The role of fillers and cementitious binders when recycling with foamed bitumen or bitumen emulsion

Internationally a debate has been on-going about the influence of active or inactive fillers when recycling pavement materials with foamed bitumen or bitumen emulsion. A research project carried out during the last few years investigated the effect of a number of cementitious binders and inactive fillers on the dry and soaked Indirect Tensile Strength (ITS) of a recycled asphalt pavement (RAP) material and foamed bitumen or a bitumen emulsion. The aim of the paper is to present the results of the study to provide guidance for future use. The research programme conducted tests on a RAP material using 1,5 % of a range of cementitious stabilization agents with various percentages of foamed bitumen and bitumen emulsion binder content. An experimental design matrix covering quantities of binder, type of binder and type of filler was presented. It was found that inactive fillers had no influence on the dry or soaked ITS compared with the bitumen emulsion or foamed bitumen treated materials without any filler. Cementitious binders resulted in increased ITS values for both bituminous materials. 1