how to find cube strength of 2nd days or 5 days... what will be passing % for that days
how to find cube strength of 2nd days or 5 days... what will be passing % for that days
- Thread starter Purshottam
- Start date
Dnyan Deshmukh
Staff member
The best and easy way to find the strength at any specified age is to do a trial mixes of the design which are proposed for use or are in use and testing the cubes at specified / required ages of concrete.
there are many factors which has effect on the strength parameter of the concrete, it is always better to do analysis and arrive at the conclusion for specific concrete mix design.
In general scenarios, you can assume following
at age of 3 days normal mixes do achieve strength up to 40 to 50% and in 7 days do achieve up to 60 to 70%.
Higher amount of cement replacement and type of cementitious admix does have impact on achievement of the strength, sometimes concrete designs are targeted to higher age like 56 days, 91 days etc where concrete does not achieve significant strength in early age but yields to desired output at targeted age.
When it comes to concrete mix designing, the factor of age is also considered for like stripping / de-shuttering of formwork. if the requirement is like need to de-shutter slab on 2nd day (36 hours or 48 hours), the minimum required strength to support the construction load shall be specified by structural consultant or Formwork designer or you can also do the calculations of load and safe stress on concrete structure. base on the calculated or specified strength at the time of de-shuttering with or without load carrying props in place, you can design or finetune the concrete mix to meet those requirement.
So knowing the strength at age like 2 days or 5 days only make sense when there is requirement for executing something for which the amount of stress going to develop shall be known, hence the requirement of strength at particular age is specified. once something is specified, concrete mix designing shall be done to meet those requirement and that becomes what shall be the minimum strength at 2 days or 5 days.
there are many factors which has effect on the strength parameter of the concrete, it is always better to do analysis and arrive at the conclusion for specific concrete mix design.
In general scenarios, you can assume following
at age of 3 days normal mixes do achieve strength up to 40 to 50% and in 7 days do achieve up to 60 to 70%.
Higher amount of cement replacement and type of cementitious admix does have impact on achievement of the strength, sometimes concrete designs are targeted to higher age like 56 days, 91 days etc where concrete does not achieve significant strength in early age but yields to desired output at targeted age.
When it comes to concrete mix designing, the factor of age is also considered for like stripping / de-shuttering of formwork. if the requirement is like need to de-shutter slab on 2nd day (36 hours or 48 hours), the minimum required strength to support the construction load shall be specified by structural consultant or Formwork designer or you can also do the calculations of load and safe stress on concrete structure. base on the calculated or specified strength at the time of de-shuttering with or without load carrying props in place, you can design or finetune the concrete mix to meet those requirement.
So knowing the strength at age like 2 days or 5 days only make sense when there is requirement for executing something for which the amount of stress going to develop shall be known, hence the requirement of strength at particular age is specified. once something is specified, concrete mix designing shall be done to meet those requirement and that becomes what shall be the minimum strength at 2 days or 5 days.
