RECYCLING OF ASPHALT MIXTURES CONTAINING CRUMB RUBBER

An investigation of the effects of Crumb Rubber Modifier (CRM) on asphalt binder and mixture properties was conducted to determine whether or not CRM would have a detrimental effect on the properties of recycled paving mixtures containing CRM and recycled asphalt pavement (RAP). Although CRM increased the viscosity and lowered the temperature susceptibility of the binder, the effect was not pronounced at CRM of 12% or less. Recycled structural asphalt mixtures containing 50% RAP with 12% CRM had essentially the same shear strength and air void content properties as a conventional asphalt mixture without any CRM. However, mixtures containing 18% or more CRM could have different properties which may affect recycling operations.