Life of any concrete structure primarily depends on the compressive strength of concrete and it is very important for any concrete construction project. Concrete strength also depends on the curing of concrete. We have already discussed “When to Start Curing Concrete?”. But, we must also know the “How many days should Concrete be Cured?”.
Most of the common people does not know the minimum Curing Period of Concrete. During construction of any concrete structure, some people cure the concrete for 3 to 5 days or some people do it for 10 to 15 days to a month. Mostly people use plenty amount of water for concrete curing and, we thus waste much amount of water for curing of concrete.
Curing of concrete should be carried out until it will gain 70% to 80 % strength. As per Indian Standard (IS-456), exposed concrete surface should be kept continuously in a damp or wet condition by using various concrete curing methods such as ponding or by covering with a layer of sacking, canvas, hessian etc. for at least seven days from the date of placing concrete in case of ordinary Portland Cement. Curing period should be extended to 10 days where mineral admixtures or blended cements are used. The curing period of concrete should not be less than 10 days for concrete exposed to dry and hot weather condition. It is recommended that above minimum periods may be extended to 14 days where mineral admixtures or blended cements are used in the concrete.
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Here we give you compressive strength gained by concrete table after 1, 3, 7, and 28 Days.
From the above given table, concrete gains 16 % compressive strength in 1 day, 40 % in 3 days, 65 % in 7 days and 99 % in 28 days.
It means that concrete gains its strength rapidly in the initial days after casting the concrete. Concrete gains its 90 % strength in 14 days and remaining 9 % strength is gained in 28 days. So, after 14 days concrete strength increases slowly. It means process of hydration of cement is higher during the first 14 days of casting and then it slows down. It is therefore advisable that concrete should cured minimum for 14 days to achieve durability related properties.