Lightweight concrete uses lightweight aggregates to reduce density. It can be prepared in three ways: by inserting air bubbles, omitting fine aggregates, or using lightweight aggregates. Porous concrete has high insulation and moisture movement but high shrinkage. Lightweight aggregate concrete is used in roofs, walls and precast elements for its strength, low density, and insulation. It has advantages like rapid construction, reduced weight and transportation costs, but disadvantages like water sensitivity, difficult finishing, and longer mixing times.

1. LIGHTWEIGHT
CONCRETE

2. DEFINITION
concrete which uses lightweight
aggregates
May consist of lightweight aggregates are
used in ordinary concrete of coarse
aggregate and sand, clay, foamed slag,
clinker, crushed stone, aggregates of
organic and inorganic.

3. Methods of preparation of
lightweight concrete
3.Providing lightweight
aggregate concrete
1.Preparation of porous
concrete
2.Without providing
concrete smoother
(rough concrete)

4. 1.PREPARATION OF POROUS
CONCRETE
a) Lightweight concrete obtained by
inserting gas bubbles or air into the mixture
of plastic cement (mixed with fine sand)
b) Lightweight concrete did not contain
stones included as porous mortar.

5. Characteristics of porous concrete :
2. a high
moisture
movement
3. a high
shrinkage
1. high
thermal
insulation
POROUS CONCRETE

6. Types of porous concrete
a) type of
cast in situ
b) type of
first cast

7. Aggregates used shall comply with
the following conditions:
a) At least
95% of
aggregates
must be via
the 18mm
BS sieve.
b) The stone
aggregate used
shall not
exceed 10% by
10 mm BS
sieve.
c) Stone did
not diffuse
through the
BS 4mm
sieve.

8. 2. Preparation of concrete without
the smooth (rough concrete)
 Lightweight concrete such as is
obtained when the fine aggregate
(sand) is not used and the
concrete mix of cement, water and
coarse aggregates.
Concrete can be used for
structural purposes and not to
bear burden to bear a load.

9. 3. Preparation of lightweight
aggregate concrete
• Concrete is often used in:
a) before
pouring the
concrete block
b) the roof and
walls cast in
situ for use in
insulation.
feature of lightweight aggregate concrete.

10. The main purpose of the concrete
requirements are:
c) have low
drying shrinkage
(to avoid
cracking/rift)
b) have a low
density (for
better insulation)
a) has sufficient
strength

11. The above factors depend on:
d) the
methods and
techniques of
preservation
c) the
density
b) the
mixture
a) types of
aggregates
used

12. Characteristics of
Lightweight Concrete
Rain
penetration
Water
absorption
Durability
Fire
insulation
Thermal
insulation
Acoustic
properties

13. Thermal insulation
Thermal insulation efficiency is defined as resistance
to heat flow either through conduction, or radiation.
Lightweight concrete has a high heat insulation
resistance.
such as porous concrete walls 150mm to provide four
times better insulation than 225mm thick brick wall.

14. Fire insulation
• Fire prevention is associated with thermal
insulation.
two types
of fire
protection
b) a non-combustible
materials - such as
non-organic materials
such as stone, bricks,
rocks and other.
a) combustible
materials - such
as organic
wood

15. Durability
It is defined as the ability to bear the effects of environment
such as the effects of chemical, physical stress and mechanical
effects. The intended effect of the chemical, including ground
water containing sulfate, air pollution and reactive liquid spills.
Physical stress is the shrinkage, the stresses of temperature,
cooled, and others. If all the physical stress will cause cracks in
the structure of lightweight concrete.
Mechanical effect is the impact and costs are excessive. The
situation in the steel structure unit should be protected from
rusting.

16. Water absorption
Absorption water by the concrete is high and
more than that found in solid concrete. This is
because the lightweight concrete has holes in it.

17. Penetration of rain water
It is an important element to
the wall

18. Acoustic properties
The key factor is the density of
the sound insulation material.
Therefore, for sound insulation,
lightweight concrete can not show
the desired characteristics.

19. iv) Most of lightweight
concrete have
better nailing and sawing
properties
than heavier and stronger
convensional concrete
iii) Significant reduction
of overall
weight results in saving
structural
frames, footing or piles
ii) Economical in
terms of
transportation as
well as reduction
in manpower
i) rapid and
relatively
simple
construction
Advantages

20. Disadvantages
iii) Mixing time is
longer than
conventional
concrete to assure
proper mixing
ii) Difficult to place and finish
because of the porosity and
angularity of the aggregate. In
some mixes the cement mortar
may
separate the aggregate and float
towards the surface
i) Very sensitive with
water content
in the mixtures

21. Example :
• ‘The Phantheon’

22. Lightweight concrete specimen after adhesive
tensile test

23. New innovative Lightweight Foam
Concrete Technology

24. Lightweight Concrete (MSDS) - Spec Mix®
Set Delayed Mortar