Welded Wire Fabric Concrete

Welded wire fabric is a specialized construction material, composed of parallel longitudinal wires fused to cross wires through an electric fusion method. This meticulous welding process, executed by machinery, guarantees precise dimensions, resulting in significant savings in time, labor, and money.

General Specifications of Welded Wire Fibre Concrete

1. Material : The wires used in manufacturing welded fibre are either stainless steel rebar rods or galvanized steel rods. These materials exhibit excellent resistance to corrosion, making them suitable for use in wet conditions. The wires adhere to IS:432-Pt II/1982 standards, specifying an ultimate tensile strength of 570 N/mm2 and a characteristic strength of 480 N/mm2.

2. Shape and Size : Welded wire fibre is available in common shapes like rectangles and squares. The fabric can be manufactured in widths up to 3000mm, with lengths limited by transportation considerations. Standard lengths include 5500mm for ready-to-lay flat sheets or 15m, 30m, or 45m for rolled forms. The wire diameter ranges from 2mm to 12mm, conforming to IS:1566-1982, with varying long and cross-wire spacings (25mm to 400mm).

3. Cutting and Forming : The fabric is easily cut with wire cutters, and if needed for staircases, it can be conveniently bent to the required size.

4. Lapping and Clearance : Lapping is usually unnecessary due to customizable wire sizes, but if required, a minimum 6-inch lapping is recommended. Additionally, 1 to 3 inches of clearance is standard between the wire fabric and formwork.

5. Vibrating :Vibrating concrete reinforced with welded fibre mesh is recommended to ensure complete mix distribution and proper embedding, reducing the risk of cracking.

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Comparison: Welded Wire Fibre vs. Conventional Reinforcement

Aspect	Welded Wire Fabric	Conventional Reinforcement
Permeability	Increased	Reduction
Bond over time	Can deteriorate	Bonds permanently
Surface protection	Not provided	Improves durability
Resistance	Minor if properly placed	Improves impact resistance
Installation and cost	Difficult and expensive	Easy and cost-effective
Placement in concrete	Difficult, 1″ minimum cover	Easy, no minimum cover
Finish effect and maintenance	No effect on finish, challenging	Easy finish, minor impact
Deterioration without protection	Yes	No
Corrosion resistance	No	Yes
Tensile strength improvement	Yes	Yes
Reinforcement dimensionality	One plane	Three-dimensional
Ductility	Increases if properly placed	Increases
Aesthetics and remedy	Permanent with limited remedy	No lasting aesthetics, easy remedy
Specifications compliance	Meets ASTM if placed properly	Meets/exceeds ASTM
Storage	Difficult and detrimental outside	Can be stored for long periods

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Advantages of Welded Wire Fabric in Concrete

Higher Design Strength

• Comparable to HYSD bars or plain mild steel bars.
• Higher strength due to the characteristic strength of welded wires.

Better Bonding

• Rigid mechanical interconnections ensure quick stress transfer.
• Welds resist up to 210 N/mm2, facilitating efficient stress transfer.

Effective Crack Resistance

• Strong mechanical anchorage at intersections reduces cracks.
• Close spacing of thinner wires counters strain-induced stresses.

Economical

• Immediate savings in labor and time.
• No cutting, marking, or tying of binding wires.

Flexible in Handling and Placing

• Thin wires and long lengths in roll form make it flexible and convenient.
• Ideal for repair work, re-plastering, or guniting.

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Uses of Welded Wire Fabric in Concrete

• Structural flat slabs or beam-slab constructions.
• Large area floor slabs to achieve crack-free, joint-less surfaces.
• Concrete elements of curved or difficult shapes (arches, domes, etc.).
• Precast elements like thin arches, shells, roof girders, etc.
• Bonding fabric during repairs or rehabilitation of structures.
• Form reinforcement in prestressed concrete girders.
• Ferrocement works, forming the reinforcing matrix for precast elements.