Lightweight concrete has a lower density than ordinary concrete due to the use of lightweight aggregates. It has strengths between 7-40 MPa, improved workability, thermal insulation, and water absorption. Lightweight concrete exhibits higher moisture movement and fire resistance compared to ordinary concrete. It is used in prestressed concrete, high-rise buildings, and to reduce dead load. While more expensive, it allows for rapid, simple construction and reduced transportation costs.
Top Rated Pune Call Girls Budhwar Peth ⟟ 6297143586 ⟟ Call Me For Genuine Se...
Light weight concrete
1.
2. LIGHT WEIGHT CONCRETE
The concrete which has considerably lower mass per unit volume than the
ordinary concrete is called light weight concrete .
It is often made by the use of light weight aggregates due to which it is
also known as light weight aggregate concrete.
3. CHARACTERISTICS
Density : 240 - 1820 kg/m^3
Strength : 7 - 40 MPa
Satisfactory durability
Improved workability
Good thermal insulation
Better water absorption
4. COMPARISON WITH
ORDINARY CONCRETE
Exhibits higher moisture movement as compared to ordinary
concrete.
Coefficient of thermal expansion is generally much lower than
ordinary concrete .
Exhibits higher fire resistance property than the ordinary
concrete .
Better resistance to freeze and thaw .
Expensive than ordinary concrete .
5. USES
This type of concrete is used in applications such as :
prestressed concrete .
high rise buildings .
where extra load is not applied .
to reduce dead load .
for sound proofing .
6. ADVANTAGES
Rapid and relatively simple construction .
Economical in terms of transportation .
Significant reduction in overall weight results in saving
structural frames , footing or piles .
Most of the light weight concrete have better nailing and
sawing properties .
7. DISADVANTAGES
Very sensitive with water content in the mixture .
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 .
Mixing time is longer than conventional concrete to assure
proper mixing .
9. PREPARATION
It is prepared by adding the air entraining admixture.
Air entraining agents / admixtures are used for the purpose
of making entrained air in concrete.
Due to entrained air , bubbles having diameter ranges from
10 to 1000 micrometers are produced .
10. FUNCTIONS
Air entrainment in concrete performs the following functions :
It lowers the surface tension of water and thus bubbles are created.
Secondly the air entraining agents prevents fusing of bubbles.
11. METHODS OF
PRODUCING AERATION
Gas concrete :
It is obtained by a chemical reaction of generating
a gas in the fresh mortar , so that when it sets it contains a large
number of gas bubbles .
Foamed concrete :
It is formed by adding a foaming agent to the mix.
12. PROPERTIES
Durable .
Low thermal conductivity .
Better fire resistance .
Good resistance to frost .
Reduced segregation
13. USE
Heat insulation .
Fire proofing .
It is used where concrete is subjected to freezing and thawing
.