What is foamed bitumen?
Foamed bitumen (also known as foamed asphalt, foam bitumen or expanded asphalt) is a mixture of air, water and bitumen. When injected with a small quantity of cold water, the hot bitumen expands explosively to about fifteen times its original volume and forms a fine mist or foam.
Can bitumen be recycled?
Bitumen used in road surfaces and other applications can be collected and reused again and again in new materials. In 2017, for example almost 47 million tonnes of asphalt were recycled in Europe. Quantities recycled directly back into road surfaces vary from country to country, but can be as high as 85%.
Where is foamed bitumen used?
Foamed bitumen technologies are widely used to produce the WMA mixtures in the asphalt industry recently. Some of them straightly inject water into the asphalt binder. The water turns to the steam at a high mixing temperature, and then disperses into asphalt binder, which causes the expansion of the binder.
How foamed bitumen is produced?
Foamed bitumen is produced by foaming standard road-grade bitumen. In the process, small amounts of water and air are injected into the hot bitumen at high pressure, which results in the bitumen foaming and expanding to around 20 times its original volume.
How do you make foamed bitumen?
Foamed bitumen is produced by adding small amounts of water to hot bitumen (approximately 2-3% by weight of bitumen). The binder used for this process if ordinary penetration-grade bitumen, type B60 to B200, which is also used for asphalt production in new road construction.
Is bitumen environmentally friendly?
Bitumen has claims to be one of the most environmentally friendly crude oil products. The substance is environmentally friendly because it is not burned, therefore no co2 emissions go into the air. Another positive of Bitumen is that is can be recycled and reused, one of the best ways to be green.
How does asphalt recycling work?
Asphalt chunks or millings are mixed in an asphalt recycler (or reclaimer) along with some water and additives. For hot mix asphalt, the mixture is tumbled and heated for approximately 20 minutes before it is ready for use. Cold recycling, on the other hand, avoids the use of heat and saves energy in the process.
What is foam bitumen Stabilisation?
Foamed bitumen stabilisation (FBS) involves insitu or plant mix stabilisation of pavement materials with bitumen as the primary binder. The process is used to improve the strength of granular materials while retaining a flexible pavement.
How is foamed asphalt made?
Foamed asphalt is formed by combining hot asphalt binder with small amounts of cold water. The result is a thin-film, high volume asphalt foam with approximately 10 times more coating potential than the asphalt binder in its normal liquid state (World Highways, 2001). …
Why is bitumen bad for the environment?
Asphalt, also known as bitumen, is a major source of air pollution, especially in sunny and hot places. For one kind of harmful particulate pollution, asphalt emissions from roads and roofs may be a bigger problem than emissions from all petrol and diesel-powered vehicles.
Why is bitumen not used as a fuel?
Bitumen itself is a black and very sticky liquid. It’s also highly viscous and so full of carbon that it cannot be used for combustion (unlike gasoline, diesel and jet fuel).
Is recycled asphalt any good?
Asphalt recycling is good for the environment. If not recycled, old asphalt will stay in the landfill forever. It’s also very durable – as much, if not more, than new asphalt.
How is Foamed Bitumen used in road construction?
The use of foamed bitumen as a binding agent for this procedure has recently generated much lively interest within the industry. While the principle of foamed bitumen is not new, the utilization of this process for binding cold material in road construction is relatively new and innovative.
How is Foamed Bitumen added to a mixer?
The bitumen foam can be injected directly on to the homogenized aggregate that has been placed into a laboratory mixer. In order to establish the optimum bitumen content, varying bitumen quantities with optimum water content are added to the aggregate mix.
How is the half life of Foamed Bitumen measured?
Half-life is defined as the time it takes for the foamed bitumen to reduce by 50% from its maximum achieved volume. This is normally measured in seconds. As a rule, the larger the expansion and the longer the half-life, the better the quality of the foamed bitumen.
How long can cold treated bitumen be stored?
Cold-treated material produced with foamed bitumen (without the addition of cement) can be stored for very long periods of time. The storage properties depend upon the water content.