Study on the Geopolymer Based on Fly Ash and Slag

The fly ash, slag and metakaolin have been employed to prepare the geopolymer. The max compressive strength of the geopolymer could reach 30.79 MPa under the optimal proportion. The results of toxicity characteristic leaching procedure indicated the heavy metals could be effectively solidified into the geopolymeric matrices. Both the compressive strength and the immobilization behavior are affected by the amount of alkali activator. The SEM showed the structure of fractured surface was related to the compressive strength and the solidification effect. The results of XRD and FTIR indicated the MSWI fly ash was reacted with kaolin to form a new Si-Al polymer under the activation of alkali and the structure of geopolymer was amorphous.