An understanding of how roads are built is necessary to appreciate the importance of the role played by bitumen. Modern road design and construction techniques aim to build flexible road layers, or courses, and bitumen plays an important part in this, as well as ensuring that the courses are weather resistant and durable.
Bitumen is a crucial component of asphalt – the most widely used material for constructing and maintaining roads in the world. There are over 4,000 hot mix asphalt plants in Europe alone, producing some 300 million tonnes of asphalt per year. Asphalt is typically a mixture of approximately 95% aggregate particles and sand, and 5% bitumen, which acts as the binder, or glue. The viscous nature of the bitumen allows the asphalt to sustain significant flexibility, creating a very durable surface material. There are many different types of asphalt, each with its own combination of different amounts and type of bituminous binder and mineral aggregate, and each type of asphalt has performance characteristics appropriate for specific applications. Thus, for each application there is a suitable asphalt mixture available. Asphalt is totally recyclable and recycling has increased significantly in recent years. Quantities recycled directly back into road surfaces vary from country to country, but can be as high as 70%. Asphalt is routinely milled and re-laid along with fresh materials, saving money and preserving non-renewable natural resources.
Water repellent and flexible, the mechanical properties of bitumen membranes make them ideal for waterproofing a multitude of applications. Traditionally used to weatherproof low slope roofs, bitumen membranes are also increasingly used to support green roofs or roof gardens, in commercial or residential developments.
Bitumen’s waterproofing properties, durability and resistance to heavy loads are also used in numerous other specialty applications, and are applied in bridge decks, reservoirs, canals and tunnels, industrial and floating floorings, roof top car parks, hydraulic construction and pipe coating. Bitumen’s waterproofing properties, durability and resistance to heavy loads are applied in industrial and floating floorings, roof top car parks, hydraulic construction and pipe coating. Where strength and weatherproofing are essential requirements, bitumen is a prime contributor to the performance of a vast range of final products. Bitumen membranes are also extensively used as
- Sound absorbent membranes in the auto-car market.
- Industrial floorings and floating floors in private and public buildings
- Anti-corrosion pipe coating and many underground waterproofing applications
- Sound absorbing panels used in the automotive sector
- Waterproofing paints for metal, brickwork, stone, felt and even drinking-water tanks.