Equestrian Surface: Tyre chip for an all-weather
gallop
Product:
Tyre derived rubberMaterial:
Rubber tyre chipApplication:
SurfacingProject Type:
Ground coverLocation:
North KentDate:
CurrentSpecification:
The application of a mix of sand and tyre-derived rubber chip is used in the construction of a half mile gallop for the training of racehorses. The gallop is situated in the Kent Downs to the north of Maidstone.Waste Tyres Case Study
Overview
The use of recycled rubber or plastic materials in the mix has overcome a number of the problems associated with artificial all-weather surfaces. Indeed, it is estimated that some 40 to 50 tonnes per year of chipped car and truck tyres are now used in the construction of equestrian arenas, menages and gallops in the UK. Mixed with sand, they provide a firm but safe surface which has a number of benefits both in terms of year-round, all-weather availability and the general safety and well-being of the horses.
Technical Information
Description Units
Tyres used Truck / tractor
Size of clean cut tyre chip nominal 20mm
Density of chip 600kg per m³
Total tyres used 67.5 tonnes
Background
Racehorses compete from a young age and are prone to damage their leg joints when racing. Indeed, when cantering and galloping, at one point in the stride the entire weight of the horse can be on one leg. Micro-fractures of hind fetlocks are commonplace.
Good turf surfaces will have some cushioning effect to minimise jarring and will allow some forward movement of the foot on landing to give controlled deceleration. However, turf can get especially hard in dry summer weather and unduly soft or rutted in winter. It can also freeze in winter. This can happen on both grass and synthetic racecourses, but the problem is exacerbated when exercising and training on a daily basis on a relatively narrow gallop. An alternative surface is, therefore, required for this purpose.
The ideal training surface is soft, has a degree of springiness, and maintains these properties all year round and in all weathers.
Historically, horse racing, and the training and exercising of horses, has been carried out in the UK on natural grass surfaces or on sand. In hotter, drier climates, such as the Middle East and parts of North America, racecourse surfaces were constructed with sand alone. Intensive use of a grass surface inhibits the regeneration of the grass and causes surface damage due to hoof penetration and rutting. In dry weather, such surface damage presents
safely grip a damaged grass surface. At racecourses some of these problems are avoided by having a long ‘off’ season and through frequent maintenance of the course including watering. However, this is not possible in training establishments where frequent and intensive use is required.
Artificial surfaces involving a mix of materials were introduced in the UK in order to address these problems and to provide virtually all-weather, year-round activity. Such surfaces were originally made of peat or sand. Later, wood fibre was added to provide the “spring” required. However, new problems arose with these materials or mixes, such as the clogging of sand in wet weather, high dust levels in dry weather, and “kick back” (surface material flying backwards at a high level) that might affect the horses in a race. Wood chip has been used, mixed with the sand, particularly in arenas and ménages, but the chips tend to break down when damp, and horses (and riders) can get very dirty from the kick back created. This case study is for the application of a mix of sand and tyre-derived rubber chip in the construction of a half mile gallop for the training of racehorses. The site is owned and managed by the trainer John Best of John Best Racing. The gallop is situated in the Kent Downs to the north of Maidstone.
Case Study: John Best’s gallop
John Best Racing manages between 30 and 40 racehorses from a stable in Hucking, Kent, and trains them on a half mile gallop on the Kent Downs near Pilgrim’s Way, north of Maidstone. The gallop surface has been constructed from a mix of used tyre rubber chips and sand (Figure 1).
The gallop used by John Best Racing was set down in 1997. It is approximately 750 metres long and 3 metres wide. It has a railed turning circle at one end. Rails are located at intervals along the track to guide the horses. The track comprises a mix of tyre rubber chips that are free from steel wire, and silica sand.
Waste Tyres Case Study
Fig. 1: View of gallop from the west
Each day, three batches of 10 to 12 horses will be taken to the 750m gallop to complete six lengths. The intensity of use of the gallop is therefore at least 180 traverses (6 lengths of the gallop times 30 horses) per day.
