SULFUR-EXTENDED ASPHALT - REACTION-KINETICS OF H2S EVOLUTION

The interest in sulphur-asphalt mixtures was especially high in the 19 70s and 1980s. At present, there is concern about the behaviour of sul phur-extended asphalts (SEA) because of the problems that could arise during the recycling of old SEA pavements. This paper studies the kine tics of H2S evolution during the reaction of sulphur with asphalt; suc h a reaction starts well below 150 degrees C, as previously stated. Th e activation energy and the reaction order are different for various t ypes of material: for cracked bitumens the reaction order is 0.5, whil e for straight run products it is higher and dependent on the type of bitumen. The results of the study suggest operating with great caution when heating SEA mixtures. (C) 1998 Elsevier Science Ltd. All rights reserved.