Development of Polymerized Asphalt Rubber Pelleted Binder for HMA Mixtures

There are over 300 million scrap tires produced in the USA each year.
There are many applications that these scrap tires could be utilized including in paving
operations. This paper will describe the benefits of producing the newly developed patching
materials, in pellets; containing crumb rubber, stiffeners and virgin binders. The binders
utilized in these pellets satisfy the requirements of ASTM D8-02 (minimum of 15% crumb
rubber in the asphalt binder). The laboratory testing results of the mixtures containing these
pellets are as follows: TSR (tensile strength ratio) of over 96%; average rut depth of 2.84 mm
(Asphalt Pavement Analyzer); stability of 995 kg; flow (0.01 in) of 15.8; and %VMA of 20.2.
Test results and field trials have indicated that these pellets can be successfully utilized in a
variety of HMA type mixes and improve performance of the mixtures.