On Study of Development Expansive Coal Gangue Portland Cement by Microwave Technology

Added carbon powder or M mineral powder in unburned kaolinite coal gangue, the mixtures could be changed better expansive mineral additive of Portland cement by microwave irradiation. The microwave activation coal gangue mixtures 5%, 10%, 15%, 20%, 25%, 30% and 35% (by weight) were respectively added into I 42.5 Portland cement. The compressive/flexural strength of various expansive coal gangue Portland cements were determined after 3 and 28 day. The fineness, initial and final setting time, soundness and volume expansive ratio was also measured. The expansive reasons of coal gangue Portland cement were considered that there were lots of thicker and bigger flaky crystal during hydration processes by scanning electron microscope, and found the Al, Si, O and other elements in flaky crystal by Edax. The expansive mechanism of coal gangue Portland cement is different from traditional expansive cements theories by microwave irradiation.