Abstract: The effects of calcination temperature, constant temperature time and cooling mode on the activity of unburned coal-gangue were studied by strength evaluation method, and the coal-gangue admixture was prepared and compared with fly ash and slag on performance.On this basis, the influence of fineness and content of coal-gangue admixture on mortar consistency and alkali-aggregate reaction was studied by its mortar fluidity and accelerated mortar bar test.The results show that coal-gangue powder with mechanical and thermal activation has the effect on micro-aggregate and activity, which can improve the consistency of the mixture and inhibit the expansion of the concrete, and the inhibitory effect of fineness is more obvious.The work-ability of concrete with the local coal-gangue admixture is improved and the inhibition of alkali-aggregate reaction gets the best effect, when the local coal-gangue calcined at 750 ℃ for 3 h, the fineness is 1150 m2/kg and the content is control in 5%.

Key words: coal-gangue;admixture;mechanical activation;thermal activation;alkali-aggregate reaction