Estimation of high-temperature properties of rubberized asphalt using chromatograph

The rutting resistance index (G*/sin δ ) and chemical composition of rubber-modified binder (RMB) were evaluated using a Dynamic Share Rheometer (DSR) and a Gel-Permeation Chromatography (GPC) system, respectively. A source of base asphalt binder, PG 64-22, was used to make a total of 36 RMBs from two rubber types (ambient and cryogenic), three sizes (passing #14, #30 and #40 sieves), two contents (10% and 15% by wt.of binder) and three reaction times (15, 30 and 45 minutes). Routine PG binder tests were carried out on each binder. RMB was tested as the original binder in the DSR at high temperature. The RMB was then RTFO aged and tested as RTFO in DSR at high temperature. Chromatogram of each binder was measured using a GPC system and relative quantity (%) of large molecular size (LMS) was calculated for each binder. Correlation of LMS with G*/sin δ was evaluated by service temperature; 70, 76 and 82°C. It was found that there was a significant correlation between LMS and rutting resistance index. The size and content of crumb rubber were also significant factors affecting the rheology of binder. In addition, G*/sin δ could be estimated using LMS, crumb rubber type and content with R 2 of over 0.92 by the developed prediction model. Therefore, it is possible to predict the G*/sin δ value of rubber-modified binder, with some degree of accuracy, based on LMS value, rubber content and size.