the service life of the pressure relief wall. The method provided in this application achieves the unity of high strength, durability and reliable pressure relief function of the wall by optimizing the joint structure and connection method without changing the pressure relief performance of the plate itself, which significantly improves the overall quality and safety performance of the lightweight pressure relief wall of the chemical plant. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0029] Figure 1 This is a schematic diagram of the installation structure of the fiber-reinforced cement board provided in an embodiment of the present invention;

[0030] The components include: 1. Secondary keel; 2. Countersunk screws; 3. Expansion bolts; 4. Rock wool; 5. Fiber-reinforced cement board; and 6. Main keel. Detailed Implementation

[0031] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0032] As attached Figure 1 As shown:

[0033] Example:

[0034] This invention provides a construction method for improving the strength of fiber-reinforced cement boards, comprising:

[0035] Complete the detailed construction drawings based on the architectural design specifications, prepare a special construction plan for the lightweight pressure relief wall, prepare machinery and materials, determine the construction monitoring plan and testing, and complete the construction preparation;

[0036] Before construction begins, the work area should be thoroughly cleaned.

[0037] Measurement and layout include verifying the elevation and cross-sectional dimensions of the main concrete structure, projecting the wall axis and edge lines of the lightweight pressure relief wall, marking the wall elevation lines, laying out the joists and panels, and marking out the fixed points on the main concrete structure according to the detailed drawings.

[0038] Accept and install the main and secondary keels that have been brought to the site, and install the main and secondary keels on the concrete main structure to form a skeleton;

[0039] Acceptance inspection of rock wool 4 and fiber-reinforced cement board 5 upon arrival at the site;

[0040] Install the outer double-layer fiber-reinforced cement board 5. According to the wall size and keel spacing, arrange the inner and outer layers of fiber-reinforced cement board 5. Use M3*25@200mm countersunk screws 2 to fix the outer inner layer of fiber-reinforced cement board 5 to the U-shaped steel and C-shaped steel that serve as secondary keels 1. The construction joint between the inner layers of the outer double-layer fiber-reinforced cement board 5 is 3-5mm. Use M3*40@200mm countersunk screws 2 to fix the outer outer layer of fiber-reinforced cement board 5 to the square tube that serves as the main keel 6, and leave the construction joint on the rigid connection of the square tube. The vertical joints of the upper and lower layers of the two layers of the outer double-layer fiber-reinforced cement board 5 are staggered, with a stagger of ≥300mm. The staggered joints between the fiber-reinforced cement boards 5 are filled with water-resistant flexible putty, and fiberglass mesh is hung on the outer fiber-reinforced cement board 5.

[0041] All countersunk screws 2 heads are coated with anti-rust paint, and the screw holes are filled with fireproof repair paste on the flat surface. The countersunk screws 2 heads are sunk into the interior of the board surface, below the surface layer of the board.

[0042] Fill the spaces between the keel cavities with four pieces of rock wool;

[0043] Install the inner fiber-reinforced cement board 5, and use M3*25@200mm countersunk screws 2 to rivet and fix the inner fiber-reinforced cement board 5 to the U-shaped steel and C-shaped steel that serve as the secondary keel 1. The construction joint between the inner fiber-reinforced cement board 5 is 3-5mm. The vertical joints of the upper and lower layers of the inner fiber-reinforced cement board 5 are staggered, with a stagger of ≥300mm. Use M3*25@200mm countersunk screws 2 to fix the construction joint of the upper and lower layers to the square tube that serves as the main keel 6, so that the construction joint is left on the rigid connection of the square tube. The staggered joints between the fiber-reinforced cement boards 5 are filled with water-resistant flexible putty.

[0044] After installation, conduct an inspection, clean up any debris, and then accept the installation.

[0045] During installation, both the outer double-layer fiber-reinforced cement board 5 and the inner fiber-reinforced cement board 5 are installed one by one starting from one end of the layout position, and the boards are fixed to the keel by gradually tightening from the center of the board to the surrounding area.

