1. The use of an aqueous composition comprising at least one polymer A of the formula (I) as a cement grinding agent where M=each independently H +, alkali metal ion, alkaline earth metal ion, di- or trivalent metal ion, ammonium ion or organic ammonium group, R=each R, independently of the others, is hydrogen or methyl, R 1 and R 2 =each independently C 1 to C 20-alkyl, cycloalkyl, alkylaryl ...