What is the Curing time for M25 Concrete with M sand?

Dear Jordan,

The best suitable grade of cement for structural members such as columns and pillar depends upon the design. Which type of cement is considered at the time of the design of these structural members? For general construction, it is recommended to use 43-grade cement as the 53-grade cement is used for fast-paced construction, rapid setting and it requires proper care while curing. Grades of Ordinary Portland Cement-Based on IS Codes

Either you use natural sand or M-sand, there is no such difference in the strength of the concrete.

Lastly regarding the curing time, the curing period for any concrete member shall be 28days.

Curing of Cement Concrete -Time and Duration

Dear Jordan,

Curing time for a various grade of concrete is described in ACI 308( Guides of concrete curing).

Definition: curing is the process of maintaining the temperature and moisture condition of concrete for hydration reaction to work normally so that concrete becomes hard and strong.

43 grade and 53 Grade Cement is used for large and rapid construction. Because is grade of cement has a rapid setting and hardening properties.

Mixing M sand or natural sand does not make any effect on strength of concrete. Both acts similarly. Also, it's curing period is 28 days.

You may also refer IS Mix design for, time and duration of curing for a various grade of concrete.