Lean Concrete | Uses, Examples and Advantages of Lean Concrete

Concrete is a composite material that is composed of a mixture of fine and coarse aggregates bonded together with biding material which hardens over time.

The binding material mostly includes fluid cement paste, lime putty, lime, etc.

Lean concrete is a concrete paste where the quantity of cement is less than the quantity of liquid present in the strata.

The more the aggregate/cement ratio, the leaner the concrete. In lean concrete, less amount of paste is kept for giving lubrication, per unit surface of aggregate and hence the mobility of aggregate is limited.

The ratio of cement to water and of course aggregate would be less.

  2. Examples 

M5 Grade of Concrete→ 1:5:10 (Cement: Sand: Aggregates) 5 MPA

M7.5 Grade of Concrete→1:4:8 (Cement: Sand: Aggregates) 7.5 MPA

  3. Lean Concrete and Normal Concrete  

Normal concrete contains a cement more than 10 and less than 15%. Plain cement concrete(PCC) with a mix ratio of 1:2:4 is normal concrete with a cement amount of about 14%. Normal concrete is normally utilized in damp proofing coarse, R.C.C., and floor finishing.

The rich concrete contains a cement amount of more than 15%. A plain cement concrete(PCC) mix of 1:1.5:3 is an example of rich concrete with a cement amount of 18%. This concrete is utilized for the construction of minor structural members that can bear heavier loads.

  4. Uses  

The uses of lean concrete are as follows:

a. Lean concrete is utilized to give a level surface, where the main foundation (raft, isolated, or any other type) can be kept.

b. The aim of lean concrete is to protect the main foundation from the soil below.

  5. Advantages  

a. The common utilization of lean concrete is to give a regular surface to the foundation concrete and to avert the direct contact of foundation concrete with the soil.

b. Lean concrete is utilized under the foundations.

c. Lean concrete is used to provide a level surface, where a major foundation (raft, isolated, or any other type) can be kept.

d. The other aim is the protection of the foundation from the soil below, as moisture or other chemicals in soil like sulphates may attack concrete and can enfeeble it.

Read More: Timbering of Trenches