Enhancing sulfate resistance of cement-stabilized recycled aggregate with steel slag: Optimized mix design and mechanistic insights

Cement-stabilized recycled aggregate (CSR) has garnered considerable attention as a sustainable material in pavement construction. However, its performance significantly deteriorates under sulfate attack. This study aims to enhance the sulfate resistance of CSR by incorporating steel slag aggregate...

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Main Authors: Yuyuan Deng, Xuancang Wang, Jing Zhao, Haoxiang Liu, Lv Chen
Format: Article
Language:English
Published: Elsevier 2025-12-01
Series:Case Studies in Construction Materials
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Online Access:http://www.sciencedirect.com/science/article/pii/S2214509525007028
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author Yuyuan Deng
Xuancang Wang
Jing Zhao
Haoxiang Liu
Lv Chen
author_facet Yuyuan Deng
Xuancang Wang
Jing Zhao
Haoxiang Liu
Lv Chen
author_sort Yuyuan Deng
collection DOAJ
description Cement-stabilized recycled aggregate (CSR) has garnered considerable attention as a sustainable material in pavement construction. However, its performance significantly deteriorates under sulfate attack. This study aims to enhance the sulfate resistance of CSR by incorporating steel slag aggregate (SSA) and optimizing the mix design using the D-optimal mixture design (DOD) method. Dosage ranges for recycled aggregate (RA) and SSA were determined by unconfined compressive strength (UCS) and thermal shrinkage tests. The optimal mix proportion of cement-stabilized RA and SSA (CSRS) was established using the DOD model. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy-energy dispersive spectroscopy (SEM–EDS) were employed to investigate the mechanism by which SSA enhances the sulfate resistance of CSR. The results indicated that the replacement ratios of RA and SSA for natural aggregate (NA) should be limited to 60 % and 36 %, respectively. The optimal CSRS mix proportion determined by the DOD model comprised 40 % NA, 48.5 % RA, and 17 % SSA. Experimental validation demonstrated that all absolute relative deviations (ARD) were below 5 %, verifying the accuracy of the DOD model. The reactive minerals in SSA, primarily C2S and C3S, participated in hydration reactions, leading to the formation of additional C-S-H gel, which refined the interfacial transition zone (ITZ), reduced its width to 27 μm, limited sulfate ingress pathways, and mitigated sulfate attack on CSRS. These findings provide valuable insights for optimizing similar mixture designs and promoting RA utilization in pavement base applications.
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spelling doaj-art-06d144ef6d384cd0854a3f9f3475a6892025-08-20T03:21:28ZengElsevierCase Studies in Construction Materials2214-50952025-12-0123e0490410.1016/j.cscm.2025.e04904Enhancing sulfate resistance of cement-stabilized recycled aggregate with steel slag: Optimized mix design and mechanistic insightsYuyuan Deng0Xuancang Wang1Jing Zhao2Haoxiang Liu3Lv Chen4School of Highway, Chang’an University, Xi’an, Shaanxi 710064, China; Key Laboratory for Special Area Highway Engineering of Ministry of Education, Chang’an University, South 2nd Ring Road Middle Section, Xi’an, Shaanxi 710064, ChinaSchool of Highway, Chang’an University, Xi’an, Shaanxi 710064, China; Key Laboratory for Special Area Highway Engineering of Ministry of Education, Chang’an University, South 2nd Ring Road Middle Section, Xi’an, Shaanxi 710064, China; Corresponding author at: School of Highway, Chang’an University, Xi’an, Shaanxi 710064, China.School of Highway, Chang’an University, Xi’an, Shaanxi 710064, China; Key Laboratory for Special Area Highway Engineering of Ministry of Education, Chang’an University, South 2nd Ring Road Middle Section, Xi’an, Shaanxi 710064, ChinaSchool of Highway, Chang’an University, Xi’an, Shaanxi 710064, China; Key Laboratory for Special Area Highway Engineering of Ministry of Education, Chang’an University, South 2nd Ring Road Middle Section, Xi’an, Shaanxi 710064, ChinaSchool of Highway, Chang’an University, Xi’an, Shaanxi 710064, China; Key Laboratory for Special Area Highway Engineering of Ministry of Education, Chang’an University, South 2nd Ring Road Middle Section, Xi’an, Shaanxi 710064, ChinaCement-stabilized recycled aggregate (CSR) has garnered considerable attention as a sustainable material in pavement construction. However, its performance significantly deteriorates under sulfate attack. This study aims to enhance the sulfate resistance of CSR by incorporating steel slag aggregate (SSA) and optimizing the mix design using the D-optimal mixture design (DOD) method. Dosage ranges for recycled aggregate (RA) and SSA were determined by unconfined compressive strength (UCS) and thermal shrinkage tests. The optimal mix proportion of cement-stabilized RA and SSA (CSRS) was established using the DOD model. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy-energy dispersive spectroscopy (SEM–EDS) were employed to investigate the mechanism by which SSA enhances the sulfate resistance of CSR. The results indicated that the replacement ratios of RA and SSA for natural aggregate (NA) should be limited to 60 % and 36 %, respectively. The optimal CSRS mix proportion determined by the DOD model comprised 40 % NA, 48.5 % RA, and 17 % SSA. Experimental validation demonstrated that all absolute relative deviations (ARD) were below 5 %, verifying the accuracy of the DOD model. The reactive minerals in SSA, primarily C2S and C3S, participated in hydration reactions, leading to the formation of additional C-S-H gel, which refined the interfacial transition zone (ITZ), reduced its width to 27 μm, limited sulfate ingress pathways, and mitigated sulfate attack on CSRS. These findings provide valuable insights for optimizing similar mixture designs and promoting RA utilization in pavement base applications.http://www.sciencedirect.com/science/article/pii/S2214509525007028Pavement baseRecycled aggregateSteel slag aggregateD-optimal mixture designSulfate resistance
spellingShingle Yuyuan Deng
Xuancang Wang
Jing Zhao
Haoxiang Liu
Lv Chen
Enhancing sulfate resistance of cement-stabilized recycled aggregate with steel slag: Optimized mix design and mechanistic insights
Case Studies in Construction Materials
Pavement base
Recycled aggregate
Steel slag aggregate
D-optimal mixture design
Sulfate resistance
title Enhancing sulfate resistance of cement-stabilized recycled aggregate with steel slag: Optimized mix design and mechanistic insights
title_full Enhancing sulfate resistance of cement-stabilized recycled aggregate with steel slag: Optimized mix design and mechanistic insights
title_fullStr Enhancing sulfate resistance of cement-stabilized recycled aggregate with steel slag: Optimized mix design and mechanistic insights
title_full_unstemmed Enhancing sulfate resistance of cement-stabilized recycled aggregate with steel slag: Optimized mix design and mechanistic insights
title_short Enhancing sulfate resistance of cement-stabilized recycled aggregate with steel slag: Optimized mix design and mechanistic insights
title_sort enhancing sulfate resistance of cement stabilized recycled aggregate with steel slag optimized mix design and mechanistic insights
topic Pavement base
Recycled aggregate
Steel slag aggregate
D-optimal mixture design
Sulfate resistance
url http://www.sciencedirect.com/science/article/pii/S2214509525007028
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AT jingzhao enhancingsulfateresistanceofcementstabilizedrecycledaggregatewithsteelslagoptimizedmixdesignandmechanisticinsights
AT haoxiangliu enhancingsulfateresistanceofcementstabilizedrecycledaggregatewithsteelslagoptimizedmixdesignandmechanisticinsights
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