Hydration and rheological properties of municipal sludge co-processing cement

The recycling and co-processing of municipal sludge in the production of cement clinker is a promising technology for the valorization of municipal solid wastes. However, the Al and Si rich in municipal sludge and the presence of heavy metals usually results in the different performance of municipal...

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Main Authors: Jianyun Wang, Xianglong Ji, Depeng Chen, Chunxiang Qian, Gang Liu
Format: Article
Language:English
Published: Elsevier 2025-07-01
Series:Case Studies in Construction Materials
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Online Access:http://www.sciencedirect.com/science/article/pii/S2214509524012786
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author Jianyun Wang
Xianglong Ji
Depeng Chen
Chunxiang Qian
Gang Liu
author_facet Jianyun Wang
Xianglong Ji
Depeng Chen
Chunxiang Qian
Gang Liu
author_sort Jianyun Wang
collection DOAJ
description The recycling and co-processing of municipal sludge in the production of cement clinker is a promising technology for the valorization of municipal solid wastes. However, the Al and Si rich in municipal sludge and the presence of heavy metals usually results in the different performance of municipal sludge co-processed cement (CPC) from normal ordinary Portland cement (OPC). To understand the variation in fresh behaviour, this study evaluated the flowability and rheological properties of CPC and OPC pastes with dosages of superplasticizers (SP). The hydration kinetics and hydration products of pastes in the fresh state were characterized. The influences of SP on the hardening properties of CPC and OPC samples were further addressed. The result indicated that the incorporation of SP provided a superior flowability of CPC pastes compared to OPC after mixing, however, the fast decline in flowability of CPC pastes in the first 40–80 minutes was confirmed. Consequently, CPC pastes presented faster development of static yield stress and dynamic yield stress compared to OPC with the SP dosage from 0.05 % to 0.125 %. CPC consumed significantly higher SP to achieve similar workability to OPC pastes. The characterization of reaction products indicated that hydration of CPC produced more ettringite and less portlandite in the first few minutes compared to OPC with or without SP. The application in OPC and CPC all reduced the volume of pores larger than 100 nm. The optimal SP could effectively promote the strength development of CPC and OPC at early ages.
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spelling doaj-art-fdce8945ac1e4ff3a78719e8696251e62025-08-20T02:32:04ZengElsevierCase Studies in Construction Materials2214-50952025-07-0122e0412610.1016/j.cscm.2024.e04126Hydration and rheological properties of municipal sludge co-processing cementJianyun Wang0Xianglong Ji1Depeng Chen2Chunxiang Qian3Gang Liu4School of Human Settlements and Civil Engineering, Xi’an Jiaotong University, Xi’an 710049, PR ChinaSchool of Human Settlements and Civil Engineering, Xi’an Jiaotong University, Xi’an 710049, PR ChinaSchool of Architectural and Civil Engineering, Anhui University of Technology Ma’anshan 243032, PR ChinaSchool of Materials Science and Engineering, Southeast University, Nanjing 211189, PR China; Corresponding authors.School of Human Settlements and Civil Engineering, Xi’an Jiaotong University, Xi’an 710049, PR China; Corresponding authors.The recycling and co-processing of municipal sludge in the production of cement clinker is a promising technology for the valorization of municipal solid wastes. However, the Al and Si rich in municipal sludge and the presence of heavy metals usually results in the different performance of municipal sludge co-processed cement (CPC) from normal ordinary Portland cement (OPC). To understand the variation in fresh behaviour, this study evaluated the flowability and rheological properties of CPC and OPC pastes with dosages of superplasticizers (SP). The hydration kinetics and hydration products of pastes in the fresh state were characterized. The influences of SP on the hardening properties of CPC and OPC samples were further addressed. The result indicated that the incorporation of SP provided a superior flowability of CPC pastes compared to OPC after mixing, however, the fast decline in flowability of CPC pastes in the first 40–80 minutes was confirmed. Consequently, CPC pastes presented faster development of static yield stress and dynamic yield stress compared to OPC with the SP dosage from 0.05 % to 0.125 %. CPC consumed significantly higher SP to achieve similar workability to OPC pastes. The characterization of reaction products indicated that hydration of CPC produced more ettringite and less portlandite in the first few minutes compared to OPC with or without SP. The application in OPC and CPC all reduced the volume of pores larger than 100 nm. The optimal SP could effectively promote the strength development of CPC and OPC at early ages.http://www.sciencedirect.com/science/article/pii/S2214509524012786Co-processing cementMunicipal sludgeRheologyWorkabilitySuperplasticizer
spellingShingle Jianyun Wang
Xianglong Ji
Depeng Chen
Chunxiang Qian
Gang Liu
Hydration and rheological properties of municipal sludge co-processing cement
Case Studies in Construction Materials
Co-processing cement
Municipal sludge
Rheology
Workability
Superplasticizer
title Hydration and rheological properties of municipal sludge co-processing cement
title_full Hydration and rheological properties of municipal sludge co-processing cement
title_fullStr Hydration and rheological properties of municipal sludge co-processing cement
title_full_unstemmed Hydration and rheological properties of municipal sludge co-processing cement
title_short Hydration and rheological properties of municipal sludge co-processing cement
title_sort hydration and rheological properties of municipal sludge co processing cement
topic Co-processing cement
Municipal sludge
Rheology
Workability
Superplasticizer
url http://www.sciencedirect.com/science/article/pii/S2214509524012786
work_keys_str_mv AT jianyunwang hydrationandrheologicalpropertiesofmunicipalsludgecoprocessingcement
AT xianglongji hydrationandrheologicalpropertiesofmunicipalsludgecoprocessingcement
AT depengchen hydrationandrheologicalpropertiesofmunicipalsludgecoprocessingcement
AT chunxiangqian hydrationandrheologicalpropertiesofmunicipalsludgecoprocessingcement
AT gangliu hydrationandrheologicalpropertiesofmunicipalsludgecoprocessingcement