Recycling use of sulfate-rich sewage sludge ash (SR-SSA) in cement-based materials: Assessment on the basic properties, volume deformation and microstructure of SR-SSA blended cement pastes
Recycling use of sulfate-rich sewage sludge ash (SR-SSA) in cement-based materials: Assessment on the basic properties, volume deformation and microstructure of SR-SSA blended cement pastes
复制标题
富含硫酸盐的污泥灰（SR-SSA）在水泥基材料中的回收利用：SR-SSA混合水泥浆体的基本性能、体积变形和微观结构评估
DOI：
10.1016/j.jclepro.2020.124511
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发表时间：
2021-02-01
影响因子：
11.1
通讯作者：
Ni, Tongyuan
中科院分区：
文献类型：
--
作者：
Gu, Chunping;Ji, Yongjie;Ni, Tongyuan
污水污泥灰（SSA）是从废水污泥焚烧中获得的废物。污泥灰可以回收利用于水泥基材料中，但我国污泥灰通常富含硫酸盐，其对水泥基材料性能和微观结构的影响尚不清楚。本研究旨在探讨SR-SSA在水泥基材料中回收利用的可能性。试验研究了SR-SSA对水泥石基本性能、体积变形和微观结构的影响。研究结果表明，SR-SSA的掺入降低了水泥净浆的和易性、抗压强度和抗折强度，延缓了凝结时间，降低了自收缩，并导致水泥净浆的长期干燥收缩和潜在膨胀增大。过量钙矾石的形成和粗大的孔结构是导致高掺量SR-SSA水泥浆体性能下降和体积不稳定的主要原因。但用SR-SSA取代5%的水泥对水泥浆体的性能影响不大。通过取代高达5%的水泥，在水泥基材料中回收SR-SSA是可行的。同时，用SR-SSA替代5%的水泥可以减少4.98%的CO2排放量，降低25.42%的财务成本。在中国全部回收利用SR-SSA的情况下，预计每年可减少CO2排放68亿kg CO2-e，财务成本为161亿元人民币。该研究有助于SR-SSA的回收利用，提高水泥基材料的可持续性。(C)2020爱思唯尔有限公司保留所有权利。
Sewage sludge ash (SSA) is the waste obtained from the incineration of wastewater sludge. SSA could be recycled in cement-based materials, but normally SSA in China is sulfate rich, and how the sulfate-rich sewage sludge ash (SR-SSA) influence the properties and microstructure of cement-based materials is still unknown. This study aimed to investigate the possibility of recycling use SR-SSA in cement-based materials. The effect of SR-SSA on the basic properties, volume deformation and microstructure of the cement paste was experimentally studied. The findings of this study indicated that the addition of SR-SSA reduced the workability, compressive strength and flexural strength, retarded the setting times, reduced the autogenous shrinkage and caused greater long-term drying shrinkage and higher potential expansion of the cement paste. The formation of excessive ettringite and the coarse pore structure contributed to the properties reduction and volume instability of cement pastes with excessive SR-SSA. However, replacing 5% cement with SR-SSA didn't induce much detrimental influence on the properties of cement paste. It is feasible to recycle SR-SSA in cement-based materials by replacing up to 5% cement. At the same time, replacing 5% cement with SR-SSA could result in 4.98% lower CO2 emission and 25.42% lower financial cost. In case of recycling all SR-SSA in China, it is possible to expect annual reduction in CO2 emission of 6.8 billion kg CO2-e and financial cost of 16.1 billion RMB yuan. This study could help to recycle SR-SSA and improve the sustainability of cement-based materials. (C) 2020 Elsevier Ltd. All rights reserved.