In both traditional and modern constructions, natural resources are used directly and indirectly, which leads to their depletion as they are not renewable. The cost to benefit ratio, or the price we pay, or are going to pay, in the future for development, is much skewed and highly dangerous. Cement, steel, tiles, aluminum, paints, and other materials used in the interiors consume a large amount of energy during manufacturing. This high embodied energy has a huge negative impact on these materials, without which, we cannot construct anything.
In such a scenario Ferrocement Technology-based construction comes as a breath of fresh air and gives hope and respite from the onslaught of the rampant depletion of natural resources.
Ferrocement is a very green initiative for constructing sustainable structures. Calculations done on live examples have proven that the technology enables lower carbon footprint and leads to green credit ratings. Firstly, it does not have aggregates and bricks as ingredients. Secondly, it has weld and chicken meshes as the main reinforcement, which requires lesser energy to manufacture. Cements containing high fly ash content, or GGBS, can also be used. The tor steel usage is extremely limited and used as skeletal steel, which offsets the need for formwork and precious timber, and the structural steel used for formwork of modern RCC structures is majorly eliminated. Most importantly, as the thickness of the Ferrocement is very low, consumption of cement, sand, (even manufactured sand can be used) gets reduced.
Today, with the advent of Geopolymers in construction, it is possible to have Ferro Geopolymer-based construction. It has the greatest advantage of replacing cement and sand by 100%.
Fly Ash, which is an environmental burden, and a challenge for safe disposal, can be used and activated using simple chemicals and made to behave like cement. It only requires sunlight (which is abundant in this country for almost 9 months of the year), and a temperature of about 30 to 35*C for curing, and most importantly, it completely eliminates the need for water (the most precious thing on this earth today). In fact, Ferro-geopolymers could be the game changer technology of the future.
The behavior of Ferrocement as a 2-phase, homogenous composite as against concrete (which acts as a heterogeneous composite) makes Ferrocement far more superior than RCC. Its ability to take both tensile and compressive stresses almost equally with very low crack widths, resistance to shrinkage, drying and cracking, makes it a technology of choice for structural designers.
Further, with the reduced self-weight, foundations can be smaller and kept on weaker soils having medium to poor bearing strength. The earthquake loads get considerably reduced, though wind loads could be a matter that needs to be addressed; however, it can be resolved by adding eco-friendly and cost-effective dead weights.
Eco-friendly & Magical Technology
Ferrocement is a combination of cement, sand, weld mesh and chicken mesh pressed and filled with mortar. Skeletal steel in the form of 6mm/8mm bars are used for getting the form and shape to eliminate use of formwork.
“A little change in the type and pattern of the reinforcement, the use of fine wire meshes instead of large diameter bars, and press filling mortar either by hand, machines, or pre-casting, makes it a wonder material!”. This is how Dr. (Prof) Divekar explained it after living with it in body, mind, and soul for over 40 years, having designed and constructed a large number of such structures.
Chicken mesh a hexagonal wire woven GI mesh. It is flexible and is stretched while fixing it to the skeletal steel. Weld mesh is a square grid of small diameter bars that are pre-welded in a factory and is more rigid. The skeletal steel is a skeleton of 6/8mm mm diameter steel bar, welded to the required shape and size. The weld mesh is fixed to it and the chicken mesh stretched on both sides of the skeleton steel.
In the second part, a thick cement mortar is prepared. It is a mix of 1 part cement and 2 parts of fine sand and a small quantity of water. This thick mortar is press filled in the chicken-mesh layers, after which the finishing and levelling is done using a plate trowel for aesthetics. Pressing makes it stiff. There is no wastage. After some days it appears like a wooden plank, very slim, and very tough. Curing is required - just like concrete.
The application of this technology in the construction industry is enormous and wide ranging from very small to large structures - both cast in situ and precast. Ferrocement can be used for making security cabins, compound walls, small buildings, domes, pyramids, water tanks, treatment plants, repairs, waterproofing, permanent forms, check dams, silos, roads, pathways, pontoons, blast fences, and a lot more.
Low cost precast ZATPAT house
Jayant Murudkar, a 78-year-old engineer from Satara MIDC manufactured a ZATPAT house in a day by assembling ferrocement components like readymade walls and readymade slabs and joined them with the help of nut bolts. The precast ferrocement wall panels are standardized as 3.5 x 2.5 meter and the thickness is 25 mm. The roofing panels are 4 x 0.6 meter in size with the same thickness. The panels are ribbed so they have greater strength even though light in weight.
Inspected by the Ferrocement Society, the Zatpat house is becoming popular in Maharashtra as it can provide immediate shelters to rehabilitate affected families and can be used for mass housing such as for the Prime Minister’s Awas Yojana. The houses can be dismantled and reused anywhere, which makes them eco-friendly. They are not built by using bricks and timber, yet their walls have tremendous strength since they are made from chicken meshes and are earthquake resistant too.
Er Murudkar has set up a factory to produce the ferrocement components and has installed a machine to manufacture panels of 0.6 x 3 meters, weighing about 100 kg only. A precast wall panel of 3.5 X 2.5 meter size weighs 750 kg only. Thickness of 25 mm is available. A 100 mm thick wall panel is manufactured using thermocol as an insulation filler.
Zatpat house is very affordable. If the plan dimensions of the room are 4.5 m by 3.5 m and height is 2.5 m, the cost of the house is only Rs 1,71,000. This includes excavation, foundation concrete, masonary, door and window, one bathroom and one toilet externally attached to the room. The rate is Rs 1010 per sq foot. A detailed video can be viewed on https://www.youtube.com/watch?v=bIsOE3X4Ros).
Versatile & futuristic material
Ferrocement has been in use for the last 30 years across the country. Everybody is aware of it, but many do not know the details of the technology and the cost. It is a simple, straight, and easy to build technique. It is a futuristic material and is an easy solution for many of the problems which concrete even today cannot resolve.
The typical domes of Shikhar on Ramakrishna temple built in Pune are precast thin petals of ferrocement. They are a classic example of the potential of ferrocement when designed and constructed properly. In America, Mexico, England, France, Germany, and Indonesia, the technology is being used extensively. In India, let us understand and adopt this magical innovation, save our natural resources, and be friendly with our environment.