Bitumen has been used as a construction product for thousands of years. As we become more environmentally aware there is an increased focus on sustainability in all aspects of life and business and it is natural that we should consider the sustainability of our activities.
Bitumen used in road surfaces and other applications can be collected and reused again and again in new materials. The reason why we prefer to address reuse than recycling is that for bitumen, the process is focussing on highest level of reimplementation of used material into the process.
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%.
The use of "old" road material (Reclaimed Asphalt Pavement (RAP)) as a component in making fresh asphalt is relatively common practice. The asphalt mixture specifications indicate the amount allowed and the methods to calculate the contribution of the old (hardened) bitumen to the new mixture.
Asphalt roads can be recycled by two main processes:
- In situ - where the broken-up asphalt pavement is re-formed into the new structure
- Off-site – where the RAP is taken to a plant to be used as a component of a new mixture.
Asphalt recycling contributes to the sustainability of our industry in a number of different ways: it reduces waste, preserves non-renewable natural resources (aggregate and bitumen) and also reduces transport and logistical costs and emissions associated with removing the original material and delivering the new road elements.
The importance of environmental protection and the possible impacts associated with products manufactured and consumed, has increased interest in the development of methods to better comprehend and compare the sustainability of products, on the basis of robust scientific data.
Due to the manufacturing process, which removes the lower boiling molecules, emissions to the atmosphere do not occur under normal conditions of service. Bitumen emissions at ambient temperature are negligible.
Water & Soil
Bitumen is a very inert material that is insoluble in water. Moreover, bituminous materials are often used to line drinking water reservoirs and in products to line water pipes that supply potable drinking water. Retention ponds are often paved with asphalt to keep liquid industrial waste material from leaching into the soil. Similarly, bitumen is used to line and cap hazardous waste sites – preventing rainwater from permeating through the hazardous waste and from leaching into groundwater.
Soil quality and vegetation are not influenced by bitumen, this is why 90% of rural paths are built on asphalt foundations. Such paths allows people to spend their free time in and around the local green space while ensuring that the environmental impact of human contact is at a minimum. In agricultural settings bitumen has been used as a ‘mulch’ to help retain water in the soil and therefore help crops to grow as well as being used to bond organic pots for seedling germination.
Eurobitume Life Cycle Inventory (LCI)
The bitumen LCI is a cradle to gate study covering the extraction of crude oil; transport to Europe, including pipeline and ship transport; manufacturing bitumen in a complex refinery; and hot storage of the product. It also takes into account the construction of production facilities (infrastructure).
The source data used to compile this report are available in an Excel spreadsheet that is compatible with commercially available LCI software, making it easy for LCI practitioners to incorporate the data as part of a construction product life cycle assessment. The LCI database is available in two versions: With Infrastructure and Without Infrastructure, which can be requested by sending an email to viviane.dupont(at)eurobitume.eu.
Eurobitume’s new LCI report is the subject of our feature article, ‘The bitumen Life Cycle Inventory’. To read the article, please click here.