Concrete properties

Cement concrete has the following important properties:

It has a high compressive strength.

It is corrosion free and has no appreciable effect of environmental agents.
It provides a hard surface that is able to resist abrasion.
It is more economical than steel, as sand and coarse aggregates, which are the bulk of concrete, are generally available at a lower cost. The formwork can be reused for other construction works.
Concrete surfaces can be given a better appearance and a variety of finishes.
It continues to harden and gain strength over time. It is this property of cement concrete that gives it a distinct place among construction materials.
It can form a good bond with steel. Steel reinforcement is usually placed at appropriate intervals in cement concrete to withstand the tensile stress, as plain concrete is weak in tension. It is called Reinforced Cement Concrete or RCC.
Concrete has a tendency to become porous due to the presence of voids, which form during its placement. It can be checked through
Use of minimum water cement ratio
Proper classification of collections and
Better compaction after placement of concrete.
Due to lack of moisture over time, cement concrete tends to shrink. Shrinkage can be minimized by proper curing of concrete.
Concrete mixes are designated as M10, M15, M20, M25, M30, M35 and M40. ‘M’ refers to the mix and the number indicates the ultimate strength of the concrete mix in N/mm2 at the end of 28 days.