ACTIVITY MECHANISM OF FELDSPAR FOR AUTOCLAVED FLY ASH PRODUCTS

The effects of different feldspars on autoclaved fly ash products were investigated using X-ray diffraction,scanning elec-tron microscopy and atomic absorption spectrophotometry by admixing feldspars into fly ash.The experiments show that feldspars can activate fly ash in 1.2 MPa saturated steam pressure as NaOH;however,their activating modes and effects are different.The alkali cations are released slowly from feldspars during autoclaving and activate fly ash continuously.This is favorable for the formation of tobermorite in the autoclaved products and for increasing the compressive strength of the products.The effect of albite on activating fly ash is better than microcline's.