Page 24 - HIGHWAY ENGINEERING LABORATORY_FLIP BUILDER

REFERENCE
WORK PROCESS
DOCUMENT

• Rigidly locate the first test specimen with its longer dimension
lying in the track of the pendulum, and centrally with respect to
the rubber slider and to the axis of suspension of the pendulum.
Locate it in such a way that the slider of the pendulum will
traverse it in the same direction as the specimen travelled in the

polishing machine
• NOTE For this purpose it is advisable to mark one longitudinal
edge of each specimen. If this mark is on the side of the

specimen furthest from the operator during polishing, it should
be nearest to him during friction testing and vice versa.
• Adjust the height of the axis of suspension of the pendulum so
that in traversing the specimen the rubber slider is in contact
with it over the whole width of the slider and over a length of

76.0 mm, as accurately as can be visually gauged. Then wet
the surfaces of the specimen and the rubber slider with a
copious supply of clean water, being careful not to disturb the

slider from its set position. Release the pendulum and pointer
from the horizontal position and note the reading of the pointer
to the nearest whole number. Perform this operation five times,
rewetting the specimen each time, and record the mean of the
last three readings to the nearest 0.1 unit. Test the specimens in

the following order: 13, 1, 10, 3, 5, 12, 8, 7, 11, 6, 4, 9, 2, 14

5. Calculations
• Calculate the mean of the recorded values of the two PSV
control stone specimens for each test run. Record to the nearest
0.1 unit providing two

results for the complete duplicated test cycles.
• If the difference between the two mean values of the PSV
control specimens for each test run is greater than 4.7, the
results for the test shall be rejected. If the mean value of the two

PSV control specimens for either test run does not lie within the
range 49.5 to 55.5 the test results shall be rejected.

Higway Engineering Laboratory page 11