Effect of cross-linking agents on the rheological properties of polymer-modified bitumen

The use of polymer-modified bitumen (PMB) has increased significantly for more than two decades. Cross-linking agents are used in PMB as an additive, mainly for improving the durability of this material as the cross-linking agent chemically reacts with the PMB by forming a covalent or ionic bond. This study tries to investigate the effect of cross-linking agents on the rheological properties of PMBs. Two types of elastomers – linear and radial – and seven types of cross-linking agents were used. A functional polyethylene (FPE) was added to all the binders. The rheological properties (creep and recovery) were studied using the dynamic shear rheometer. The viscosity and storage stability for each of the modified binder were also studied. Among all the cross-linking agents used in this study, sulphur was found to be the most effective. Two more cross-linking agents were found to have similar results as that of sulphur.