The rubber tends to rise to the surface during use. Sand sinking to the floor of the track can form a hard surface which, if it gets exposed, represents a risk to the horse. During and after each session the surface of the track has to be harrowed to maintain the desired surface. This equates to six traverses of the harrow per day.
Harrowing both smoothes out the surface after the horses and also re-mixes the sand with the rubber to maintain the required degree of springiness. The harrow comprises a number of tines (Figure 2) which can be adjusted to achieve the desired degree of penetration.
Fig. 3: Horses’ footfall creating minimal dust
Some rubber and sand is kicked out of the track during use (Figure 3). This can be a problem for following horses in a densely packed race, but is not serious in a training environment. The material accumulates on the side of the gallop (Figure 4).
Fig. 4: Rubber and sand accumulated at the edges of the gallop
This loss decreases with time as the ridge formed at the side of the gallop gets higher and this tends to trap the flying materials. Stockpiles of both rubber chip and sand are maintained close to the site (Figure 5). These are used to top up the gallop as required, using a spreader attached to a tractor for this purpose.
Waste Tyres Case Study
Fig. 5: Stocks of rubber chips and sand for top-up
In dry weather the surface can become dry and does require some watering. This is carried out with a spray attachment fitted to a tractor. Also, in these conditions, harrowing is kept shallow to avoid bringing excessive dust to the surface which would impede the horses. In wet weather the drainage provided by the construction of the gallop and the natural drainage properties of the chalk base ensure that the surface does not get waterlogged. Also, the surface does not freeze as natural surfaces or wood chip would.
The surface provided by the rubber/sand material mix therefore gives a (virtually) all-weather surface which maintains the optimum surface properties for the well-being of the horses (Figure 6). The only condition under which it cannot be used is heavy snowfall.
Specification, Quality Assurance and Design
For safety purposes it is vital that the rubber tyre chip used in an equestrian surface is free from exposed steel strands which could injure the horses. This is achieved by sourcing the rubber chip either from tyre tread, which will be entirely free from steel, or from whole tyres processed using the latest machinery which can produce virtually steel-free rubber from whole car or truck tyres, albeit at smaller chip sizes.
The Maidstone gallop uses a Softrack surface constructed from tread derived from used truck tyres or agricultural tyres. The rubber is taken from just 40% of the tyre, mainly the tread, to ensure 100% absence of steel. After chipping it is washed to ensure that minimum dust is included in the finished material. The actual size of rubber chip varies, but is nominally 20mm. The rubber chip is screened to confirm the nominal particle size and undergoes visual checks for absence of contaminants before leaving the factory (Figure 7).
Fig. 7: Screened and cleaned 20mm rubber tyre chip
The specification of the Softrack mix will vary with the application and with the preferences of the customer. Sand is used in all equestrian synthetic surface applications. In some applications the mix also includes natural fibre. Material for a new track is sometimes pre-mixed in the factory and supplied directly to the site. The density of the rubber chip when laid is approximately 600kg per cubic metre.
The gallop at John Best Racing is located in a field in open farmland (Figure 8). The site was initially surveyed and marked out, and the topsoil was removed to the appropriate depth and relocated around the field. The gallop site was then cut, filled and compacted to achieve the required levels.
Waste Tyres Case Study
Fig. 8: View of the gallop from the south east
Concrete drainage sections were installed in a suitable pattern to provide optimum drainage along the length of the gallop. These were then back-filled with shingle. A geotextile membrane was laid on the shingle and the overlapping joins were heat sealed. A layer of clean 40mm crushed stone was laid on the surface of the geotextile and compacted to a depth of 150mm. A further heat sealed geotextile was laid on the crushed stone layer. Perimeter post-and-rail fencing was installed to guide the horses at points along the length of the gallop and at each end to form a turning area (Figure 9).
proprietary brand of sand) and 50mm depth of tyre rubber chip. The surface was then harrowed to prepare the surface for initial use.
Fig. 10: Close-up of equestrian surface The quantity of rubber used in the initial construction was therefore: Length x Width x Depth x Density
750m x 3m x 0.05m x 600/1,000kgm-³ = 67.5 tonnes
Technical Benefits
The use of a rubber and sand mix over a base incorporating a suitable drainage system has a number of advantages over natural grass or sand alone.
