Ferrocement in Himachal Pradesh: Sustainable Construction Solutions

Er. Umesh Pathania, Sr. Technical Officer, Council For Science, Technology & Environment, Shimla (HP), projects Ferrocement Technique used for Rainwater Harvesting, Structures, School Buildings, Toilets, Bathrooms, etc. in Himachal Pradesh.

Precast Ferrocement roof - Sundernagar

Ferrocement is a composite made of Ferro (Iron) and cement (cement micro-conc). Ferro cement can be considered as a type of thin-walled reinforced concrete construction in which small-diameter wire meshes are used in form of uniformly distributed throughout the cross section. Discretely placed reinforcing bars and selected Portland cement mortar is used instead of concrete. In ferro cement, wire-meshes are filled with cement mortar. It is a composite, formed with closely knit wire mesh; tightly wound round skeletal steel and impregnated with rich cement mortar (micro concrete).

It is possible to fabricate a variety of structural elements, which are used in foundations, walls, floors, roofs, shells etc. They are thin walled, lightweight, durable and have a high degree of impermeability. It combines the properties of thin sections and high strength of steel. Cast-in-situ and precasting methods are very popular in ferro-cement construction.

In addition, it needs no formwork or shuttering for casting. Ferro cement have various applications useful in fields of civil construction, including water and soil retaining structures, building components, space structures of large size, bridges, domes, dams, boats, conduits, bunkers, silos, treatment plants for water and sewage and retrofitting of masonry and RCC structures. Encasement of steel structures for protecting them from fire and corrosion effects. These have proved to be very effective in Himachal Pradesh, which lies entirely in the Western Himalaya (North Western India), largely made up of hills & mountains ranging from 450mts to 6500mts. There is a gradual rise in the average elevation from South to North. Valleys are prominent physiological features of Himachal Pradesh and they are the cradle in which human civilization has flourished in this mountainous region. Himachal Pradesh has a large geographical area of 55,698-km2 most of which are under Forests (31%) permanent pastures and grazing lands (33.6%). About 10% net area is under cultivation. Irrigation sources are meager and 83% of area depends on the rains. The land and water resources are scarce and have to be managed efficiently.

There are two rainy seasons in Himachal Pradesh. About 25% of the precipitation occurs during December to March with 75% occurring during the summer monsoon months of end of June to end of September. Average annual rain fall is 1134-mm but temperature varies widely geographically, because of the mountainous terrain the agro-climatic zones are difficult to delineate precisely. Common sources of water supply both for drinking and irrigation purposes are springs, streamlets and lift water supply schemes. Most of the rainwater flows down through deep gorges and valleys. In these circumstances in which Himachal Pradesh is situated, the rainwater harvesting system provides an effective and important tool for most of the region as a means for supply of water for other needs other than drinking.

Roof Top and tank systems provide an onsite source of water supply next to homes or public buildings such as schools or health community centers. As a water source, the major advantages of Rainwater collection systems are (a) in most areas, rainfall water quality is excellent and (b) the ability to operate independently of outside systems is useful in remote areas and difficult terrain.

The storage structures can be constructed from various technologies like Brick masonry, Stone Masonry, Synthetic Polymers, Ferro-cement, Reinforcement Cement Concrete and steel. As per convenience the adoption of different mode of construction of storage structures can be considered as per the material available, its cost of construction and its easiness to construct and maintain.

HP Council for Science Technology and Environment in collaboration with Structural Engineering Research Centre Ghaziabad (especially Dr. P.C. Sharma Head material Sciences) had organized many training programmes in the field using Ferro-Cement Technology such as construction of Roof Top Rain Water harvesting structures of different capacities, toilets, bathrooms, construction of school buildings using hollow blocks and F.C slabs in different parts of the state of Himachal Pradesh. Training for staff of different departments and to NGOs were also conducted during the financial year 1993-94. A brainstorming session was conducted by HP Council for Science Technology and Environment at HP Secretariat Shimla and the then Hon’ble Chief Minister of Himachal Pradesh presided over the session. This session was for all Administrative Secretaries, Head Of Departments etc. on making the collection of rain water compulsory. Dr. P.C. Sharma gave the Technical Presentations in this session.

Precast Ferrocement roof of a rural school in HP

The first training programme was organized at Shimla in collaboration and technical guidance from Structural Engineering Research Centre Ghaziabad and a 10,000-litre capacity rainwater harvesting structure was constructed near U.S. Club in Shimla. Thereafter, training to masons and department engineers was also conducted at Jwali Distt. Kangra by SERC team. Subsequently, HP Council for Science Technology and Environment has also demonstrated this technology using know-how transferred from SERC in different parts of the State. Some of the photographs are presented below.

The school building at village Bari has been constructed by using concrete blocks in the superstructure and roofing units made of Ferro-Cement. This technology was demonstrated by Community Development Cell of Govt. Polytechnic Sundernagar Distt. Mandi. (The photographs of the school building are given below):

Beside this Ferro-Cement technology demonstration work continued and the Community Development Cell of the Govt. Polytechnic Sundernagar developed precast ferro-cement toilets and bathrooms and demonstrated them all over H.P. State and people adopted this technology without any problem.

Khatris: Khatris are the structures of different sizes deeply curved out in the hard but porous rocks. The specially trained masons construct these water bodies. These traditional water harvesting structures are found in the District of Hamirpur, Kangra and Mandi of Himachal Pradesh. While Dr. P.C. Sharma heading UNICEF & CSTE Team visiting these districts, studied the Khatri structures and suggested many improvements using ferrocement for making them more hygienic and durable and these were implemented in many of these.

Khatris are of two types:

For animal and washing purposes in which rain water is collected from the roof top through pipes.
For human consumption in which rain water is collected by seepage through rocks. The Khatris are owned by individuals as well as the community.

Sometimes some of the Katris start leaking and the water gets empty. We got the solution and know how to repair these by using ferrocement technology. This technology was provided and demonstrated by Dr. P.C. Sharma, SERC(G). Some experiments were carried out on actual structures and found that the water stored in the Khatris after repair was not leaking and quality of water was improved and maintained for longer periods.