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Artificial Turf Alternative Infill Materials (list of)

Artificial turf infill (top dressing) is a material used by professional installers to weigh down the artificial turf surface materials so that the artificial grass will lay flat and will not be prone to buckles, wrinkles or movement.

Not all types of turf are built to use infill materials. If you are using a turf that requires infill, always check with the manufacturer or distributor for how much and what type of infill materials they recommend for best results. This answer will change for different applications so be specific about what you are using the turf for when you discuss this with your turf supplier.

Why Infill Infill materials were first used with 2nd generation synthetic turf products in the late 1980s and are intended to be used to fill the gaps between rows of turf blades while adding ballast (weight) to the surface face. The distributed weight holds the turf in place and helps to achieve a more natural feel underfoot for sports uses.

Types of Infill Defined as an "artificial root system", the first infill material used was quarried silica sand. Then, crumbed rubber was added to the infill component choices and is the most widely used, in the United States for sports field installations.

Due to controversy of crumb rubber infill material's safety and effectiveness, new products are becoming readily available. Acrylic, ceramic or rubber coated silica granules and beads of olefin polymers are now options.

Let's explore the alternative artificial turf infill material options as they were introduced into use.

Silica

Silica is a naturally occurring crystal, made up of, what is essentially, the same materials found on the world’s beaches. There are two types of silica granules used as infill today. Round silica grains are quarried in only 3 locations in North America, while sub-angular granules of silica can be mined almost anywhere in the world.

Like most granulated products, silica sand is quarried and screened into a variety of sizes or “mesh”, during packaging processes. The raw products may also be washed prior to shipping in bulk, bagging in super bags (of 1000, 2000 or 3000 pounds per bag) or packaged in 100 or 50 lb sacks.

The size of the mesh screen used at the quarry will determine it's size rating. Most silica sand granules used for infill will range from a very small size of 30 mesh to a larger size of 10 to 20 mesh. The larger the number the smaller the granule. Anything above a 30 mesh is too small of a granule (powdery)to be appropriate for use as infill materials.

Sub-angular silica granules are shaped much like crushed, hard rock, such as granite. Though silica is rated as the second hardest substance to diamonds, sub-angular sand grains contain microscopic fissures, cracks and sharp, pointed edges. The structure of the grain can easily crushed into smaller pieces and the pointed edges can get knocked off, creating finer particles and dangerous dust that can lessen the ability of the surfaces to drain (called silting) and may, over time, make the surfaces become quite "hard" and less resilient.

A naturally occurring round silica sand granule is preferred to any type of "fractured" silica or sub-angular silica material for infill. Available in only a handful of quarry locations around the world, grains form as round shapes which are less likely to chip or compact over time. This new material increased the use of silica as a single infill material again. It is very popular used as putting green top dressings.

TPE coated silica

There are several materials that are inappropriate to use as infill. They are inappropriate due to the risk of danger for the installer, consumer or to the effectiveness, durability or warranty of the turf system.

Coal, copper and nickel slag

by-product of smelting, or super-heating various materials. Slag is a crushed material and is used as an abrasive in surfacing metals. As described by name, the slag starts as either coal, copper or nickel.

The material is made up of sharp sub-angular shards of glass-like grains that can cut and cause splinters in any flesh or get into eyes or respiratory system. Fines can stick to clothing and fur potentially causing skin irritations.

Materials are sharp enough to cause damage to turf blades, especially in high traffic areas, causing blades to weaken and break off. Though many products available for public consumption pass minimum testing, slag materials are not considered to be environmentally sound.

Masonry and Play Sand

These products contain large quantities of dust and clay fines which can cause compaction of surfaces, reducing resiliency, increasing matting and possibly decreasing the effectiveness of percolation systems. These materials often contain a variety of sizes of various materials including silica sand grains, small pebbles and rocks, fines and other material. Small rocks and pebbles can often vary in size so that the largest could cause significant damage to professional equipment and will prove to be unruly in creating an evenly infilled surface.

Crushed Graphite and other processed or crushed glass materials

These materials, like slag, can be sharp and can contain large quantities of dusts that are dangerous to handle for the installer and consumer. The sharp edges of the grains can damage turf blades, especially in high traffic areas.

Alternative Infill Sources

Acrylic Coated Silica: SuperFILL [1]
TPE TPE Infill [2]
TPE Coated Silica: FlexSand [3]