WHAT IS UNCONVENTIONAL?
Anything which is not aligned with the general trend or set of rules.
Unconventional materials include those materials which are not
common construction materials. These may be recycled materials,
reusable scraps like boxes, cans, pipes etc.
However several materials have come up which is a modification of the
existing ones like AAC, WPC etc.
The materials covered further are
Pervious Permeable Concrete
Wood composite polymer
Autoclaved Aerated Blocks
Fiber Reinforced concrete
Polymer modified mortar
Hempcrete is a combination of
chopped hemp and binder comprising
of natural hydraulic lime and a small
amount of cement. It is firm and self
Hempcrete is suitable for uses such as
timber frame infill, insulation and, with
the addition of aggregate, floor slabs.
Hemp is a renewable biomaterial and
lime is an abundant quarried material.
It is carbon negative and the
obvious choice for buildings aiming
to achieve a low carbon footprint
and the highest sustainable
building code levels.
It regulates the temperature and
humidity of a building; in some
cases completely eliminating the
need for heating and cooling
systems, resulting in huge energy
The addition of hemp fibres not
only improves the strength and
flexibility, it also increases the
thermal properties of the plaster
and so is an excellent way of
adding some insulation to your
It is extremely flexible and
breathable which makes it suitable for
use in them restoration of old 'solid wall'
construction buildings and ideal as a
'wattle and daub‘ replacement in
It is also suitable in ecological new
builds as it can be applied to a variety
of substrates e.g. wood fibre boards,
wood wool boards, straw bale.
It is fire and termite resistant,
lightweight and forms a hard wall
surface yet is vapour permeable to
help reduce humidity and prevent
BENEFITS OF HEMP OVER OTHER MATERIALS
It grows several metres within months. It grows 4m within 100-120 days.
It is versatile - it can be used to produce several products most are non-
toxic, bio-degradable and renewable.
It is 10 times stronger than cotton, it naturally repels weed growth and
hemp has few insect enemies which means it requires no herbicides and
few or no pesticides whereas cotton requires enormous pesticide use.
It can be used as clean biomass. It has more potential as an energy
source than any other crop.
Given the right conditions, it is resistant to rot, is fireproof, waterproof,
weather resistant and importantly provides insulation. Hemp lime plaster is
easy to use and can be applied in much thicker coats than conventional
lime plaster hence offering labour savings! It is also much lighter than sand
plasters and so has transport savings to.
The addition of hemp fibres dramatically improves the compressive and
flexural strength of the product which make its more durable and stronger
that other lime plasters.
made from a natural, renewable plant fibre (instead of depleting a
natural aggregate resource).
WOOD POLYMER COMPOSITE/ WOOD PLASTIC COMPOSITE (WPC):
WPC (Wood Polymer Composite), a promising and sustainable green material is being
evolved as a fundamental product for India, after being well adopted by the world.
During WPC process, polymers are reinforced by incorporating the wood powder and
fibres discharged from mills and factories as well as agriculture residues. WPC
production is a 100% safe manufacturing practice, releasing no air or water pollution
and having no process waste of materials. WPC is a highly eco-friendly product having
no formaldehyde emission.
The conceptualization of WPC is based on the ‘Cradle to Cradle’ approach where the
material is recycled at the end of its cycle to produce a new cradle (new) product. The
resultant is minimization of solid waste content and conservation of natural resources.
Hence cost, energy and depletion of the core materials are reduced considerably.
MATERIALS UTILIZED IN WPC:
Wood and plastics (virgin or recycled) with various types, grades, sizes, and conditions are the
main materials utilized in WPC production. WPC is composed mainly from a plastic matrix
reinforced with wood and other additives sometimes are added using the appropriate processing
WPC utilizes polyethylene and they classified the types of plastic used in WPC as follow:
polyethylene (83%), polyvinyl chloride (9%), polypropylene (7%), others (1%).
Wood flour is obtained from wood wasted from wood processors. It should be from high quality
and free of bark, dirt, and other foreign matter. Moreover, species are mainly selected based on
regional availability of high quality flour and color. Pine, oak, and maple are the most common
used in the United States.
Additives should be added to the mix because the majority of the WPC physical and
mechanical properties are depending mostly on the interaction developed between wood and the
plastic which is increased by additives
•THE REAL ALTERNATIVE TO EXOTIC HARDWOODS: Exposed to the elements, the
lifecycle of wood, whether soft or hardwood, is limited. Wood is vulnerable to UV radiation,
humidity, fungal growth or insect attack, and requires regular treatment to delay greying, splitting,
splintering or the spread of rot. Wood plastic composite provides an appealing alternative: rot
proof and durable, it is guaranteed splinter-free and non-slip, it will not split or crack, and is
resistant to insects and fungal infection.
