Richard,
The consensus appears to have been reached that there are no code criteria governing your specific situation. I do not believe this consensus is accurate.
ACI 318-08 6.2.1 states, "Forms shall be removed in such a manner as not to impair safety and serviceability of the structure. Concrete exposed by form removal shall have sufficient strength not to be damaged by removal operation." This requirement precedes the exclusion of slab-on-grade in stated in 6.2.2. Since your situation does not qualify for the exclusion of 1.1.7 (you're still transmitting load from other elements to the soil), construction must comply with 6.2.1.
Evaluation and acceptance of concrete strength is per 5.6.1 which states, "Concrete shall be tested in accordance with the requirements of 5.6.2 through 5.6.5. Qualified field testing technicians shall perform tests on fresh concrete at the job site, prepare specimens required for curing under field conditions, prepare specimens required for testing in the laboratory, and record the temperature of the fresh concrete when preparing specimens for strength tests. Qualified laboratory technicians shall perform all required laboratory tests."
Bottom line: strength tests are required for early loading. Make a cylinder, wait a specified time, break a cylinder.
Keith Erick Fix |
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