The potential alkali reactivity of aggregates and the influence of alkali-silica reaction(ASR) on compactibility,impermeability and behavior of diffusivity of chloride of mortars were investigated by AC impedance spectroscopy.It is shown that the AC impedance response is different when the potential alkali reactivity exists in the aggregate,and a good parallel correlation exists as compared to the results of accelerated mortar bar test.The position of impedance plot in complex plane and phase angle can be used to estimate the potential alkali reactivity.Impedance spectroscopy is of promise to be developed as a measure to evaluate the potential alkali reactivity of aggregate.In addition,if the ASR is controlled to a certain extent so that the deterioration induced by expansion of concrete structure does not appear,the durability and service life of concrete could be improved.The compactibility is shown by impedance technique to increase significantly and the impermeability,the diffusivity of chloride decreases to a great extent in the presence of ASR.These effects are expected to be of great promise in the future use of some alkali reactive aggregates.