•A SUSTAINABLE BUILDING MATERIAL: Manufactured using processes designed to protect
the environment, a board in wood plastic composite is ecologically sound. The wood ﬁbres are
mainly recycled pine. The resin component – recycled polypropylene – is a fully recyclable,
environmentally-neutral plastic, widely recognised as a non-toxic substance. These raw materials
– both wood and plastic – are all sourced from the recycling industry.
•DURABILITY: AN ESSENTIAL QUALITY:
1. WEATHER RESISTANT: WPC is used in very diverse climates, and under difficult
conditions where exposure to extreme heat and sunshine, or constant humidity, are the
2. EXCEPTIONAL DENSITY: While hardwood will gradually succumb over time to
weathering and hostile outdoor conditions, the extrusion process used in the
manufacture condenses the material irreversibly. The subtle intricacies of the
technology and the resins used form a perfect adhesive, without the addition of any glue
WPC is used in both outdoors and indoors:
• Swimming pool surrounds,
• Walkways, Steps,
• Outdoor furniture or panelling,
• Screens or louvered shutters,
• Wood ﬂooring or wall coverings,
• Garden arbors or pergolas.
The WPC boards, accessories and ﬁxing clips reduce laying times to half those required
when installing hardwood decking or support structures. Using standard tools, even the most
inexperienced installer can produce straight, neat cuts without splintering. The boards are
supplied with an ingenious system of invisible clips for easy laying and rapid dismantling, (if
required) minimising the number of screws needed. These clip fasteners allow the structure
to expand and shrink while maintaining ﬁrm but elastic contact between the boards and their
supporting structure. The stainless steel screws we strongly recommend are black.
Wood composite polymer is manufactured by sevral market
companies including ECOSTE(India), EINWOOD(Dubai, Malaysia),
JELUPLAST (Germany) etc.
Costing of one of them is as follows:-
ECOSTE WOOD COMPOSITE POLYMER
18 mm thick : Rs. 140/sq. ft
12 mm thick : Rs. 90/sq. ft
6 mm thick : Rs. 40/sq. ft
In conventional concrete, micro-
cracks develop even before structure
is loaded because of drying
shrinkage and other causes of
volume change. When the structure
is loaded, the micro cracks open up
and propagate. The development of
such micro-cracks is the main cause
of inelastic deformation in concrete.
However, research has shown that the addition of small, closely
spaced and uniformly dispersed fibers, to concrete substantially
improves its static and dynamic properties. These fibers offer increased
resistance to crack growth, through a crack arresting mechanism and
improve tensile strength and ductility of concrete.
Fiber reinforced concrete can be defined
as a composite material consisting of
cement mortar or concrete and
discontinuous, discrete, uniformly
dispersed fibers. The continuous meshes,
woven fabrics, and long wires or rods are
not considered to be discrete fibers.
The inclusion of fibers in concrete and
shotcrete generally improves material
properties including ductility, toughness,
flexural strength, impact resistance,
fatigue resistance, and to a small
degree, compressive strength. The type
and amount of improvement is
dependent upon the fiber type, size,
strength and configuration and amount
TYPES OF FIBRES :
A fiber is a small discrete reinforcing material produced from steel, plastic,
glass, carbon and natural materials in various shapes and sizes. A
numerical parameter describing a fiber as its Aspect Ratio, which is
defined as the fiber length divided by an equivalent fiber diameter.
Typical aspect ratio range from 30 to 150 for length dimensions of 0.1 to
7.62 cm. Typical fiber diameters are 0.25 to 0.76 mm for steel and 0.02 to
0.5 mm for plastic.
STEEL FIBRES :
Steel fibers have been extensively used in
overlays of roads, pavements, airfields,
bridge decks and floorings subjected to
wear and tear and chemical attack. The
main problem encountered in the use of
steel fibers is the tendency of the fibers to
ball or cling together during mixing. This
leads to non-uniform dispersion of fibers.
Incorporation of steel fibers also decreases
workability of concrete.
Glass Fibres :
These are produced in three
basic forms (a) rovings (b)
strands (c) woven or chopped
strand mats. Major problem in
their use are breakage of
fibers and the surface
degradation of glass by high
alkalinity of the hydrated
cement paste. However, alkali
resistant glass fibers have
been developed now. Glass
fiber reinforced concrete
(GFRC) is mostly used for
decorative applications rather
than structural purposes.
