Rheological behaviour of polymer-modified bituminous mastics: A comparative analysis between physical and chemical modification

Lack of experimental data concerning the behaviour of mastics and, above all, polymer-modified mastics has been lately claimed. Thus, this work presents a comparative analysis between the effect that “physical” and “chemical” modification by polymers exert on mastics prepared by blending modified binders with different contents of calcium carbonate (filler/bitumen ratios ranging from 65/35 to 80/20). Tri-block copolymer SBS and a “reactive” isocyanate-based prepolymer were used as modifying agents in the preparation of the binders. Linear viscoelasticy tests revealed that polymer type exerts, at high temperatures, a significant influence on the binder contribution to the overall rheological properties of the mastic.

► Modified mastics rheology highly influenced by polymer type at high temperature.
► Existence of a plateau in E′ at 70 °C in mastics “physically” modified by SBS.
► No plateau in E′ found in mastics “chemically” modified by an isocyanate-based polymer.