CEMENT: A QUESTION OF RESPONSIBLE USE

The paper recognises the difficulties encountered in producing an ‘ideal’concrete for a specific application(s). Notwithstanding this, however, it argues a case for 21^st century concrete construction, that offers alternatives, considers the use of widely based constituent materials (in particular cement components), encourages the use of recycled and secondary materials and attempts to minimise environmental impact and cost (including whole life cost). The development of new European Standards, which are coming into use in the area of cement and concrete, namely EN 197-1, EN206-1 (together with the complementary standard BS8500 in the UK), and Eurocode 2 are discussed, and demonstrate the advancements in concrete specification that have been achieved. The paper then focuses on the need to optimise cement, using a two stage framework:

Physical optimisation, aimed at minimising voids.

Chemical optimisation, aimed at producing the highest resistance against a given exposure.

A series of exposure classes are used to further explain the process of optimising the use of cement. It is shown that for most applications, the use of Portland cement clinker in combinations with other cementitious materials and/or fillers, offers a sound technical, economical, sustainable and environmentally friendly solution. It is suggested that there is an urgent need for further research (with special emphasis on durability) for refining the method for using cement combinations that are safe to use and can easily be understood and routinely specified by engineers.

• INTRODUCTION

• KEY PARAMETERS IN DETERMINING CONCRETE PEFORMANCE

• SUSTAINABELITY ISSUES

• HIGH PERFORMANCE APPLICATIONS

• CONCLUDING REMARKS

• REFERENCES