Comparative study of the effect of long-term ageing on the behaviour of bitumen and mastics with mineral fillers

This paper is based on a part of the research project carried out at the request of the German Research Foundation (DFG), under research project No. WE 1642/1-2 and LE 3649/1-2 (FOR2089).This study aims to evaluate the effect of mineral fillers on bitumen ageing. Two different bitumens and four mastics were investigated in the unaged and long-term aged states, based on different properties (consistency, rheology, fatigue resistance and ductility). Mastics stiffened less due to ageing treatment than bitumens, especially with granite filler. However, the results of the performance tests were not definitive regarding the effect of the filler. Aged bitumen showed greater fatigue resistance and higher specific energy of ductile fracture than unaged bitumen, whereas the mastics showed minor variations in the specific energy of ductile fracture with ageing treatment, which is indicative of less ageing, but the fatigue resistance decreased significantly in mastics with one of the bitumens.authorsversionpublishe

Mixed-Member Proportional Electoral Systems: A Complete Review and Case for U.S. Adoption

This thesis traces mixed-member proportional systems from their origin in Germany to their present day impacts. Theoretical analysis of electoral reform and mixed-member systems are employed to motivate the case studies of Germany and New Zealand. The work closes by advocating that the United States adopt a mixed-member proportional system for elections to the U.S. House