Comparison of wax extraction methods used in synthetic granular composite sport surfaces

Synthetic granular composites made from sand, polymeric fiber, rubber, and a hydrocarbonbased binder are used for the surface of many Thoroughbred horse racetracks around the world. The binder is typically a high-oil content, paraffin-based wax. In order to perform the analysis required to maintain these tracks, the wax is extracted from bulk track samples and analyzed for mass fraction, oil content, molecular composition, and thermal response of the binder. Two extraction procedures for the wax are compared using four representative track samples that vary in wax content and constituent composition. Both sampling methods start with a representative sample of track material and utilize isooctane solvent. One method involves ultrasonic mixing, oven evaporation and decanting; while the other method uses a Soxhlet extraction method. Results indicate that the Soxhlet method gives a more thorough separation of wax from the samples but also reveals that sample preparation is critical to obtain results that are representative of the track surfaces.