Section 7 Flashcards
For cylinders with a diameter of 6 inches or greater the tamping rod must have a diameter of
5/8 in
The minimum frequency of an internal vibrator used in this procedure is
150 hz (9000 vibrations a min)
Concrete containing aggregate with particles not exceeding _____ can be used to cast specimens without the need for wet screening
2 in
For concrete with a slump of less than 2 inch the test specimen must be consolidated by
vibration
if the concrete is to be consolidated by vibration a standard 4x8 in cylinder mold must be filled in ____ equal layers
2
When rodding a standard 6x12 cylinder, each layer must be rodded ____ times.
25
When rodding each upper layer of concrete in a cylinder the tamping rod should penetrate int the underrating later by about
1 inch
When using an internal vibrator to consolidate a 6x12 specimen the vibrator must be inserted at ______ different points for each layers
2
What consolidating a flexural stench test specimen by rodding, rod one stroke for each ____ of the top surface area
2 in squared
When internal vibration is used to consolidate a standard flexural strength test specimen, the technician should insert the vibrator at intervals of _____ along the center line of the beam
6 in
Concrete mixtures with specified strengths of 6000 psi or greater shall have an initial curing temp of
68-78 deg
True or false: Upon completion of initial curing the test specimens may be left in their molds and sealed in plastic bags
false- sperimentare remolded and placed in water storage tanks or moist rooms with free water at temps between 73.4 plus or minus 3.5 degrees
During transportation, test specimens must be protected from damage due to 1____,2___.3____
jarring, extreme temps, moisture loss
Specimens shall not be transported until _____ after final set
8 hr
transport time shall not exceed
4 hr
