Porous Asphalt Sports Courts - Rust-Spotting Inhibition by SurfTech

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As it’s the nation’s desire to participate in sport all year round and due to our characteristic climate, the UK’s outdoor sports courts are, in many instances, built using porous asphalt. Indeed, the permeable nature of this material allows surface rainwater to readily drain through its interstitial spaces, enabling a swift return to play once rain subsides. Once built, porous asphalt sports courts are invariably painted, with the paint itself helping to protect against elemental degradation and abrasive foot activity, alongside providing the court with performance characteristics required by national governing bodies – LTA (tennis) and AENA (netball), together with SAPCA and Sport England.

The main constituent of porous asphalt is granite aggregate, with this aggregate being bound together with bitumen to create the composite material from which the court is built. Granite is an igneous rock formed by the cooling and solidification of magma or lava. Moreover, granite mined from seams in the UK can be contaminated with iron disulphide, or pyrite. In the presence of water, pyrite reacts with oxygen to form iron oxide, or rust. As water is frequently present in a porous asphalt court, rust can be readily generated within the body of the court, with the extent of this determined by the quantity of pyrite in the court and the volume of water draining through it. It’s reasonable to say, therefore, that the rate at which rust is generated within a court can be seasonally influenced, with the generally wetter autumn and winter months yielding higher concentrations.

With the permeable nature of porous asphalt sports courts and due to capillary action, rust can be readily conveyed from the body of a sports court up to its surface, with this leading to characteristic reddish brown staining on the court’s painted surface, colloquially referred to as rust-spotting. Although rust-spotting has no deleterious effects on the court’s surface, in the most severe cases its aesthetic appeal can be compromised. Furthermore, the appearance of reddish brown stains on the surface of a sports court can be somewhat distracting for the players, particularly in the case of tennis.

Rust-spotting can manifest itself very soon after a porous asphalt sports court has been built and painted, with the extent of this determined by the quantity of pyrite within the body of the court together with seasonal rainfall patterns. However, following extensive laboratory work and field trials, SurfTech’s highly-innovative technical team has developed a process that subdues the visual appearance of rust spots, lessening their cosmetic impact and their capacity to distract players.

SurfTech’s process is designed to eradicate unsightly rust-spotting on a sports court’s painted surface and to lessen its impact when it inevitably returns at some point during the remainder of the court’s service life. In other words, we have developed a process that will eliminate rust-spotting currently visible on a court’s painted surface, with this process also minimising the impact of rust-spotting that occurs thereafter. Indeed, SurfTech’s process can be repeated each time a porous asphalt sports court is re-painted, considerably reducing the visual impact of rust-spotting over its life span.

SurfTech’s rust inhibition process is applicable to the following types of porous asphalt sports courts:

  • Tennis courts
  • Netball courts
  • Sport England Type 1 multi-use games areas (MUGAs)
  • Sport England Type 2 multi-use games areas (MUGAs)

For more information and prices, please contact SurfTech here.