Alkali-Activated Slag Concrete - Development for Practical Use
V. Bilek, M. Urbanova, J. Brus, and D. Kolousek
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alkali activated slag; shrinkage; strength
Alkali-activated slag concretes (AASC) are relatively well-known composites. For practical application various different problems must be solved. For example, they are the optimum content of alkaline activator and its nature; the composition of the activator for optimum setting and hardening time; the design of concrete for good workability, for the reaching of the smallest volume exchanges, and for maximum strength and for high durability. These problems are discussed in the present paper. Water glass and/or natrium hydroxide were chosen as the best type of activator and the optimum ratio Na2O and SiO2 were found. Calorimetry, MAS NMR (27Al and 29Si), SEM and other methods were used for the characterisation of the mixes. The concrete mixes are designed as self compacting for easier introduction of these materials into practice. Strengths, volume changes and their time development were measured during the aging of the mixes. Some elements will be produced from the concretes in 2005 and 2006 (elements for cable pipe-lines).