engleski

Influence of SBS structure on rheological properties of polymer modified bitumen

The use of polymer modified bitumen (PmB) in road pavement has been continually increasing worldwide. Relatively small quantity of added polymer can significantly enhance performance and durability of bitumen (BIT). Rheology of BIT and PmB is one of the most useful tools for defining their properties. Investigation of rheology leads to a better knowledge of BIT and PmB behaviour that occurs when subjected to different thermal and mechanical conditions in road construction and use. This paper investigates the rheological properties of BIT modified with different structure of styrene –butadiene-styrene (SBS) block copolymers. Linear and radial SBS polymers are used. The primary viscoelastic functions are determined, complex shear module, G*, complex shear viscosity, ni* and phase angle, delta in dependence of frequency. The measurements are done by dynamic shear rheometer, DSR, in the linear viscoelastic range. The master curves are designed at reference temperature 30°C. Thermooxidative aging of BIT and PmB is conducted in a standardized device for hardening in a Rolling Thin Film Oven Test, RTFOT in order to gain insight into the intensity of thermooxidative degradation and changes in rheological properties. Conventional characteristic are determined against norms. From the G*/sin delta the resistance on temperature and stress against Strategic Highway Research Program is investigated i.e, the BIT and PmB resistance on permanent deformation. Linear and radial SBS block copolymer improved the rheological properties of BIT. The improved of rheological properties is more expressed with radial SBS as modifier. After thermooxidative ageing the rheological properties are affected. The rheological characteristics are correlated with the results obtained by conventional tests.

PmB; rheology; SBS-L; SBS-R; Master curve; SHRP

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