METHOD TO EVALUATE THE REACTIVITY OF MICROCRYSTALLINE QUARTZ IN CARBONATE ROCK

In order to quantify the alkali reactivity of microcrystalline quartz in carbonate rock, the profile-fitting technique was adopted to analys e its X ray diffraction lines of 2 theta = 66.5-70 degrees using the F WHM (full width at half maximum) to monitor its crystallinity. It was found that for all the alkali-reactive carbonate rocks tested, silica was present as well-crystallized quartz, so expansion is not due to th e alkali-silica reaction (ASR). This evidence supports the suggestion that expansion is caused by reaction between alkali and dolomite, rath er than with silica. It is noted that the X ray diffraction method is a powerful means to investigate the reactivity of quartz.