Abstract: Ratio tests and round-pipe experiment were researched by paste filling model system indoor to study the changes of basic performance and the rheological property of paste filling material which using building waste as aggregate and using fly ash and additives as fine aggregate on the basis of theory and technology of pumping paste backfill mining.The ratio of paste backfilling materials is additives∶fly ash∶building waste=1∶4∶6，and the test's operations included three steps：preparation、 the matreial preparation of paste backfill、 pumping test&data collection under using the scheme of mass concentration modulation from high to low by adding water.The results showed that：the slump and layering degree of paste filling material decreases with the increase of pumping time，but the quality concentraton increased slightly.The slump and layering degree of paste filling material that the concentration was 76% respectively reached 18.5 cm and 0.9 cm after 4 h piping.The concentration、speed and diameter were main influence factors for pipe friction loss，and the flow velocities of paste backfills which of the mass concentration was 76% between 0.8 m/s and 1.0 m/s was ideal .

Key words: Building waste, Recycled aggregate, Paste filling, Round-pipe experiment