Pump House at RDSO, lucknow

RESQ Point for Shivgarh Resorts, Lucknow

10,000 litre water Tank at Aashiana, Lucknow  

Toilet for Tundla

Construction of Circular Museum at Khajuraho using Prefab FC folded plates  – 1984 

1,2 Two storey residence in a resort, Lucknow - Assembly of Semi large prefab FC components in full scale buildings for Resorts in and around Lucknow – 1995

Assembly of Semi large prefab FC components for water tanks for RDSO, Lucknow and  Industries of up to 70,000 litres capacity – 2004

Boundary wall 5' high at RDSO, Lucknow

Pump House, U P Jal Nigam, Hardoi

Gang Huts at Chunar for N Railway

Sheds at Azamgarh

A K Jain did his B. Tech and M. Tech from IIT Kanpur in 1969 and 1971 respectively. He is self employed since 1972 and has managed a Ferrocement Prefabrication Industry at Lucknow, U P. Presently he is a visiting faculty at MNNIT, Allahabad. His area of interest is prefabricated structures.

Sumit Kumar Agarwal is a leading employability skills trainer of the Country. He heads Tanjun Associate, a social enterprise solutions provider that specializes in Skill development space. Sumit has worked with reknowned names in the field of earthquake proof architecture, alternate and sustainable living and bamboo housing.He has assisted the Planning Commission in designing solutions for the Tsunami victims in the Andamans, IIA for Kutch Earthquake victims and the Concrete Institute India for Conservation of Concrete in Housing.

 

Er.Arun N Purandare is a Graduate in Civil Engineering from VJTI Mumbai and a Post Graduate from Imeprial College Londan. He has been in practice from 1965 and has more than 1500 large projects to his credit including the D.Y.Patil Cricket Stadium Navi Mumbai and MCA Stadium, at Gahunje,Pune. He is also an Environmental Consultant dealing with the issue of solid waste management and disposal. He is a member of several professional organisations. He has read and writted papers nationally and internationally on Earthquake engineering and Landfill Design. He has designed and patented Ferrocast Precasting system and is carrying our research in this field.

Building industry is passing through a very difficult time. The quantum of construction is increasing very fast specially in residential and commercial projects. This increase is not matched by equal increase in the availability of trained labour force as well as supervisory personal. This has resulted in totally untrained and persons with little skills working in all trades. The obvious outcome is the serious drop in quality of executed work. One such trade is carpenters for shuttering. There is a serious shortage of carpenters and those doing this work are of very doubtful quality, leading to bad concreting, bad line and level and no dimensional accuracy. Similar problem is experienced with respect to masons for brick work and plastering. The only other remedy to improve quality is to precast the structural elements in specially set up casting yards and erect them at site.

Precasting industry, though in great need , has not taken root due to its heavy capital costs in plant and machinery. A system had to be devised which can be started with substantially less capital cost. All this is possible with Ferrocast Structural elements. The dead load of individual ferrocast member is about 1/3 of the full section R.C. precast member making it easy to handle in the casting yard. The subsequent transportation and erection becomes easier due to lighter dead loads. In case of residential buildings, the individual elements will not weigh more than 600/700 Kg, thus making use of 2/3 T.  Hydra – mobile crane more than adequate to carry out all lifting and shifting jobs in the casting yard. This reduced capital cost makes it very attractive even for “B” and “C” class towns well as on site casting yard.

The present system of making ferrocement element consists of hand plastering stiff mortar into weld mesh / chicken mesh layers fixed on welded reinforcement forming a required shape. Hand applied plaster on weld mesh forms has several inadequacies. The complete section formed with hand plaster will not have expected strength throughout the cross section and length. This is a major problem leading to Codes not offering a value for tensile as well as compressive capacity. The plastered section does not have dimensional accuracy. The final sectional thickness also cannot be ensured. This is a detriment to proper structural design of the member. To get over this difficulty, members in this system cast in moulds, with self compacting mortar. This ensures correctly cast section with correct section dimensions. This method has been developed for column, beam and slab elements.

As ACI does not give any design values for tensile, shear or compression capacity for ferrocement, this material was not used for the normal structural elements used in building construction. The present method of ferrocement construction, with variable and doubtful quality, must have led to this reluctance on the part of the persons drafting the recommendations. The method suggested was like R.C. design without taking into consideration the high tensile qualities of ferrocement. This quality problem is fully eliminated with the use of ferrocasting the structural members.

In order to get correct design stresses, research was started. Concrete was encased in a ferrocast ring with variable layers of weld mesh. The confinement provided by the ferrocast ring enhanced the crushing strength of M-30 concrete beyond. 60 MPa. This was double the concrete mix strength. This clearly indicated that the confinement offered by ferrocast ring is vastly superior to that possible with reinforcement used as binders and ties. The enhancement in crushing strength indicated large ductility for core concrete. This is great step forward. The cracking tensile stress in beam tests showed elastic behavior upto 25 MPa. This tensile capacity can be used for the slab and beam design for tension. Both these experiments are pointing to enhanced compressive stresses in column design and tension capacity in the bottom flange of beams. All this will lead to substantial savings in the construction of the building frame.

