A brief discussion about the use of locally or naturally available materials for construction purposes, their use in roads and railways.

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CEN-391 Technical Communication
Local Material for Civil Infrastructure Projects
Adarsh (14113004)
Abstract: This report deals with the contribution of local materials in civil infrastructure
projects. Advantages of natural materials over the industrial materials have been discussed such
as their contribution towards a sustainable environment, reduction in transportation costs and
several other things. Different natural building technologies involving the use of local materials
such as clay, timber, flyash, straw bale, stone, etc. have been discussed in this report. These
materials can be used effectively in construction such as clay, timber, straw bales, etc. can be
used to construct small structures, fly ash in embankments and road construction and several
other uses.
Keywords: Adobe, Cob, Cordwood, Earthbag, Wattle and Daub
Introduction
Civil Engineering is considered to be the
initial footsteps of mankind into the world
of engineering. It keeps us overwhelmed by
its astonishing outcomes. The development
in the fields of structural, hydraulics,
transportation, environmental and survey
engineering has helped the people to have a
safe place to live in, to travel with ease and
get a sustainable environment.
All these things involved, the civil
infrastructure projects incur huge costs and
extensive use of materials such as cement,
steel, composite material for road
pavements, etc. The major problem related
to these is that they involve huge costs in
the project related to their production and
transportation. Of course there is not a very
great alternative to this, so it has to be
fulfilled. But lately, considering the
resources available and economically
viable projects, natural or local materials
can be used effectively such as clay and
sand, harvested wood, fly ash, etc.
Natural buildings mainly strive towards
increasing environmental sustainability that
include range of building systems and
materials. Its basis is to lessen the
environmental impacts of buildings and
other supporting systems without
compromising life and health. These
natural buildings use abundantly available,
recycled or reused materials. Also they rely
on non-industrial, minimally processed and
locally available materials.
Features
Natural or local materials have less energy
embodied and less toxic than man-made
materials. They require less processing and
have very less impact on the environment.
Also the products become more sustainable
when they are incorporated into building
materials.
Construction waste can also be reduced if
use of natural materials is emphasised. For
example, if we consider concrete, we can

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see how much of it goes waste regarding its
handling, the time in which it should be
used, etc. and several other factors. This
results in a considerable amount of waste
which needs to be dealt with properly and
also there is wastage of money. On the other
hand, less waste generation will be there in
case of local materials because only that
amount will be used that is required. Also
some of the natural materials that are
considered as waste such as harvested wood
in forests, fly ash, etc. can be used in
construction projects thereby reducing the
waste.
Also the transportation cost can be reduced
in case of local materials as it can be readily
available as compared to the man-made or
industrially produced materials.
Materials
Some of the materials that can be used for
natural building are clay, wood, straw
(straw can be loosely defined to include any
dried non-woody plant material such as
palm fronds, reeds, etc.), fly-ash, rice-hulls,
slag, wool, bamboo and stone. Variety of
non-toxic recycled or reused materials are
very common in natural buildings such as
urbanite (salvaged chunks of used
concrete), vehicle windscreens and other
recycled glass.
Clay is abundantly available for many
natural building techniques. Straw bales
can be available seasonally from the farms.
Bamboo can be a very effective material in
constructing sustainable structures. Also
fly-ash is being used nowadays in
construction of roads and in embankments.
It is not always possible to use locally
available materials but if used, should be
done selectively and in a small volume.
Natural Building Techniques &
Technologies
As we have already seen how locally
available materials can be advantageous in
the civil infrastructure projects, let us
discuss the technologies in which they can
be used:
Adobe
It is one of the oldest building methods.
Adobe is simply a mixture of clay and sand
with water. For strengthening it, chopped
straw or other fibres are added sometimes.
The mixture is then dried in the desired
shape. Usually it is used to form bricks that
be stacked to form walls. Also, adobe can
be plastered over with lime-based mixes for
protection and appearance. It is not a good
insulator hence insulators can be used
preferably on the outside. However, thick
traditional un-insulated adobe has proved to
very effective in regions where weather
conditions are not very harsh.
Fig 1. House constructed of bricks formed by adobe
Cob
The term cob is used to describe a
monolithic building system based on a
mixture of clay, sand, straw and earth. The
construction uses no forms, bricks or
wooden framework; it is built from the
ground up. Cob is one of the simplest and
least expensive building techniques
available, though it is typically very labour-
intensive. It can easily be shaped into any
form owing to its versatility. Cob is
generally associated with low-rise
structures. Cob-like mixes are also used as
plaster or filler in several methods of
natural building, such as adobe, earth bags,
timber frames, and straw bales. Earth is
thus a primary ingredient of natural
building.

