Editorial

When I was first introduced to concrete in the early 1960s, it seemed to be a relatively 'simple' material, produced using only Portland cement, aggregate and water.Chemical admixtures were mostly confined to air-entraining admixtures and primitive water reducers, and supplementary cementing materials were not commonly used.Cement and concrete were inexpensive, both selling in North America for about $20-25 per tonne.There were then no concerns about 'sustainability', or greenhouse gas emissions, and hence little interest in other (non-Portland) cementing systems.Studies on the hydration mechanisms, or the detailed structure of hydrated cement were considered to be the province only of a few eccentric academics, and were not thought to be of much practical importance.So much has changed since then!The seven papers presented in this issue of Advances in Cement Research would have been largely incomprehensible to the cement researchers of that time, and are excellent exemplars of how much cement science has advanced in the last 50 years.