Practice C31: Making and Curing Concrete Test Specimens in the Field Flashcards
ASTM Method gives standardized requirements for ___, ___, ___, and ___ of test specimens.
Making, curing, protecting, transporting
For cylinders with a diameter of 6 inches or greater, the tamping rod must be a round, straight, steel rod with a diameter of ____.
5/8 inches
The minimum frequency of an internal vibrator used in this procedure is ____.
9000 vibrations per minute (150 Hz)
The container for obtaining the concrete sample used in this procedure can be a ___, ___, or ___.
Metal pan, wheelbarrow, flat, clean, nonabsorbent mixing board
A 6 by 12 inch cylinder mold can be used for concrete containing aggregate with particles not exceeding ____ in size, without the need for wet sieving the concrete.
2 inches
The sample of concrete used in molding test specimens must be obtained in accordance with what ASTM standard?
C172
When strength specimens are to be made, what three other tests must be made?
Slump, air content, temp
After molding test specimens, you should wait 2 hours before moving them to the location of initial storage. T/F
False - move immediately
The supporting surface on which specimens are stored shall be level within ____.
1/4 inch per foot
For concrete with a slump of less than 1 inch, the test specimens must be consolidated by _____.
Vibration
If the concrete is to be consolidated by vibration, a standard 4 x 8 inch cylinder mold must be filled in ___ equal layers.
2
When rodding a standard 6 by 12 inch cylinder, each layer must be rodded ___ times.
25
When rodding each upper layer of concrete in a cylinder, the tamping rod should penetrate into the underlying layer by about ___.
1 inch
When using an internal vibrator to consolidate a 6x12 inch compressive strength test specimen, the vibrator must be inserted at ___ different point for each layer.
2
When consolidating a flexural strength test specimen by rodding, rod one stroke for each ___ of top surface area.
2 square inches
When internal vibration is used to consolidate a standard flexural strength test specimen, the technician should insert the vibrator at intervals not exceeding ___ along the center line of the beam.
6 inches
Concrete mixtures with specified strengths of 6000 psi or greater shall have an initial curing temp between ______.
68 and 78 degrees F
Up to 48 hours after molding, text specimens that are to be standard cured shall be stored in a temp range between ____ to _____.
60 and 70 degreees F
Upon completion of initial curing, the test specimens may be left in their molds and sealed in plastic bags. T/F
False - specimens should be demoled and placed in water storage tanks or moist rooms with free water at a temp of 73.5 +- 3.5 degrees F
