PCI Level III Quality Control Technician - Ch. 6 Questions
with all Correct & 100% Verified Answers |Already
Graded A+
List three methods for estimating compressive strength of concrete in lieu of 6 x 12-in. cylinder tests.
✔Correct Answer-Any three of the following:
1. Impact rebound hammer
2. Windsor probe
3. Pulse velocity
4. 4 x 8-in. cylinder tests
5. Pullout strength of hardened concrete
6. Compressive tests of cores or prisms
According to ASTM C31, what is the maximum permissible size of coarse aggregate that can be used
in 6 x 12-in. test cylinders? ✔Correct Answer-2 in. (one third of the diameter)
List three advantages for using 4 x 8-in. instead of 6 x 12-in. concrete compression test cylinders.
✔Correct Answer-Reduced size and weight of specimens.
Reduced storage capacity needed.
Lower capacity testing machine is needed.
What size tamping rod is used for rodding 4 x 8-in. test cylinders? ✔Correct Answer-3/8 in.
diameter, 12 in. long with hemispherical end.
What is the permissible rate of load application(after the first half of the anticipated load has been
applied) in pounds per second for a 4 x 8-in. test cylinder? ✔Correct Answer-250 to 625
List two reasons for performing pulse velocity tests of concrete. ✔Correct Answer-Any two of the
following:
1. Assess uniformity and relative quality of concrete.
2. Indicate presence of voids or cracks.
3. Estimate depth of cracks.
4. Indicate changes in the properties of concrete.
5. Estimate the severity of deterioration or cracking of concrete.
From Fig. 6.4, what rebound number would be required for a release strength of 3500 psi?
✔Correct Answer-37.3
For a certain project, concrete cylinder tests indicate that the 28-day strength of some inverted-tee
beams was 4680 psi. Required strength for the beams is 5500 psi. The owner's representative will
accept the beams if core strengths are adequate. At which location(s) should the cores be taken?
Indicate which of the following choices is correct.
a. Horizontally near the top and near the end of the beam.
b. Vertically through the ledge near the support.
c. Horizontally just above the ledge near midspan.
with all Correct & 100% Verified Answers |Already
Graded A+
List three methods for estimating compressive strength of concrete in lieu of 6 x 12-in. cylinder tests.
✔Correct Answer-Any three of the following:
1. Impact rebound hammer
2. Windsor probe
3. Pulse velocity
4. 4 x 8-in. cylinder tests
5. Pullout strength of hardened concrete
6. Compressive tests of cores or prisms
According to ASTM C31, what is the maximum permissible size of coarse aggregate that can be used
in 6 x 12-in. test cylinders? ✔Correct Answer-2 in. (one third of the diameter)
List three advantages for using 4 x 8-in. instead of 6 x 12-in. concrete compression test cylinders.
✔Correct Answer-Reduced size and weight of specimens.
Reduced storage capacity needed.
Lower capacity testing machine is needed.
What size tamping rod is used for rodding 4 x 8-in. test cylinders? ✔Correct Answer-3/8 in.
diameter, 12 in. long with hemispherical end.
What is the permissible rate of load application(after the first half of the anticipated load has been
applied) in pounds per second for a 4 x 8-in. test cylinder? ✔Correct Answer-250 to 625
List two reasons for performing pulse velocity tests of concrete. ✔Correct Answer-Any two of the
following:
1. Assess uniformity and relative quality of concrete.
2. Indicate presence of voids or cracks.
3. Estimate depth of cracks.
4. Indicate changes in the properties of concrete.
5. Estimate the severity of deterioration or cracking of concrete.
From Fig. 6.4, what rebound number would be required for a release strength of 3500 psi?
✔Correct Answer-37.3
For a certain project, concrete cylinder tests indicate that the 28-day strength of some inverted-tee
beams was 4680 psi. Required strength for the beams is 5500 psi. The owner's representative will
accept the beams if core strengths are adequate. At which location(s) should the cores be taken?
Indicate which of the following choices is correct.
a. Horizontally near the top and near the end of the beam.
b. Vertically through the ledge near the support.
c. Horizontally just above the ledge near midspan.
