Abstract: For the engineering application of alkali-active aggregate in mass concrete，the alkali-silica reaction inhibition test，compressive strength test，autogenous volume deformation test and the fast freeze-thaw test using alkali-active aggregate with different dosage of fly ash，light-burned MgO were carried out.The tests showed that：alkali-silica reaction is effectively restrained when the fly-ash content is 30% and light-burned MgO content is 3%~5%；Fly-ash make concrete early strength reduced，the late strength increased fast，and the amount of 3%~5% light-burned MgO dosage has little impact on the strength；light-burned MgO autogenous volume deformation will be reduced by hydration of fly-ash，but fly-ash cannot change this characteristics of light-burned MgO；fly-ash has adverse effects on frost resistance of concrete，and light-burned MgO can improve the frost resistance of concrete.So，the reasonable dosage of fly-ash and light-burned MgO make the alkali-active aggregate concrete possible be applied in the mass concrete.

Key words: Alkali-active aggregate, Alkali-silica reaction, light-burned MgO, Mass concrete, Micro expansion