The 100% RAP mixtures designed to target AC-11 grading curve were produced at ~5.5% design binder content with ~5% rejuvenator in RAP bitumen. The mixtures show poor rutting resistance in wheel tracking test at 60°C.
Based on my experience with 100% RAP mixes you've added ten times too much rejuvenator. Try to redesign your mix recipe.
Bartłomiej Grzesik The actual rejuvenator dose is 4.8% by weight of RAP binder. This was calculated based on bitumen testing to target the 70/100 binder in the mixture. What is the rejuvenator dosage that you have used with your experience on 100% RAP mixes?
Sorry, I haven't notice, that you wrote "in RAP bitumen". Well, we use 0.1 to 0.5% rejuvenator in relation to total weight of final mix. So your doasage looks good.
Are you sure, that your RAP contains 70/100 binder? If yes, try to test (rutting) samples made without rejuvenator first. In case of such soft binders, even aged, in RAP, usually you don't need rejuvenator at all.
Bartłomiej Grzesik Thanks for the information. We are definitely planning to test mixtures without rejuvenator and perhaps also changing the aggregate gradation by fractionating RAP into sizes.
We do not know the original binder of RAP but because we are also using some 70/100 virgin binder along with rejuvenator, we targetted this grade for RAP binder. This was also to have a reasonable comparison with other mixtures contaning 70/100 binder.
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