FERROCEMENT Presented by, MOHAMMED AAQIB 4JN11CV410 Under the guidance of, PRIYANKA B A B.E, M.Tech Lecturer Dept. of civil engineering

CONTENT Introduction Materials used in construction Typical cross section Cement mortar mix Types of wire mesh Advantages of Ferro cement Construction methods Application of Ferro cement Conclusion Reference

INTRODUCTION Italian engineer Pier Liugie Nervi is credited with inventing Ferro cement in the 1940’s. The properties of Ferro cement, such as strength, watertightness, toughness, light weight, durability, fire resistance & environmental stability are hard to match with any other thin constructional material

DEFINITION “Ferro cement is a type of thin wall reinforced concrete, commonly constructed of hydraulic cement mortar, reinforced with closely spaced layers of continuous and relatively small size wire mesh. The mesh may be made of metallic or other suitable material.” -ACI Committee 549, 1980

FERRO CEMENT– A composite of steel & cementitious material is an ingenious invention of the mid 19th century which has a good potential for use in a wide variety of applications. It is basically a scaled down variation of concrete – as we know it today. The large size reinforcing steel bars are replaced with wires or meshes, while the coarse aggregate is removed completely from the cementitious matrix. The resultant composite – called Ferro cement lends itself to casting in thin sections – sometimes less than 1”.

Materials used in Ferro cement Cement mortar mix. Skeleton steel. Steel mesh reinforcement or Fibre-reinforced polymeric meshes. Admixtures.

CEMENT MORTAR MIX MIX PROPORTIONS OPC and fine aggregate matrix is used. The matrix constitutes 95% of the composite and governs its behavior. FA (sand) occupies 60 to 75% of the volume of the mortar. Plasticizers and other admixtures are used. MIX PROPORTIONS Sand: cement ratio (by mass) 1.5 : 2.5 Water: cement ratio (by mass) 0.35 :0.60

Steel mesh reinforcement Consists of galvanized steel wires of diameter 0.5 to 1.5 mm, spaced at 6 to 20mm centre to centre. Available as woven/interlocking mesh and welded mesh. Welded wire mesh has hexagonal or rectangular openings. Expanded-metal lath is also used.

TYPES OF WIRE MESHES

TYPICAL SECTION OF RETAINING WALL USING FERRO CEMENT

ADVANTAGES OF FERRO CEMENT High ductility High resistance to cracking width Ability to undergo large deflection Improved impact resistance and toughness Good fire resistance Good impermeability Low strength to weight ratio Low maintenance costs

CONSTRUCTION METHODS Skeletal Armature Method Closed Mould Method Integral Mould Method Open Mould Method

1) Skeletal Armature Method In this method the skeleton steel is welded to desired shape, on either sides of which are tied several layers of stretched meshes. This is strong enough, so that mortar can be filled in by pressing for one side and temporarily supporting from the other side.

2) Closed Mould Method Several layers of meshes are tied together against the surface of mould which holds them in position while mortar is being filled in.

3) Integral Mould Method Using minimum reinforcement any integral mould is first to be considered to act as a framework. On this mould layers of meshes are fixed on either sides and plastering is done on both the sides. (Source: Naaman 1999)

4) Open Mould Method

APPLICATIONS OF FERRO CEMENT Marine applications Water supply and sanitation Agricultural Residential buildings Rural energy Other structures

1. Marine Applications Boats, fishing vessels, barges, cargo tugs, catamarans, yachts and flotation buoys. Key criteria for marine applications: light weight, impact resistance, thickness and water tightness. 2. Water supply and sanitation Water tanks, sedimentation tanks, swimming pool linings, well casings, septic tanks etc..

4. Residential Buildings 3. Agricultural Grain storage bins, silos, canal linings, pipes, shells for fish and poultry farms. 4. Residential Buildings Houses, community centers, precast housing elements, corrugated roofing sheets, wall panels etc..

5. Rural Energy 6. Other structures Biogas digesters, biogas holders, incinerators, panels for solar energy collectors etc.. 6. Other structures Bus shelters, industrial shelters, pedestrian bridges, skateboard rings, sculptures etc..

Conclusion Ferrocement being a labour intensive and a material saving technique, has never been able to compete with reinforced cement concrete. However, innovative structures in different parts of the world have clearly indicated the unique, unmatched properties of this material. The application of Ferrocement to the dome structure has made it possible to construct a light but strong, durable weather resistant shell with a weight reduction to almost 1/10th of the conventional material.

REFERENCE Andrews, G., Sharma, A.K., “Repaired Reinforced Concrete Beams” ACI, Concrete International, pp. 47-50,1998 Gambhir, ML, Concrete Technology: Theory and Practice, McGraw Hill Santhakumar, AR, Concrete Technology, Oxford University Press Shetty, MS, Concrete Technology, S Chand Publishers