After how many days can concrete framework be removed? Do admixture chemicals like superplasticizer or accelerating admixtures allow early removal of concrete framework?
You pour test cylinders with every batch of mix used. These are then tested in a compression tester. When the test cylinders are up to strength, you can remove the form work. An engineer needs to determine what strength is necessary. Yes, admixtures, temperature, water content, mix formula, and aggregate selection effect the strength-gain curve.
There are also real-time Bluetooth systems with imbedded sensors so you can match temperatures.
The American Concrete Institute (ACI) is a source of standards in the US construction industry.
There is a guide which has been posted on the web: ACI Guide to Formwork for Concrete
Some portions of the Guide: