Accepted by whom? Information about ancient concrete and other types of cementation can be found in various books, e.g. [1].

I saw picture of cement klin (oven?, non-native speaker) in Peru, built more than thousand years ago, which looks _exactly_ like freshly build cement klin near to my home (Rivne, Ukraine), but labeled as "an ancient temple, filled with dirt".

[1]: Lea's Chemistry of Cement and Concrete