Overview

Despite making significant progress over the years so that asphalt performance has become well controlled and fairly predictable, there is always room for further improvement. A key development over the past 20 years or so in the UK has been the utilisation of polymer-modified bitumens (PMB) to further improve asphalt performance. This has manifested itself either by enabling asphalt to have improved durability or alternatively by enabling asphalt layer thicknesses, in particular the main surface course layer, to be significantly reduced. Such reduction can offer material savings that appeals to clients concerned with lowering costs, but who are also tasked with meeting sustainability targets, e.g., local authorities.

The utilisation of polymer-modified binders in the UK has grown sharply over the past ten years from humble beginnings in the late 1970s when there was no means of specifying their use. Back then the asphalt industry's liability was largely limited to supplying materials in accordance with specifications that called up standard recipe-based materials.

The UK aggregates and asphalt industry is fairly capital-intensive in terms of manufacturing plant and traditionally conservative in nature. Likewise the client side of the industry has traditionally taken a conservative view towards adopting new technology because of the need to protect public safety. However, in recent years there has been a growing acceptance that new technologies can offer the tax payer better value for money. This change has resulted in growing industry acceptance for new materials such as the adoption of polymers in asphalt, even though it...