Experimental Study on the Road Performance of Phosphogypsum-Modified Lime-Fly Ash Stabilized Red Clay
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Published:2023-11-27
Issue:23
Volume:13
Page:12689
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ISSN:2076-3417
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Container-title:Applied Sciences
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language:en
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Short-container-title:Applied Sciences
Author:
Huang Shibin12,
Ma Yanzhou12,
Wang Jiaquan12ORCID,
Lin Zhinan12ORCID,
Chen Tianxin12
Affiliation:
1. Guangxi University Key Laboratory of Disaster Prevention and Mitigation and Prestress Technology, Guangxi University of Science and Technology, Liuzhou 545006, China
2. Guangxi Zhuang Autonomous Region Engineering Research Center of Geotechnical Disaster and Ecological Control, Liuzhou 545006, China
Abstract
To assess the impact of solid waste phosphogypsum on the road performance of lime-fly ash-stabilized red clay, we conducted comprehensive tests on the road performance, swelling and shrinkage characteristics, and mechanical properties of lime-fly ash soil with varying phosphogypsum content and curing age. Additionally, we analyzed the microstructure and composition changes using scanning electron microscopy and X-ray diffraction tests. The results revealed that phosphogypsum significantly enhances the early strength and moisture stability of lime-fly ash soil. The mechanical properties of lime-fly ash soil continue to improve with increased curing age, with performance improvements tapering off after 60 days and eventually stabilizing. Moreover, as the phosphogypsum content increases, the unconfined compressive strength (UCS), splitting strength, and CBR value of the lime-fly ash soil initially increase and then decrease. The optimal mixing ratio was determined to be 4% phosphogypsum, resulting in a 7-day UCS increase of 67.2%, a 28-day UCS increase of 3 times, and a 28-day splitting strength increase of 4.3 times. The moisture stability coefficient also exhibited a 43% increase after 7 days, and its anti-disintegration ability was enhanced, reaching 0.91 after 28 days, which meets the specified standards. Microscopic analysis revealed that the addition of phosphogypsum improved the overall integrity of the lime-fly ash soil, and the formation of ettringite effectively filled the soil’s pores. However, excessive ettringite caused increased expansion and deformation. To optimize the use of phosphogypsum-modified lime-fly ash-stabilized red clay as subgrade filler, it is advisable to incorporate additives to further reduce swelling deformation.
Funder
National Natural Science Foundation of China
Key Project of the Guangxi Natural Science Foundation
High-Level Innovation Team and Outstanding Scholars Program of Guangxi Higher Education Institutions
Graduate Education Innovation Program of Guangxi University of Science and Technology
Subject
Fluid Flow and Transfer Processes,Computer Science Applications,Process Chemistry and Technology,General Engineering,Instrumentation,General Materials Science
Reference27 articles.
1. Jiang, W.Y. (2015). Study on the Soil Characteristics and Filling Performance of Guangxi Red Clay. [Ph.D. Thesis, Guangxi University].
2. Advancement in the techniques for special soils and slopes;Kong;J. Civ. Eng.,2012
3. Mechanical behaviors and water-sensitive properties of intact Guangxi laterite;Zhao;Rock Soil Mech.,2003
4. Discussion on compaction degree index of subgrade filled with laterite;Tan;Rock Soil Mech.,2010
5. Microstructure and geotechnical properties of lime-treated expansive clayey soil;Khattab;Eng. Geol.,2012