3days Compressive strength of concrete

Mehboob

Senior Member
Compressive strength of concrete after 3days is 20N/mm² for M25 grade.is this good or bad because 3days strength should be 40 percent please anyone put some on this thank you
 

PALANISAMY C

Junior Member
Compressive strength of concrete after 3days is 20N/mm² for M25 grade.is this good or bad because 3days strength should be 40 percent please anyone put some on this thank you
Its good but may be its not M25 should be more in the way of design or execution problem. check 28th days and analyze well then you know the cause of this and please share to us what is the cause .
 
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This may be true when High alumina cement use at site. Due high alumina content , too early gain of strength take place.Early gain of strength is good when you have to do fast erection but problem is due to release of large heat of hydration very short span of time , this develops temperature gradient within concrete & results into cracking. This cracking can cause corrosion of steel & make concrete structure less durable.
It is advisable to use high alumina cement for shallow concrete ( member which have less concrete volume & thickness)
 

Dnyan Deshmukh

Staff member
How much strength should be there at any given age is purely dependent on the Concrete Mix Design and achieved results during Trials.

As per the IS Code ultimate acceptance criteria is the 28 Days strength.

For stripping of the formwork, one should have the Formwork Design and the calculations of load for their site conditions in which you get minimum concrete strength requirement for stripping of the formwork (mostly for slab and beam bottom forms).

In absence of those design calculation, one can follow what is specified in IS codes (for % strength requirement along with age).

If my mix is actually giving more than what i have targeted for - If the structural consultant allows for reducing cement or cementitious content in mix and has a good quality control on production unit - can go for mix design optimization.

If its a random odd result - one should investigate for reasons of high or low results and take appropriate actions to ensure it wont recur again.