The National Road Research Alliance constructed recycling-agent field sections on Trunk Highway 6 near Emily, Minnesota in August 2019. The project evaluated 40% RAP wearing-course mixtures with seven recycling agents, plus 30% and 40% RAP control sections. The study followed plant-produced mixtures, recovered binders, laboratory aging, field cores, and field performance over multiple years.
The third-year report identifies SIP-1111™ as source code 6003 (D1) in Table 2-1, listed as US Soybean. The 6003 section provides a side-by-side view of SIP-1111™ against other recycling agents and controls in a high-RAP field setting.
Download the MnDOT/NRRA final report PDF.
Code legend for the recycling-agent sections
The Emily report uses coded mixture IDs for the recycling-agent sections. Table 2-1 maps those codes to the supplier description, as-extracted performance grade, RAP content, and production day.
- 6001 (D1): Cargill; as-extracted PG 58.1-37.6; 40% RAP; Day 1.
- 6002 (D1): Poet; as-extracted PG 61.4-38.8; 40% RAP; Day 1.
- 6003 (D1): US Soybean, the SIP-1111™ section in this review; as-extracted PG 54.9-38.4; 40% RAP; Day 1.
- 6004 (D2): Ingevity; as-extracted PG 62.6-33.7; 40% RAP; Day 2.
- 6005 (D2): Kraton; as-extracted PG 61.7-34.7; 40% RAP; Day 2.
- 6006 (D2): Asphalt and Wax Innovations; as-extracted PG 66.8-30.5; 40% RAP; Day 2.
- 6007 (D2): Georgia Pacific; as-extracted PG 70.5-33.2; 40% RAP; Day 2.
For context, Table 2-1 also lists three controls: 30% RAP (D0), as-extracted PG 64.1-31.5; 40% RAP (D1), as-extracted PG 65.5-31.6; and 40% RAP (D2), as-extracted PG 60.8-33.7.
High-RAP field data with side-by-side recycling-agent comparisons
High-RAP asphalt mixtures preserve valuable binder and aggregate, while aged binder in RAP can raise cracking risk when a mix lacks enough relaxation capacity. The Emily sections placed recycling agents into the same project environment and then compared how the mixtures and binders aged in the lab and field.
The Emily report gives SIP-1111™ a practical demonstration record: material chemistry, binder rheology, mixture cracking indicators, and field distress observations all appear in one project.
Three-year black space: 6003 separated from the RA pack
Figure 3-13(c) shows the clearest 6003 separation. In the three-year field-core black-space plot, 6003 reaches the highest phase angle and the lowest dynamic modulus, |E*|, among the recycling-agent sections. 6005 follows as the closest second-place RA, with lower phase angle and higher |E*| than 6003.
The report describes lower-right movement in black space as decreased stiffness and increased relaxation ability from recycling-agent inclusion. Over the three-year field-aging trend, every recycling-agent mixture except 6003 moved back toward the upper-left region associated with diminishing recycling-agent efficacy and loss of cracking resistance.
Binder Glover-Rowe: 6003 broke away after severe aging
Figure 4-11 extends the comparison into recovered-binder Glover-Rowe behavior. After 7-day aging at 95 C, 6001 and 6002 moved back toward the 40% control, while only 6003 showed lower G-R values than the controls.
The severe-aging result separates 6003 from the Day 1 recycling-agent pack on binder G-R and reinforces the three-year black-space result.
Mixture G-Rm: sustained cracking-resistance indicators
Figure 3-12 compares mixture Glover-Rowe values and percent change from the 40% D1 control. As field aging reduced the effectiveness of most recycling agents, the report identifies 6003 and 6005 as exceptions.
For SIP-1111™, the mixture G-Rm result places 6003 in the small group of recycling-agent sections that maintained stronger cracking-resistance indicators as the field cores aged.
Recovered-binder chemistry supports the same direction
For the three-year field cores, the report notes that 6003 showed lower asphaltene ratios and higher colloidal indices than the control mixtures. Those compositional indicators align with the black-space and G-R observations: 6003 continued to show a restoration and dispersion signal after field exposure.
Field performance: less transverse cracking than the 40% D1 control
The field-performance chapter reports that every recycling-agent section outperformed the 40% D1 control in transverse cracking over the first three years of service. SIP-1111™, represented by 6003, participated in that lower-cracking group.
What Emily shows for SIP-1111™
The Emily, Minnesota NRRA study gives SIP-1111™ a strong demo-project story. In the third-year data, 6003 separates from the recycling-agent pack in black space, breaks away on Day 1 binder G-R after severe aging, remains one of the sustained-effectiveness exceptions on mixture G-Rm, and joins the field sections with less transverse cracking than the 40% D1 control.
Those results give asphalt producers, agencies, and terminal teams a field-backed view of SIP-1111™ in a high-RAP asphalt system: side-by-side recycling-agent comparison, aged-material testing, recovered-binder chemistry, and measured field distress in one project record.
