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TNK - Our Name is in Mud
Mukesh Jain
Use
of mud inspite of proven and durable building material since long,
is restricted to the poorer communities only. It is the oldest
building material to be used by man. In the river sites of the
Mesopotamian, Egyptic, Chinese and the Indus valley civilizations,
readily available alluvial soil was used to make the first mud brick
dwellings. Jericho, history's earliest city, had houses built in raw
earth. Harappa and Mohenjo Daro saw the use of adobe walls faced
with oven baked bricks. In the Americas too, there are ancient
examples of earth being used as a building material. The Mexican
city of Tenochtitlan had structures built of earth walls faced with
lime rendering. With the advent of industrial revolution, new
construction technologies spread, and earth construction skills were
lost or relegated to the vernacular builder. Impetus was given to
earth architecture in the post World War II years due to economic
and energy saving concerns.
To
create awareness about its useful, durable, comfortable qualities
among middle class and affluent groups, Tara Nirman Kendra is taking
a step forward. With manual compaction using simple press like
BALRAM and scientifically backed technology inputs like
stabilisation, durable 3-4 storey load bearing structures can easily
be built in mud. The bricks used in mud buildings are called
Compressed Earth Blocks - CEB.
Advantages of CEB
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Low cost in comparison with burnt clay bricks. |
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Low energy consumption because it is sun dried. |
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Comparable in strength with burnt clay bricks |
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Aesthetic in nature |
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Labour intensive |
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Utilises local resources, materials and labour |
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Can
be made with compact, transportable and low cost manul press
BALRAM - costing Rs. 14000/- only |
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Stabilisation with cement / lime increases resistance to erosion |
Production
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1000 - 1200 blocks/ day produced by team of 5 labourers. |
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Blocks cured for 2-3 weeks, then air dried for 1 week. |
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Manually operated machine like BALRAM is adequate for
production of high density stabilised soil blocks. |
Technical Details
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Size of CEB is 230 X 108 X 76 mm, same as that of burnt clay
bricks. 230 X 230 X 76 mm size also possible. |
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Ideal soil for stabilised CEB is red sandy loam. |
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Unsuitable soils for CEB are |
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Acidic soils with pH < 7 . |
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Soils with high gravel or silt percentage. |
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Soils containing more than 0.5% organic matter. |
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l
Suitability of soil for CEB
Acceptable range of particle size gradation
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(in
%) |
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coarse gravel |
0 |
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fine
gravel |
0-10 |
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coarse sand |
20-35 |
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fine sand |
20-30 |
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silt |
15-30 |
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clay |
10-30 |
Stabilisation - wih 4-7% cement
Stabiliser is added to CEB during its production to prevent
softening of blocks on absorption of moisture. The possible
stabilisers are cement, lime or both. Cement is recommended for red
sandy loams, low clayey soils. If clay content is very low, the lime
remains free. It can be remedied by replacing 15-40% of cement (by
weight) with a pozzolanic materials like fly ash, rice husk etc.If
clay content is high than lime cement combination may be used or
sand may be added to the soil to reduce the clay content.
Other Details
Dry compressive strength – 50-70 kg/sqcm
Wet compressive strength - 30-40 kg/sqcm (aftger 48 hrs) against
recommended 20 kg/sqcm as per IS code adequate for 2/3 storey house.
Water absorption 10-14% only, against allowance of 20% as per IS
code for CEB.
Economy in use of CEB
i)
CEB masonry leads to about 15-20% saving in cost when compared with
conventional masonry because
ii) Only 400-425 CEBs are needed/cum of masonry against 500/cum of
burnt clay brick masonry.
iii) Mud mortar is used in CEB masonry against cement sand mortar
in conventional masonry.
Building in CEB
Tara Nirman Kendra has built many modern buildings in CEB -
Indira Gandhi National Centre for Arts at Delhi; workshop building
of Sushant School of Architecture at Gurgaon; hospital building at
Bodhgaya, construction project for Rural Development and Self
Employment Institute at Nelamangala; Bangalore district ,
Institutional building for the Dharmadhikari of The Temple Trust of
Dharmasthala, 50 IAY houses at Azadpura in Bundelkhand.The world
Headquarter building of TNK's parent organisation, Development
Alternatives is also built entirely in CEB. All these buildings are
standing testimony to the strength and virtuosity of the technology. q
For more info contact
Mukesh Jain
TARA Nirman Kendra
Village Sultanpur, Mehrauli Gurgaon Road,
New Delhi - 110 030
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