Bio-modification of rubberised asphalt binder to enhance its performance

Abstract

The application of crumb rubber in the asphalt industry has demonstrated many advantages in pavement, yet the challenges associated with its application in pavement construction have limited its usage. In this study, Bio-Binder was used as an additive for crumb-rubber-modified (CRM) asphalt binder to enhance its rheological properties while improving workability and reducing segregation. The product produced by adding Bio-Binder to CRM binder is called Bio-Modified-Rubber (BMR) binder. Rheological studies showed a reduction in the mixing and compacting temperatures of BMR binder in comparison to CRM binder, which consequently leads to improvement in the workability and pumpability of the resulting asphalt mixture. The segregation which was quantified using a phase separation index, reduced from 58% in CRM binder to 33% in BMR binder. In addition, BMR binder showed better fatigue cracking resistance than both CRM and neat binders. Evaluating low-temperature properties of specimens conditioned at −12 °C for 12 h showed that BMR binder had improved low-temperature properties compared to CRM binder. In addition, mixture studies were conducted on the fine aggregate matrix (FAM). It was shown that low-temperature properties of FAM mixes made with BMR were significantly better than those of CRM mixtures.

Keywords:

• Bio-Binder
• crumb rubber
• CRM
• asphalt binder
• rheology
• additive

Acknowledgments

The authors would like to acknowledge the invaluable assistance provided by Faisal Kabir, a PhD student at North Carolina A&T State University. The contents of this paper reflects the view of the authors, who are responsible for the facts and the accuracy of the data presented. This paper does not constitute a standard, specification, or regulation.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research is sponsored by the National Cooperative Highway Research Program [grant number NCHRP-IDEA 171], [grant number NCHRP IDEA 194], and the University Transportation Center: Center for Highway Pavement Preservation.