Ageing Evaluation of Foamed Polymer Modified Bitumen with Bio-Flux Additive

Abstract

This paper presents the results of an analysis of the changes in the stiffness of asphalt binders modified with a bio-flux additive and subjected to the processes of foaming and short-term ageing. The purpose of the analyses was to determine changes in the rheological properties of asphalt binder as a result of technological processes characteristic of hot and warm mix asphalt technology. Three asphalt binders with similar penetration but varying degrees of polymer modification were tested: 50/70, 45/80–55 polymer-modified bitumen, and 45/80–80 highly modified bitumen. Tests were carried out on four groups of binders: original binders, foamed binders after 14 days of storage, non-foamed binders after Rolling Thin Film Oven Test (RTFOT) ageing, and foamed binders after 14 days of storage subjected to RTFOT ageing. The master curves of the complex shear modulus G* were analysed, and three indexes of binder stiffening were determined, characterising the investigated effects. The tests showed that some of the stiffening indices significantly depended on the degree of polymer modification and the content of the bio-flux additive. Moreover, it was found that the foaming process in the case of paving-grade bitumen and polymer-modified bitumen did not contribute to the additional stiffening of the binders.

The Combined Effects of Additives on the Conventional and High-Temperature Performance Properties of Warm Mix Asphalt Binders

“…Therefore, a number of studies have been conducted to evaluate the effects of aging temperature on the properties of WMA asphalt binders. The observations made in the field sections were confirmed in laboratory studies [8][9][10][11][12][13][14], showing a great dependence of the high-temperature properties of the asphalt binders on the laboratory aging protocols and the aging temperatures in particular. In studies comparing asphalt binders recovered from asphalt mixtures and the RTFOT-aged binders [15][16][17], it was shown that the standard temperature during short-term aging (163 • C) was too high to reflect the aging processes during the production of WMA mixtures, while 123 • C can be considered too low.…”