Mechanical characteristics and microstructural changes in phosphogypsum-cement-lime composite modified loess

Loess is widely distributed in China but suffers from inherent deficiencies limiting its direct use as a subbase material in road construction without modifications. This study investigated the utilization of Phosphogypsum (PG), an industrial waste, in a composite stabilizer containing cement, lime...

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Main Authors: Jin Chang, Jue Li, Yudan Wang, Haina Zhang
Format: Article
Language:English
Published: Elsevier 2024-12-01
Series:Case Studies in Construction Materials
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Online Access:http://www.sciencedirect.com/science/article/pii/S2214509524010325
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author Jin Chang
Jue Li
Yudan Wang
Haina Zhang
author_facet Jin Chang
Jue Li
Yudan Wang
Haina Zhang
author_sort Jin Chang
collection DOAJ
description Loess is widely distributed in China but suffers from inherent deficiencies limiting its direct use as a subbase material in road construction without modifications. This study investigated the utilization of Phosphogypsum (PG), an industrial waste, in a composite stabilizer containing cement, lime and slag powder for modifying loess in the subbase application. An orthogonal test design was employed to optimize the composite proportions. Laboratory tests evaluated the mechanical properties including unconfined compressive strength (UCS), splitting tensile strength, resilient modulus and water stability of modified loess over curing periods up to 90 days. Microstructural evolution was analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results showed the composite containing 25 % PG, a cement-slag ratio of 4:6 and 5 % lime imparted the highest strengths. Mechanical performances increased with curing time and stabilizer content. Water stability and heavy metal immobilization were satisfactory. Microstructural results revealed microstructural densification occurred through hydration product development binding soil particles. This work demonstrated the technical and environmental viability of recycling PG through loess improvement, offering a sustainable solution for problematic soil stabilization and industrial waste utilization.
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spelling doaj-art-8567028ef7d94145a762cc211d2a14ff2025-08-20T02:08:43ZengElsevierCase Studies in Construction Materials2214-50952024-12-0121e0388110.1016/j.cscm.2024.e03881Mechanical characteristics and microstructural changes in phosphogypsum-cement-lime composite modified loessJin Chang0Jue Li1Yudan Wang2Haina Zhang3College of Civil Engineering, Changsha University, Changsha 410022, China; Shanghai Key Laboratory for Digital Maintenance of Buildings and Infrastructure, Department of Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; Hunan Provincial Key Laboratory for Big Data Smart Application of Natural Disaster Risks Survey of Highway Engineering, Changsha University, Changsha 410022, China; Key Laboratory of Road Structure and Material of Ministry of Transport (Changsha), Changsha University of Science & Technology, Changsha, Hunan 410114, ChinaNational & Local Joint Engineering Research Center of Transportation and Civil Engineering Materials, Chongqing Jiaotong University, Chongqing 400074, China; Corresponding author.National & Local Joint Engineering Research Center of Transportation and Civil Engineering Materials, Chongqing Jiaotong University, Chongqing 400074, ChinaKey Laboratory of Road Structure and Material of Ministry of Transport (Changsha), Changsha University of Science & Technology, Changsha, Hunan 410114, China; College of Civil Engineering and Architecture, East China Jiaotong University, Nanchang, Jiangxi Province 330013, ChinaLoess is widely distributed in China but suffers from inherent deficiencies limiting its direct use as a subbase material in road construction without modifications. This study investigated the utilization of Phosphogypsum (PG), an industrial waste, in a composite stabilizer containing cement, lime and slag powder for modifying loess in the subbase application. An orthogonal test design was employed to optimize the composite proportions. Laboratory tests evaluated the mechanical properties including unconfined compressive strength (UCS), splitting tensile strength, resilient modulus and water stability of modified loess over curing periods up to 90 days. Microstructural evolution was analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results showed the composite containing 25 % PG, a cement-slag ratio of 4:6 and 5 % lime imparted the highest strengths. Mechanical performances increased with curing time and stabilizer content. Water stability and heavy metal immobilization were satisfactory. Microstructural results revealed microstructural densification occurred through hydration product development binding soil particles. This work demonstrated the technical and environmental viability of recycling PG through loess improvement, offering a sustainable solution for problematic soil stabilization and industrial waste utilization.http://www.sciencedirect.com/science/article/pii/S2214509524010325PhosphogypsumLoessComposite stabilizerMechanical propertiesEnvironmental assessment
spellingShingle Jin Chang
Jue Li
Yudan Wang
Haina Zhang
Mechanical characteristics and microstructural changes in phosphogypsum-cement-lime composite modified loess
Case Studies in Construction Materials
Phosphogypsum
Loess
Composite stabilizer
Mechanical properties
Environmental assessment
title Mechanical characteristics and microstructural changes in phosphogypsum-cement-lime composite modified loess
title_full Mechanical characteristics and microstructural changes in phosphogypsum-cement-lime composite modified loess
title_fullStr Mechanical characteristics and microstructural changes in phosphogypsum-cement-lime composite modified loess
title_full_unstemmed Mechanical characteristics and microstructural changes in phosphogypsum-cement-lime composite modified loess
title_short Mechanical characteristics and microstructural changes in phosphogypsum-cement-lime composite modified loess
title_sort mechanical characteristics and microstructural changes in phosphogypsum cement lime composite modified loess
topic Phosphogypsum
Loess
Composite stabilizer
Mechanical properties
Environmental assessment
url http://www.sciencedirect.com/science/article/pii/S2214509524010325
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AT jueli mechanicalcharacteristicsandmicrostructuralchangesinphosphogypsumcementlimecompositemodifiedloess
AT yudanwang mechanicalcharacteristicsandmicrostructuralchangesinphosphogypsumcementlimecompositemodifiedloess
AT hainazhang mechanicalcharacteristicsandmicrostructuralchangesinphosphogypsumcementlimecompositemodifiedloess