The new system consists of casting ferrcast tubes of 25mm wall thickness. Concrete is poured into the annular space to form the column. The beam sections are “U” forms resting on columns. Slab units are placed on the two sides of the beam. Negative steel for continuity of slabs and beams is tied over supports and topping concrete is poured. A perspective view of a proposed construction with all structural elements in place is shown. The advantages of this system are,

1.            Light Weight, leading to saving in concrete and steel

2.            Advantage in Seismic Design                              

3.            Smaller foundation

4.            Factory made product with assured strength

5.            Form finished, does not need plastering

6.            Slab every 7/8 days

7.            Cheaper than R.C. Frame

 

Dr. Gajanan M. Sabnis has spent almost fifty years in the US with his career and is Emeritus Professor at Howard University, Washington, DC, USA with experience in teaching, industrial and research experience.

A native of Mumbai, he obtained his B.E. from VJTI and M. Tech from IITB and Ph.D. from Cornell University in 1967. After retiring in 2008, he splits his time in the USA and India to help improve the quality of concrete and infrastructure in India by using technology that he has developed or obtained from USA. Dr. Sabnis believes in sustainability of concrete. He built and lived in an energy-efficient award-winning home he built in concrete with recycled construction materials. Dr. Sabnis has published more than 20 books and 200 research papers read by engineers in many parts of the world and includes three in India.

He was James Berkeley Gold Medalist in 1961 from University of Bombay and is the Distinguished Member of ASCE and Fellow of ACI, IEI, ICI, ACCE and the registered PE in the US. In ACI, he was actively involved in the technical committees for over 30 years and helped establish many ACI Chapters including one in India in 1979. He was the first winner of ACI Chapter Activities Award in 1976. He was first Indian on the ASCE Board as International Director responsible for more than 25 countries and was responsible for membership growth and active participant in the ASCE Board activities initiating new programs in that area.

The journey for Ferrocement for us in the US, began in India and Asian countries and once it reached the US, it took another dimension. It became a hit in ACI, where many of us have been active since 1960’s and ACI 546, Ferrocement was established and both Bala and I participated; I was the early initiator. This presentation is an outcome of our common interest of improving quality of concrete structures to make them better, less expensive and sustainable, not just as material of practice, but also using some of “Nano-technology” to delve in the future of this a very simple, non-engineering, village material, which will become a real common material of construction and make better concrete.

At the present time, we can site examples from both the East and the West, with the use of Ferrocement in various kinds of structures. They range from simple panels to tanks to complex shaped roofs, some of which are presented in other presentation(s). At the same time, considerable research has been done to indicate in general a better structural behavior of this simple and yet very effective construction material. Various books are available to indicate the available literature (Ref. 1, 2, 3) and considerable research has been done; however, with recent research presented in the previous paper. Research has continued leading to more possibilities for the future applications.

There are specific initiatives that need to be emphasized if ferrocement is to become a much more accepted construction material, just based on the earlier presentations. How to make this material more useful and scientific should be the aim, is a challenge. Yes, ferrocement shell is good for making the structural elements of building, such as column, slab and beam work as a unit with the final outcome much better. There three main aspects, the light is shed on in this presentation.  First one is the bond between the shell and the core of elements, in spite of the natural bond; the recent work using nano-technology to use cementitious material coating to work as an adhesive and make them monolithic. In addition, this monolithic action is extended beyond to the entire system work as a unit, the basic need in precast construction. The second one is to make these units waterproof, which is another problem that is faced in India due to harsh environment especially in coastal region like Mumbai. The third advantage that the research has proven is for making the structure better looking and often even more futuristic by using the special properties of nano-cement used in the finishing of the entire structure. This property makes the structure, not just better acting but a better looking with its dust-proof or graffiti-proof property. All the three initiatives are based on the research in the last decade or more at Rutgers University in the US, mainly by the second author and is looked upon as a possibility to make Indian structures (mainly in concrete) stand out as special and economic as well.

The presentation is concluded with some examples as possibilities in the future for structurally sound and aesthetically pleasant, so that ferrocement may be well recognized. The word, nano-technology had become household just like “sustainability” to use ferrocement and precast technology contribute to more economic structures in the future. Based on the projected cost, the saving of up to 30% cost is achievable a brighter future for ferrocement. 

References:

1. Sabnis, G.M. (editor), ACI SP-61, Ferrocement and Its Applications, Published by ACI, 1978

2.  P. Balaguru and S. P. Shah, Fiber Reinforced Cement Composites, McGraw- Hill, 1992, 530 pages.

3.  Naaman, A.E., Ferrocement & Laminated Cementitious Composites, Published by Techno Pre 3000