Influence of Biomass-Modified Asphalt Binder on Rutting Resistance

Table 2

Benefits and drawbacks of various biomodifiers on other properties.

Benefits	Drawbacks and limitations
By using bio-oil, a general improvement in the intermediate-temperature fatigue resistance and low-temperature thermal resistance is acknowledged.	Excessive ash content might lead to issues such as increased stiffness and reduced flexibility, and it may cause nonhomogeneous dispersion in asphalt binders.
Biochar particles may enhance the adhesion between asphalt binder and aggregate, as well as cohesion within the asphalt binder itself. This improvement in adhesion and cohesion contributes to a more stable and durable asphalt mixture.	Some bio-oil modifiers significantly increase asphalt binder’s susceptibility to moisture damage. This aspect was evident regardless of the source of the bio-oil.
The stiffening effect of lignin in the asphalt demonstrates the potential of warm mix asphalt technology, which could produce a relatively soft asphalt mixture because of less aging at lower production temperatures.	In order to prevent oxidation effects, the temperature at which lignin is mixed with asphalt binder must be regulated.
Bio-oil addition favors the reduction of the carbonyl peak (C = O stretch), hence emphasizing the rejuvenation effect in the aged binder.	Biochar is better suited for use in tropical and subtropical regions because of its poor performance at low temperatures. Consequently, its application is restricted to low-temperature regions.
The effects of hardening are proportional to the amount of lignin present, and as lignin content increases, so do the mixing and compaction temperatures, which must rise to meet production efficiency standards.	The inclusion of lignin results in a stiffer behavior with a more elastic response of the modified asphalt binders and may marginally decrease the fatigue performance. In contrast, no similar behavior was observed for the low-temperature properties.
Reclaimed asphalt pavements (RAPs) and virgin asphalts’ aging and hardening characteristics can also be decreased by using bio-oil-modified binder in asphalt pavements.	The addition of lignin leads to a stiffer behavior with a more elastic response of the modified asphalt binders. It can slightly reduce fatigue performance, while no similar behavior was found for low-temperature properties.