[0046] As shown above, by attaching a continuous U-shaped steel bar at the joint of the inner fiber-reinforced cement board 5, the edges of adjacent boards are jointly constrained to the keel, forming a double-board cooperative stress-bearing structure. This effectively solves the problems of easy loosening, warping, and deformation of boards under the traditional single-board fixing method, significantly improving the overall connection between the boards and the keel and the deformation resistance of the wall. At the same time, water-resistant flexible putty is used to fill the joint of the outer board and fiberglass mesh is pressed in. This not only offsets the joint stress caused by the shrinkage and expansion of the fiber-reinforced cement board 5 due to dryness and wetness and temperature changes, preventing the putty layer from cracking and rainwater leakage, but also avoids the formation of a rigid filling layer that hinders the normal pressure relief of the wall. In addition, the constraint effect of the U-shaped steel bar can effectively buffer and disperse the impact of external forces and local damage energy, reduce the non-explosive damage rate of the boards caused by accidental collisions or vibrations, and extend the service life of the pressure relief wall. This technical solution achieves the unity of high strength, durability and reliable pressure relief function of the wall by optimizing the joint structure and connection method without changing the pressure relief performance of the boards themselves, significantly improving the overall quality and safety performance of the lightweight pressure relief wall of the chemical plant.

[0047] When constructing a lightweight pressure relief wall for a chemical plant using the above construction method, the specific steps include:

[0048] Construction preparation:

[0049] Technical preparation:

[0050] According to the architectural plan and section drawings, and the general architectural design specifications, a professional manufacturer must be invited to complete the detailed design of the lightweight pressure relief wall, in accordance with the atlas "14J938 Explosion-resistant and Explosion-relief Doors, Windows, Roofs, and Walls". The detailed design must be confirmed by all five responsible parties before it can be used for on-site construction.

[0051] Prepare a special construction plan for lightweight pressure relief walls, and provide the plan to the on-site management personnel and the construction workers with technical and safety instructions, clarifying the installation sequence, fixing method, welding requirements of the main and secondary keels, the installation spacing and anti-corrosion treatment measures of the countersunk screws, and the sealing treatment method of the board joints, etc.

[0052] Before constructing the lightweight pressure relief wall, the structural elevation and dimensions of the completed main structure concrete beams and columns should be checked. After the check is correct, the positioning and layout should be carried out: the edge lines, elevations, dimensions, positioning axes, and reserved dimensions for door and window openings of the main and secondary joists should be marked.

[0053] According to the detailed drawings of the lightweight pressure relief wall, the following should be strictly controlled during construction: the position of the main and secondary keels, the size of the joints of the fiber-reinforced cement boards in the inner and outer walls (the vertical joints of two adjacent rows of boards must be staggered, usually with a stagger distance of not less than 300mm, to avoid through joints), to ensure that the overall framework is flat, stable, and horizontally and vertically straight.

[0054] Preparation of materials and machinery:

[0055] According to the detailed drawings, the requirements for lightweight pressure relief wall materials are specified as follows: specifications, models, and grades of primary and secondary keels (lightweight keel specifications: Q235 C-shaped steel 100*45*0.6mm, Q235 U-shaped steel 100*40*0.6mm; primary keel specifications: Q235 square tube 100*50*3.0mm); dimensions, thermal conductivity, and weight of fiber-reinforced cement board 5; specifications and models of countersunk screws 2; requirements for the type of anti-corrosion sealing material; combustion performance and thermal conductivity of rock wool 4, etc.

[0056] Based on the height, thickness, framing, panel type, and joint construction of the lightweight pressure relief wall, aerial work platforms and electric hoists are preferred for material hoisting, followed by the use of electric drills, screwdrivers, torque wrenches, and caulking guns for securing the materials. Upon arrival at the site, the equipment should be immediately debugged, maintained, and serviced to ensure its normal operation.

[0057] Construction monitoring preparation:

[0058] During the construction of the lightweight pressure relief wall, the verticality, flatness, spacing, elevation, and connection firmness of the main and secondary keels with the main structure should be monitored at all times; the installation position and tightening torque of the embedded parts and connectors should be checked to prevent loosening or displacement.

