Date of Degree
MS (Master of Science)
Civil and Environmental Engineering
Hosin "David" Lee
The objective of this research is to examine the effects that different methods of RAP stockpile fractionation have on the volumetric mix design properties for high-RAP content surface mixes, with the goal of meeting all specified criteria for standard HMA mix designs. The processing of RAP materials results in the degradation of the aggregate structure of the original pavement. The increased presence of fine RAP materials in the stockpile can be attributed to the amount of crushing done on the RAP millings. Fractionation methods were designed to separate the stockpile at certain sizes to isolate the fine RAP materials which contained higher amounts of fine aggregate and negatively impacted the volumetric properties of the mix design. These isolated RAP materials were used in reduced proportions or completely eliminated, thereby decreasing the amount of fine aggregate material introduced to the mix. Mix designs were created using RAP materials included from each original stockpile and the two fractionated stockpiles created from each original stockpile at high-RAP contents of 30%, 40% and 50% by virgin binder replacement. Fractionation of RAP materials was effective in improving the volumetric properties of high-RAP content mixtures through reduction of fine aggregate material introduced by the RAP materials.
Copyright 2012 Cory Patrick Shannon
Shannon, Cory Patrick. "Fractionation of recycled asphalt pavement materials: improvement of volumetric mix design driteria for High-RAP content surface mixtures." thesis, University of Iowa, 2012.