What Is Asphalt & Why Is It Important in Road Construction?
Key Takeaways:
1. Asphalt is a composite material with two primary ingredients: aggregates and bitumen.
2. Because of its strength, cost-effectiveness, versatility, and more – asphalt is a key road surfacing material in UK highway construction.
3. Asphalt testing is vital to ensuring the best construction materials are selected for the task, ensuring the safety and longevity of infrastructure.
The Vital Role of Asphalt in Road Construction
Asphalt is a mixture of bitumen with coarse and fine aggregates. The bitumen is a viscous form of petroleum used as a binder for the aggregates (usually crushed stone, sand, and gravel), which makes asphalt a bituminous material.
Bituminous materials can be used in a wide range of applications, including highways, airport runways, car parks, driveways, and even playgrounds. Providing fast, cost-efficient construction and smooth, quiet transportation – asphalt is one of the best road surface materials in the UK.
1. Strong & Flexible
Asphalt is exceptionally durable – capable of withstanding the weight of heavy vehicles and machinery for lengthy periods.
Its strength is largely attributed to its flexibility, which allows it to adapt to underlying imperfections and pressures from the traffic above. This not only helps maintain the road’s surface quality over time but also ensures safe and more enjoyable driving conditions.
2. Quick & Versatile Installations
Bituminous materials can be laid and cured quickly, minimising the amount of time roads are closed to traffic. It’s also highly cost-effective to install, with low material and labour costs.
Once installed, asphalt can be painted with road markings to suit various applications. It can also be produced in distinct colours, making it an ideal surface solution for distinguishing bus lanes, cycleways, residential roads, school zones, and playgrounds.
3. Smooth & Weather Resistant
Asphalt ensures a smooth and safe driving experience, offering high traction and resistance to temperature fluctuations. Its ability to rapidly disperse surface water also lessens the risk of aquaplaning and decreases spray, improving visibility for drivers.
4. Easy to Repair & Recycle
Bituminous materials are easy to mix and repair, allowing for quick and cost-effective long-term maintenance. Patching and resurfacing can be done efficiently, minimising disruption to traffic and extending the lifespan of the road.
Modern asphalt is also fully recyclable and can be reused repeatedly by melting down old asphalt, significantly improving waste management, and reducing environmental impact.
5. Reduces Noise Pollution
By absorbing sound and quieting road noise, asphalt contributes to reduced noise pollution across the UK. This is especially beneficial in urban areas, where lower noise levels can greatly improve the quality of life for residents.
Road Construction Materials: Strengths vs Weaknesses
Asphalt offers numerous benefits, but it also has some weaknesses. Regular maintenance can be expected, including sealing, resurfacing, and patching. Additionally, the production and recycling of asphalt release greenhouse gases, contributing to environmental pollution.
Bituminous materials are also not as durable as concrete, which is the main alternative road surfacing material to asphalt. While asphalt roads typically need resurfacing every 10-15 years, concrete roads can last for many decades with less frequent maintenance.
That said, when concrete does require maintenance, it is more challenging to repair. It is also more expensive to install, noisier, and less smooth. One of the biggest disadvantages of concrete over asphalt is that it offers less traction, making it unsafe in wet conditions.
The Impact of Asphalt Testing on Road Safety
Despite its drawbacks, asphalt remains one of the best road surface materials in the UK. This is supported by the comprehensive testing and compliance standards now required for the use and maintenance of asphalt and other bituminous materials.
Asphalt can come in various grades that make it suitable for different applications. For example, a bituminous mix with a low softening point should not be used in hot climates, as the laid material will soften beyond the point of safe use.
With a range of asphalt road testing methods, assessing properties such as asphalt durability, viscosity, ductility, and more – asphalt testing gives project owners, engineers, and local authorities confidence in the road construction materials selected.
How to Test Asphalt and other Bituminous Materials
By providing insights into the characteristics of bituminous road construction materials, asphalt testing plays a vital role in preventing premature deterioration, reducing maintenance costs, and ensuring structural integrity for many years.
Common bituminous road testing methods include:
Penetration Test: Measures hardness and consistency by penetrating a needle vertically into a sample under specific temperature conditions.
Softening Point Test: Determines the temperature at which the mix becomes soft enough for a steel ball to sink through by submerging a sample into a heated bath.
Ductility Test: Identifies the elasticity of a bituminous mix by measuring the distance the sample can stretch before breaking.
Asphalt & Bituminous Material Testing from CTS
CTS offers on-site and laboratory-based Bituminous and Asphalt Testing to help clients make informed decisions, manage risks, and minimise costs. Our experienced team is fully accredited, adhering to all applicable standards and regulations for asphalt road testing methods.
Whether it's for an ongoing pavement project, one-off or routine quality checks, or part of a failure investigation - we can work with you to ensure the highest standards of quality and compliance in your next project.