AS 1141.42:2017 pdf free.Methods for sampling and testing aggregates Method 42: Pendulum friction test.
4.1 Pendulum friction tester
A tester with an auxiliary scale constructed in accordance with details available from the ARRB (Australian Road Research Board) (see Figure I). All bearings and working parts of the instrument shall be enclosed as far as possible, and all materials used shall be suitably treated to prevent corrosion under wet conditions.
The tester shall be used and stored in a dust-free environment that is not subject to large temperature variations.
The pendulum friction tester shall be calibrated to ensure compliance with the following requirements at intervals not exceeding two years or when results obtained from the set of friction tester control specimens vary from the established values by more than three units.
The tester shall incorporate the following:
(a) A spring-loaded rubber slider of the mass, size and shape specified in Clause 4.2 and mounted on the end of a pendulum arm so that the sliding edge is 515±2mm from the axis of suspension.
The slider shall be mounted on an axis set at an angle of 25±10 to the horizontal when the pendulum is at the lowest point of its swing. so that only the rear edge of the slider contacts the test surface. The slider can turn about its axis without obstruction to follow unevenness of the surface.
The slider shall be spring-loaded against the test surface and the nominal static force on the slider is set during calibration.
(b) Means for levelling the instrument.
(c) Means for raising and lowering the axis of suspension of the pendulum so that the slider can
(i) swing clear of the surface of the specimen; and
(ii) be set to slide over a fixed length of surface.
(d) Means for holding and releasing the pendulum arm so that it falls freely from a horizontal position.
(c) The mass of the swinging arm including the slider shall be 1 .50 ±0.03 kg with the centre of gravity lying on the axis of the arm at a distance of 410 ±5 mm from the centre of suspension.
(f) A pointer balanced about the axis of suspension, indicating the position of the pendulum arm throughout its forward swing and moving over the circular scale attached to the instrument. The mass of the pointer, excluding felt friction washers, shall be not more than 5 g and the friction in the pointer mechanism shall be adjustable so that. with the pendulum arm swinging freely from a horizontal position, the outward tip of the pointer may be brought to rest on the forward swing of the arm at a point 10 mm below the horizontal, the point corresponding to the zero position on the attached circular scale.AS 1141.42 pdf download.