When compared to natural grass the benefits are:
• Maintains the desired cushioning effect in all weathers
• Maintains the desired “give” in all weathers
• Does not freeze
• No loss of grass through divots and lack of regeneration
• Hoof prints and rutting can be quickly and cheaply smoothed by harrowing
• Easy and cheap to top-up
• Long lasting.
Waste Tyres Case Study
In order to overcome some of the shortcomings of natural turf, some racecourses have synthetic “all-weather” tracks: Lingfield, Wolverhampton and Kempton Park are examples. These are similar to the gallop described here, but use rubber with a waxed coating which reduces the amount and height of the “kick back”. Whilst this is important in the high density environment of a horse race it is not so critical in a gallop. John Best Racing also consider that the wax coating has a propensity to compact the rubber thereby reducing the softening effect of the sand mix.
An alternative equestrian surface is wood chip, traditionally used in equestrian ménages. However, many believe that wood chip is not consistent enough for the purpose, as it absorbs moisture and therefore softens in rain and can be dangerous in freezing conditions. It also bio-degrades and has to be topped up regularly and replaced altogether every five years or so.
Cost Benefits
Synthetic surfaces that provide the desired all weather equestrian conditions can be constructed from virgin or waste rubber or plastics. The use of tyre derived rubber chip has become popular in the UK because it is relatively cheap - compared to virgin rubber or plastics - and is readily available in significant quantities.
Whilst the price of 20mm tyre rubber chip will vary with market conditions and transport costs, it currently stands at approximately £60 to £70 per tonne delivered. This compares to in excess of £250 per tonne for equivalent virgin materials.
Environmental Benefits
As stated above, the main reason for the use of synthetic surfaces for equestrian use is that they provide the benefits of natural turf but are available in all weathers and throughout the year. Environmental benefits must, therefore, be considered in comparison to alternative materials for synthetic surfaces and not to the use of natural turf.
Rubber chips from used tyres used in this application displaces virgin synthetic materials, in particular rubber or plastics derived from petro-chemicals.
Used tyres are also widely available and, currently, projects targeted at new and extended applications for recovered tyres are being encouraged. Annual arisings of used tyres in the UK are approximately 480,000 tonnes. The majority of these tyres are recovered for re-use, retread or recycling or are burned for recovery of energy in the manufacture of cement. Historically, however, a significant proportion of tyres (c. 5% in 2004) have been legally
particles.
All environmentally sound applications for tyre-derived rubber will minimise the danger of surplus stockpiles of used tyres building in the UK and will reduce the potential danger of illegal fly-tipping of tyres.
Details of Parties
Client
John Best Racing Hucking Maidstone Kent Tel: 01622 880276 Email: [email protected]
Principal Contractor
Softrack39a High Street Sittingbourne Kent ME10 4AW
Tel/Fax: 01795 439735
This case study was developed for WRAP by Oakdene Hollins Ltd
Published by:
The Waste and Resources Action Programme The Old Academy, 21 Horse Fair,
Banbury, Oxon OX16 0AH Tel: 01295 819900 Fax: 01295 819911 www.wrap.org.uk
WRAP Business Helpline: Freephone 0808 100 2040
Disclaimer:
WRAP and Oakdene Hollins Ltd believe the content of this report to be correct as at the date of writing. However, factors such as prices, levels of recycled content and regulatory requirements are subject to change and users of the report should check with their suppliers to confirm the current situation. In addition, care should be taken in using any of the cost information provided as it is based upon numerous project-specific assumptions (such as scale, location, tender context, etc.). The report does not claim to be exhaustive, nor does it claim to cover all relevant products and specifications available on the market. While steps have been taken to ensure accuracy, WRAP cannot accept responsibility or be held liable to any person for any loss or damage arising out of or in connection with this information being inaccurate, incomplete or misleading. It is the responsibility of the potential user of a material or product to consult with the supplier or manufacturer and ascertain whether a particular product will satisfy their specific requirements.
