关键词: 粉煤灰;再生混凝土;强度贡献率

Abstract: The experiment focuses on the C30 concrete with different coarse aggregate(recycled aggregate,natural aggregate),fly ash(15％,30％,50％)and the curing conditions(standard curing,indoor natural curing),exploring the effect of fly ash as volcano ash active mineral admixtures on the long-term strength of the concrete with different coarse aggregate.The experiment results show that with the increase of replacement ratio of fly ash,at an early age the strength contribution of recycled concrete and ordinary concrete rate has declined,but with curing age increasing,the contribution rate of middle and long-term strength has declined slowly after 180 d.When in standard curing,the fly ash replacement rate is within 30％,the strength contribution rate reaches the maximum at 180 d,the strength contribution rate is decreased more than 180 d beyond 30％;but when the fly ash replacement rate is 50％,the strength contribution rate even more than 180 d will increase.When in the indoor natural curing,with curing period increasing,the long-term strength contribution of different replacement ratio of fly ash and different aggregate concrete has been increased.

Key words: fly ash;recycled concrete;strength contribution rate