Influence of bitumen foam characteristics on moisture susceptibility of foamed bitumen stabilised mixes

• Published in: The international journal of pavement engineering 2023-01, Vol.24 (2)
• Main Authors: Mondal, Purbayan Ghosh, Kuna, Kranthi K.
• Format: Article
• Language: English
• Subjects: Bitumens; Foamed bitumen; foamed bitumen stabilised mixes; minimum threshold foam characteristics; Moisture resistance; moisture susceptibility; receiver operation characteristics analysis; Tensile strength
• ISSN: 1029-8436; 1477-268X
• DOI: 10.1080/10298436.2022.2128352

The objective of the present study is to investigate the effect of foam characteristics of bitumen such as maximum expansion ratio (ER m ) and half-life (HL) on the moisture susceptibility of foamed bitumen stabilised mixes (FBMs). The study investigated the individual as well as the interaction effect of ER m and HL on moisture susceptibility of FBMs. Considering the individual effect of ER m , it was observed that for a given HL, the beneficial effect of ER m on the moisture susceptibility of FBMs exists up to a certain level of ER m , beyond which the performance of the FBMs was found to be compromised. On the other hand, at controlled ER m , the higher HL was found to have beneficial effect on the moisture susceptibility of FBMs, provided the controlled ER m was sufficiently high. When the interaction effect of ER m and HL was considered, the FBMs were found to have higher moisture damage resistance with the increase in ER m as long as the HL was above a certain threshold level. The study also proposed performance-based minimum threshold limits for ER m and HL based on the Receiver Operation Characteristics (ROC) analysis on the retained tensile strength (TSR) results obtained for the FBMs prepared at varying foam characteristics.