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Performance evaluation and mechanistic-empirical design of bio-oil modified asphalt mixes
Journal
Construction and Building Materials
ISSN
09500618
Date Issued
2022-03-28
Author(s)
Girimath, Shashibhushan
Singh, Dharamveer
Rajan, Bharat
Abstract
The present study explores the application potential of wood bio-oil (WBO) as a replacement to conventionally used asphalt binder in flexible pavements. The study considers three different dosages of WBO i.e., 0% (control), 2% (WBO_2%) and 4% (WBO_4%) by weight of binder. First, a detailed physical (water content and density) and chemical characterization of WBO is carried out using pH, SARA, CHNS-O analysis. Further, the effects of WBO replacement on control binder is studied as per consistency and chemical properties. Later, detailed mix performance and mechanistic-empirical pavement design are carried out. The mix performance i.e., rutting, fracture and design indicators are captured using Flow Number (FN), Semi-Circular Bending (SCB), and Resilient Modulus (RM), respectively. The results showed that the WBO is acidic in nature and has a comparatively similar proportion of carbon and hydrogen as that of asphalt binders, thus makes it suitable for partial replacement in asphalt mixes. The increase in resins and aromatics with the addition of WBO causes an increase in softening point, penetration and aging tendency. However, WBO_4% satisfied the Superpave mass loss limit (0.96 < 1%). The FTIR analysis indicated the significant presence of O–H group in WBO, which confirms the presence of water. Moreover, WBO addition has not caused an increased peak in control binder's FTIR spectra. The mix performance and characteristic evaluation revealed no significant difference in rutting, fracture, and modulus value of control and WBO modified mixes. Finally, the mechanistic-empirical design indicated, compared with control and WBO_4%, the WBO_2% could be helpful to reduce design thickness by 15 mm and hence the cost. Overall, it is expected that the study will be helpful to understand, visualize and comprehend the effects and benefits of WBO addition from asphalt mixes and flexible pavement design perspective.
Volume
325
Subjects