Monitoring rubber swelling and de- and re-vulcanization through AR elastic recovery

Abstract

Healthy economies require an appropriate transportation system, in which roadways are an essential part. Therefore, the construction and maintenance of road pavements should be long lasting and have a significant impact on the economic vitality of a nation. The elastic recovery is a property characteristic of the elastomers, or binders modified with those polymers, being used to classify them and especially to survey the polymerization reactions in rubber production and the crosslink density during the vulcanization process. In this work, a large range of pen grade bitumens from the same source were used to produce different asphalt rubber binders (ARs). Then, the elastic recovery (ER) of each AR binder was determined while the rubber used to produce the AR was recovered, weighted and observed by optical microscopy. Finally, the elastic recovery of the AR binder was related to the corresponding weight percentage and dimensions of the rubber particles recovered from the final AR binder. The main conclusion draw from this study is that the analysis of the elastic recovery of the AR binder can give very useful information about the magnitude of rubber swelling, de- and re-vulcanization and final degradation of the rubber networks. The results of the elastic recovery of the AR binders and the recovered rubber properties also suggested that it possible to select a bitumen to produce AR binders with enhanced characteristics.