What is lean concrete & where it is used

Lean concrete is a mix where the amount of cement is lower than the amount of liquid present in the strata.

The higher the Aggregate/cement ratio, the leaner the concrete. In lean concrete, less quantity of paste is available for providing lubrication, per unit surface of aggregate and hence the mobility of aggregate is restricted .

Lean Concrete is ‘not Rich’, in other words the ratio of cement to water and of course to aggregate would be low.

Casting of lean in concrete in site

Example:-

M5 GRADE OF CONCRETE → 1:5;10 (CEMENT:SAND:AGGREGATES) {5mpa}

M7.5 GRADE OF CONCRETE→1:4:8 (CEMENT:SAND:AGGREGATES) {7.5mpa}

Advantages of lean concrete:-

  1. Main function of the lean concrete is to provide the uniform surface to the foundation concrete and to prevent the direct contact of foundation concrete from the soil.
  2. Lean concrete is used under the foundations.
  3. Lean concrete is used to provide a level surface , where main foundation (raft, isolated or any other type) can be placed.
  4. Another purpose is protection of main foundation from soil below, as moisture or other chemicals in soil like sulphates may attack concrete and can weaken it.

If you need a quality foundation and the entire structure as a whole, then use lean concrete.

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