Plastic Fibres :
Fibers such an acrylic, aramid, nylon, polyproplylene and polyethylene have
high tensile strength but low Young’s Modulus thus sharing inability to
produce reinforcing effect. However, due to their high ultimate elongation,
their addition to concrete have shown better resistance to cracking,
reduced crack size and higher impact strength. Their use in concrete is
gaining popularity due to numerous advantages.
Carbon Fibres :
These fibers posses high tensile strength and high Young’s Modulus. The
modulus of rupture of an aligned carbon fiber reinforced cement composite
with 8 % fiber volume can be as high as 1623 kg/cm². The composite also
possesses high fatigure resistance. The use of carbon fibers in concrete is
promising but it is costly and availability of carbon fibers in India is very
Mineral Fibres :
Asbestos fiber has proved to be the most successful fiber, which can be
mixed with OPC. The composite has considerably high flexural strength. The
maximum length of asbestos fiber is 10 mm but generally fibers are shorter
CLASSIFICATION ACCORDING TO VOLUME FRACTION
ƒ Low volume fraction(<1%)
ƒ Moderate volume fraction(between 1 and 2%)
ƒ High volume fraction(greater than 2)
LOW VOLUME FRACTION
ƒ The fibers are used to reduce shrinkage cracking. These fibers are used
in slabs and pavements that have large exposed surface leading to
high shrinkage crack. ƒ Disperse fibers offer various advantages of steel
bars and wiremesh to reduce shrinkage cracks:
–(a) the fibers are uniformly distributed in three-dimensions making an
efficient load distribution;
–(b) the fibers are less sensitive to corrosion than the reinforcing steel
–(c) the fibers can reduce the labor cost of placing the bars and
MODERATE VOLUME FRACTION
ƒ The presence of fibers at this volume fraction increase the modulus of
rupture, fracture toughness, and impact resistance. These composite
are used in construction methods such as shotcrete and in structures
that require energy absorption capability, improved capacity against
delamination, spalling, and fatigue.
HIGH VOLUME FRACTION
ƒ The fibers used at this level lead to
strain- hardening of the composites.
Because of this improved behavior,
these composites are often referred
as high-performance fiber-reinforced
composites (HPFRC). In the last
decade, even better composites
were developed and are referred as
reinforced concretes (UHPFRC).
ADVANTAGES OF FIBRE REINFORCED CONCRETE
• Reduction in shrinkage and cracking :
Research has shown that high fiber count (number of fibers per unit volume),
reduces the effects of restrained and drying shrinkage cracking. The addition
of polypropylene fiber also reduces crack width significantly. After cracking,
the fibers transfer tensile stress across cracks and act to confine crack tip
extension so that many fine (hair line) cracks occur instead of fewer larger
• Improved Bond Strength
The fibers exhibit improved mechanical bonding as a direct result of cement
matrix penetrating the fibers network. This feature is called pegging.
• Fatigue strength and endurance limit :
One of the important attributes of FRC is the enhancement of fatigue strength
as compared to plain concrete. The addition of polypropylene fibers, even in
small amount has increased the flexural fatigue strength.
• Better Toughness :
Addition of fibers improve post-crack behaviour and energy absorbing
capacity of concrete. The ability to absorb elastic and plastic strain energy
and to conduct tensile stresses across cracks is an important performance
factor for serviceability of concrete. Fibers have significant influence on post-
crack load carrying capacity of concrete..
Based on the test of one hundred and ninety five specimens made with the
available local materials, the following conclusions can be derived:
1. No workability problem was encountered for the use of hooked fibers up to
1.5 percent in the concrete mix. The straight fibers produce balling at high
fiber content and require special handling procedure.
2. Use of fiber produces more closely spaced cracks and reduces crack
width. Fib- ers bridge cracks to resist deformation.
3. Fiber addition improves ductility of concrete and its post-cracking load-
carry- ing capacity.
4. The mechanical properties of FRC are much improved by the use of
hooked fibers than straight fibers, the optimum volume content being 1.5
percent. While fib- ers addition does not increase the compressive strength,
the use of 1.5 percent fiber increase the flexure strength by 67 percent, the
splitting tensile strength by 57 per- cent, and the impact strength 25 times.
5. The toughness index of FRC is increased up to 20 folds (for 1.5 percent
hooked fiber content) indicating excellent energy absorbing capacity. 6.
FRC controls cracking and deformation under impact load much better than
plain concrete and increased the impact strength 25 times.
Developed in Sweden in the 1920s in response to increasing demands on timber supplies,
AAC is a lightweight manufactured building stone. Comprised of all natural raw materials,
AAC is used in a wide range of commercial, industrial, and residential applications.
