Abstract: The recycled fine powder from construction waste can effectively replace cement, reduce the use of cement resources, and improve the resource utilization rate of construction waste. In this paper, the effects of brick-concrete recycled fine powder and foaming agent content on the mechanical properties of low-strength foamed cementitious materials were studied by methods such as bubble parameter analysis and mechanical property test. The results show that the addition of recycled fine powder leads to a reduction in the compressive strength of the cementitious material. The strength of the cementitious material increases slightly with the addition of recycled fine powder, when the amount of fine powder is higher than that of cement. At the same time, the flowability of slurry decreases first and then increases with the increase of recycled fine powder. When the amount of recycled fine powder is small, the amount of foaming agent has a great effect on the flowability of slurry, but when the amount of recycled fine powder is large, the amount of foaming agent has no significant influence on the flowability of slurry. The performance of different batches of recycled fine powder is almost the same. By adjusting the content of recycled fine powder and the foaming agent, foam cementitious materials that meet the requirements of different mechanical properties and have good fluidity can be prepared, which can meet the large-scale promotion in low-grade backfill materials.

Key words: construction waste, recycled fine powder, foamed concrete, cementitious material, micro-analysis, mechanical property