ACCORDING TO ASTM STANDARD CLASSIFICATION for Rubber Compounding Materials-Recycled Vulcanizate Particulate Rubber (ASTM D 5603-01): • Recycled rubber is defined as recyclable, vulcanized rubber that has been processed to give particulates or other forms of different shapes, sizes, and size distributions. • Parent Compound: original compound used in rubber product. • Vulcanizate: cured (vulcanized) rubber.