Diffusion of Oils in Asphalts

THE RATE AT WHICH TRITIUM-TAGGED DODECYLBENZEN PENETRATED THREE ASPHALT SAMPLES WAS FOLLOWED BY THINLY SLICING THE ASPHALTS AND MEASURING THE DECREASE OF RADIOACTIVITY WITH DEPTH. DIFFUSION RATE COULD BE INCREASED BY ADDING DILUENT OR RAISING THE TEMPERATURE BUT WAS UNAFFECTED BY THE PRESENCE OF A LEACHED PHOTOOXIDATION SKIN ON THE ASPHALT SURFACE. ONLY AN AVERAGE DIFFUSION COEFFICIENT COULD BE DETERMINED FOR COMMERCIAL OIL FRACTION PENETRANTS BECAUSE CONSTITUENTS OF DIFFERENT SIZE AND MOLECULAR CONFIGURATION DIFFUSED AT DIFFERENT RATES. REJUVENATION OF OLD ASPHALT ROADS BY OVERSPRAYING WITH SUCH OILS WOULD TAKE PLACE SLOWLY AND CAN ONLY BE EFFECTIVE IF THE OIL IS PROTECTED FROM TRAFFIC BY ABSORPTION INTO PORES PRESENT IN THE PAVEMENT SURFACE. /AUTHOR/