Workability and maturity properties of ground granulated blastfurnace slag concretes.

The intimate mixing of ordinary Portland cement (OPC) with ground granulated blastfurnace slag (GGBS) to produce a cementitious binder for concrete has several environmental, technical and economic advantages which have led to it becoming accepted in many countries. Almost all published work on GGBS concretes in the United Kingdom has used GGBS from a single long-established source. Several sources of GGBS are now available, so an extensive project was undertaken by the author to determine the importance of the origin and grinding of the granulate. In the main programme of research two types of GGBS were incorporated in concrete mixes with three cementitious contents and three cementitious blends. Five different curing conditions and five ages of testing were employed. Alternative methods of assessing the workability, hydration characterisics, strength and potential durability were examined. The results seem to indicate that both the level and source of GGBS in the cementitious blend have an important bearing on fresh and hardened concrete properties; dependent on other factors, such as the cement content, age and curing conditions. The relationships between the hardened concrete assessment parameters were also found to be influenced by the presence of GGBS. Novel tests to assess the mix stability, hydration characteristics and potential durability of concrete performed favourably.