ACTIVATING FLY-ASHES: ENLARGING THE CONCEPT OF CEMENTITIOUS MATERIAL

摘要

The alkali activation of waste materials (especially those coming from industrial and mining activities) has become an important area of research since it is possible to use these materials to synthesise inexpensive and ecologically sound cement-like construction materials. In the present paper, the mechanism of activation of a fly ash with highly alkaline solution is described: The main product of reaction is an amorphous aluminosilicate gel having a structure similar to that of zeolite precursors. XRD and SEM/EDX have been used in the characterisation process of the material. The study of technological properties has shown that the AAFA mortars and concrete have: rapid gaining of mechanical strength, low shrinkage and excellent adherence between the steel reinforcement and the matrix.