INTRODUCTION

In the past few decades, there has been a growing awareness amongst engineers of the need to ensure that provisions are made for durability in concrete structures coupled with a growing awareness of the importance of sustainability in concrete construction. Indeed, it has been clearly demonstrated that concrete durability is one of the key issues for it becoming construction's sustainable option and a great progress has been made both in development of specifications and application technologies over the last 20 to 30 years.

For almost a century, a maximum w/c ratio has been used as the main parameter for specifying durability. However, data shows that this approach is unlikely to lead to a constant performance in practice. Thus, an alternative more sustainable way of specifying durability is clearly required. Performance-based specifications ensuring long service life of structures have been rapidly developed, based on the information from many concrete structures which are in outstandingly good condition for their age, as well as examples of structures deteriorating within a few years, but then well maintained and lasting for many years. Obtaining this information mainly depends on assessment and prognosis technologies, together with the development of durability models, which are based on a detailed understanding of the deterioration mechanisms of concrete.

To retain and extend performance for sustainable construction, concrete has now diversified into a group of innovative products of high strength, low permeability, and self compacting, reinforced by not only traditional steel, but also polymer and carbon fibres, and its applications extended to cover normal to extreme conditions, such as tropical and marine environments and explosive and seismic situations.

To achieve long lasting concrete structures it is important to use a multi step approach. Therefore, replace, repair and retain become more and more important issues in the sustainable approach to maintaining and managing concrete structures.

The Proceedings ‘Concrete Durability: Achievement and Enhancement' dealt with all these subject areas and the issues raised four clearly defined themes: (i) Retaining and Extending Performance, (ii) Fundamental Mechanisms, (iii) Replace, Repair and Retain, and (iv) Extreme Exposure Conditions. Each theme started with a Keynote Paper presented by the foremost exponents in their respective fields. There were a total of 92 papers presented during the International Conference which are compiled into these Proceedings.