The administration licenses, regulates, and provides financial assistance to small business investment companies and section 301(d) licensees (formerly minority enterprise small business investment companies).
Cured and Dry. Concrete continues to harden for several years after it is poured, but the standard period of initial curing is 28 days, or roughly one month. At this point, the concrete is very close to full strength and is ready to accept most commercially available sealants. However, sealers typically must be applied to dry concrete. You can test the concrete for moisture content by securing a piece of aluminum foil on the sidewalk with duct tape and waiting 24 hours. If the foil is dry when you remove it, the sidewalk is ready for sealing.
The rate of hardening depends on the rate of hydrolysis of cement. The concrete becomes almost fully hardened within 28 days if the cement used in the mix in OPC. (Hydrolysis of cement continues even after 28 days). If the cement is blended type then the process of hardening is little slower and it will take more than 28 days.