On the Applicability of ATR-FTIR Microscopy to Evaluate the Blending between Neat Bitumen and Bituminous Coating of Reclaimed Asphalt

Abstract

The utilization of Reclaimed Asphalt (RA) in the road construction sector induces considerable economic and ecological benefits. The blending of the recycled material with new components is believed to be of great importance for the mixture’s properties. An extensive knowledge of the blending of the materials is crucial in optimizing the use of RA, especially at higher recycling rates. In this paper, the applicability of Fourier transform infrared (FTIR) microscopy in attenuated total reflectance (ATR) mode to study the bituminous coating of RA granulates is investigated. This method is a promising alternative to trace heterogeneous areas within the coating compared to methods that require extraction and recovery of bitumen. A method for sample preparation and FTIR spectra analysis is proposed. Four different samples were analyzed: a reference RA granulate, two types of RA granulates mixed with neat bitumen, and a RA granulate with rejuvenator. The results show that the use of ATR-FTIR microscope allows the tracing of different components, indications of blending, as well as proof of rejuvenation of the aged bituminous area.

Fatigue Resistance of Bituminous Mixtures and Mortars Containing High Reclaimed Asphalt Content

“…In a previous study, it was concluded that the actual bituminous coating of RA is a bituminous mortar, as demonstrated by microscopic images [ 16 ]. Commonly for conventional bituminous binders, certain viscosity levels are defined to allow them to adequately mix and cover the aggregates in a bituminous mixture.…”

“…Moreover, testing bituminous mastics (bitumen and filler) has also been widely used, and this has the advantage of including the filler, where different filler types can greatly influence their fatigue behaviour [ 14 , 15 ]. The mortar scale also allows for the inclusion of sand (the whole fraction or part of it), which has been demonstrated to play a significant role in the bituminous coating and the bonding of the coarse aggregate skeleton [ 16 , 17 ].…”

Affinity between Bitumen and Aggregate in Hot Mix Asphalt by Hyperspectral Imaging and Digital Picture Analysis

“…Fourier transform infrared (FTIR) has also been used to achieve this result. In [28], the bitumen overlay of aggregates with reference to FTIR microscopy in attenuated total reflectance (ATR) mode is investigated. This method is a promising alternative to trace heterogeneous areas within the coating compared to methods that require extraction and recovery of the bitumen.…”

The impact of reclaimed asphalt rate on the healing potential of bituminous mortars and mixtures

“…Consequently, the inclusion of RAB, especially at higher levels, might have a negative effect on the healing potential. In a previous study, it was demonstrated that the bituminous coating of RA grains consists of bituminous mortar, a mixture of bitumen, filler and finer particles of sand (<250 μm) (Margaritis et al 2019). Thus, it is especially interesting, when healing is evaluated for mixtures with RA, that the mortar is considered as a subscale since this will be the actual bonding material.…”