On Trunk Highway 6 near Emily, Minnesota, a field study put seven recycling agents into 40% reclaimed asphalt pavement mixtures and tracked them beside 30% and 40% RAP controls. SIP-1111™ appears in the report as 6003 (D1), US Soybean. The project provides a direct comparison across recovered-binder grade, mixture rheology, cracking tests, and field distress.
Project design
The National Road Research Alliance sections were constructed in August 2019. All seven recycling-agent mixtures used a PG 58-28 base binder, 40% RAP, and a supplier-selected dosage intended to reach a recovered grade of XX-34. The report identifies three controls: 30% RAP (D0), 40% RAP (D1), and 40% RAP (D2).
| Code | Report description | As-extracted continuous PG | RAP |
|---|---|---|---|
| 6001 | Cargill | 58.1-37.6 | 40% |
| 6002 | Poet | 61.4-38.8 | 40% |
| 6003 | US Soybean / SIP-1111™ | 54.9-38.4 | 40% |
| 6004 | Ingevity | 62.6-33.7 | 40% |
| 6005 | Kraton | 61.7-34.7 | 40% |
| 6006 | Asphalt and Wax Innovations | 66.8-30.5 | 40% |
| 6007 | Georgia Pacific | 70.5-33.2 | 40% |
Three-year phase angle and dynamic modulus
At 20°C and 5 Hz, Figure 3-13(c) places 6003 at approximately 32 degrees phase angle and 2,600 MPa |E*|. Those are respectively the highest phase angle and lowest dynamic modulus among the seven recycling-agent sections. The nearest recycling-agent comparator is 6005 at approximately 29 degrees and 3,100 MPa. In this plot, higher phase angle and lower |E*| indicate a softer mixture with more relaxation capacity under the stated test condition.
The metrics identify different strengths. The phase-angle and |E*| comparison favors 6003, the DCT result favors 6005, and the rutting data show no positive 6003 distinction.
Glover-Rowe results
In the mixture Glover-Rowe analysis, lower and more-negative change relative to the 40% D1 control is favorable. The report identifies 6003 and 6005 as the two exceptions to the general decline in recycling-agent effectiveness as field cores aged.
Recovered-binder grades
The as-extracted 6003 binder grades PG 52-34 under AASHTO M 320. After three years, binder recovered from the 6003 section grades PG 58-28, with continuous grade 62.1-33.5, while the 40% RAP Day 1 control grades PG 64-22, with continuous grade 72.0-27.7. The three-year samples came from small-cylinder specimens, so the report cautions against treating them as directly interchangeable with prior-year top-core samples.
Field cracking context
What the project establishes
Emily shows how SIP-1111™ behaved in one 40% RAP field design against a full recycling-agent set and two RAP levels of control mixture. The strongest 6003 results are the three-year phase-angle and |E*| position, project-specific PG 52-34 recovery, relative binder Glover-Rowe behavior after severe aging, and participation in the lower-cracking recycling-agent group. The DCT lead for 6005 and the rutting result complete the project tradeoff.
Review SIP-1111™ · See related demonstration projects · Discuss a high-RAP application with SoyLei
Source Documents
- Long-term Testing and Analysis on Asphalt Mix RA Field Sections, Minnesota Department of Transportation, 2024
