装修/拆房垃圾低品物料再生免烧砖研究

Research on Regeneration of Baking-free Brick from Low Quality Materials of Decoration and Demolition Wastes

近年来我国城市化进程加快,城市化率迅速增长,导致装修、拆房等建筑垃圾的大量产生,由于其成分复杂,破碎过程中会产生灰渣和除尘灰等难利用的低品质物料,严重影响装修/拆房垃圾处理生产线的整体资源化率。首先通过研究除尘灰和灰渣物理化学性质,探究其再利用可行性;随后,通过碱激发改性低活性除尘灰替代部分水泥,由灰渣替代部分标准砂进行免烧砖制备试验,分析不同配比和掺入量对再生免烧砖抗压强度和其发展规律的影响。结果显示:免烧砖强度随着灰渣掺量的增加而降低40%~70%,但可以通过控制水泥(至少20%)和粗骨料掺量(总骨料7.5%~15.0%)减少免烧砖抗压强度的衰减,28 d强度可以达到MU15砖的要求;采用碱激发除尘灰替代10%水泥,免烧砖7 d强度可以达到MU10砖的要求,而替代20%则需28 d。

In recent years,the urbanization process in China has accelerated and the urbanization rate has increased rapidly,resulted in a large number of construction and demolition debris.Due to its complex composition,a lot of lowquality materials such residue ash(RA)and dust powder(DP)would be produced in the crushing process,which seriously affected the overall resource utilization rate of decoration and demolition waste disposal production line.Firstly,the feasibility of its reuse was explored by studying the physical and chemical properties of RA and DP.Then,modified low-activity DP activated by alkali was used to replace part of cement,and RA was used to replace part of standard sand to carry out the experiment of preparing baking-free brick.The influences of different ratio and dosage on the compressive strength and development rule of recycled baking-free brick were investigated.The results showed that the strength of baking-free brick reduced by 40%~70%with the increase of RP content.However,the reduction of compressive strength of baking-free brick could be mitigated by controlling the dosage of cement(at least 20%)and coarse aggregate(7.5%~15.0%of total aggregate).The strength could meet the requirement of brick MU15 in 28 days.When the dust ash activated by alkali was used to replace 10%cement,the strength of baking-free brick could reach the requirement of brick MU10 in 7 days,while replacing 20%took 28 days.