Loughborough University Study Validates Superior Quality of Cryogenic Versus Ambient Rubber

Researchers at Loughborough University’s sports technology lab in England, recently conducted compression and compaction testing on small samples of five types of ambient and cryogenic performance infills.

Since the invention of the 3G artificial turf systems, the industry has relied on cryogenic rubber and ambient rubber as the two types of crumb rubber infill material.

Cryogenic rubber is the cleanest, highest grade of rubber granule available and is used in FieldTurf’s Elite systems. Ground-up recycled tires are cryogenically frozen, then shattered into small, smooth-edged particles. This smooth shape allows for consistent flow of water through the infill without raising and displacing any rubber while still suspending rubber and sand in a layered system. The result is the optimal mix for a safe and consistent playing surface

Ambient rubber is an environmentally conscious, cost-efficient and durable solution that has withstood the test of time and is used with FieldTurf’s prestige systems and is more commonly used by competing manufactures. Processed through a rubber cracker mill at ambient temperature, the result is a more jagged rubber granule than its cryogenic cousin, creating a looser infill with air pockets that can lead to infill migration.

The differences between each infill system are really questions of “good” vs. “better” and “safe” vs. “safer.”

Two sets of loads were applied to the infill, up to 2,500 cycles. As a result of their testing, researchers came to the following three conclusions:

1. AMBIENT INFILL IS MORE SUSCEPTIBLE TO PREMATURE COMPACTION

Both infill systems are comprised of solids and air (no liquid). Because air is obviously more compressible than solids, there exists a greater air void in ambient infill, creating more premature compaction that can cause future safety complications and performance issues.

2. ELASTIC RECOVERY IS QUICKER AND MORE COMPLETE IN CRYOGENIC INFILL

Ambient infill showed a 4 percent greater compaction after 2,501 cycles, which could indicate premature compaction and, again, cause future safety complications and performance issues.

3. REDUCED LONG-TERM SHOCK ABSORBENCY WITH AMBIENT INFILL

This is because its elasticity and air density make it more susceptible to loss of volume. The infill will incrementally increase in stiffness under repeated use, likely reducing shock absorbency and increasing ball bounce.

“The cryogenic [showed] more immediate elastic recovery and less permanent deformation,” according to researchers. “After one cycle of load, the cryogenic samples were observed to be less compressible from the further 2,499 cycles than the ambient. This suggests the cryogenic is perhaps a better quality sample for performance, more elastic and less compactable.”

Additionally, stiffness and strain evaluations show the cryogenic and ambient infill systems to exhibit similar characteristics early in their lifecycle, but the ambient infill becomes stiffer with increased use, thanks to compaction.

Loughborough University’s research supports FieldTurf’s long-held contention that there are important differences between the two infill systems.

For access to the report, please send a request to contact@fieldturf.com. For more details on how to choose the right infill system for your project, contact your FieldTurf Expert.