Performance of field produced rejuvenated 30% RAP surface mix in Northwest Iowa

Abstract

In this research, as part of a broad investigation, it was determined that 3.6% epoxidized methyl soyate (EMS) by weight of PG 58-34H binder (0.125% by total mix weight) was needed to achieve a PG 52-40H binder due to there being 30% RAP in the mix design (29.80% in the total binder content). Both lab and field produced mix verification showed that 0.125% EMS met the criteria for moisture susceptibility/rutting and low temperature cracking according to Iowa DOT specifications. For comparison purposes, there was a Control mix (PG 58-34H binder and 18% RAP) with no rejuvenator, and a 30% RAP mix design made using a commercial tall oil derivative (CTOD) rejuvenator from the contractor of which both met Iowa DOT criteria for low temperature cracking, but that the Control group did not have adequate rutting performance for a binder rated as PG 58-34H. Initial comparisons between lab low temperature mix performance from field produced and lab compacted specimens to field transverse cracking measurements (1 year after construction) lined up fairly well with trends from previous works for all three groups.

KEYWORDS:

• Restorative reactive modifier
• epoxidised methyl soyate
• superpave
• rutting
• low temperature cracking
• field density

Acknowledgements

The authors would like to thank the United Soybean Board (USB) for their support in this work as well as thank Jon Arjes and William Dotzler from the Iowa Department of Transportation for their assistance in using their Hamburg Wheel-Tracking Device and help in getting information from the Iowa DOT’s PMIS database.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Some or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.