[0059] Check the spacing, depth, and uniformity of self-tapping screws to ensure a reliable connection between the panels and the joists. Monitor the overall flatness, verticality, and squareness of the internal and external corners of the wall.

[0060] Experimental preparation:

[0061] Before the construction of the lightweight pressure relief wall, for the materials brought to the site, under the supervision of the supervising engineer, 5 fiber-reinforced cement boards, 4 main and secondary keels, and 4 rock wools are randomly selected and sent to a qualified third-party testing unit for testing. Only after passing the test can they be used for on-site construction.

[0062] Site cleanup:

[0063] Before construction, the work area should be thoroughly cleaned to create safe, clean, and explosion-proof working conditions for the measurement, layout, and installation of the lightweight pressure relief wall.

[0064] Remove debris, dust, oil stains, hardened mortar lumps, and scum from the floor sills, beam bottoms, and column sides within the wall installation area to ensure the structural base is flat, clean, and dry, facilitating joist positioning, marking, and fixing. Trim or cut off any protruding concrete, rebar ends, or embedded parts that may obstruct installation, ensuring the wall surface is straight and free of obstructions.

[0065] Within the explosion-proof area of ​​a chemical plant, flammable, explosive, and combustible materials, including oil, paint, thinner, cardboard boxes, plastic bags, and cotton yarn, must be thoroughly cleaned from the work area and surrounding areas to eliminate fire and explosion hazards.

[0066] Ensure sufficient operating space at the wall installation location, eliminate the risk of falling objects from height, and remove loose components and debris above in advance. When working at height, set up a warning area below and clear it thoroughly, and prohibit cross-operation.

[0067] Measurement and layout:

[0068] Elevation and cross-sectional dimension verification: Before measuring and setting out the lightweight pressure relief wall, the elevation, cross-sectional dimensions, and positioning axis of the main structure's concrete beams and columns are first verified in conjunction with the structural drawings. This is to avoid incorrect positioning or tilting of the pressure relief wall after installation due to deviations in structural elevation and dimensions. Furthermore, by verifying the actual net width and height, the slab layout, staggered joint method, and cutting dimensions can be determined in advance.

[0069] Axis projection: After completing the verification of structural elevation and interface dimensions, based on the verified main control axis of the building on site, project the wall axis, edge line, and door and window opening position line of the lightweight pressure relief wall, and transfer the axis to the ground, column surface, beam side and top slab structural surface, and make clear markings;

[0070] Elevation transfer: Transfer the unified elevation control points on site to the work surface, and mark the bottom elevation line, top elevation control line, and keel spacing elevation line of the wall to ensure that the elevation of the entire wall is uniform and the level is consistent;

[0071] Layout and marking of keel and board: According to the design spacing in the detailed drawing, mark the positioning lines of the main keel 6, secondary keel 1, and edge keel, and mark the center line and edge line of the keel; according to the board layout and staggered joint requirements, mark the board joint control line in advance to ensure that the staggered joint distance meets the specification requirements during installation.

[0072] Fixed point layout: Based on the detailed drawings, mark the fixed point lines for embedded parts and connectors on the structural beams, columns, ground, and roof to ensure that the fixed points are accurately positioned, evenly spaced, and reliably stressed.

[0073] Inspection of primary and secondary keels upon arrival:

[0074] First, based on the material specifications and model requirements in the detailed drawings provided by the professional manufacturer, verify the product certificates and performance test reports of the incoming primary and secondary keels (Q235C steel, U-shaped steel, and square tubing). Once the incoming documents are verified to be correct, then check the appearance and dimensions of the materials.

[0075] Appearance quality inspection: The surface of the keel should be flat, smooth, free of burrs, deformation, and warping. There should be no obvious defects such as rust, cracks, damage, bending, or twisting. Cuts should be straight, without curled edges or burrs, and should not affect installation.

