Structure Formation and Phase Composition of Sulfur-Bitumen Systems

Abstract

Nowadays, modification of the bitumen by sulfur is considered as an effective way to enhance the properties of materials for road construction. By means of using the sulfur we eliminate the need to reconstruct existing production facilities for asphalt concrete. There is a plenty of research had already been performed for investigation of the sulfur-extended asphalt. Still, formation of new compounds in sulfur-bitumen systems depends on many factors, including mixture and thermal conditions. In the present work we have carried out both experimental and theoretical examination of the specific sulfur-bitumen binder made of grade 60/90 petroleum bitumen and technical sulfur at temperatures that are typical for ordinary asphalt concrete technology. The obtained results indicate that there is no noticeable formation of new chemical products in sulfur-bitumen melts at temperatures below 145 °C. Sulfur is partially dissolved in bitumen during the technological operations; the limiting concentration of dissolved sulfur is near 10%. Later in the course of cooling, the crystallization of the sulfur takes place, accompanied with formation of a separate solid phase.