BS EN 1476:2012 pdf download
BS EN 1476:2012 pdf download.Bitumen and bituminous binders – Accelerated long-term ageing conditioning by a Pressure Ageing Vessel(PAV).
5.1.3 Pressure vessel, having the same dimensions described in 5,21, with an integral temperature control system that is capable of
a) bringing the loaded pressure vessel to the desired conditioning temperature ± 0.5 C, as recorded by the thermometer Inside the vessel, within two hours,
b) maintaining the temperature at all points within the vessel at the ageing temperature ± 0,5 C.
The vessel may be a separate unit to be placed in a forced draft oven or an integral part of a temperature control system.
SAFETY PRECAUTIONS — The pressure ageing vessel operates at high temperatures and high pressures. All safety guidelines issued by equipment manufacturers shall be adhered to.
5.2 Pressure controlling devices, which include the following:
5.2.1 Pressure release valve, which prevents pressure in the vessel from exceeding 2,5 MPa during the ageing procedure.
5.2.2 Pressure regulator. capable of controlling the pressure within the vessel to ± 0.1 MPa and with a capacity sufficient to reduce the pressure from the source of compressed air so that the pressure within the vessel Is maintained at the operating pressure of (2.1 ± 0,1) MPa.
5.2.3 Slow release bleed valve which allows the pressure in the vessel at the completion of the test to be reduced from 2.1 MPa (the operating pressure) to atmospheric pressure within 8 mm to 15 mm.
5.2.4 Pressure gauge capable of measuring the pressure within the vessel to within 0,1 MPa during the test. and which shall be calibrated to an accuracy of * 0.1 MPa at appropriate intervals.
5.3 Th.rmom.t.r, accurate to 0.1 C for measuring the temperature inside the pressure vessel. NOTE A resistance thermal detector (RTD) has been found to be suitable
5.4 Temperature recording devic., which is a data acquisition system capable of recording the temperature throughout the test to 0.1 C.
NOTE The current method of monitoimg temperature is via a coniputerised log of twiie and temperature. It is assumed that the temperature recorded is the temperature at every area withwi the ageing vessel,
5.5 Metal containers, with diameters of (140 ± 1) mm, the standard for which is defined In
EN 12607-2:2007, 4.3.
Swnilar containers with other diameters can be used if their diameters are determined with the same tolerance and the amount of binder is adjusted as given In Formula (1). Weigh (50,0 t 0.5) g in the container (nominal diameter 140 mm 0). If a container with another diameter is used weigh the amount given in Formula (1):
5.7 Vacuum oven (optional), which shall be capable of maintaining a temperature up to 180 C with an accuracy of i 5 C.
The vacuum system shall be capable of maintaining pressures below (15,0±2,5) kPa absolute. Alternatively. the pressure vessel itself may be used ii lieu of the vacuum oven if it is capable of maintaining a temperature of 180 C and a vacuum of (15,0 ± 2,5) kPa
5.8 Commercial bottled air, which Is suitable for the purpose of providing a sufficient supply of pressurized air to carry out the test. (Only bottled air is suitable.)
6 Procedure
SAFETY PRECAUTIONS — Use laboratory safety procedures when handling the hot bituminous binders and preparing the specimens and when removing the residue from the pressure vessel. Take particular care when lifting the lid of the pressure vessel.
Pro-heat the PAV vessel or forced draft oven to the ageing temperature. The binder is firstly pro-conditioned as necessary, prior to the long-term ageing procedure. The procedure used shall be stated In the report
If it is necessary to prepare more than one set of samples in the short-term agelngfconditioning procedure (u&ng either EN 12607 series or a stabilisatiori procedure) in order to obtain sufficient quantity for this procedure, sub-samples shall be combined and hornogenised before the test. The stabilisation procedure shall be stated in the report.
NOTE 1 The hot residue may be poured immediately into the container ow allowed to cool for PAV ageing later If allowed to cod, the container with the binder should be covered and stored at ambient temperature. When It ES 10 be used, the sample shoid be re-heated In accordance wth EN 12594 for the minimum posode time and stirred prior to pouring into the container
NOTE 2 Pre-heating the vessel up to 15 C above the condilionang teceratiiro may be used to reduce the diop in PAV temperature during the loading process and minimise the time required for s*abdisabon of the set tenerature after loading. However, pressunsing the vessel causes an increase in temperatia’e arid the vessel may cool slowly, making it difficult to achieve the specified Iemperaitjre at the start of the test,
Pro-heat the container to the PAV conditioning temperature. PLace the heated container on a balance and pour (50.0±0,5)9 into the container. Ensure that the bindet Is d.stnbuted over the entire base of the container by tilting the tilled container If necessary.
NOTE 3 The binder 1dm thickness iel be about 3,2mm The number of containers per binder will depend on the amount of bonder required for subsequent testing. The heating of the container should be sufficient ID enable the flow of the binder.
