A general system describing the visco‐elastic properties of bitumens and its relation to routine test data

Abstract After dynamic and static experiments on the mechanical behaviour of bitumens an attempt was made to incorporate all the essential factors into a simple system. This was found to be possible in the form of a nomograph, by means of which the deformation of bitumens can be calculated as a function of stress, time and temperature. Origin or method of manufacture proved to be of less importance than hardness and rheological type. For correlation with standard test‐methods, the ring‐and‐ball temperature and the penetration index were found to be suitable parameters. The nomograph enables the average behaviour of a given grade to be calculated with an accuracy sufficient for engineering purposes. Another feature of the nomograph is that it creates the possibility of giving an interpretation of other routine tests. By way of example both penetration and Fraass breaking test are discussed.