Micronized crumb rubber influence on index properties of warm asphalt binders

Primarily, the main aim of recycling waste tires in the form of micronized crumb rubber into asphalt cement as modifiers are to enhance their engineering properties in addition to the associated solid waste management benefits. Often, these modifiers are used to achieve reasonably stiffer binders i.e.; low penetration; high softening point; and high penetration index, to realize higher resistance to deformation under the influence of traffic and temperature. The study assessed the effects of Micronized Crumb Rubber (MCR) on the penetration, softening point, and penetration index of 80-100 PEN bitumen impregnated with 2.5 % Sasobit (fixed by weight). The MCR modified warm asphalt binders were prepared by further blending with different percentages of minus 40 mesh size MCR powder (from0 – 15 % by weight of the bitumen stepped at 2.5%). Subsequently, penetration and softening point tests were conducted on each blend, and the corresponding penetration indices were evaluated. The results show that MCR addition gradually decreases the penetration values while conversely increases both the softening point values and the penetration indices as well. Thus, MCR might be used to improve the flow and thermal susceptibility resistance of warm asphalt binders