BS EN 15323-2007 pdf download.Bitumen and bituminous binders Accelerated long-term ageing/conditioning by the rotating cylinder method (RCAT).
accelerated long4erm ageing conditioning
simulated long-lemi ageing that the binder undergoes during the accelerated rotating cylinder ageing procedure
NOTE 1 In the case of hot.mix asphalt binders the long.term ageing is carned out on binders that have already been conditioned through short-term ageing/conditioning.
NOTE 2 In the case of bituminous emulsions or cut-back or fluxed bitumen the long-term ageirig is carried Out Ofl binders that have already been conditioned through the stabilisation procedure
3.6
mastic
homogenous mixture of filler and bituminous binder
NOTE 1 The mixture can be prepared directly in the rotating cylinder
NOTE 2 See Annex B
4 Principle
A rotating film of binder is rieatea to a specified temperature uriaer a speciriea rotation speea ana uncier a specified oxygen flow for a given period of time. This is to simulate the changes that occur to the binder during service (pavement or other bituminous applications. eg. roofing).The standard procedure is RCAT9O as described in Subclause 6.4, For other purposes, e.g. research, other conditions may be used
The effects of this ageing procedure are evaluated on the residual binder after the test. However, as samples can be taken at intermediate exposure times, the ageing process can be monitored on the basis of a kinetic approach.
NOTE Ageing of binders during service is affected by ambient temperature and air pressure as well as by mixture- associated variables such as volumetric mixture proportions, mixture permeability, aggregate properties and other factors. This procedure is intended to provide an evaluation of the relative ageirig behaviour of binders under specified conditions. but cannot account entirely for mixture variables or provide relative resistance to ageing at in-service conditions.
5 Apparatus
Usual laboratory apparatus and glassware. together with the following:
5.1 Test system comprised of a cylinder with a grooved inner roller, an oxygen supply system with flow control devices, a forced—draft oven equipped with an appropriate outlet for the evacuation of volatile components and placed under an appropriate hood, temperature control/measuring devices, a temperature measuring apparatus and preferably. a temperature recording device (Figure 1).
5.2 Testing cylinder of stainless steel construction (Figure 2), with a volume of 3.7 I The cylinder shall be closed at one end and be fitted with a removable screw-on closure at the other An effective seal is provided by a heat- and solvent-resistant flat rubber gasket. The removable closure has a central orifice 42 mm to 43 mm in diameter through which it is possible to take small test samples at predetermined intervals (“exposure times”). During testing this opening is fitted with a PTFE plug (type 1) as illustrated in Figure 3. A long stainless steel tube is inserted through the opening in this plug to provide an oxygen atmosphere (Figure
5.3 Grooved solid stainless steel roller 34 mm in diameter (Figure 2) making a gravity-induced rotating movement about its axis inside the rotating cylinder This roller is fitted at both ends with a rim 3,5 mm thick and 40 mm in diameter. Using this roller, the binder in the cylinder is constantly pressed and distributed against the inner wall of the cylinder. As a result, the bitumen surface exposed to oxygen is constantly renewed and remixed with the bulk of the mass of binder.
5.4 Drive mechanism rotating the testing cylinder about its axis on two round drive bars in a ventilated oven. The mechanism is such that the cylinder makes one revolution per minute (1 ± 0,05) r!min.
5.5 Forced-draft oven to be used with 5.2. 5.3 and 5.4, capable of bnngeng the oven temperature to the desired ageing temperature ± 0.5 °C, as recorded by a suitable thermometer, within 1 h and maintaining the temperature of the binder inside the cylinder at the ageing temperature ± 0.5 “C. The oven is thermostatically controllable by a control and measuring device with a reading to 0.1 ‘C. The oven shall have interior dimensions 480 mm x 380 mm x 500 mm (width x height x depth) ± 20 mm and a protected cylindrical fan that is able to efficiently homogenize the temperature of the air. The temperature in the oven shall be set very accurately (between 70 ‘C and 95 ‘C, depending on the test). It must remain constant to within ± 0,5 ‘C during the procedure.
SAFETY PRECAUTIONS — The ageing procedure operates at high temperatures and with a slow flow of oxygen. All safety guidelines issued by the equipment manufacturer must be followed.
5.6 Pressure reducer fitted with a pressure gauge adjustable between 0 MPa and 0.5 MPa (5 bar) with
0.01 MPa subdivisions If possible. the pressure reducer should be fitted with a sensitive excess flow valve.
Otherwise, a general control needle valve shall be used to limit oxygen flow to approximately 10 I/h in case of
a break in the oxygen line
5.7 Oxygen temperature safety break valve which prevents oxygen flow when the temperature in the oven exceeds 105 ‘C during the ageing procedure when operating with oxygen.BS EN 15323-2007 pdf download.
BS EN 15323-2007 pdf download
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