ASPHALTIC SURFACES
Go Karting Circuits, Jogging Tracks, Carparking
Asphalt is a mixture of aggregates, binder and filler, used for constructing and maintaining all kind of roads, parking areas but also play- and sport areas. Aggregates used for asphalt mixtures could be crushed rock, sand, gravel or slags. In order to bind the aggregates into a cohesive mixture a binder is used. Most commonly, bitumen is used as a binder. An average asphalt pavement consists of the road structure above the formation level which includes unbound and bituminous-bound materials. This gives the pavement the ability to distribute the loads of the traffic before it arrives at the formation level. Normally, pavements are made of different layers:
To be able to provide the best performance to different applications, a large variety of asphalt mixes can be used. Due to the different requirements (amount of traffic, amount of heavy vehicles, temperature, weather conditions, noise reduction requirements, etc.) the respective mix used needs to have an sufficient stiffness and resistance to deformation in order to cope with the applied pressure from vehicle wheels on the one hand, yet on the other hand, they need to have an adequate flexural strength to resist cracking caused by the varying pressures exerted on them. Moreover, good workability during application is essential in order to ensure that they can be fully compacted to achieve optimum durability.
An asphalt pavement consists of different asphalt layers.
In general the asphalt layers are paved on a bound or unbound road base layer. Starting at the road surface, the first layer is called the surface course. The second layer is mostly called the binder course. The lower layers are the base courses.
Surface course
The surface course constitutes the top layer of the pavement and should be able to withstand high traffic- and environmentally-induced stresses without exhibiting unsatisfactory cracking and rutting, in order to provide an even profile for the comfort of the user and at the same time possess a texture ensuring adequate skid resistance. Depending on local conditions, functional characteristics such as skid resistance, noise reduction and durability are often required for wearing courses. In some cases, rapid drainage of surface water is desired while in other cases, the wearing course should be impermeable in order to keep water out of the pavement structure. A wide range of surface layer products can be used depending on specific requirements. Surface layers types are:
Asphalt Concrete (AC)
Béton Bitumineux Mince (Thin Layer Asphalt Concrete – AC-TL)
Asphalt Concrete Very Thin Layers (AC-VTL)
Asphalt Concrete Ultra Thin Layer (AC-UTL)
Stone Mastic Asphalt (SMA)
Hot Rolled Asphalt (HRA)
Porous Asphalt (PA)
Double layered Porous Asphalt (2L PA)
Mastic Asphalt (MA)
Soft Asphalt (SA)
Hot Mix Asphalt (HMA) pavements are a very important part of today’s recreational surfacing industry. Hot Mix Asphalt provides an affordable and durable all weather pavement that athletic surfaces are applied to throughout the world. The acrylic coatings used for tennis, basketball, volleyball and other sports were originally developed for application on asphalt.
No industry is static, the HMA and acrylic surfacing industries are no exception. Even though these two industries work side by side on many occasions, there can be a lack of understanding of some of the fundamental requirements of proper pavements for recreational surfaces.
The US Tennis Court and Track Builders Association, manufacturers of acrylic coatings (including California Products Corporation) and the National Asphalt Pavement Association recognize the need for well drained pavements with base of adequate thickness and stability for recreational surface to be successful. Moisture has a number of negative effects on asphalt pavements. It can cause frost heaves, distortion of the surface, cracking and deterioration of the mix.
By controlling moisture the pavement life is prolonged. Even when properly constructed asphalt pavements have a finite life expectancy. The mix is deteriorated by UV sunlight, moisture, traffic (or lack of) and temperature changes. It is generally accepted that well constructed asphalt pavements have a life expectancy of 15-20 years before they require significant reconstruction.