Ferrocement is a type of thin-walled reinforced concrete, materials used in Ferrocement manufacturing process is hydraulic cement mortar, reinforced with continuous and relatively small size wire mesh.
The mesh may be made of metal or other suitable material.
Ferrocement is much thinner than reinforced concrete, and the mesh can be formed to any shape without a conventional form, and then plastered or mortared by hand.
The material used in Ferrocement:
Ordinary Portland cement and fine aggregate are used.
The particle size of sand should not more than 2.36mm and less than 1.18mm.
More than 2.36mm particle can make the mortar porous and particles less than 1.18mm requires more water to the impermeable structure.
Sand occupies 60- 75% mortar volume.
It used in Ferrocement & they are further classified as
A. Skeleton Steel:
The skeleton steel frame is made conforming exactly to shape of the structure and the geometry.
The steel rods are spaced at 70 to 100 mm apart and diameter may vary from 3 to 8 mm.
This is used for holding the wire mesh in the shape of the structure and position.
In the case where higher stresses may occur, the mild steel bars are used.
B. Wire Mesh:
The wire mesh consists of galvanized wire spaced at 6 to 20 mm centre to centre and 0.5 to 1.5 mm in diameter.
The wire mesh may be of the shape as welded wire mesh or square is woven wire mesh, Hexagonal wire or mesh expanded metal etc.
The yield strength of plain wires used in fabric should not be more than 415 MPa and 500 MPa for deformed wires.
The metal content might vary between 300 kg to 500 kg per cubic meter of mortar.
Ferrocement manufacturing process:
1. Hand plastering:
In this method, control thickness is hard and the minimum thickness is a stream that is 2cms.
The strength achieved by this technique shall be lower than different methods.
Units can be inserted by this process and used if various higher methods are not present.
These items can be utilized for pipes, storm buildings, and gas holder units.
2. Semi mechanized process:
This system also is known as semi-mechanized because the mould can be rolled to facilitate the dynamic of the mortar.
The consistency of this system may be greater than the earlier system.
Better compaction can be obtained using a straight edge pressed against the inner mould in this method.
Local, un-skilled people can handle this process.
The gun-running process can be adapted to apply the mortar to the wire mesh system.
This is the most suitable process for the large-scale construction of Ferrocement prefabricated units.
If this process is utilized with a skilled gunner, can provide a compact and uniform surface.
4. By Centrifuging:
Centrifuging courses are often adopted for the development of solid cylindrical units.
Ferro cement pipes are cast by centrifuging and it is used as tension pipes.
Difference between Ferrocement and Ferroconcrete:
Ferrocement is a composite material made of mortar reinforced with mild steel mesh, which is used to make thin sections.
Ferroconcrete is a construction material made of Portland cement concrete with a matrix of steel bars or wires (rebars) to increase its tensile strength.
Properties of Ferrocement:
- It has high tensile strength and stiffness.
- Improves the influence and punching shear resistance.
- Undergo massive deformation earlier than rupture or high deflection.
- Low weight.
- A low w/c ratio produces the impermeable structures.
- It is a very durable, inexpensive and versatile material.
Advantages of Ferrocement:
- It can be fabricated in any desired shape, hence it is more suitable to a special structure like shells and structure like roofs, water tank etc.
- Also, it is a highly suitable material for precast merchandise.
- It has high ductility and resistance to crack.
- Also, it has favourable to tensile properties.
- It has low maintenances.
- Also, it is environmentally friendly.
Disadvantages of Ferrocement:
- Sensitivity to stress failure.
- Low shear strength.
- It can be perforated by hitting sharp objects.
- Corrosion of the reinforcing materials as a result of incomplete protection of metallic by mortar.
Frequently Asked Questions:
What is meant by ferrocement?
Ferrocement is a composite material made of mortar reinforced with mild steel cloth or mesh, which is used to make thin sections.
What is ferrocement slab?
Ferrocement slab panels (FSPs) are thin-walled elements made of cement, sand, water and various types of mesh.
How many methods of ferro cementing are there?
1. Hand plastering.
2. Semi mechanized process.
4. By Centrifuging.
Is ferrocement waterproof?
Ferrocement is completely waterproof without any treatment or coating.
Ferrocement has often used in the constructions for resistant to earthquakes.