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Fig 2. A small Cob building
Cordwood
Cordwood construction is a term used for a
natural building method in which short
lengths of pieces of debarked tree are laid
up crosswise with masonry or cob mixtures
to build a wall. Cordwood masonry can be
combined with other methods (e.g.,
rammed earth, cob or light clay) to produce
attractive combinations. Cordwood
masonry construction provides a relatively
high thermal mass, which helps to minimise
fluctuations in temperature.
Fig 3. A section of a Cordwood home
Earthbag
Earth is the most typical fill material used
in bag-wall construction techniques. This
building method uses stacked
polypropylene or natural-fiber bags filled
with earth or other mixes without a
stabilizer such as portland cement, to form
footings, foundations, walls and even
domed roofs. Recently, this method has
been gaining popularity as it facilitates self-
contained, often free-form rammed-earth
structures.
Since earth is a poor insulator, substitutes
like pumice, rice-hulls, etc. are being
utilised for their use in harsh weather
conditions.
Fig 4. An Earthbag structure
Rammed Earth
Rammed earth is a wall system made of
compacted earth, or another material that is
compacted. It is extremely strong and
durable. Quality rammed earth walls are
dense, solid, and stone-like with great
environmental benefits and superior low
maintenance characteristics. Rammed earth
walls are formed in place by pounding
damp sub-soil (containing sand, clay and
sometimes gravel) into movable, reusable
forms with manual or machine-powered
tampers.
Fig 5. Multi-coloured rammed earth wall

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Stone
Stone has been used as a building material
for thousands of years and is recognized as
a material of great durability. They form
freestanding structures such as field walls,
bridges and buildings that use irregularly
shaped stones carefully selected and placed
so that they fit closely together without
slipping. Stone is a highly durable, low
maintenance building material with high
thermal mass. It is versatile, available in
many shapes, sizes, colours and textures,
and can be used for floors, walls, arches and
roofs.
Fig 6. A Stone structure
Straw bale
Grasses and straw have been in use in a
range of ways in building since pre-history
around the world. Straw bale building
typically consists of stacking a series of
rows of bales (often in running-bond) on a
raised footing or foundation, with a
moisture barrier between. Bale walls are
often tied together with pins of bamboo or
wood, or with surface wire meshes, and
then plastered with either lime-based
formulations or earth/clay renders. Basic
bale-building method is now increasingly
being extended to bound modules of other
often-recycled materials, including tire-
bales, as well as those of cardboard, paper,
plastics and used carpeting, and to bag-
contained "bales" of wood-chips, rice-hulls,
etc.
Fig 7. A straw bale structure
Timber frame
The basic elements of this technique are
joint timbers, clay walls and thatch roofs.
These structures are mostly common in the
European countries. Timber frame
structures are frequently used in
combination with other natural building
techniques, such as cob, straw bale, or
cordwood/masonry.
Fig 8. A timber frame structure
Wattle and Daub
Wattles are made from flexible wood or
fibres and are woven loosely to create an
underlying structure for a wall. Plaster is
then daubed onto the wattle to finish the
wall and provide thermal mass. Straw
wattle is a better-insulated variation where
clay-embedded long straw fibres are woven
around light-weight uprights and then
plastered.
Wool Bricks
These bricks are exactly what the name
suggests. By addition of wool and some
natural polymer, their strengths are
increased by about 37% as compared to the

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other bricks. They also dry hard, reducing
the embodied energy as they don’t need to
be fired like traditional bricks.
Fig 9. Wool Bricks
Uses of Flyash
Flyash can be used in the cement mixture as
a substitute to Portland cement and sand, in
the embankments or structural fills, waste
stabilisation and solidification, as a subbase
material for roads and in the bricks as a
substitute material.
Conclusion
From the content above we have seen
various kinds of construction technologies
being used involving the use of naturally or
locally occurring materials. They can be
used in small quantities in large scale
projects which can result in a considerable
reduction in the cost of the project. Also
they can be a great alternative to the
industrial materials in small projects. The
way in which they prove to be sustainable
to the environment, it can be a better choice
to use these materials in the civil
infrastructure projects.
References
Kim J., Graves J., “Sustainable Architecture Module:
Qualities, Use, and Examples of Sustainable Building
Materials.” (1998). Sustainable Architecture Module:
Qualities, Use, and Examples of Sustainable Building
Materials, National Pollution Prevention Center for
Higher Education, 430 E. University Ave., Ann Arbor,
<http://www.umich.edu/~nppcpub/resources/compend
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“Naturalbuilding.” (n.d.). Wikipedia, Wikimedia Foundation,
<https://en.wikipedia.org/wiki/natural_building> (Oct. 16,
2016).
By lining the trench with 2. (2010). “NaturalBuilding Materials,
Techniques & Technologies at Dancing Rabbit.” Dancing
Rabbit Ecovillage, <http://www.dancingrabbit.org/about-
dancing-rabbit-ecovillage/eco-living/building/natural-
building/> (Oct. 16, 2016).
“Five Sustainable Building Materials that Could Transform
Construction.”(2010). This Big City Comments, Joe Peach,
<http://thisbigcity.net/five-sustainable-building-materials-
that-could-transform-construction/> (Oct. 16, 2016).