Dodecylbenzenesulfonic Acid as a Bitumen Modifier: A Novel Approach To Enhance Rheological Properties of Bitumen

Bitumen deterioration has been traditionally overcome by its modification with polymers, sometimes producing unstable blends as a result of their mutual lack of affinity. A new and different approach based on the use of dodecylbenzenesulfonic acid (DBSA) is herein reported. DSBA is a surfactant that contains a strong acid group capable of interacting with asphaltene molecules, commonly used as a dispersing agent for asphaltenes in crude oils. However, the contrary effect can also be obtained, as long as a critical concentration is not surpassed. In this work, the influence that the additive concentration and processing temperature exert on the thermomechanical behavior of DBSA-modified bitumen has been assessed by means of rheological, thermal, and thermogravimetric analyses. Within the concentration range used (0.4-3 wt %), the attachment of DBSA to asphaltene molecules promoted the association of asphaltene molecules/aggregates into larger clusters in bitumen, with 3 wt % DBSA noticeably improving rheological properties of bitumen.