[0076] Dimensional and specification acceptance: Verify the keel model, cross-sectional dimensions, wall thickness, and length according to design requirements. Actual measure the length, width, thickness, and verticality; deviations must be within allowable limits. Specifications for primary and secondary keels, ground keels, top keels, and reinforcing keels must not be mixed or substituted.

[0077] Install main keel 6:

[0078] According to the detailed design specifications in the secondary detailed design drawings, the vertical main keel 6 will be connected to the main frame concrete structure, the vertical main keel 6 will be connected to the horizontal main keel 6, and the horizontal main keel 6 will be connected to the main frame concrete structure. After the construction of all main keels 6 is completed, it must be ensured that the overall frame is flat, stable, and horizontally and vertically straight. All welds must be coated with anti-rust paint to prevent corrosion. The reserved length and width dimensions of all windows must be rechecked to ensure they are consistent with the dimensions required in the drawings. The verticality, spacing, and elevation of the keels must be strictly controlled according to the drawings to ensure that the subsequent fiber-reinforced cement board 5 is installed flat and with reasonable staggered joints.

[0079] Install secondary keel 1:

[0080] According to the detailed design instructions of the second detailed drawing, after the main keel 6 is installed, the secondary keel 1 is fixed on the square tube of the main keel 6; and the secondary keel 1 is fixedly connected to the top of the concrete beam, the bottom of the slab and the ground curb around the main frame.

[0081] Rock wool 4 and fiber-reinforced cement board 5 - incoming inspection:

[0082] First, based on the material specifications and model requirements in the detailed drawings provided by the professional manufacturer, the product certificates, quality certificates, test reports, combustion performance, thermal conductivity, and other parameters of the fiber-reinforced cement board 5 and rock wool 4 that arrived on site were checked. After verifying that the incoming documents were correct, the appearance and dimensions of the materials were then checked.

[0083] Appearance quality inspection: The surface of the board should be flat, clean, and uniform in color, free from defects such as cracks, missing edges, chipped corners, delamination, bubbles, dents, and scratches. Edges should be straight, without chipping or burrs, and the dimensions should be regular for easy installation and splicing. Rock wool 4 boards should have a flat surface, uniform color, and be free from damage, moisture, mold, loose material, and flaking. Edges should be regular, and there should be no obvious deformation, oil stains, or impurities.

[0084] Dimensional Specification Acceptance: Verify the length, width, thickness, squareness, and flatness of the boards according to design requirements, as well as the length, width, and thickness of rock wool 4. Measure the actual dimensional deviations to ensure they are within allowable limits. Boards that do not meet specifications, are insufficient in thickness, or are deformed or warped must not be used for pressure relief walls.

[0085] Performance indicators: Check key indicators such as board strength, density, moisture content, impact resistance, and non-combustibility to ensure they meet the stress, explosion-proof, and fireproof requirements of the pressure relief wall. The boards should be lightweight and high-strength, easily release pressure upon explosion, and not produce sharp fragments. Check that the rock wool (4 type) has uniform density, feels dense, has normal resilience, and exhibits no powdering, excessive slag, or delamination, meeting the requirements for fireproofing, thermal insulation, sound insulation, and pressure relief wall construction.

[0086] 5. Install fiber-reinforced cement board for exterior walls:

[0087] After the keel frame is installed, the verticality, spacing and elevation of the keel are checked to ensure that the subsequent fiber reinforced cement board 5 is installed flat.

[0088] First, install the outer double-layer fiber-reinforced cement board 5. Arrange the inner and outer layers of boards according to the wall size and the spacing of the keel 1. Determine the board joint position, cutting position and staggered joint method. After the arrangement is completed, the boards should be installed one by one from one end. Do not skip any boards.

[0089] First, install the outer inner layer panels. Use M3*25@200mm countersunk screws (2) to rivet and fix them to the secondary keel 1 (U-shaped or C-shaped keel). The fixing sequence is to gradually tighten from the center of the panel outwards. During installation, the vertical joints of the upper and lower panels should be staggered, with a stagger of ≥300mm. Through joints are strictly prohibited. The construction joint between the outer inner layer panels should be controlled at 3-5mm. When installing the outer outer layer panels, the vertical joints of the inner layer panels should be staggered (stagger ≥300mm). Use M3*40@200mm countersunk screws (2) to fix the construction joint of the upper and lower panels to the main keel 6 (square tube), ensuring that the construction joint is left on the rigid connection of the square tube, which can effectively prevent cracking of the subsequent waterproof flexible putty layer.

