Improved compressive strength of alkali activated slag upon heating

This paper presents a study on thermal stability of alkali activated slag (AAS) prepared from electric arc furnace slag (EAFS) using a mixture of alkaline sodium hydroxide and sodium silicate solutions. The samples were investigated by means of XRD, SEM, TG/DTA and porosity analysis. Compressive strengths of MS samples before and after exposure to elevated temperatures ranging from 600 degrees C to 1000 degrees C were determined. The significant microstructural modifications highlighted by changes in porosity due to the sintering process are responsible for the strengthening of MS sample after heating at 600,800 and 1000 degrees C. Moreover, in MS sample after heating to and above 600 degrees C wustite transforms to spinel.