Curable, two-package compositions are provided comprising a first and second reactive package. The first reactive package comprises:
a) a polyether functional polyamine;
b) a polyamine comprising an aspartic ester functional polyamine and/or one or more hindered amines; and
c) an aliphatic secondary polyamine.
The second reactive package comprises a polyisocyanate having a viscosity of ≦2000 centipoise (cPs) at a temperature≧7° C. The curable composition, upon mixing of the reactive packages at ambient temperature, demonstrates a gel time of less than 120 seconds, and is suitable for use as a mortar or caulk.