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Professionals stress why the concrete industry needs a good curing compound. The article "Some Concretes Need 7 Day Initial Curing" points out that today's concrete mixes, with fly ash in them, require a better cure.
"Use of additional cementitious material such as fly ash has become more prevalent in concrete construction. Several investigations have reported that the strength, development and durability of concrete containing fly ash is related to the extent and degree of curing. It has also been substantiated that drying ambient conditions greatly reduces the strength potential of fly ash concrete because the secondary (pozzolanic) reaction fails to contribute to the development of the strength." 1
With 7 days curing, "the strength and strength development characteristics of the cement-fly ash paste was superior to plain cement paste" 1
The concrete curing compound you request should exceed: ASTM C-1315-95.
ASTM C-1315 is more in line with a maximum of .40 km/m2 moisture loss, compared to ASTM C-309's .55 km/m2, and a minimum coverage rate of 300 sq. ft./gal. (which is close to the actual coverage in the field), compared to ASTM C-309's 200 sq. ft./gal.. ASTM C-309, as a standard, falls short for cement-fly ash concrete.
Timing In Finishing And Curing
There are many reasons for the surface of exposed concrete to fail. The timing of finishing, and the timing of the placement of curing compound is critical. The placement of curing compounds is to be done when the bleed water has stopped and the sheen has left the surface, not hours later.
References
1. Haque, M. N., "Some Concretes Need 7 Days Initial Curing", Concrete International, February 1990, pp. 42-45.
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