The present invention relates to reactive compositions containing A) one or more blocked polyurethane prepolymers which have a content of blocked isocyanate groups (calculated as NCO) of 0.1 to 20 wt. % and are prepared from i) at least one aromatic, aliphatic, araliphatic and/or cycloaliphatic diisocyanate having a content of free NCO groups of 5 to 60 wt. %, ii) a polyol component containing at least one polyester polyol, and/or at least one polyether polyol and/or at least one polycarbonate polyol, iii) CH-acidic cyclic ketones corresponding to formula (I) as blocking agents wherein X represents an electron-attracting group, R1 and R2 independently of one another represent the radicals H, C1-C20 (cyclo)alkyl, C6-C24 aryl, C1-C20 (cyclo)alkyl ester or amide, C6-C24 aryl ester or amide, mixed aliphatic/aromatic radicals with 1 to 24 carbon atoms that can also be part of a 4- to 8-membered ring, n is an integer from 0 to 5, and B) one or more OH-functional compounds in which the OH component undergoes activation by a deposition amine component. The present invention also relates to a composite system containing two adherends bonded together with the reactive composition according to the invention.