Effect and Optimization of Inactive Solid Waste as Fine Aggregate on Backfill Strength
The inactive solid waste(sludge)was partially replaced by fine aggregate to prepare sludge fine aggregate backfill.Through microstructure characterization and physical and mechanical tests,the fluidity,initial setting time,final setting time,water absorption rate,pore index and other physical properties and compressive strength of the sludge fine aggregate back-fill with different content(0%,4%,6%,8%,10%)were analyzed.The optimum amount of fine aggregate was optimized.The results show that the fluidity of the backfill samples containing 4%,6%,8%and 10%sludge fine aggregate is reduced by 3.0%,11.2%,12.2%and 14.3%,respectively,compared with the backfill samples without sludge fine aggregate.The samples with 4%,6%,8%and 10%sludge fine aggregate content did not have significant fluidity reduction.After 28 days of curing,the mechanical properties of the sample with 8%sludge fine aggregate filling were the best,and its compressive strength was 51 MPa,which was 21.4%higher than that of the sample without sludge fine aggregate filling(42 MPa).The compressive strength of the samples with 4%,6%,8%and 10%fine aggregates increased by 9.5%,19.0%,21.4%and 14.3%,respec-tively,compared with the samples without fine aggregates,reflecting that the addition of fine aggregates significantly improved the compressive strength of the backfill.After soaking in water for 28 h,the sample of fine aggregate backfill without sludge ab-sorbed more water than that of fine aggregate backfill with sludge,reflecting that the pore index of the later was lower than that of the former,the water absorption rate was also lower.The initial and final coagulation time of 6%sludge fine aggregate filling body is the longest,the coagulation time is extended with a certain amount of sludge fine aggregate,and the best replacement rate of sludge fine aggregate is 8%.
solid waste materialfine aggregatebackfillfluiditycompressive strengthpore indexsetting time
万方数据
维普
