Third generation of synthetic turf field (3G STF)is a highly technical, pliable composite of polymeric grass tufts, woven flexible backing, and elastomeric infill particles that were designed for high impact sports activities, e.g., American football.  The infill is typically granulated crumb rubber (GCRI) that is milled from only the outer two tread layers of used tires.  The elastomeric GCRI addressed important safety aspects of the sports field and sparked a renaissance in STF construction.  However, issues concerning player exposure to the GCRI particles and their contents (volatile organic compounds (VOC's), lead and lethal pathogens such as MRSA), landfill disposal of the left-over tire carcasses and overall costs of the GCRI production process have become concerns.

To alleviate these concerns, an alternate infill must match safety and performance while alleviating environmental and health concerns associated with GCRI.  Plus, a candidate could come from other sources of benign waste streams, such as recycled PET from drink bottles to non-salvaged components of post-consumer carpet (both broadloom and selected tiles), to remain economical.  In addition, the infill's properties such the shape and size could be optimized by statistical modeling to reduce the amount of required material while maintaining performance and safety levels in the filled turf.

This proposal outlines two topics of the dissertation research.  First, compare the composition, bulk properties and impact performance of several waste material streams to the properties of GCRI.  Second, determine important infill properties by modeling to optimize the infill itself and possibly use polymer particles with controlled size, shape, and other factors.  Ideally this work will define specifications for raw material that leads to ideal performance of the final product.  Ultimately, the selected infill candidate will replace GCRI without increased cost, reduced performance or impaired impact safety while remaining beneficial to health and environment.