Mixing and blending coloured asphalt
The integration of the colouring agents into the asphalt mix involves careful blending of the pigments with the hot asphalt binder and aggregates to achieve the required colour. It’s only added once the aggregates have reached the desired temperature and is then carefully measured into the mixing drum.
Together, the asphalt mix and colouring agents are thoroughly combined to achieve a uniform distribution of colour throughout the mixture. The process ensures that the pigments are evenly coated and dispersed amongst the aggregates and asphalt binder. Allowing a consistent colour result throughout the whole job. This is particularly important on larger projects with multiple loads to ensure the colour is same throughout and joints are minimised.
Maintaining the correct temperature all the way through is essential to guaranteeing proper workability of the asphalt mix and effective blending of the colouring agent.
Due to the intricacies of the mixing and blending process, hands-on expertise is needed to achieve consistent colour, maintain performance standard, troubleshoot issues, ensure safety and ultimately deliver a high-quality end product.
Application techniques for coloured asphalt
A clean and properly prepared surface will mean the coloured asphalt adheres well to the underlying layers such as the binder course or base layer, which is crucial for the pavement’s robustness and long-lasting performance.
Adequate preparation will also contribute to the long-term durability of the coloured asphalt as it helps resist wear, weathering and the stresses caused by traffic, extending the lifespan of the road. Additionally, an even and smoother surface provides a better base for laying. Irregularities or rough patches in the underlying pavement can translate into an uneven final surface that affects ride quality for motorists and cyclists.
Another reason to prepare properly is to assist with uniform colour consistency, as any debris, stains or contaminants on the surface can negatively affect the final appearance of the coloured asphalt.
When it comes to structural integrity, putting time into preparation ensures that the coloured asphalt layer is supported by a stable foundation, which helps distribute loads evenly and prevents structural failures in the future.
Investing time and effort in surface preparation can lessen the likelihood of costly repairs and maintenance in the future by reducing the need for frequent interventions.
Overall, successful surface preparation is essential for a thriving-coloured asphalt project. It guarantees strong adhesion, lasting durability, precise colour rendering, structural soundness and safety, culminating in an attractive, enduring, and operational coloured asphalt surface.
There are several methods for applying coloured asphalt, each suited to different project requirements and surface conditions. It’s laid and compacted using conventional asphalt paving equipment such as pavers and rollers. This method is most suitable for large-scale projects like roads and car parks. All equipment must be thoroughly cleaned to an extremely high standard before use, to avoid any contamination with black asphalt that the equipment might usually handle.
The hand lay method is recommended with coloured asphalt, and can be used on smaller works or areas with limited access for large equipment. This involves manually placing, spreading and compacting the coloured asphalt mix with hand tools such as shovels, rakes and small rollers. This way of laying reduces the risk of contamination and is most commonly associated with paths, pedestrian areas and small decorative spaces.
Considerations for colour retention and durability
Coloured asphalt is exposed to various environmental factors, including sunlight (UV radiation), weather conditions and traffic loads, which can impact the colour's vibrancy and the overall performance of the pavement.
High-quality, UV-resistant pigments with excellent colour fastness properties should be chosen as these will maintain their colour intensity over time. Applying a protective surface coating with UV-blocking properties over the finished surface can form a barrier against UV radiation, helping to preserve the colour and longevity.
It’s important to implement a maintenance programme to keep the coloured surface clean and in excellent condition. Regular cleaning and sealcoating will help protect the surface from environmental stressors and help maximise the colour’s vibrancy. Ensuring the pavement has adequate drainage to prevent water pooling or ponding can also aid with colour retention.