This document discusses light weight construction materials, specifically foamed concrete. It describes four types of foamed concrete based on density and their typical uses. Densities range from 300-600 kg/m3 for thermal insulation up to 1200-1600 kg/m3 for precast panels. Advantages include economy, durability, thermal insulation, fire safety and wide range of applications. Disadvantages include reduced strength at lower densities and specialized tools needed for fastening. It also categorizes light-weight concretes based on aggregates and concludes that structural light-weight concrete combining strength and lightness will have economic advantages.

1. Brig. S.K. Sharma (Retd.)
Pro Vice Chancellor and Professor
Department of Civil Engineering,
The Northcap University, Gurgaon
UNIT-1
LECTURE – 2
LIGHT WEIGHT CONSTRUCTION MATERIALS
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2. INDEX
 TYPES OF FOAMED CONCRETE
 ADVANTAGES & DISADVANTAGES OF FOAMED
CONCRETE
 GROUP OF LIGHT WEIGHT CONCRETE (BY
AGGREGATES)
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3. TYPES OF FOAMED CONCRETE & THEIR
USES
(BY DENSITIES)
Foamed concrete with density of 300-600 kg/m3: This
concrete also called foamed cement or foam concrete, is
made of cement and foam only. This material is used for
thermal insulation of roof and floors, soundproofing and is
applied on rigid floors. It is used for tennis courts and void
filling between brickwork leaves in underground walls,
insulation filling in hollow blocks and any other filling
situation where high insulating properties are required.
Foamed concrete with density of 600-900 kg/m3: The
constituents of this concrete are cement sand and foam. It
is used for the manufacture of precast blocks and panels
for curtain and partition walls, slabs for false ceilings,
thermal insulation and soundproofing screeds in multistorey
residential and commercial buildings. The concrete of this
density range is also suitable for bulkfill applications.
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4. TYPES OF FOAMED CONCRETE (Continued…)
Foamed concrete with density of 900-1200 kg/m3: This
concrete made of cement, sand and foam, is used in
casting the concrete blocks and panels for outer leaves of
buildings, architectural omamentation as well as partition
walls, concrete slabs for roofing and floor screeds.
Foamed concrete with density of 1200-1600 kg/m3: This
lightweight foamed concrete containing cement, sand and
foam is used in precast panels of any dimension for
commercial and industrial use, in-situ casting of walls,
garden omaments and other uses where structural
concrete of light weight is recommended.
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5. Foamed lightweight concrete: The lightweight matrix
formed by the mixture of cement, water, lightweight
aggregate and foam, can be used without the tendency to
float when the mix is vibrated. Typical aggregates used are
expanded shale or clay, pumice, vermiculite or fly ash.
The inclusion of such material shale or clay, pumice,
vermiculite or fly ash. The inclusion of such material is only
recommended if it is locally available as its procurement
from outside source may result in a higher cost of the final
product.
TYPES OF FOAMED CONCRETE (Continued…)
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6. Foamed dense-weight concrete: The addition of up to
10 per cent foam into a normal dense-weight concrete
mix reduces its density and the cost. The increase in the
slump allows the water-to-cement ratio to be reduced.
Introduction of foam eliminates bleed water, allows early
troweling of the surface, makes the concrete pumpable
even in hot weather and improves the resistance to freeze-
thaw attrition. Although the reduction in water-to-cement
ratio produces an increase in strength, it is usually
necessary to slightly increase the cement content of the
mix to maintain the specified compressive strength.
TYPES OF FOAMED CONCRETE
(Continued…)
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7. ADVANTAGES AND DISADVANTAGES OF
FOAMED CONCRETE/MORTARS
ADVANTAGES:
 Economy: Due to accurate geometrical dimensions the
foam concrete blocks and panels may be laid on glue, to
avoid frost bridges in a wall and to make the inner and
outer plaster thinner. The weight of foam concrete is about
10 to 80 per cent less than the conventional vibrated
concrete. This reduction in weight leads to sufficient
economy particularly on foundations and basements.
Foams concrete is easy to work with using common tools.
The saving in cost is generally of the order of 10 per cent.
 Durability: Foam concrete is a durable material and
deterioration with time is very small. It is as durable as
rock.
