Efficient building materials solutions in the field of modern construction​

In the field of contemporary construction engineering, welded steel mesh, as a standardized and efficient form of steel bar application, is gradually replacing traditional manual lashing steel bars and becoming a key building material to improve construction quality and speed up project progress.It uses professional welding equipment to cross-weld high-strength steel bars according to preset spacing to form steel products with regular grid structure, which are widely used in housing construction, transportation engineering, water conservancy facilities and other fields.​
1. The core classification of welded steel mesh​
The classification of welded steel mesh needs to be combined with the actual needs of the project. It can be divided from three dimensions: steel material, mesh specifications and surface treatment methods.：​
According to the material of steel bars: the common ones are low-carbon steel wire welded mesh and HRB400 grade rebar welded mesh.The tensile strength of low-carbon steel wire welded mesh is moderate, and it is mostly used for small components or non-load-bearing structures, such as indoor floor leveling and wall drawing nets; HRB400 grade rebar welded mesh has become the preferred material for core parts such as high-rise building slabs, bridge load-bearing structures, and subway tunnel lining with a tensile strength of ≥400MPa.​
Divided according to grid specifications: it can be divided into fixed-length grids and customized grids.The common specifications of fixed-length grids are 100mm×100mm, 150mm×150mm, and 200mm×200mm, which are suitable for general architectural scenes; customized grids adjust the spacing (as small as 50mm) and the diameter of steel bars (usually 4-16mm) according to engineering design requirements to meet the force requirements of special structures such as nuclear power plants and grandstands of large venues.​
Divided by surface treatment: including black wire welding mesh, hot-dip galvanized welding mesh and plastic-coated welding mesh.Black wire welded mesh is used in dry indoor environments; hot-dip galvanized welded mesh improves corrosion resistance through zinc layer (zinc layer thickness ≥85µm), which is suitable for humid environments such as basements and underground garages; plastic-coated welded mesh is based on the galvanized layer with PVC coating, which can be used in outdoor scenes such as exterior wall insulation systems and garden landscape guardrails.​
2. Significant product advantages of welded steel mesh​
Compared with traditional manual lashing of steel bars, welded steel mesh shows obvious advantages in performance, efficiency and economy.：​
Stronger structural stability: the resistance spot welding process is used, the shear resistance of the solder joints is ≥600N, and the grid size deviation is ≤3mm, which can effectively transfer the load and reduce the generation of structural cracks.In floor construction, the use of welded steel mesh can control the crack width within 0.2mm, which is far better than the 0.3mm standard for manual lashing.​
The construction efficiency is increased by more than 50%: a single sheet of welded steel mesh can reach an area of 6-12 square meters and weighs only 15-30kg. It can be laid quickly by 2 workers without on-site cutting and lashing.Taking the 1000 ㎡ floor slab as an example, the traditional manual lashing takes 5-7 days, while the laying of welded steel mesh takes only 2-3 days, which greatly shortens the construction period.​
Material loss is reduced to less than 3%: standardized production in the factory can accurately control the length and spacing of steel bars to avoid waste caused by on-site cutting.The loss rate of traditional manual lashing steel bars is usually 8%-12%, while the loss rate of welded steel mesh is only 2%-3%, which can save 3-5 tons of steel bars per 1,000 square meters of construction.​
Higher quality controllability: the production process is monitored by automated equipment throughout the process, and each batch of products needs to be tested for solder joint strength, grid size, and mechanical properties of steel bars, and a quality certificate is issued.There is no need to rely on the technical level of workers for on-site construction to reduce the hidden dangers of human-made quality.​
3. Production process and quality control of welded steel mesh​
(1) Standardized production process​
Raw material screening: Choose hot-rolled ribbed steel bars that meet the GB/T 1499.2 standard or low-carbon steel wires that meet the GB/T 343 standard. Before entering the market, the yield strength, tensile strength and elongation must be tested to ensure that the raw materials are qualified.​
Steel bar straightening and cutting: The wire bar steel bar is straightened by the straightening and cutting machine, and cut off according to the design length, and the length deviation is controlled within ±5mm.​
Automated grid welding: The longitudinal and transverse steel bars are arranged on the welding machine according to preset spacing, and the resistance spot welding process (welding current 800-1200A, welding time 0.3-0.5s) is used to complete the welding to form a grid structure.​
