Foaming Performance and FTIR Spectrometric Analysis of Foamed Bituminous Binders Intended for Surface Courses

Abstract

This study explores the effects of foaming on three selected bituminous binders: 50/70 paving grade bitumen, 45/80-55 polymer modified bitumen and 45/80-80 HiMA binder. The first part of the investigations included the evaluation of the foaming performance in terms of foaming temperature and foaming water content with the utilization of desirability functions and based on the equality of maximum expansion ratio and bitumen foam half-life. The second part of the study investigated the effects of foaming on the chemical structure of the binders using Fourier-transform infrared spectroscopy. The results of the spectroscopic measurements permitted calculation of structural indices specific to functional groups associated with bitumen oxidation, as well as those indicative of elastomeric modification. The results have shown that the different types of bitumen exhibited different foaming characteristics, which was most evident in bitumen foam half-lives, with the HiMA binder performing the best. The spectrometric measurements did not show any significant effects of foaming on the chemical structure of the evaluated binders related to oxidative stress, neither were any major changes in the PmB-specific regions found.

Effects of Short-Term Ageing Temperature on Conventional and High-Temperature Properties of Paving-Grade Bitumen with Anti-Stripping and WMA Additives

“…There is also some proof that synthetic waxes have capacity to slow down the formation of carbonyl compounds in asphalt binders and therefore decrease their ageing index [ 42 , 43 ]. In recent years, a number of studies [ 26 , 44 , 45 , 46 , 47 , 48 ] have been published regarding the effects of foaming on the properties of bituminous binders. In these works, no clear evidence was found for detrimental effects of foaming on high-temperature rheological and functional properties of bituminous binders.…”

A Study of Adhesion in Foamed WMA Binder-Aggregate Systems Using Boiling Water Stripping Tests

“…It is most often reported that carboxylic acids and sulfoxides are most easily displaced by water, while ketones have the least propensity to be displaced by water among the strongly adsorbed compounds. Although these functional groups were identified in the evaluated asphalt binders, their concentrations were low, typical of neat binders [ 37 ]. Additionally, the carbonyl indices of the evaluated binders were mainly shaped by the absorption bands of ketones ( Figure 8 a).…”

“…The first step of the sample preparation was to conduct foaming of the asphalt binders. The bitumen was foamed using WLB10S laboratory foamer (Wirtgen, Windhagen, Germany) using 2% foaming water content as in the work of [ 37 ], transferred to glass containers, and cooled to ambient temperature. Non-foamed binders were also poured into such containers and cooled.…”

“…Many studies have been recently published regarding the effects of foaming on the properties of bituminous binders. The majority of the works focus on the functional properties of the foamed binders, mostly showing no significant detrimental effects of the foaming process; however, decreased aging of the binders is often raised as a potential problem for the short-term high-temperature performance of these mixtures [ 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ]. A number of studies have been published on the resistance to moisture damage of warm-mix-asphalt produced using mechanical water foaming, showing that these mixtures may be more susceptible to the action of water [ 43 , 44 , 45 , 46 ].…”

Homogeneity and Viscoelastic Behaviour of Bitumen Film in Asphalt Mixtures Containing RAP

“…They consist of the assessment of the chemical properties of mixtures or the analysis of the microstructure of the bitumen film. Direct methods include, among others, FTIR spectrographic, GPC gel chromatography, X-ray spectroscopy or microscopy analysis [ 11 , 12 , 13 , 14 , 15 ]. The second group consists of indirect methods.…”