A Review on Bitumen Aging and Rejuvenation Chemistry: Processes, Materials and Analyses

Abstract

During the last decades, extensive research has been carried out on using reclaimed asphalt pavement (RAP) material in the production of hot recycled mix asphalt. Unfortunately, the aged, stiff, and brittle binder in the RAP typically increases the mixture stiffness and can therefore cause fatigue and low-temperature damages. In the scientific literature, there are many studies concerning the aging and rejuvenation of bitumen, but there is a lack of up-to-date reviews that bring them together, especially those facing the phenomena from a chemical point of view. In this paper, a recap of the chemical aspects of virgin, aged, and rejuvenated bitumen is proposed in order to provide a useful summary of the state of the art, with the aim of both encouraging the use of an increasing quantity of RAP in hot mix asphalt and trying to give indications for further research.

Biobased Spore Microcapsules for Asphalt Self-Healing

“…Figure S2 shows the protocol to evaluate the potential of spore microcapsules for the self-healing of microcracks by a fluorescent microscopy healing technique . , Self-healing occurs due to diffusion-controlled reactions of the rejuvenator, which help in renovating the physical and chemical characteristics of the aged bitumen by breaking the intermolecular associations between the asphaltenes …”

Is this the end of the road for bio-inspired road construction materials?

“…An asphalt binder generated from biological sources (Bio-binder) offer an environmentally friendly and economically viable alternative to asphalt bitumen. Consideration has been given to plant based alternatives to bitumen [17], using tall oil, rapeseed oil, soybean oil, sunflower oil, corn oil, used cooking oil, castor oil residues and organic oils. These products are generally mixtures of fatty acids (and esters) [45], Table 1 list some of the plant based oils and their content.…”

“…Several studies have highlighted that these rejuvenators can restore the original properties of bitumen, while also being eco-sustainable [17]. There are no many commercially available plant based asphalt bitumen rejuvenators, some of the commercially available plant based asphalt rejuvenators (see Table 2).…”

“…Despite promising results from several studies using plantbased oils as rejuvenator [17,47,49,50] diverting plants from potential food resources to asphalt production is unacceptable given the increased pressure on food resources globally. Biomass is a promising alternative material source.…”

“…Traditionally petroleum based oils are used as aged asphalt bitumen rejuvenators. However, recent studies [13][14][15][16][17] have demonstrated that food by-products (i.e. vegetable oil) can also be used as an asphalt rejuvenator.…”