Finished product shaping and inspection: perform flatness correction (flatness deviation ≤5mm/m) on the welded steel mesh, and then perform appearance inspection (no leakage welding, virtual welding, no cracks in the solder joints) and sampling inspection of mechanical properties.​
Packaging and transportation: wrapped in moisture-proof packaging materials, classified and stacked according to specifications, and fixed with special brackets during transportation to avoid grid deformation.​
(2) Strict quality control points​
Quality control of solder joints: 3% of the solder joints are randomly selected for shear testing in each batch, and the shear strength must meet industry standards; at the same time, check the appearance of the solder joints, and the number of virtual welding and leakage welding shall not exceed 0.5% of the total solder joints.​
Dimensional accuracy control: the deviation of the grid spacing is ≤±3mm, the diagonal deviation is ≤±10mm, and the deviation of the length and width of the mesh is ≤±10mm to ensure the adaptability of on-site installation.​
Corrosion resistance control: Hot-dip galvanized products need to test the thickness of the zinc layer (using a zinc layer thickness gauge), the average thickness of the zinc layer is ≥85µm, and the thickness of the local zinc layer is ≥65µm; plastic-coated products need to test the adhesion of the coating, and the coating does not peel off after the grid test.​
4. Application scenarios and installation points of welded steel mesh​
(1) Main application areas​
Housing construction engineering: used for cast-in-place concrete slabs, roof panels, walls, beams and columns stirrup nets, which can improve the crack resistance of components.In the three-story slabs of high-rise buildings, double-layer welded steel mesh (upper Φ12@100, lower Φ14@100) is used, which can effectively withstand vertical loads.​
Transportation engineering: The pavement layer of highway and railway bridge decks (using Φ10@150 welded steel mesh) can prevent cracking of the bridge deck; the use of welded steel mesh in the lining of subway tunnel pipes and shield tunnels can enhance the impermeability and durability of the pipe sheets.​
Water conservancy engineering: reservoir dam, canal slope protection, sewage treatment pond wall, using hot-dip galvanized welded steel mesh (Φ8@200), which can resist water erosion and chemical corrosion, and extend the service life of the project.​
Special projects: nuclear power plants, civil defense projects, and underground pipe corridors use high-seismic-grade welded steel mesh (HRB500-grade steel mesh with a grid spacing of 100mm×100mm) to meet the requirements of explosion and earthquake resistance.​
(2) Key points of on-site installation​
Preparation before installation: check the specifications, quantity and quality certificates of the reinforced mesh, and check whether the mesh size is consistent with the design drawings; clean up the base surface of the construction to ensure that there are no debris and stagnant water.​
Laying and fixing: Steel mesh is laid according to the design position, the lap length between the meshes is ≥200mm, and the lap is fixed with iron wire lashing (one for every 200mm); the edge parts need to be firmly connected with the template or embedded parts to prevent displacement when pouring concrete.​
Protective layer control: Use concrete pads of the same strength level (the thickness meets the design requirements, usually 15-30mm), and arrange them at a density of 4-6 per square meter to ensure uniform thickness of the protective layer of the reinforced mesh.​
Concrete pouring: When pouring, avoid the vibration rod directly hitting the reinforced mesh, and use a flat plate vibrator to vibrate to ensure that the concrete is dense and prevent deformation of the mesh.​
5. Industry development trends and purchase suggestions​
With the acceleration of the industrialization of construction, the welded steel mesh industry is developing in the direction of intelligence and greening.On the one hand, automated production lines have gradually introduced AI visual inspection technology to realize real-time monitoring of solder joint quality; on the other hand, the proportion of recycled steel bars in the production of welded mesh has been continuously increasing, promoting the recycling of building materials.​
When purchasing welded steel mesh, it is recommended to pay attention to the following three points: first, choose a manufacturer with the "Steel welded mesh Production License" to ensure complete production qualifications; second, it is required to provide raw material quality certificates and finished product inspection reports to verify product performance; third, choose the appropriate surface treatment method according to the engineering environment, such as hot-dip galvanized products are preferred in humid environments, and plastic-coated products are preferred in outdoor environments.​
As a “new choice for efficient building materials” in the construction industry, welded steel mesh can not only improve project quality and efficiency, but also promote the green and low-carbon development of the construction industry.In the future, with the continuous innovation of technology, its application scenarios will be further expanded to provide better solutions for modern construction projects.