Improvements on asphalt mixtures rutting performance characterization by the use of low shear viscosity

Abstract

The relationship between the rutting performance of dense asphalt concretes and the low shear viscosity (LSV) of different asphalt binders was analysed in a previous work. A LSV limit was found for the original asphalt to prevent the rutting of the mixtures, and in addition, a model to predict the rutting performance based on the LSV of the asphalt binder was validated. With the aim of amplifying the criterion previously found, the performances of micro and stone mastic asphalt mixtures are studied in this work. Conventional, multigrade and polymer modified asphalts were used as binders. Considering that the properties of original and aged asphalts must be taken into account for a better asphalt binder characterization, LSV measurements on aged asphalts were also done in order to analyse their relationship to the mixtures rutting performance. The micro and stone mastic asphalt mixtures showed a similar behaviour as the dense grade asphalt concrete in the previous study. Regarding the control of rutting, a LSV limit of 500 Pa.s was found for original asphalts, while 2,000 Pa.s was the limit for aged asphalt binders. The model to predict the rutting performance of asphalt mixtures was amplified, incorporating both original and aged asphalt LSVs as appropriate input data.

Wheel tracking test (WTT) conducted under different standards. Study and correlation of test parameters and limits

“…Recently, the Rr limit of Agnusdei et al was verified considering the rheological properties of the binder such as low shear viscosity (LSV) in Morea et al [4,5]. In this work, drastic increases in Rr were observed when the original bitumen LSV was lower than 500 Pa.s at the same temperature as that of the WTT.…”

“…2, it was possible to infer that the 0.07 mm/10 3 cycles of WTS are related to a high binder LSV of 1315 Pa.s. This LSV value is bigger than the value of 500 Pa.s proposed by Morea et al [4]. This binder viscosity is obtained in polymer modified binders or at low temperatures, limiting the types of mixture that can be used in normal conditions where rutting appears.…”

“…In previous work Morea et al [4,5], rutting measurements in the WTT (according to BS 598-110) and the LSV of binders have been related. A relation between the mixture Rr and the LSV of the original binder, see Eq.…”

“…A relation between the mixture Rr and the LSV of the original binder, see Eq. 2, has been proposed in Morea et al [4]. In this relation the LSV is considered at the same temperature as that of the WTT on the mixture.…”

Bitumen Foaming Optimisation Process on the Basis of Rheological Properties

“…Viscometer Rheotest 4.1 was used in compliance with the relevant standard [ 20 ]. Dynamic viscosity was determined at 60 °C for two levels of shear rate, i.e., for dynamic viscosity of the Newton’s law state, = 1 s −1 (experimental) and for zero shear viscosity η ZSV determined at a shear rate of 0.0032 s −1 [ 21 ].…”