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 advantage to sealing new concrete with a cure and seal is that the concrete does not have time to get dirty or stained. If a cure and seal is not being used, then you should allow the concrete to cure for 2-4 weeks. The industry standard is 28 days but that depends on the climate and mix of concrete. It is important to wait and not to seal new concrete too soon. Trapping moisture in the surface will likely lead to a premature failure of the sealer.