[0090] By filling the staggered joints of fiber-reinforced cement board 5 with water-resistant flexible putty and attaching fiberglass mesh to the outer fiber-reinforced cement board 5, the deformation stress of the joint caused by the drying shrinkage and thermal expansion of fiber-reinforced cement board 5 can not only be offset, preventing the putty layer from cracking and causing rainwater leakage at the joint, but also avoid forming a rigid filling layer that hinders the pressure relief of the wall.

[0091] The joints between the boards are filled smoothly, densely, without hollow areas or cracks, ensuring that the airtightness, fire resistance, and pressure relief performance of the wall meet the standards.

[0092] Rust prevention treatment for countersunk screws 2:

[0093] After the fiber reinforced cement board 5 is installed, check whether all countersunk screws 2 are tightened properly, the screw heads are slightly sunk into the board surface, there is no protrusion, no floating, and no stripping, and ensure that the screw heads are below the board surface and do not damage the surface layer of the board.

[0094] Apply corrosion-resistant and rust-proof paint / coating evenly to the head of each countersunk screw, ensuring that the head and screw cut are completely covered without any missed spots, drips, or exposed substrate, forming a continuous and sealed rust-proof protective layer.

[0095] After the anti-rust paint has dried and cured, use fireproof repair paste, cement-based repair material or matching caulking material to fill and level the nail holes, ensuring that the repaired surface is flat and consistent with the board surface, without depressions or protrusions.

[0096] Rock wool filling 4:

[0097] After the outer fiber-reinforced cement board 5 is installed and passes the concealed acceptance inspection, rock wool 4 is filled in. Rock wool 4 pieces are cut on site according to the size of the keel cavity. The rock wool 4 pieces should be regular and slightly larger than the cavity to ensure that the filling is dense and not loose.

[0098] According to the spacing of the keel, fill the wall from bottom to top, grid by grid, and the rock wool 4 should be filled completely, compacted, without gaps or omissions. The joints should be tightly connected without gaps, and the rock wool 4 should be tightly attached to the structural surfaces such as the top slab, beams, columns, and ground.

[0099] After filling, check whether the surface of rock wool 4 is flat, uniform, undamaged, and free from pollution. Only after passing the inspection can the inner fiber-reinforced cement board 5 be installed.

[0100] Install inner fiber-reinforced cement board 5:

[0101] After the rock wool 4 is filled, invite the supervisor to conduct an acceptance inspection. Only after the inspection is passed can the inner fiber reinforced cement board 5 be installed.

[0102] The inner fiber-reinforced cement board 5 is installed by riveting it to the secondary keel 1 (U-shaped or C-shaped keel) with M3*25@200mm countersunk screws 2. The fixing sequence is from the center of the board outwards. During the installation process, the vertical joints of the upper and lower boards are staggered, with a stagger of ≥300mm. Through joints are strictly prohibited. The construction joint between the inner boards is controlled at 3-5mm. The construction joint of the upper and lower boards is fixed to the main keel 6 (square tube) by using M3*25@200mm countersunk screws 2, ensuring that the construction joint is left on the rigid connection of the square tube, which can effectively prevent the subsequent waterproof flexible putty layer from cracking.

[0103] After installation, a comprehensive inspection should be carried out to check that the width of the board joints is uniform, straight, and meets the design requirements, and that the verticality and flatness of the wall meet the allowable deviations specified in the standards.

[0104] Cleaning and acceptance:

[0105] After installation, remove dust, cutting debris, fingerprints, oil stains, and sealant residue from the surface of the fiber-reinforced cement board 5. Clean rock wool debris and screw fragments from board joints, wall and ceiling joints, and corners, ensuring the joints are clean and dry;

[0106] Use a straightedge to check whether the overall flatness, verticality, and squareness of the inside and outside corners of the wall are within the allowable deviation range of the specifications. After the self-inspection is qualified, submit it to the supervision unit for special acceptance.

