Future Directions for Applications of Bio-Oils in the Asphalt Industry: A Step to Sequester Carbon in Roadway Infrastructure

Abstract

The global emphasis on sustainability and net zero carbon roads combined with the increased cost of crude oil has necessitated the application of new environmentally friendly alternatives to the bitumen used in asphalt by the pavement industry. Physical aging, chemical aging, and moisture damage are three important matters encountered in the pavement industry that are harmful for asphalt; bio-oils can decelerate the rates of physical aging and chemical aging in virgin bitumen, and bio-oils can substantially improve virgin bitumen’s resistance to moisture damage. Bio-oils can also restore properties in environmentally damaged asphalt up to a certain limit of aging. The main goal of this review is a comprehensive analysis of the literature about the potential of bio-oils produced from different biomass sources to influence the physical aging, chemical aging, and moisture damage of asphalt. Considering that bitumen’s physical aging is highly impacted by the bitumen’s wax content, this review also covers the effect of wax inherently present in bitumen or wax added to bitumen as a modifier. It is concluded that the chemical composition of a bio-oil has a significant impact on the bio-oil’s ability to protect or recover the bitumen’s original properties. Phenolic compounds found in bio-oils have antiaging effects while bio-oils’ acidic compounds may lead to moisture susceptibility.According to the literature, most bio-oils have positive effects only in a specific range of temperatures: low, intermediate, or high. Complete miscibility and dispersion of a bio-oil in the asphalt matrix also have a significant influence on making a bio-oil an effective modifier. Generally, bio-oils are promising as sustainable, carbon-neutral, cost-effective alternatives to replace or modify conventional bitumen in the pavement industry. This review has identified the following critical research gaps: (1) the lack of standard methods for evaluating and reporting the performance characteristics of each bio-oil in bitumen; (2) the lack of long-term field performance data on bio-oils to support comprehensive life-cycle assessments and life-cycle analyses; (3) high variation among bio-oils made from the same feedstock through different processing methods, leading to variation in performance characteristics; (4) the lack of accurate technoeconomic analysis on industrial bio-oils to facilitate entry of bio-oils into the asphalt market.

Progress and Perspective of Bio-asphalt Preparation, Structural Characterization, and Rheological Properties

“…Moisture damage is a widespread concern among researchers and is also the main factor hindering the application of bio-asphalt in the road field. Especially in bio-regenerated asphalt, although bio-oil can restore the rheological properties of aged asphalt, it does not mean that it has a positive effect on the ability of asphalt to resist moisture damage and even makes the asphalt very susceptible to moisture damage. − The moisture damage of bio-oil is usually related to its acidic component, polarizability, and water-soluble components, which leads to an increase in the moisture sensitivity of bio-asphalt, resulting in the failure of the adhesion and cohesion of the asphalt mixture . Oldham et al reduced acidic compounds in waste cooking oil through transesterification, significantly reducing its ability to resist moisture damage.…”

A Review of Hydrothermal Biomass Liquefaction: Operating Parameters, Reaction Mechanism, and Bio-Oil Yields and Compositions

“…20 Ameri et al summarized the potential effects of bio-oil produced from different biomass sources on the physical aging, chemical aging and moisture damage of asphalt. 21 Halil Durak summarized the main process parameters and technical applications of hydrothermal liquefaction, hydrothermal carbonization, pyrolysis and gasification. 22 Zhuang et al conducted a systematic comparison between direct HTL and stepwise HTL from a technical and economic perspective, and studied the transformation form of nitrogen.…”

“…Ameri et al. summarized the potential effects of bio-oil produced from different biomass sources on the physical aging, chemical aging and moisture damage of asphalt . Halil Durak summarized the main process parameters and technical applications of hydrothermal liquefaction, hydrothermal carbonization, pyrolysis and gasification .…”

The Effect of a Liquified Wood Heavy Fraction on the Rheological Behaviour and Performance of Paving-Grade Bitumen

“…Recent reviews that discuss in more detail the biomass thermochemical processes to obtain bio-oil for road construction and the properties of bio-bitumen and bio-asphalt can be found in [23,24,31,32]. These reviews point out that in comparison with base bitumen, the performance of bio-bitumen can be better or worse in different temperature ranges (low, intermediate and high), and the same occurs for bituminous mixtures.…”

“…These reviews point out that in comparison with base bitumen, the performance of bio-bitumen can be better or worse in different temperature ranges (low, intermediate and high), and the same occurs for bituminous mixtures. Ameri et al [31] showed that there is high variation among bio-oils from the same biomass source processed with different methods and that there are no established methods for evaluating and comparing the performance of bio-bitumens. Bio-oils have different chemical compounds from bitumen, and the interaction between them can increase or decrease the mobility of molecular chains at different temperatures, which affects resistance to thermal-and fatigue-cracking and rutting [32].…”