CT 216 - Relative Compaction Flashcards
This test method defines relative compaction as the ratio of______to _________, expressed as a percentage.
In-place wet desnity to test maximum wet density.
This test does not allow calculating relative compaction on a dry density basis.
False
This test method may be used to measure the test maximum density of class A cement treated base.
False
It is not important to preserve the moisture content of the sample retreived from the field.
False
The minimum weight of a field sample is ________.
35 lbs.
If _______ percent or more of the field sample is retained on the 3/4” sieve, the density must be corrected to account for oversized material.
10%
The intial wet weight of the test specimen should always be 2500g.
False
What is the preferred number of specimens to be prepared?
5
How many subspecimens should be created from each specimen?
5
Each subspecimen should be compacted with _______ blows from the tamper?
20
The piston should be tamped with _________ blows from the tamper to level the surface of the compacted core.
5
Always record the tamper reading to the next greatest reading if the top of the mold is between tamper readings.
True
Vary the moisture content of each specimen by _________ percent for most materials.
2%
The first specimen is typically compacted at the field moisture content.
True
Free water on the base plate indicates an excessive moisture content.
True
After removing a compacted specimen and reassembly the mold, tighten the wing nuts ________.
With hand pressure.
Specimens with moisture content below, at, and above the optimum moisture content are always required to calculate the relative compaction for a test area.
False
What is the correct reported relative compcation given the following test results: in-place wet desnity equals 2.01 g/cc, adjusted wet density from 3 tested specimens are 2.07, 2.18, 2.09 g/cc.
92%
If less than 10% is retained on the 3/4” sieve, how is the sample then processed?
Discard the material retained on the 3/4” sieve and divide the passing 3/4” fraction into representative 5 test specimens of equal weight.
If 10% or more is retained on the 3/4” sieve, how is the sample then processed?
A “Correction for Oversize Material” or “rock correction” must be performed.
What is the usual range of specimen weights per Table 1?
2200-2700 grams
What should you do if you have a sample that does not have at least one test specimen compacted at a moisture content less than and one greater than the moisture content of the specimen having the highest adjusted wet density within the minimum 3 test specimens (curve not broken)?
Fabricate additional specimens with increased or decreased moisture increments until this condition is satisfied.
