The apparatus requirements for the vibrator in C192 differ from those in C31 (Standard Practice for Making and Curing Concrete Test Specimens in the Field). Specifically, they differ in the frequency of the vibrator, the requirement for an internal vibrator, and that the vibrator frequency be periodically checked. The purpose of this proposed revision is to align these two standards, due to their similar purposes. The frequency cited in C31 (9,000 vibrations per minute) is used because it is the frequency recommended in Table 5.1 of ACI 309R.
concrete; cylinders; laboratory; prisms; strength testing;
Citing ASTM Standards
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