In 1989, 96 million tonnes of aggregate were used in road construction in the UK and it is estimated that the current road building plans of the Department of Transport will require a massive 510 million tonnes. With this large increase in the amount of aggregate needed comes a growing awareness of, and concern for, the environmental impact that the provision of this material will have, and for many the re-use of waste materials in construction projects is becoming a far more attractive proposal. Alternative materials in road construction considers the extent to which waste materials and industrial by-products can be used in road construction projects in place of the natural materials traditionally used. It brings together a comprehensive listing of all the available waste material products and explores their potential as both technical and economical alternatives to natural materials. In October 1994, the Royal Commission on Environmental Pollution published its report on Transport and the Environment in which it expressed its concern that 'extensive damage to the environment would be caused through extraction of the aggregates to carry out the present road building programme'.
The report went on to recommend that 'the proportion of recycled materials used in road construction should be doubled by 2005 and doubled again by 2015'. The targets set by the Royal Commission are not incompatible, but the realisation of these targets would require planning policy changes to encourage alternative sources of construction materials to enter the market. Alternative materials in road construction considers what policy changes the Government could make to encourage the use of waste materials and then lists the various options available to road engineers as potential substitutes with practical advice and guidance on their benefits and pitfalls.