This specification covers the performance requirements for membrane-forming liquids suitable for use as curing compounds and sealers for fresh and hardened concrete. Each membrane should have good alkali resistance, acid resistance, adhesion-promoting qualities, and resistance to degradation by UV light. The materials are limited to clear or translucent and white pigmented materials, all of which are classified into non-yellowing, moderately yellowing, or yellows or darkens unrestrictedly.