The ability to elevate the temperature of virgin aggregate in order to heat RAP added to the mixture will influence the amount of RAP that can be added.

• A. True
• B. False
• C. Not Applicable
• D. Not Sure

Answer: (A)

Heating the virgin aggregate to higher temperatures changes how much RAP you can add. When you can raise the temperature of the virgin aggregate, heat transfer to the RAP improves, warming the RAP’s aged binder to the proper coating and mixing temperature. Because RAP brings in stiffer, more viscous binder, getting it hot enough is essential for good coating and workability in the final mix. Thus, the higher the feasible mix temperature you can achieve with the virgin aggregate, the more RAP you can safely incorporate without compromising performance. If heating capability is limited, you’ll have to limit RAP content to maintain proper temperatures and mixing quality.