DEVELOPMENT OF A METHOD OF TESTING THE WEAR STRENGTH OF AGGREGATES FOR ROAD SURFACINGS SUBJECTED TO STRESS BY STUDDED TYRES

ENTWICKLUNG EINER METHODE ZUR PRUEFUNG DER VERSCHLEISSFESTIGKEIT VON GESTEINSMATERIALIEN FUER FAHRBAHNDECKEN GEGENUEBER SPIKES-BEANSPRUCHUNG

CONVENTIONAL METHODS USED HITHERTO FOR TESTING AGGREGATES IN ROADS DID NOT GIVE ANY VALUES WHICH AGREED WITH THE PRACTICAL RESULTS OF SURFACING WEAR (CAUSED BY THE INCREASED USE OF STUDDED TYRES). THE METHODS ARE NOT ABLE TO DISTINGUISH BETWEEN CERTAIN HIGHLY WEAR-RESISTANT STONES AND STONES WITH LESS RESISTANCE TO WEAR. THE WEAR OF THE SURFACING COURSE IS CAUSED BOTH BY THE IMPACTING AND THE SCRAPING ACTION OF THE METAL STUDS, MOST OF IT BEING CAUSED BY THE SCRAPING ACTION, DUE TO TYRE SLIP. A METHOD OF MEASURING THIS SCRAPING ACTION WAS DEVELOPED. AN ECCENTRICALLY FIXED STUDDED TYRE NAIL ROTATED ON A HORIZONTAL SURFACE OF THE TEST MATERIAL. THE PENETRATION DEPTH OF THE STUD IS MEASURED UNDER VARIOUS TEST CONDITIONS. A SIMILAR APPARATUS IS TO BE USED TO CLASSIFY 35 STONES USED IN AUSTRIA AS A SURFACING MATERIAL.