Introduction; Method Of Use - Proceq SRT 5800 Manual

1. Introduction

A portable tester, shown in Plate 1, was developed at the
Road Research Laboratory (now TRRL) some years ago to
provide highway engineers with a routine method of
checking the resistance of wet road surfaces to skidding.
The apparatus measures the frictional resistance between a
rubber slider (mounted on the end of a pendulum arm) and
the road surface.
Special attention was given to overcoming the practical
difficulties met when using such an apparatus in all
weathers, on rough and uneven road surfaces, and on
roads having considerable gradient and camber. At the
same time the characteristics of the apparatus were chosen
as far as possible to simulate sliding between vehicle type
and road at 50 km/h.
This booklet describes the method of operation of the tester,
its use on wet road surfaces, and the interpretation of the
results.

2. Method of use

Setting the tester
1. Set the base level by means of the spirit level and the
three leveling screws on the base-frame.
2. Raise the head so that the pendulum arm swings clear
of the surface. Movement of the head of the tester,
carrying the swinging arm, graduated scale, pointer,
and release mechanism, is controlled by a rack and
pinion on the rear of the vertical column. After
unclamping the locking knob A at the rear of the
column, the head may be raised or lowered by turning
either of the knobs B/B1. When the required height is
obtained the head unit must be locked in position
again by clamping knob A.
3. Check the zero setting. This is done by first raising the
swinging arm to f horizontal release position, on the
right-hand side of the apparatus. In this position it is
automatically locked in the release catch. The pointer