Properties of Concrete in Plastic State ;
A freshly mixed concrete must possess the under mentioned properties
- Good workability. Workability of concrete may be defined as the ease with which it can be mixed, transported, and placed in position in a homogeneous state.
- No segregation. Segregation may be defined as breaking of cohesion in a mass of concrete during transportation. If the quantity of water in the mix is more, the larger/sized aggregates tend to separate, thus causing segregation.
- No bleeding. Bleeding may be defined as separation of water or water sand cement from freshly mixed concrete. This is also caused due to excess water content in concrete.’
Properties of Concrete in Hardened State
A hardened concrete must possess the following, properties.
- Strength is defined as the resistance of a hardened concrete to rupture under different loadings and is accordingly designated in different ways i.e., tensile strength, compressive strength, flexural strength, etc. A good quality concrete in hardened state must possess the desired crushing strength.
- Durability is defined as the period of time upto which concrete in hardened state withstands the weathering effects satisfactorily. This property is mainly affected by water cement ratio. A good quality concrete in hardened state must be durable.
- The impermeability of hardened concrete may be defined as the property to resist- entry of water. This property is achieved by using extra quantity of cement in concrete mix. A concrete in hardened state1 must be impermeable.
- Elasticity. Though hardened concrete is a brittle / material, it is desired that it should possess adequate elasticity.
- Shrinkage. A hardened concrete should experience least shrinkage. This property is guided by water cement ratio. Shrinkage is less if the water cement ratio is less.
- Thermal expansion. A hardened concrete should possess least coefficient of expansion.
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