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8. Advantages (Continued…)
 Thermal insulation and microclimate: As already
covered, foamed concrete has far superior thermal
insulation properties than the conventional normal-
weight concrete. Due to high temperature lag,
buildings constructed with foam concrete products may
result in huge saving in the energy consumption of the
order of 20-35 per cent. Thus, the foamed concrete
which is almost a humidity-proof material prevents loss
of heat in winter by build up of very high temperatures
in summer, and controls air humidity in a room by
absorbing and releasing moisture as per environmental
conditions. Thus, it helps in creating a favorable
microclimate.
 Acoustic insulation: As brought out under properties,
foamed concrete has superior acoustic properties as
compared to other dense-weight products due to its
excellent sound absorption capacity; it does not reflect
sound. In buildings constructed with foamed concrete,THE NORTHCAP UNIVERSITY8

9. Advantages (Continued….)
 Fire safety: Foamed concrete is fire resistant, i.e., unlike
normal-weight concrete it neither spalls or splits or blows
nor gives off toxic gases under direct exposure to fire
(typically for foamed concrete with density less than 14
Kn/m3).
 Aesthetics: Due to the high workability and light weight,
foamed concrete is extensively used in architectural
ornamentation.
 Speed of construction: Due to he light weight of
foamed concrete, largesized blocks and panels as
compared to bricks, can be cast resulting in high speed
of laying these large-sized elements. Foam concrete is
convenient to process and can be cut to desired size;
and to drill holes for electrical wiring, sockets, and pipes.
The speed of construction is further enhanced through
lower tolerance (+/-1 mm) in linear dimensions.
 Quality: It is amenable to efficient production with
consistent quality. Foamed concrete has minimum bleed
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10. Advantages (Continued….)
 Ecological compatibility: Foamed concrete is
environment friendly, both in the production process and
product application, its ecological compatibility is second
only to wood.
 Transportation: The available combination of weight,
volume and packaging makes foamed concrete a
favorable construction material which is convenient to
transport by highway or railway system. It has lower
transportation costs as one cubic meter of foam is
produced only from one liter of concentrate and is mixed
at the site.
 Wide Range of applications: Foamed concrete is ideal
for thermal and acoustic insulation of roofs, walls and
floors; subscreeds and filling under-floor voids;
production of blocks and panels for removable partitions
in buildings. It is most suitable for filling redundant voids
such as disused tanks, sewer systems, pipelines, and
culverts-particularly where access is difficult.
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11. DISADVANTAGES
 Compressive strength of foamed concrete reduce as its density
reduces.
 The cellular structure of foamed concrete requires specialized
fasteners for the attachment of both structural framing members and
non-structural fittings. Metal-sleeved expanding anchors are not used
as they become loose. The retention values of attached fixtures
depend on the density of the product. Particular attention needs to be
given to those areas where continuous impact occur, e.g., door jambs.
 All drilled holes in foamed concrete require the use of high speed twist
drills suitable for steel or wood, (masonry drill bits and hammers
cannot be used).
 To provide holding power to fastners, expansion and friction grips
need be provided within the concrete.
 The production of foamed concrete requires a specially designed
equipments for mixing as the foam tends to float at the surface of the
mix and thus its effectiveness is considerably reduced. Injecting the
foam into the mix rather than onto the mix is preferred in the case of
an open mixer. The problem of mixing is readily addressed to in the
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12. GROUPS OF LIGHT-WEIGHT CONCRETE
(BY AGGREGATES)
No-fines
Concrete
Light-weight
aggregate concrete
Aerated Concrete
Chemical aerating Foaming mixture
Gravel Clinker Aluminium powder
method
Preformed foam
Crushed stone Foamed slag Hydrogen peroxide
and bleaching
powder method
Air-entrained foam
Coarse clinker Expanded clay
Sintered pulverized
fuel ash
Expanded shale
Expanded clay or
shale
Pulverized fuel ash
Expanded slate Vermiculite
Foamed Slag Pumice
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13. CONCLUSION/FUTURE THOUGHTS
Structural light-weight aggregate concrete is a concrete
having 28 day compressive strength more than 17 Mpa and
28 day air dried unit weight not exceeding 1850kg/m3.
Structural light weight concrete is going to be one of the
important materials of construction. A concrete which is
light in weight and sufficiently strong to be used in
conjunction with steel reinforcement will be a material
which is more economical than the conventional concrete.
Therefore, a concrete which combines strength and
lightness will have the unquestionalbe economic
advantage.
Video: YouTube, Autoclaved Aeated Concrete, 06:37
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14. THE NORTHCAP UNIVERSITY14
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