BS EN 13588:2008 pdf free download – Bitumen and bituminous binders – Determination of cohesion of bituminous binders with pendulum test.
In the “up” position, the pendulum and pointer are at an angle of (4,0± 1,0)° with the vertical, and no impulse is required for release.
The pointer retaining system is sensitive to temperature variation and the room ambient temperature shall be in the range 18 °C to 28 °C during preparation of the apparatus and for subsequent testing. In such case the energy dissipated in friction during a pendulum swing without a test specimen should be considered negligible compared to the energy absorbed by breaking a binder during a test.
7.6 Selection of test temperatures
Select three temperatures at 10 °C intervals according to the observed room temperature consistency of the binder, e.g. 10 °C, 20 °C and 30 °C for fluxed bitumens, 30 °C, 40 °C and 50 °C for stabilised pure or modified bitumens.
Then select additional test temperatures so that at least:
a) one result is less than 0,4 J/cm2 at both the low and high temperature ends of the curve or the determined cohesion value at (- 10 C) and (+ 80 °C), if a value of 0,4 J/cm2 has not been achieved;
b) three results are within 5 °C of the temperature of maximum cohesion.
c) At least one further result shall be between the peak and between 40 % and 60 % of the peak value, on both low and high temperature sides of the curve. Then the temperatures, at which cohesion energy is 0,5J/cm2, shall be chosen on both low and high temperature sides of the curve. Or if previous temperature cannot be reached, one further result shall be determined, on both low and high temperature sides of the curve, at a temperature of half the difference between the peak value and the minimum cohesion value determined in a).
NOTE If a binder has been already tested, larger or smaller intervals than 10 °C can be used and another range of temperatures selected according to the intention of the test.
7.7 Measurement
Set the pendulum in the “up” position, and reset the pointer in contact with the pendulum.
Open the door of the protective cage.
Transfer a test assembly from the temperature-controlled environment to the clamping device of the tester taking care to ensure that the assembly is moved without disturbance of the cube relative to the support. Close the door of the protective cage and release the pendulum. Ensure that the time taken to perform the above procedure since the transfer is less than 20 s and that all tests at one temperature are performed within a 10 mm period.
Record the swing-through angle a1 indicated by the pointer to the nearest 0,5°.
Remove the detached cube and the cube support from the protective cage and examine the faces in contact with binder for evidence of adhesion failure. If an area of bare metal greater than 5 mm2 is visible on either cube or support, discard the results and repeat the test.
Examine the impact edge of the pendulum. If any binder is adhering, remove it using absorbent paper with a small quantity of solvent.
Reset the pendulum in the “up” position and reset the pointer in contact with the pendulum.
Replace the cube support with another, clean, support and place the cube just tested on this support with its clean face downwards.