Henggen Zhang , Tao Liu , Weihua Wang , Yuxue Cui , Yankun Wu , Xinyi Qiu
{"title":"OPC-MCA对盾构隧道废泥的有效养护：试验研究与微观结构分析","authors":"Henggen Zhang , Tao Liu , Weihua Wang , Yuxue Cui , Yankun Wu , Xinyi Qiu","doi":"10.1016/j.tust.2025.106554","DOIUrl":null,"url":null,"abstract":"<div><div>To address the problems of large volume, complex composition, difficulty in treatment and environmental pollution of the waste mud (WM) generated in urban slurry shield tunnels, the ground granulated blast-furnace slag (GGBS), calcium aluminate powder (CAP), fuel gas desulfurization gypsum (FGDG), lime and alunite were incorporated into ordinary Portland cement (OPC) to develop a new modified curing agent (OPC-MCA). The optimal addition ratio of various admixtures in OPC-MCA was determined through orthogonal tests. The mechanical properties of the two different types of WM (i.e., Wuhu and Wuhan WM) after curing with 10–40% OPC and OPC-MCA were investigated by laboratory tests. The microstructure, pore and crack evolution characteristics as well as mineral composition changes of the cured WM specimens were analyzed using the scanning electron microscope (SEM), X-ray computed tomography (CT) and X-ray diffraction (XRD). The curing performance and microscopic action mechanism of the two curing agents on shield tunnel WM were investigated. The results confirmed that the optimum ratio of OPC-MCA was 51% OPC, 32% GGBS, 8% FGDG, 5% CAP, 3% lime and 1% alunite. OPC-MCA exhibited better curing performance than OPC, especially at low dosages, and the curing effect of OPC-MCA for Wuhu WM was better than that for Wuhan WM. The cured WM specimens mostly presented shear failure, but with the increase of curing age and curing agent dosage, some specimens underwent tensile failure with increased strength and brittleness. Calcium aluminium silicate hydrate (C-A-S-H) and monosulfate (AFm) were detected in the OPC-MCA cured WM specimens, while these hydration products were not detected in the OPC cured WM specimens, and the higher content of ettringite (AFt) was also observed in the OPC-MCA cured WM specimens. The proportion of large pores and the total pore volume of the OPC-MCA cured WM specimens were smaller than those of the OPC cured WM specimens at same curing agent dosage.</div></div>","PeriodicalId":49414,"journal":{"name":"Tunnelling and Underground Space Technology","volume":"161 ","pages":"Article 106554"},"PeriodicalIF":7.4000,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Effective curing of waste mud from slurry shield tunnels using OPC-MCA: Experimental investigations and microstructural analysis\",\"authors\":\"Henggen Zhang , Tao Liu , Weihua Wang , Yuxue Cui , Yankun Wu , Xinyi Qiu\",\"doi\":\"10.1016/j.tust.2025.106554\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>To address the problems of large volume, complex composition, difficulty in treatment and environmental pollution of the waste mud (WM) generated in urban slurry shield tunnels, the ground granulated blast-furnace slag (GGBS), calcium aluminate powder (CAP), fuel gas desulfurization gypsum (FGDG), lime and alunite were incorporated into ordinary Portland cement (OPC) to develop a new modified curing agent (OPC-MCA). The optimal addition ratio of various admixtures in OPC-MCA was determined through orthogonal tests. The mechanical properties of the two different types of WM (i.e., Wuhu and Wuhan WM) after curing with 10–40% OPC and OPC-MCA were investigated by laboratory tests. The microstructure, pore and crack evolution characteristics as well as mineral composition changes of the cured WM specimens were analyzed using the scanning electron microscope (SEM), X-ray computed tomography (CT) and X-ray diffraction (XRD). The curing performance and microscopic action mechanism of the two curing agents on shield tunnel WM were investigated. The results confirmed that the optimum ratio of OPC-MCA was 51% OPC, 32% GGBS, 8% FGDG, 5% CAP, 3% lime and 1% alunite. OPC-MCA exhibited better curing performance than OPC, especially at low dosages, and the curing effect of OPC-MCA for Wuhu WM was better than that for Wuhan WM. The cured WM specimens mostly presented shear failure, but with the increase of curing age and curing agent dosage, some specimens underwent tensile failure with increased strength and brittleness. Calcium aluminium silicate hydrate (C-A-S-H) and monosulfate (AFm) were detected in the OPC-MCA cured WM specimens, while these hydration products were not detected in the OPC cured WM specimens, and the higher content of ettringite (AFt) was also observed in the OPC-MCA cured WM specimens. The proportion of large pores and the total pore volume of the OPC-MCA cured WM specimens were smaller than those of the OPC cured WM specimens at same curing agent dosage.