Thermomechanical and microstructural evaluation of hybrid rubberised bitumen containing a thermoplastic polymer: Fid-Bau Portal

Thermomechanical and microstructural evaluation of hybrid rubberised bitumen containing a thermoplastic polymer

Senise, S. / Carrera, V. / Navarro, F.J. / Partal, P.

Highlights•Hybrids Systems are blends of a base rubberised bitumen with polymers and additives.•HSs develop a complex multiphasic system.•HSs yield better in-service properties and storage stability.•Capability of modification of polymeric additive: SBS>EBA>EVA>EPDMs.•HS-SBS presents the best performance due to crosslinking reactions.

AbstractCrumb Tire Rubber (CTR) modification of bitumen has been extensively proven that exerts a notable improvement the in-service properties. However, the problem of its inherent storage instability is a major concern that limits the industrial application. With this aim, here, Hybrid Systems were formulated by the addition of selected polymers (SBS, EBA, EBA and EPDMs) to a model rubberised bitumen (10wt% CTR) and cured with sulphur. The resulting binders were characterised by rheological techniques, technological tests, Modulated Scanning Calorimetry and fluorescence microscopy. The results obtained pointed out that both, in-service properties and storage stability were notably enhanced by the development of a complex multiphasic structure of: polymer-rich and asphaltene-rich phases, non-degraded rubber particles and digested rubber chains.The capability of modification of the polymeric additives were established as follows: SBS>EBA>EVA>EPDMs. The Hybrid System containing SBS (HS-SBS) presented, by far, the best overall performance due to the development a continuous SBS-rich network structure as a consequence of sulphur crosslinking reactions.