Mechanism of stabilized/solidified heavy metal contaminated soils with cement-fly ash based on electrical resistivity measurements

• Published in: Measurement : journal of the International Measurement Confederation Vol. 141; pp. 85 - 94
• Main Authors: Liu, Jingjing, Zha, Fusheng, Xu, Long, Kang, Bo, Tan, Xiaohui, Deng, Yongfeng, Yang, Chengbin
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01.07.2019; Elsevier Science Ltd
• Subjects: Anisotropy; Cementation; Compressive strength; Curing; Electric resistance; Electrical resistivity; Fly ash; Heavy metal contaminated soil; Heavy metals; Hydrates; Microstructure; Shape factor; Soil contamination; Soil investigations; Soil porosity; Soil stabilization; Solidification/stabilization mechanism; Unconfined compressive strength; X-ray diffraction; Solidification/stabilization mechanism; Microstructure; Electrical resistivity; Unconfined compressive strength; Heavy metal contaminated soil
• ISSN: 0263-2241; 1873-412X
• DOI: 10.1016/j.measurement.2019.03.070

•Soil electrical resistivity decreased with the increase of heavy metal concentration.•A linear correlation between qu/qu0 and ρ/ρ0 was proposed to predict the UCS.•Increasing the Pb2+ concentration retarded cement and fly ash hydration.•Soil microstructure can be understood by electrical resistivity. The present work aimed at investigating the S/S micro-mechanism for treating heavy metal contaminated soils by an electrical resistivity method. Results indicated that the electrical resistivity (ρ) increased as a function of curing time and decreased as the heavy metal concentration increased. Unconfined compressive strength (qu) has an exponential correlation to the electrical resistivity. The variations of the electrical resistivity parameters (such as pore water electrical resistivity (ρω), formation factor (F), shape factor (f) and anisotropy coefficient (A)) indicated that increasing curing time led to a porosity reduction and an increase in the cementation degree, which resulted in a denser structure and a greater strength of the specimens. Finally, the X-ray diffraction (XRD) and scanning electron microscope (SEM) results confirmed that hydrates increasingly filled the soil pores as the curing time increased, while increasing the heavy metal concentration hindered the development of hydrated reactions.