Autoclaved aerated concrete is a precast product
manufactured by combining silica (either in the form
of sand, or recycled flyash), cement, lime, water, and
an expansion agent - aluminum powder, and pouring
it into a mold.
During this process, the hydrogen gas that
escapes creates millions of tiny air cells, rendering
the concrete with a strong cellular structure.
THE MANUFACTURING PROCESS
Air bubbles are created by a
chemical reaction between the
hydration products and the
Weather and earthquake resistant
Concrete is about
one-fifth the density
of normal concrete
Reduces the dead load
Ensures less usage of steel and concrete
Requires lesser number of joints
Ensures a smooth and accurate masonry profile
Allows less thickness of plaster
Imparts thermal, sound insulation, fire resistant and earthquake resistant properties.
Minimizes waste and pollution
Consumes 50% lesser energy than that needed for manufacturing concrete
Well suited to withstand fires earthquakes and other natural disasters.
(a)a view showing the use of
AAC as an infill material
substitute of the original
AAC can be shaped to confirm
to any design and can
accommodate almost any detail.
AAC is excellent for all buildings.
AAC can be used for interior
partitions, load bearing walls,
back-up walls, firewalls, stair
enclosures, elevator shafts,
column wraps, shafts and chutes.
(b) a view from the outside showing
the application of the exterior cement
based plasters over the timber
framed structure with AAC infill.
a) close view to the
application of AAC
inside the timber
b) the timber framed wall
with AAC infill after the
Blocks are made to very exacting dimensions and are usually laid in thin-bed mortar that is
applied with a toothed trowel, although more conventional thick-bed mortar can be used.
AAC has low compression strength. The use of mechanical fasteners is not recommended,
as repeated loading of the fastener can result in local crushing of the AAC and loosening of
the fastener. There are proprietary fasteners that are specifically designed to accommodate
the nature of the material by spreading the forces created by any given load.
Conventional thick-bed (10mm approx.) mortar can be used with
SERIAL NO. PROPERTIES SPECIFICATIONS
1. Size 600x200x75-300
2. Compressive strength 4-5 n/sq. Mm
3. Dry density 500-600 kg/cubic m
4. Fire resistance 2-6 hours
5. Sound reduction index 45 db for 200 mm thick wall
6. Thermal conductivity 0.16 w/m deg. C
Due to its relatively low consumption of readily available raw materials, excellent
durability, energy efficiency, relative cost effectiveness, and ability to be recycled, AAC
is well deserving of its “green” designation.
The cost of AAC is moderate to high . It is about 1.5 times higher than regular concrete.
AAC is competitive with other masonry construction but more expensive than timber frame.
Lack of competition in the marketplace makes consumers highly dependent on one
• It is used as a coating for walls and ceilings
• Application can be be manual or sprayed by machine
• It can be applied directly on a concrete surface. No hacking is
• Only water needs to be added, easy to mix and application is
• It is a highly tensile adhesion strength and hence higher bonding
with the base material .
• Does not require any water curing.
• It is pre mixed and hence hassle free, involving no cumbersome
mixing of cement and sand at site.
• The application can be thin as 2-3 mm or as thick as 8-10 mm
depending upon the requirement.
• It can be used as a crack filler for external walls in repairing old
plastered surfaces, in repair of shrinkage cracks in parapet walls,
in repairs after plumbing/electricl works etc.
It is very important that it is thoroughly mixed
with water before use. It is advisable to use a
mechanical stirrer for uniform and thorough mixing.
Take a clean vessel or bucket without any holes or cuts.
Pour some water in it to ensure that no powder gets
stuck to the bottom. Add the required quantity of
polymer modified mortar powder.
Mixing Ratio - The amount of clean potable water
required is approximately 25% to 30% of the weight of
the powder, depending upon the thickness of the
product to be applied. Water is to be incrementally
added in stages, to get a smooth, uniform, workable
mix. Allow ample time for initial mixing.
Ensure that no powder is left unmixed at the bottom of
METHOD OF APPLICATION
It can be applied on the surface manually with a
After thoroughly mixing the mortar, apply the first
coat on the moistened wall surface uniformly, going
upward from the bottom. This will ensure minimum wastage and
a proper finish.
The thickness of the coating should be 3 mm (1/8 inch).
Allow the surface to dry for at least 3 hours and then apply the
Leave the surface to dry completely.
For higher thicknesses, a number of subsequent coats can be
applied to achieve the surface in plumb.
Leave the surface to dry (preferably overnight for 10-12 hours)
before subsequent application .
METHOD OF APPLICATION
No water curing is required
Prepare only the required quantity of mortar and use it within 2
to 3 hours of mixing with water. Do not add extra water.
