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Abstract: This research investigated fresh and hardened properties of concretes containing three different types of slag at three different replacement ratios and three different water/binder ratios. The three types of slag include ground granulated blastfurnace slag, ground granulated Corex slag and a ground granulated ferro-manganese arc furnace slag. Different methods for the assessment of slag hydraulic activity are compared, including chemical and physical characterisation of the various binders and binder blends, mortar compressive strength tests and heat of hydration tests, indicating the limitations of the various methods if used in isolation. The test results indicate that the use of the slags under investigation increases concrete workability at high water/binder ratios only. Setting times and 1-day strength values were strongly dependent on the slag replacement ratio. The influence of slag replacement level on compressive strength reduced over time. Strength development characteristics and long-term strength values were considerably different for different types of slag. [Copyright &y& Elsevier]

Africa is one of the regions where significant construction will be experienced in future. While the use of Limestone Calcined Clay Cement (LC3) is considered a viable option for lowering costs and environmental impact of concrete, its viability needs to be verified based on performance assessment of locally available constituent materials. In this study, the performance of LC3 mixes with clinker contents of 45 %, 55 %, and 65 % with four different clays from South Africa and Tanzania, was assessed and compared with two conventional concrete mixes. Overall, it was concluded that, LC3 mixes are characterised by reduced penetrability, increased electrical resistivity, higher chloride ingress resistance, and increased carbonation rates, indicating superior durability performance for marine exposure conditions. Factors such as the specific surface area of the clay and the alkali contents were found to influence the performance of the system, and these aspects require further study to better understand their influence. • The viability of selected African clays for LC3 mixes has been verified. • The selected clays produced concretes with adequate strength performance. • The alkali content of the clay has high influence on the performance of concrete. • The LC3 mixes show superior durability potential for marine exposure conditions. [ABSTRACT FROM AUTHOR]