Evaluation of Selected Technical Properties of Bitumen Binders Modified with SBS Copolymer and Crumb Rubber

Good quality bitumen used in the production of bitumen-aggregate mixtures is a binder with high stiffness and elasticity at high operating temperatures occurring in summer and adequate flexibility during exposure to sub-zero temperatures. Currently, one of the best technological solutions to improve the viscoelasticity of bitumen and the resistance to ageing is their modification with various types of additives. The paper presents the results of penetration tests as a function of temperature, softening point (ring and ball method) and strain energy at various temperatures of road bitumen modified with SBS (styrene-butadiene-styrene) copolymer, crumb rubber and simultaneous bitumen modification with SBS copolymer and crumb rubber. The obtained results allowed to assess temperature sensitivity, resistance to changes in selected technical properties of the tested binders as a result of technological ageing process with RTFOT (Roler Thin Film Oven Tester) method and to evaluate changes in their technical properties in relation to the 50/70 base bitumen. Multivariate analysis of variance (MANOVA) was used to analyse the impact of the modification type on the test results of technical properties (significance of the impact of the considered factors on the level of technical properties).