Do not apply under direct sunlight or in temperatures higher
than 35°C. If the application is done under direct sunlight,
necessary measures like covering the surface with net and
water curing after two hours should be undertaken.
In case of ordinary day bricks or hollow blocks where the
undulation is high, plastering is essential.
It may be applied over plaster in a thickness of 2 to 4 mm,
depending on the surface undulation for leveling.
AREAS OF APPLICATION
Residential buildings, commercial complexes,
basements, parking areas etc.
It can be directly used on surfaces made from
fly ash bricks, concrete blocks, AAC blocks etc.
In the case of ordinary day bricks or hollow
where the undulation is high, plastering is
over which it may be applied up to 2 to 4 mm
thickness depending on base plaster.
Repairs and renovation of old concrete and
Polymers improve mortars in four main ways:
1. More extensive cement cure. Cement/concrete
strength depends on proper curing, a chemical reaction
(hydration) between water and cement that causes crystals to
grow and wrap around the mix components. During the early
stages of cure (roughly the first five to seven days), there must
be enough water to maintain the hydration process or the
cement/concrete will not harden properly.
Polymers reduce the rate of water evaporation,
allowing the crystal structure to keep
growing and building strength during
these critical early curing stages. This
reduced water evaporation is especially
important in thin applications, where the
surface area for evaporation is high, relative
to the volume of the mortar.
2. Improved workability. Polymer modification noticeably
improves application characteristics, making the mortar more
fluid and easier to handle and apply. Certain polymers also
prolong the hydration period, which can increase working time,
an important characteristic in hot climates.
3. Improved adhesion. Polymer modifiers act as an adhesive to
enable the modified mortar overlay to stick to a variety of
surfaces such as concrete, masonry, brick, wood, rigid
polystyrene and polyurethane foam, glass, and metals
4. Improved strength and durability. Cured polymer-modified
mortars generally have improved tensile strength, flexural
strength, impact and abrasion resistance, water resistance, and
chemical resistance versus unmodified mortars. Also, the
polymer in the mortar helps restrain micro-crack propagation,
which improves the overall toughness of the mortar.
Highly economical. Eliminates the lengthy, cumbersome process of
transporting individual materials and mixing on site.
Saves time and labour as it is pre-mixed, requiring only water to be
mixed at site.
Consistent and assured quality, as it is pre-mixed.
No water curing required.
No crack formation during drilling or plumbing work.
Does not flake when in contact with moisture.
Cement based, ensures better bonding with the substrate.
Allows subsequent application of putty or paint just 24 hours
Provides better breathability for walls.
Can be applied over moist surfaces.
Excellent crack-filling properties
Pervious concrete is a special concrete with a
high porosity used for concrete flatwork that
allows the water from precipitation or other
sources to pass through thereby ensuring the
recharge of ground water.
1. It allows rainfall to be captured and to
percolate into the ground.
2. It reduces storm water runoff.
3. It recharges groundwater
4. It supports sustainable construction
BENEFITS OF PERVIOUS CONCRETE
1. Reduces storm water runoff
2. Eliminates the need for detention ponds and
other costly storm water management
3. Replenishes water tables and aquifers.
4. Allows for more efficient land development
5. Minimizes flash flooding and standing water
6. Prevents warm and polluted water from
entering our streams
1. the maximum size of coarse aggregate may be either 10 mm or
20mm with designed porosity of 15-25%
2. The compressive strength of concrete is 3-18Mpa. The size of pores is
in the range of 0.5 = 0.8mm.
3. Helps in storm water management system.
It has lower life cycle cost sowing to good strength and excellent
4. The maintenance of pervious is cheap and easy.
5. Pervious concrete has a 15-25% void structure and allows 3–8 gallons
of water per minute to pass through each square foot—accounting
for far more than is generated during most rain events.
1. Reduced development cost
a)Smaller capacity storm water drainage
b)Lower investments for rainwater harvesting
2. Reduces overall runoff from an area and also reduces total
amount of pollutants in runoff.
3. Help maintain growth of trees deposits aving
4. Reduces pooling of water and hence glare at night
5. Has unique surface finish and enhance tractions which provides
better skid resistance to light traffic at the time of rainfall.
INSTRUCTION FOR USING
1. Prepare properly compacted sub grade
2. Place 8”-24” open grade stone(pebble) base
3. Place pervious concrete of appropriate
thickness over the base course
4. Curing to be started within 24h and should be
continued for at least 7days.
1. No reinforcing steel….not as structurally sound
2. Works best on flat sites
• Certified installers needed
• Sets up fast
• EXACT water content is critical
4. Soils and loads must be right
5. Maintenance (not much more than other
surfaces, but different)