Does concrete start hardening from the bottom or from the top?

[Sumit Civil]

Does concrete start hardening from the bottom or from the top?

 

[VIDHYA SAGAR]

From the top.

 

[Sunitdn]

From top

 

[Dnyan Deshmukh]

Concrete is homogeneous mixture of cement, sand aggregates and water.

If we go as per the definition, the cement particles in the concrete are present in every area, the strength of the concrete is formed due to bond formation by cement particles in reaction with water.

So under normal circumstances without any external influence, concrete will start setting from everywhere as its a chemical process which happens after addition of water in concrete.

 

[Ramesh Doddi]

During casting it hardens from bottom. During curing, the surface hardens(irrespective of bottom or top). In general, the open surfaces get harder first as the bottom shuttering takes time to get removed that top and sides.