As far as Civil construction is considered,the ratio of concrete is 1: 3: 6 (M-10) and below, which is called lean concrete.
Generally 1: 3: 6, 1: 4: 8 and 1: 5: 10 mixes are used for lean concrete mixes.
Examples:-
Grade of concrete (M-5) → 1: 5; 10 (cement: sand: aggregates)
M-5 grade concrete will give a total characteristic strength of
5 MPa.
Grade of concrete ( M-7.5 )→ 1: 4: 8 (cement: sand: aggregates)
M-7.5 grade concrete will give a total characteristic strength of
7.5 MPa.
Grade of concrete ( M-10)→ 1: 3: 6 (cement: sand: aggregates)
M-10 grade concrete will give a total characteristic strength of
10 MPa.
Lean
concrete is a
mixture where the amount of cement used is less than the amount of liquid
present in the strata.Lean concrete is that concrete which has high
In technical terms ,if the
cement content of the mix falls out to be lesser than 10 percent than the mix
is called as lean concrete mix.
The higher the aggregate / cement ratio, the more the concrete bends. In lean
solids, less amount of paste is available to provide smoothness, aggregates per
unit surface and therefore mobility of aggregates is restricted.
Advantages of lean concrete: -
- Lean concrete provides a uniform surface to the
foundation surface and prevent direct contact of the foundation concrete
with the soil.
- Lean concrete is used under the foundation.
- It forms a solid concrete bed where the placing of steel reinforcement is easily done for the foundation works.
- It prevents the direct contact of foundation concrete from the soil.
- It provides the protection of the main foundation from the soil below, because moisture or other chemicals in the soil such as sulfates can attack the concrete and weaken it.
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i have learns foundation constriction dis-gin
ReplyDeleteYou mean to say foundation construction design.mostly the pcc is done by levelling the soiling first and then foundation is provided as per the requirement(mat or pile by checking the bearing capacity of soil at initial stage).
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