Influences of Crumb Rubber Sizes on Hot Mix Asphalt Mixture

Crumb rubbers (CRs) have been proposed as pavement components because they are waste materials. Previous studies have attempted to find alternative material in pavement construction that act as additives or property modifier. The current study presents a laboratory experiment using CR recycled from discarded vehicle tiresas additives in hot mix asphalt (HMA). CR was added using the dry process technique. Three rubber sizes were used with the following measurement: 0.15, 0.425, and 1.18mm. CR was added 2% of the weight of total aggregates. Bitumen80/100 penetration was used throughout the experiment. The effect of CR size on the mixture was investigated in terms of resilient modulus, indirect tensile strength (ITS), stability and dynamic creep. Experimental results revealed that the four engineering properties decreased when CR was added to HMA and when CR size was increased. However, the increased CR size similarly increased the permanent deformation values. The data analysisshowed that 0.15mm CR is the most effective material for asphalt mixturebecause of the partial interaction between rubber particles and bitumen.