Study into the effect of plasticizer nature on the properties of polymer-bitumen compositions via fluorescence microscopy

The paper studies how the nature of the plasticizer affects the properties of polymer-bitumen compositions using the fluorescence microscopy. The current petroleum road bitumen used for the construction of road, bridge, and airfield pavements does not meet the requirements for cracking/heat resistance, elasticity, and adhesion to the mineral material surface. Pavement performance characteristics can be significantly improved by introducing thermoplastic elastomers, plasticizers, and surfactants into the composition of petroleum road bitumen. The best results were obtained when using a block copolymer of styrene and butadiene, industrial oil, and cationic surfactant on the basis of polyaminoamides and polyaminoimidazolines. The choice of industrial oil as a plasticizer is attributed to its good compatibility with bitumen and polymer, as well as its high flash point (200 °С). The content of paraffin-naphthenic hydrocarbons in industrial oil is over 70%. Although industrial oil is produced in large quantities, an acute shortage of this petrochemical product is observed due to its wide application; thus, intensive studies are underway to replace industrial oil in the composition of the polymer-bitumen binder. It is proposed to use heavy gas oil produced via catalytic cracking and delayed coking, heavy pyrolysis tar, solvent-extracted oil, and tall oil as plasticizers in the creation of the polymer-bitumen binder. In this connection, the effect of proposed plasticizers on the colloidal structure of the polymer-bitumen binder was studied using the method of fluorescence microscopy. Initial polymer-bitumen binders were produced at ANHK (Angarsk) according to GOST R 52056-2003 Polymer-Bitumen Road Binders Based on Styrene-Butadiene-Styrene-Type Block Polymers. The group composition of the plasticizers under study was determined. It was shown that in order to obtain a polymer-bitumen binder resistant to stratification, plasticizers having a content of aromatic compounds of over 60% are required.