The fatigue performance and healing ability of asphalt pavements are important for mixture design, rehabilitation, and maintenance of the roads. By analyzing these parameters in an asphalt mixture, it is possible to predict the crack formation and propagation in asphalt pavements and healing of these cracks during the rest periods. The healing effect in asphalt mixtures has been observed and verified by many researchers and different methods exist to evaluate this phenomenon. However, current methods are still inadequate to fully observe and quantify the healing phenomenon in asphalt mixtures. In this study, a digital image correlation (DIC) method is used to calculate the strain map on the surface of cylindrical asphalt specimens during the indirect tensile fatigue test. This strain map is used to detect the location of crack initiations and development of the microcracks during the experiments. Next, the specimens are unloaded and the temperature of the climate chamber is increased to 60 °C for 18 h to investigate the healing phenomenon on the surface of the specimens. It is observed that the strain reduces near the microcrack areas especially at the tip of the microcracks. Furthermore, using DIC it is possible to observe the healing rate and the minimum time required to heal the microcracks on the surface of the specimens.

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.

Incorporating reclaimed asphalt (RA) in surface layer mixtures is still limited due to performance concerns, and it becomes even more challenging when combining aged polymer-modified bitumen (PMB) with virgin PMB. This study aims to evaluate, from a binder perspective, the feasibility of incorporating reclaimed polymer-modified binder (RPMB) in new surface layer mixtures. To address this challenge, blends of RPMB and virgin PMB were investigated at three replacement rates (20%, 40% and 60%) with and without a tall oil-based rejuvenator. First, the viscoelastic behaviour of the blends was assessed using a dynamic shear rheometer. Moreover, physicochemical changes were tracked using infrared spectroscopy and fluorescence microscopy. The experimental investigation revealed that, due to polymer degradation of the RMPB, only the blends with 20% RMPB exhibited polymer activity. Finally, the use of the rejuvenator compensated for the rheological properties of the aged RPMB and reduced the susceptibility to non-load-associated cracking.

With the increased use of reclaimed asphalt (RA), the ability of bituminous materials to resist fatigue cracking may face a decline mainly due to the aged reclaimed asphalt binder (RAB), especially when RA is used at higher rates and not sufficiently treated. In this study, the bulk scale (asphalt) and its subscale (mortar) were employed to evaluate the effect on fatigue resistance when a RAB is added, by considering three replacement rates: 0%, 40%, and 70% RAB. The fatigue testing of asphalt mixtures was carried out using a four-point bending (4PB) setup, while the mortars were tested using a new column-like geometry utilising a dynamic shear rheometer (DSR). The fatigue properties were further analysed using dissipated energy concepts. The aim of this study was, first, to assess whether the inclusion of a RAB can provide at least similar fatigue properties compared to an all-virgin mix, and second, to evaluate whether the proposed treatment is beneficial for the mixtures with a RAB. The asphalt tests revealed that the inclusion of a 40% RAB led to increased fatigue resistance, whereas the mortar tests showed that the inclusion of RAB has an inverse effect on fatigue life.

In an attempt to mimic the in-situ ageing of asphalt pavements, the exploration of appropriate laboratory ageing simulations has led to multiple standards on binder level. On asphalt mixture level, however, less consensus exists regarding ageing simulation protocols. This study aims to compare the chemo-rheological performance of bitumen between lab ageing protocols for binders, compacted and loose asphalt mixtures. A bituminous binder was used in bitumen ageing protocols, while it was also used to produce an AC10 mixture that was conditioned as a loose mixture and for compacted cylinders and slabs. Oven ageing of the mixtures was conducted for up to 9 days at 85 °C. The binder testing results, derived from empirical, rheological and chemical tests, indicate that 20 h of PAV ageing yields approximately similar results as 1–2 days of loose mixture oven ageing. Furthermore, in compacted samples, only the outer edge was influenced significantly by oxidative ageing.