Ch. 16 Test Instruments for Coating Concrete

Question 1

Explain the procedure for ASTM D 4263, Standard Test Method for Indicating Moisture in Concrete by the Plastic Sheet Method

Answer 1

Tape a segment 4 mil thick, clear polyethylene sheet approx 18x18 in over the concrete to be tested so that the concrete is tightly sealed from the atmosphere and sunlight. Allow the test patch to remain a min of 16 hrs.

Then, remove the plastic sheet and inspect the underside of hte sheet and hte concrete surface at the patch for hte presence of moisture.

Question 2

DFT of coating on concrete can be measured by

Answer 2

UT thickness guage

Question 3

List standards that may be used for dry film measurement of coating over concrete

Answer 3

ASTM-D6132-97 and SSPC-PA9

Question 4

Describe the proper, safe, and accurate operating procedure for a low-voltage holiday detector

Answer 4

Ground equipment and set for coating thickness VS voltage. Keep probe in contact with work, move slowly across surface. Don’t oversaturate sponge

Question 5

What are some of the errors that may occur while using a High Voltage DC Holiday detector?

Answer 5

No spark at the probe tip could be caused by a lead or connection failure

No alarm on fault could be caused by low voltage/sensitivity setting or a bad ground connection.

Lack of display due to low battery or bad/missing fuse

Continuous alarm.