concrete cube test |concrete cube test procedure |7 day compressive strength of concrete formula |concrete cube test calculation |characteristic compr
M25 cube strength of concrete | M25 cube strength in 7 days | 28 days concrete strength
Cube strength of Concrete
Compressive strength of M25 concrete after 7 days & 28 days of curing. As we know that compressive strength is measured by a compressive strength test machine (CTM).
Compressive strength is defined as the ratio of load applied by CTM machine on a concrete cube or cylinder to the surface area of concrete cube. Compressive strength is represented by F which is equal to
F = P/A,
where
F = compressive strength,
P= total load applied by CTM machine
A = cross-sectional surface area.
Generally, the strength of concrete is measured in psi (pound-force per square inch in the USA) & MPa (megapascal) in India & other country. MPa in another term represented as N/mm2 and (1MPa = 145.038 psi)
In this Article we have to find the compressive strength of M25 concrete, if it achieve strength 25MPa or 3626 Psi by cube test buy CTM machine, other than it is rejected, so compressive strength of M25 concrete is 25MPa or 3626 Psi.
The overall Strength of a concrete structure such as flexural resistance and abrasion directly depends upon the compressive strength of concrete.
Compressive strength of M25 grade of concrete after 7,14 & 28 days
This strength is measured by CTM testing machine using Standard 15cm larger & 10cm smaller cubes in India and standard cylinder specimens dai 15cm & height 30cm in USA and a few other countries.
M25 concrete strength:
strength of M25 concrete at 7 days is 16.25N/mm2 and in 28days is 25N/mm2.
The grade of M25 concrete is denoted by the letter M or C (Europe) stands for mix & followed by a numerical figure is compressive strength.
PROCEDURE FOR CUBE
Making of at least 3 concrete cube size each 150mm×150mm×150mm in the mould by cement sand and aggregate ratio 1:1:2, use tamping rod for levelling the surface of mould, it is kept for 24 hours setting after water mix in concrete, after 24 hours it is kept in water for curing for 7 days. And taken out just before test 7 days to find out compressive strength of M25 concrete after 7 days of curing
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Calculation:
Now concrete cube test by CTM machine, assuming 400kN load is applied on the concrete cube till the cube collapse. The maximum load at which the specimen breaks is taken as a compressive load.
Compressive load = 400kN,
cross sectional surface area A = 150mm ×150mm = 22500mm2 or 225cm2,
compressive strength F = P/A = 400 kN/22500mm2 = 17.77N/mm2.
Compressive strength of M25 concrete after 14 days
Calculation:
Now concrete cube test by CTM machine, assuming 600 kN load is applied on concrete cube till the cube collapse. The maximum load at which the specimen breaks is taken as a compressive load.
Compressive load = 600 kN,
cross sectional surface area A = 150mm ×150mm = 22500mm2 or 225cm2,
compressive strength F = P/A = 600 kN/22500mm2 = 26.66N/mm2.
Compressive strength of M25 concrete after 28 days
Calculation:
Now concrete cube test by CTM machine,assuming 650 kN load is applied on concrete cube till the cube collapse. The maximum load at which the specimen breaks is taken as a compressive load.
Compressive load = 650 kN,
cross sectional surface area A = 150mm ×150mm = 22500mm2 or 225cm2,
compressive strength F = P/A = 650 kN/22500mm2 = 28.8N/mm2.
Compressive strength of m25 concrete after 28 day
M25 concrete strength over time:
The relationship between M25 concrete strength according to time is not linear, it means increasing strength is not increasing according to applied load as time increases, it will increase in nonlinear.
Concrete is a macro content with Sand, Cement, & Coarse aggregate as its micro-ingredient & gains its 100% strength over time at the hardened state.
Take a look at the below table. M25Concrete Strength Overtime
Days after Casting Strength Gain
- Day 1 ____ 16%
- Day 3 ____ 40%
- Day 7 ____ 65%
- Day 14 ___ 90%
- Day 28 ____ 99%
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