</div></div>\",\"PeriodicalId\":49414,\"journal\":{\"name\":\"Tunnelling and Underground Space Technology\",\"volume\":\"161 \",\"pages\":\"Article 106554\"},\"PeriodicalIF\":7.4000,\"publicationDate\":\"2025-07-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Tunnelling and Underground Space Technology\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0886779825001920\",\"RegionNum\":1,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"2025/3/10 0:00:00\",\"PubModel\":\"Epub\",\"JCR\":\"Q1\",\"JCRName\":\"CONSTRUCTION & BUILDING TECHNOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Tunnelling and Underground Space Technology","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0886779825001920","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2025/3/10 0:00:00","PubModel":"Epub","JCR":"Q1","JCRName":"CONSTRUCTION & BUILDING TECHNOLOGY","Score":null,"Total":0}
Effective curing of waste mud from slurry shield tunnels using OPC-MCA: Experimental investigations and microstructural analysis
To address the problems of large volume, complex composition, difficulty in treatment and environmental pollution of the waste mud (WM) generated in urban slurry shield tunnels, the ground granulated blast-furnace slag (GGBS), calcium aluminate powder (CAP), fuel gas desulfurization gypsum (FGDG), lime and alunite were incorporated into ordinary Portland cement (OPC) to develop a new modified curing agent (OPC-MCA). The optimal addition ratio of various admixtures in OPC-MCA was determined through orthogonal tests. The mechanical properties of the two different types of WM (i.e., Wuhu and Wuhan WM) after curing with 10–40% OPC and OPC-MCA were investigated by laboratory tests. The microstructure, pore and crack evolution characteristics as well as mineral composition changes of the cured WM specimens were analyzed using the scanning electron microscope (SEM), X-ray computed tomography (CT) and X-ray diffraction (XRD). The curing performance and microscopic action mechanism of the two curing agents on shield tunnel WM were investigated. The results confirmed that the optimum ratio of OPC-MCA was 51% OPC, 32% GGBS, 8% FGDG, 5% CAP, 3% lime and 1% alunite. OPC-MCA exhibited better curing performance than OPC, especially at low dosages, and the curing effect of OPC-MCA for Wuhu WM was better than that for Wuhan WM. The cured WM specimens mostly presented shear failure, but with the increase of curing age and curing agent dosage, some specimens underwent tensile failure with increased strength and brittleness. Calcium aluminium silicate hydrate (C-A-S-H) and monosulfate (AFm) were detected in the OPC-MCA cured WM specimens, while these hydration products were not detected in the OPC cured WM specimens, and the higher content of ettringite (AFt) was also observed in the OPC-MCA cured WM specimens. The proportion of large pores and the total pore volume of the OPC-MCA cured WM specimens were smaller than those of the OPC cured WM specimens at same curing agent dosage.
期刊介绍：
Tunnelling and Underground Space Technology is an international journal which publishes authoritative articles encompassing the development of innovative uses of underground space and the results of high quality research into improved, more cost-effective techniques for the planning, geo-investigation, design, construction, operation and maintenance of underground and earth-sheltered structures. The journal provides an effective vehicle for the improved worldwide exchange of information on developments in underground technology - and the experience gained from its use - and is strongly committed to publishing papers on the interdisciplinary aspects of creating, planning, and regulating underground space.
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