BS EN 14771:2012 pdf download – Bitumen and bituminous binders — Determination of the flexural creep stiffness — Bending Beam Rheometer (BBR) 5 Apparatus 5.1 Bending Beam Rheometer (BBR), consisting of a loading frame with test specimen supports,acontrolled temperature liquid bath and a data acquisition system. 5.1.1 The loading frame, consisting of a set of sample supports, a blunt-nosed shaft to apply the load tothe mid-point of the test specimen, a load cell mounted in line with the loading shaft, a means for zeroing theload applied to the specimen, a means for applying a constant load to the test specimen and a deflectionmeasuring transducer attached to the loading shaft. A schematic picture of the device is shown in Figure 1. 5.1.1.1 The loading system, which shall be capable of applying a contact load of 25 mN to 45 mN to thetest specimen and maintaining a test load of 930 mN to 1030 mN within ±10 mN.The rise time from thecontact load to the test load shall be less than 0,5 s. Details of the loading pattern are shown in Figure 2. 5.1.1.2 The loading shaft,which shall be continuous and in line with the load cell and deflectionmeasuring transducer with a spherically shaped end (6,3±0,3) mm in radius. 5.1.1.3 The load cell, which shall have a minimum capacity of no less than 2,0 N and a resolution of atleast 2,5 mN. 5.1.1.4 The LVD-transducer, or other suitable device to measure the deflection of the test specimen thatshall have a linear range of at least 6 mm, and be capable of resolving linear movement of 2,5 um. 5.1.1.5 The sample supports, which shall consist of two non-corrosive metal supports with a (3,0±0,3)mm contact radius and spaced 101 mm to 103 mm apart. The spacing of the supports shall be measured to0,3 mm (see Figure 3). 5.1.2 A temperature measurement device,used as a calibrated temperature transducer that shall becapable of measuring the temperature with an accuracy of ± 0,1 °C over the range of – 36 °C to 0 °℃.Themeasuring head shall be mounted within 50 mm of the mid-point of the test specimen. 5.1.3 A liquid bath,capable of maintaining the desired test temperature near the test sample within±0,2 °C during isothermal conditioning and during the test procedure in the range of – 36 °C to 0 °℃.Bathliquid shall not affect the properties of the bituminous binder being tested. The density of the...
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