Engineering Performance Evaluation of Recycled Red Mud Stabilized Loessial Silt as a Sustainable Subgrade Material

Industrial solid waste red mud discharge has caused serious environmental problems. This study utilized red mud as an additive to loessial silt being used for roadway subgrade material. In this study, unconfined compressive test, direct shear test, electrical resistivity test, and hydraulic conducti...

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Bibliographic Details
Published in:Materials 2022-05, Vol.15 (9), p.3391
Main Authors: Ma, Qianwei, Duan, Wei, Liu, Xiaofeng, Fang, Peiying, Chen, Ruifeng, Wang, Tingyuan, Hao, Zirui
Format: Article
Language:English
Subjects:
Aluminates
Compressive strength
Curing
Electrical resistivity
Engineering
Ettringite
Feasibility studies
Hydrates
Hydraulics
Mechanical properties
Mixtures
Moisture content
Nondestructive testing
Performance evaluation
Red mud
Roads
Shear tests
Silt
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Summary:Industrial solid waste red mud discharge has caused serious environmental problems. This study utilized red mud as an additive to loessial silt being used for roadway subgrade material. In this study, unconfined compressive test, direct shear test, electrical resistivity test, and hydraulic conductivity test were conducted on red mud stabilized loessial silt (RMLS) with different red mud dosage ( ) to investigate effect on mechanical-electrical-hydro properties. Scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses were carried out to reveal the mechanism from micro perspective. The results showed addition of appropriate amount of red mud (30-42%) effectively improved unconfined compressive strength of treated loessial silt but reduced resistivity and hydraulic conductivity. Significant correlation between resistivity and strength performance of RMLS mixture was developed. Microscopic analysis indicates red mud addition will promote generation of hydration products such as calcium silicate hydrations (C-S-H), calcium silicate aluminates hydrations (C-A-S-H), and ettringite (Aft), which will tightly connect surrounding particles of loessial silt and hydrates. Red mud particles adhere to surface of soil particles and fill in pores between them improving a compact and stable structure. This study demonstrated the feasibility of using red mud as a stabilization material for roadway subgrade and proved that resistivity measurement is a nondestructive testing method to evaluate mechanical properties for RMLS mixture.
ISSN:1996-1944
1996-1944
DOI:10.3390/ma15093391