Study of Combination of Polymers with Bitumen

Abstract

We have considered a possibility of modifying the roofing bitumen by the developed mixed thermoplastic elastomer (TPE) in view of its increased resistance to atmospheric aging. We evaluated the preliminary selection of TPE composition with accordance to the time of dissolution in the bitumen melt and main physical and mechanical properties. In order to determine the best polymer and bitumen compatibility, we calculated the solubility parameter of polymer in hydrocarbon solvents in terms of the shortest dissolution time as well as determined the TPE solubility parameter. The proximity of these indicators demonstrates the successful compatibility of TPE in saturated bitumen maltenes. The assessment of physicotechnical properties of TPE and its components in bitumen showed that highdensity polyethylene (HDPE) and synthetic triple ethylene-propylene rubber (EPR) have a major influence. HDPE increases the heat resistance of polymer modified bitumen composition (PMB) and accelerates the dissolution of TPE in bitumen at processing temperatures. EPR is responsible for the low-temperature properties of PMB composition and increases resistance to atmospheric aging, however, it takes a long time to dissolve in bitumen. We as well used the widely used styrene-butadiene-styrene thermoplastic elastomer (SBS) to compare the modifying effect. Modification of bitumen by TPE is more visible than by SBS or individual components, especially at high concentrations (≥ 10%), and allows to obtain high durability of PMB.