Influence of Rubber Concentration on the Microstructure and Performance Properties of High Cis1, 4-Polybutadiene Rubber- Modified Bitumen

In this study, different concentrations (0-7 wt %) of high cis1, 4-Polybutadiene rubber (PBR) was used to modify a 60/70 penetration grade bitumen. Blending of the ingredients of the mixtures was carried out in a high shear mixer. Florescence microscopy was used to investigate the morphology of the mixtures. The results showed that the mixtures containing low concentration of rubber reveals disperse–matrix morphology and increasing the amount of rubber leads to formation of co-continuous morphology. Furthermore, the structural difference between the studied systems was also reflected by measuring of viscosity versus shear rate. To evaluate high temperature storage stability, ring and ball softening point and needle penetration tests were carried out on top and bottom of aluminum tube samples and the results were compared. This showed considerably better high temperature storage stability for the mixture with matrix-dispersed droplet morphology. Susceptibility of modified bitumen to rutting was determined by dynamic creep test, which consisted of 100 cycles of 1-s creep followed by 9-s recovery. The accumulated shear compliance during repeated creep and recovery tests was calculated. Modified system showed smaller accumulation compliance in compare with neat bitumen

کلیدواژه ها:

Rubber Modified Bitumen ، Creep Test ، Morphology ، Performance