This specification covers liquid membrane-forming compounds suitable for application to concrete surfaces to reduce the loss of water during the early-hardening period. White-pigmented membrane-forming compounds serve the additional purpose of reducing the temperature rise in concrete exposed to radiation from the sun. The membrane-forming compounds covered by this specification are suitable for use as curing media for fresh concrete, and may also be used for further curing of concrete after removal of forms or after initial moist curing. Liquid membrane-forming compound types 1 and 1-D shall be clear or translucent. Type 2 liquid membrane-forming compounds shall consist of finely-divided white pigment and vehicle, ready-mixed for immediate use as is. Liquid membrane-forming compounds, when tested, shall restrict the loss of water not more than the requirements prescribed. Type 2 liquid membrane-forming compounds, when tested, shall exhibit a daylight reflectance of not less than 60 %. Liquid membrane-forming compounds, when tested, shall dry to touch in not more than 4 h.