Editorial

摘要

It is with great pleasure that I write my second editorial as a member of the editorial advisory board of Construction Materials. My main area of expertise is concrete technology but I do recognise that although concrete is a ubiquitous material it is not the only construction material. Concrete still, however, features heavily in current research but the emphasis has shifted towards sustainability related issues. There has been increasing concern recently over how our activities affect the environment. Cement production is said to contribute 5% of the world's total carbon dioxide emissions. This figure is likely to rise with the increased demand for infrastructure in developing countries. At the same time the production of concrete requires large volumes of raw materials most of which are quarried. We seem to forget, however, that the inert fraction of concrete - that is, the aggregate - has many applications in construction projects and is not only used for the production of concrete. Bituminous road pavements is another large volume use of aggregate in construction projects. It is therefore important that we consider reducing our reliance on quarried materials by seeking secondary materials that are either recycled from concrete itself or that are derived from suitable waste streams that would otherwise be sent to landfill. It is essential, however, that we fully investigate not only new quarried aggregate sources but also recycled materials for their short- and long-term effects on concrete construction before their widespread use by industry. Durable concrete structures are required for a sustainable built environment. We therefore need to improve our understanding of how we can increase the design life of structures through selection of appropriate materials or through better understanding of how inadvertent factors, such as alkali-aggregate reactivity, can affect their long-term behaviour.