[0107] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A construction method for improving the strength of fiber-reinforced cement board (5), characterized in that, include: Construction preparation; Before construction begins, the work area should be thoroughly cleaned. Measurement and layout; Accept the main and secondary keel (1) that have been installed on the site, and install the main and secondary keel (1) on the concrete main structure to form a skeleton; Acceptance of fiber-reinforced cement board (5); Install the outer double-layer fiber reinforced cement board (5). Arrange the inner and outer fiber reinforced cement boards (5) according to the wall size and keel spacing. Use countersunk screws (2) to fix the outer inner fiber reinforced cement board (5) to the U-shaped steel and C-shaped steel as secondary keel (1). Use countersunk screws (2) to fix the outer outer fiber reinforced cement board (5) to the square tube as main keel (6) and leave the construction joint on the rigid connection of the square tube. Install the inner fiber reinforced cement board (5), and use countersunk screws (2) to rivet and fix the inner fiber reinforced cement board (5) to the U-shaped steel and C-shaped steel that serve as the secondary keel (1); use countersunk screws (2) to fix the construction joint of the upper and lower plates to the square tube that serves as the main keel (6), so that the construction joint is left on the rigid connection of the square tube. After installation, conduct an inspection, clean up any debris, and then accept the installation.

2. The construction method for improving the strength of fiber-reinforced cement board (5) according to claim 1, characterized in that, When installing the outer double-layer fiber reinforced cement board (5) and the inner fiber reinforced cement board (5), the boards are installed one by one starting from one end of the layout position, and the boards are fixed to the keel by gradually tightening from the center of the board to the surrounding area.

3. The construction method for improving the strength of fiber-reinforced cement board (5) according to claim 1, characterized in that, The vertical joints of the upper and lower layers of the outer double-layer fiber-reinforced cement board (5) are staggered by ≥300mm; the vertical joints of the upper and lower layers of the inner fiber-reinforced cement board (5) are staggered by ≥300mm.

4. The construction method for improving the strength of fiber-reinforced cement board (5) according to claim 1, characterized in that, The construction joint between the inner layers of the outer double-layer fiber reinforced cement board (5) is 3-5mm, and the construction joint between the inner layers of the inner fiber reinforced cement board (5) is 3-5mm.

5. The construction method for improving the strength of fiber-reinforced cement board (5) according to claim 1, characterized in that, Water-resistant flexible putty is filled between the staggered joints of the fiber-reinforced cement boards (5), and fiberglass mesh is hung on the outer fiber-reinforced cement board (5).

6. The construction method for improving the strength of fiber-reinforced cement board (5) according to claim 1, characterized in that, The countersunk screw (2) has its head sunk into the interior of the board surface, below the surface layer of the board.

7. The construction method for improving the strength of fiber-reinforced cement board (5) according to claim 1, characterized in that, The construction process specifically involves completing detailed construction drawings based on the architectural design specifications, preparing a special construction plan for the lightweight pressure relief wall, preparing machinery and materials, and determining the construction monitoring plan and testing procedures.

8. The construction method for improving the strength of fiber-reinforced cement board (5) according to claim 1, characterized in that, The measurement and layout process specifically includes verifying the elevation and cross-sectional dimensions of the main concrete structure, projecting the wall axis and edge lines of the lightweight pressure relief wall, popping out the wall elevation line, laying out the keel and board, and popping out the fixed point layout on the main concrete structure according to the detailed drawings.

9. A construction method for improving the strength of fiber-reinforced cement board (5) according to claim 1, characterized in that, The countersunk screw (2) head is coated with anti-rust paint and the screw hole is filled with fireproof repair paste to find the flat surface.

10. A construction method for improving the strength of fiber-reinforced cement board (5) according to claim 1, characterized in that, Rock wool (4 blocks) were used to fill the cavities between the keel.

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