More Than Just A Green Carpet – The Science Behind Artificial Turf

by Jackie Edwards

Globally the artificial turf market is worth a staggering $2,060 million and it is growing at more than 6% per year. In the US and Canada artificial turf systems have had an oddly mixed past, cycling between periods of high popularity and, in some cases (such as in Vancouver), being outright banned. Modern artificial turf systems are far more complicated than you would ever imagine and while they don’t yet produce the smell of cut grass, they do mimic real turf in surprising ways.

The Bad Old Days

The original artificial turf systems seemed to be exactly what everyone needed. These instant lawns needed little upkeep, could be laid indoors and looked great. These were, in essence, simply green plastic carpets. The simplicity of them led to a boom in their use across the country but this boom proved to be a bubble. The original systems provided no real cushioning for those who impacted upon them causing a rise in sports injuries compared to real grass. In addition the plastic blades could be over 30 degrees hotter in the sun than grass. The bubble burst and many artificial turfs were ripped up and replaced with the real thing. Something had to change.

Starting From The Ground Up

Manufacturers realized that there was more to a lawn than just the grass itself. Artificial turf was often laid on top of concrete or tarmac because it needed stability to remain useful. Such a surface was unyielding and dangerous. Initial attempts were made to create subsurface structures that resembled soil. Crumbled rubber was good but it was still hot and did not allow for good drainage. Sand was great for drainage but it was abrasive and dangerous if it got in your eyes.

Mixtures of both had some results but in the end the best systems proved to be a sand layer covered in a mixed rubber and sand one, with rubber crumbs on top. This too saw huge steps in recent years with new structures such as Hydrochill that can trap moisture and release it later when heated. This evaporation is exactly what happens in real soil and causes a cooling effect that reduces the difference between artificial and grass turfs.

Working On The Blades

Grass is a complicated plant and one that is often lacking the right level of appreciation. Grass blades have complicated shapes and surface structures that funnel water to their roots. A lawn is rarely shiny as grass wants to absorb as much light as it can. On top of all this because grass is a living thing it grows, often in a nonuniform way. A lawn is not a consistently flat surface like a crew cut but one with waves and layers. Older artificial turfs were brush like strands with total uniformity. The structures of these systems had no purpose beyond simply looking green and standing up. With a soil now in place it was time for the grass to follow.

Form And Function Collide

It is quite often the case that the best way to make something artificial appear natural is to look at the functions of the thing it is mimicking. Modern plastic grasses have to do a variety of different things: they shock absorb, funnel the rubber crumbs back to the sublayer, some absorb water and some are cooling systems. In order to carry out these roles the shapes and colors of the strands had to change. Instead of being flat some of the newer plastic blades have a profile that looks like a “W”. This shape allows water and heat to move through the system providing further cooling. The shape is dictated by the job, but the knock-on effect is that the blades look duller and have a texture that is more like grass. In order to catch and funnel the rubber crumbs back to the base the ends of the blades need to be frayed and varying in length; making it visually even more like the real thing.

Modern artificial turf systems are amazing structures that have increased in popularity because they can now absorb impacts, feel as cool as real grass and look almost identical to a lawn. Unfortunately it is possible that the cycle is turning against them again but this time it is not their fault. Despite numerous surveys showing that the new systems are safe and that they do not release dangerous chemicals in concentrations that come anywhere near dangerous levels, there are some who refuse to believe it. This time the concerns are not genuine problems but ignorant mistrust of science.  

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