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intelliRock® III– Operating Instructions Guide
Repeat this process at specified intervals to complete the calibration curve. It is up the engineer to
decide when these five break points will occur.
Some examples:
Standard 6 sack mix: 1, 3, 7, 14, 28 days (ASTM C 1074-98 recommended intervals)
High early: 12 hour, 1, 2, 4, 7 days
High early (faster): 4, 6, 8, 12, 24 hours (patching applications)
Slow setting: 7, 14, 28, 42, 56 days
Generally, the maturity data that is of most interest comes from early in the maturity cycle. The expected
strength development of the placed concrete and the strength regions of interest influence the
determination of cylinder break intervals. If extra data points are necessary, additional cylinders can be
cast at the beginning of the process to create those additional breaks and data points.
When completed the calibration curve represents corresponding strength numbers for each maturity
reading. For example, if it is determined that 4300 degree CH corresponds to 3000 PSI, then during the
curing process the engineer is looking for maturity of 4300 degree CH in order to proceed with
construction activities, e.g. opening to construction, sawing, post-tensioning, stripping of forms
and reshoring or other activities.
