Compressive Strength Of Concrete Cubes
According to wikipedia, compressive strength of concrete is defined as the characteristic strength of 150mm size concrete cubes tested at 28 days. why do we test at 7, 14 & 28 days? concrete is a macro content with sand, cement, & coarse aggregate as its micro-ingredient (mix ratio) and gains its 100% strength over time at the hardened.Additional specimens may be required for 7 days strength. in all the cases 28 days strength shall alone be the criterion for acceptance or rejection of the concrete. the test results of the sample shall be the average of the strength of three specimens. the individual variation should not be more than + 15 percent of the average. if more, the.