Recycled tire granular for playground in hot regions: technical assessment

Scrap tire granulation used for crumb rubber tiles and poured-in-place rubber surfaces are waste management strategy for the overgrowing tire stockpiling. However, limited technical studies have been done assessing how these surfaces perform during their usage particular in hot climate region. In this work, the serviceability of the rubber tile is assessed on numerous field samples collected from different playgrounds in UAE. They are subjected to structural and thermal analytical techniques, i.e., ball-drop test, static and dynamic stress analyses, frictional coefficient, microscopic analysis (ESM), thermogravimetric and emission. Results show that tiles rather disintegrate relatively fast and attain unsafe user condition. The ball-drop and stress tests detected increase in stiffness and stress over 25% to initiate earlier tile failure. Friction results in drastic reduction in the needed traction. The SEM analysis suggests deterioration of the binding agent, elemental analysis showed an excess sulfur content per the detected SK compound in the aged sample and surface erosion, while TGA revealed higher thermal degradation and potential formation of hazardous polymers. Finally, PAHs study confirm rubber volatilization in the vapor phase and their partial contaminant leaching at toxic concentration. These observations do not favor using rubber granules for surfaces in hot regions and seeking alternative recycling is strongly recommended.