DEVELOPMENT OF A METHOD OF DETERMINING THE SURFACE ROUGHNESS OF AGGREGATES (PART 2)

ENTWICKLUNG EINER METHODE ZUR BESTIMMUNG DER OBERFLAECHENRAUHIGKEIT VON MINERALKOERNERN (TEIL II)

SURFACE ROUGHNESS IS AN IMPORTANT CRITERION FOR THE INTERNAL FRICTION OF PARTICLE MIXTURES AND AN IMPORTANT PARAMETER FOR THE ADHESION MECHANISM: MINERAL SURFACE - BITUMEN. A MEASUREMENT PRINCIPLE ASSOCIATED WITH METAL TESTING TECHNOLOGY IS TO BE USED FOR ESTABLISHING SURFACE ROUGHNESS. IN CONNECTION WITH THE ROUGHNESS IT IS NECESSARY TO EXPLAIN THE APPEARANCE OF THE REACTION BLISTERING EFFECT, ESPECIALLY AS THIS APPEARS TO BE ASSOCIATED WITH THE ADHESION OF BITUMEN TO ROUGH MINERAL SURFACES. A SENSITIVE DEVICE IS TO BE USED TO CUT ROUGHNESS DEPTHS FROM A MINERAL OF 1.0 MICROMETRES TO 600 MICROMETRES. THE LARGE QUANTITY OF MEASURING DATA NECESSITATES PROCESSING BY COMPUTER. AFTER QUANTIFICATION OF THE RESULTS OF THE MEASUREMENTS AN ATTEMPT IS TO BE MADE TO CLASSIFY THE STONES CURRENTLY USED IN ROADS BY ROUGHNESS. QUALITATIVE AND QUANTITATIVE MEASUREMENTS OF THE EFFECT OF THE OCCURRENCE OF REACTION BLISTERS IN THE BITUMEN LAYER ARE TO BE CARRIED OUT UNTIL THE CAUSE IS KNOWN. AS THE BLISTERING IS VERY DIFFICULT TO OBSERVE UNDER THE MICROSCOPE, A PHASE INTEGRATOR HAS TO BE USED FOR THE QUANTITATIVE EVALUATION, WHICH CAN DETERMINE STRUCTURE, SURFACE AND SIZE AND RELATE THESE TO TIME.