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Softening Point of Bitumen: A Practical Guide for Ring-and-Ball Apparatus

LDHs was introduced into 70# asphalt binder by different weight ratio. Asphalt penetration test, soft point test, ductility test, viscosity test, dynamic shear rheometer (DSR) test and Fourier transform infrared (FTIR) test, were conducted to characterize and predict the LDHs modified asphalt. Research results indicated that the LDHs has great effect on resistance to UV of asphalt, which makes the asphalt absorb less ultraviolet radiation under the same UV intensity. Complex modulus, phase angle and FTIR test results indicate that the LDHs can significantly enhance the property of anti-ultraviolet aging of asphalt. The test results show that the LDHs has an obvious improvement on the anti UV aging of asphalt.

Softening Point Test For Bitumen Pdf Download

Technical warning - The change from mercury thermometers to electronic temperature devices has revealed that the temperature definition in the mercury thermometer has not been precise enough to make a correct, unbiased transfer to electronic devices. Care should be taken for softening points ring and ball above 100 C as the condition may have changed from previous practise to present days testing equipment. Below approx. 100 C the difference in temperature readings between electronic and mercury stem thermometer is acceptable compared to the repeatability of this test methods. [Reference: ASTM E20 Group]

The current experimental method used in Europe to characterise asphalt binder at high temperature is based on the Ring & Ball softening point. However, for modified binders it was demonstrated that such a method is unable to correctly characterise the material. In the present work, an alternative solution to determine the high-temperature properties of asphalt binders using the dynamic shear rheometer (DSR) is proposed: the Binder-Fast-Characterisation-Test (BTSV) (Bitumen-Typisierungs-Schnell-Verfahren, in German). Two parameters are identified for the rheological characterisation of asphalt binders: the temperature TBTSV, which is related to the Ring & Ball softening point and is an indicator of the binder stiffness, and the phase angle δBTSV, which provides information on the degree of binder modification. These two key parameters are used to discriminate among the different asphalt binder domains in the high-temperature range.

For a suitable determination of bitumen performance in different environments, different systems of classifications have been adopted based on empirical tests (like penetration grade classes, European classification EN 12591 [1]) or fundamental tests based on rheology (like Superpave specifications) [3, 16]. According to the European Standard EN 12591 [1], the penetration grade of bitumen is determined by two main characterization tests: Penetration (PEN) and Softening Point (SP) measures [17, 18]. The penetration and softening point of bitumen are used to characterize the consistency and stiffness of bitumen at ambient and high service temperature respectively, which are undoubtedly affected by the physical and chemical properties of bitumen [3, 16]. The interpretation of these two standard tests is difficult and cannot be directly linked to the temperature susceptibility or the viscoelastic properties of bitumen [16]. However, the penetration grade classes system is still widely used in European countries for bitumen classification.

In consequence, researchers have put a lot of effort to correlate and possibly model the penetration and softening point test of bitumen with its different physical or chemical properties by using different analytical techniques. It was found that an increase of viscosity leads to a SP increase and a PEN decrease. Some models have been proposed to predict SP or PEN from viscosity [19, 20]. A proven relationship between SARA fractions and SP or PEN has been demonstrated by many researchers [14, 21, 22]. For instance, increasing asphaltenes content has a similar effect to viscosity on PEN and SP. Weigel and Stephan [11] proposed prediction models of PEN and SP based on the contents and the molecular weights