Degradation of aggregates applied in porous road surfaces

Presents the results of a research into the influence of aggregates on the roughness and the skidding resistance of porous asphaltic concrete (pac) road surfaces. Aim of the study is to investigate the degradation processes of different types of aggregate that play a part in the development of the micro and macro texture of pac road surfaces. Ten types of aggregate (crushed rock) were studied. The petrographic and geotechnical properties of the aggregates are discussed. Seven types of aggregates were used in pac test sections constructed on Dutch state road A2 (RW2) near Best. The course of the surface wear was followed by means of a.o. SRT measurements (Skid Resistance Tester). In the laboratory samples were subjected to a.o. the Wehner/Schulze polishing test and results of PSV tests (Polished Stone Value) were studied. The use of an image analysis system and a laser profilometer in this project is evaluated.