scholarly journals Investigations on Engineering Properties of Solidified/Stabilized Pb-Contaminated Soil Based on Alkaline Residue

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Fusheng Zha ◽  
Dongdong Pan ◽  
Long Xu ◽  
Bo Kang ◽  
Chengbin Yang ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Contaminated Soil ◽  
Microstructural Analysis ◽  
Engineering Properties ◽  
Contaminated Sites ◽  
Adsorptive Capacity ◽  
Curing Time ◽  
Test Results ◽  
Hydration Products ◽  
Microstructure Characteristics

Solidification/stabilization (S/S) has been considered as one of the most effective techniques for remediation of the heavy metal-contaminated sites. Among various binders adopted in S/S, alkaline residue (AR) could be considered as a new binder to treat heavy metal-contaminated soil due to its strong adsorptive capacity for heavy metal ions. So in this paper, the strength, leaching, and microstructure characteristics of the solidified/stabilized Pb-contaminated soil by using alkaline residue are systematically investigated. Test results present that the unconfined compressive strength (UCS) of the treated soil will increase, while the leached Pb2+ concentration will decrease, with the increase of the alkaline residue content in the specimen. The UCS increases significantly with the curing time increasing during the initial 28 days, after which the UCS of the specimen becomes stable. The leached Pb2+ concentration decreases significantly at the initial 28 days followed by a stable trend with curing time increasing. The UCS decreases and the leached Pb2+ concentration increases with the increase of the initial Pb2+ concentration in the specimen. The microstructural analysis performed by scanning electron microscope (SEM) showed that the increase of the alkaline residue content and curing time will result in more hydration products and densified microstructure, which could effectively improve the engineering properties of the specimen.

scholarly journals Test on the Stabilization of Oil-Contaminated Wenzhou Clay by Cement

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Chuang Yu ◽  
Raoping Liao ◽  
Chaopeng Zhu ◽  
Xiaoqing Cai ◽  
Jianjun Ma
Keyword(s):  
Contaminated Soil ◽  
Contaminated Soils ◽  
Unconfined Compressive Strength ◽  
Liquid Limit ◽  
Soil Samples ◽  
Experimental Results ◽  
Engineering Properties ◽  
Contaminated Sites ◽  
Coastal Cities ◽  
Scanning Electron

Oil-contaminated soils have been paid much attention due to the reclamation of industrial lands in coastal cities of China. As known, oil-contaminated soils are inapplicable for construction due to their weak engineering properties, thus leading to the requirement of remediation and reclamation for oil-contaminated sites. This study presents an experimental investigation on the stabilization of contaminated soils with Portland cement. Investigations including the Atterberg limits, unconfined compressive strength, direct shear strength, and microstructure of cement-stabilized soils have been carried out, verifying the suitability of applying cement to improve engineering properties. Experimental results show that the geotechnical properties of contaminated soil are very poor. With the application of cement, the liquid limit and plasticity index of contaminated soil samples decrease dramatically, and the strength of treated soils has been improved. Experimental results from scanning electron microscope (SEM) indicate that cement-stabilized oil-contaminated soil is featured with a stable supporting microstructure, owing to the cementation between soil particles. This also confirms the applicability of cement to be served as an additive to treat oil-contaminated soils.

scholarly journals Application of nanoscale zero-valent iron in hexavalent chromium-contaminated soil: A review

2020 ◽  
Vol 9 (1) ◽  
pp. 736-750
Author(s):  
Xilu Chen ◽  
Xiaomin Li ◽  
Dandan Xu ◽  
Weichun Yang ◽  
Shaoyuan Bai
Keyword(s):  
Heavy Metal ◽  
Hexavalent Chromium ◽  
Contaminated Soil ◽  
Zero Valent Iron ◽  
Toxic Heavy Metal ◽  
Factors Affecting ◽  
Metal Pollutants ◽  
Nanoscale Zero Valent Iron ◽  
Low Toxicity ◽  
Heavy Metal Pollutants

AbstractChromium (Cr) is a common toxic heavy metal that is widely used in all kinds of industries, causing a series of environmental problems. Nanoscale zero- valent iron (nZVI) is considered to be an ideal remediation material for contaminated soil, especially for heavy metal pollutants. As a material of low toxicity and good activity, nZVI has been widely applied in the in situ remediation of soil hexavalent chromium (Cr(vi)) with mobility and toxicity in recent years. In this paper, some current technologies for the preparation of nZVI are summarized and the remediation mechanism of Cr(vi)-contaminated soil is proposed. Five classified modified nZVI materials are introduced and their remediation processes in Cr(vi)-contaminated soil are summarized. Key factors affecting the remediation of Cr(vi)-contaminated soil by nZVI are studied. Interaction mechanisms between nZVI-based materials and Cr(vi) are explored. This study provides a comprehensive review of the nZVI materials for the remediation of Cr(vi)-contaminated soil, which is conducive to reducing soil pollution.

scholarly journals Experimental Study on Improvement of Marine Soft Soil with Alkali Residue

2018 ◽  
Vol 53 ◽  
pp. 04021
Author(s):  
SHAO Yong ◽  
LIU Xiao-li ◽  
ZHU Jin-jun
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Void Ratio ◽  
Soft Soil ◽  
Compressive Modulus ◽  
Engineering Properties ◽  
Test Results ◽  
Use Of Resources ◽  
One Year

Industrial alkali slag is the discharge waste in the process of alkali production. About one million tons of alkali slag is discharged in China in one year. It is a burden on the environment, whether it is directly stacked or discharged into the sea. If we can realize the use of resources, it is a multi-pronged move, so alkali slag is used to improve solidified marine soft soil in this paper. The test results show that the alkali residue can effectively improve the engineering properties of marine soft soil. Among them, the unconfined compressive strength and compressive modulus are increased by about 10 times, and the void ratio and plasticity index can all reach the level of general clay. It shows that alkali slag has the potential to improve marine soft soil and can be popularized in engineering.

Experimental Research on the Engineering Properties of Foam-Improved Red Clay Soil

2011 ◽  
Vol 261-263 ◽  
pp. 1831-1835
Author(s):  
Guo Gang Qiao ◽  
Da Jun Yuan ◽  
Bo Liu
Keyword(s):  
Experimental Research ◽  
Clay Soil ◽  
Soil Improvement ◽  
Engineering Properties ◽  
Screw Conveyor ◽  
Test Results ◽  
X Ray Diffraction ◽  
Shield Tunneling ◽  
Red Clay ◽  
Improvement Measures

Red clay soil is widely distributed in south China, the microstructure of red clay soil was studied applying scanning electron microscopy (SEM), and the X-ray diffraction analysis (XRD) test found that a large number of swelling inducing minerals, for example, montmorillonite, illite-montmorillonite or chlorite-smectite were contained in the red clay soil. Shield tunneling in this kind of stratum is prone to arising “cake” and “arch” phenomena and it prone to lead screw conveyor device unsmooth dumping, so soil improvement measures must be taken. Foam as the most advanced soil conditioner has been widely used in shield construction. Using self-developed foam agent, experimental research on foam conditioning red clay soil was carried out, test results show that foam can not only significantly reduce the soil shear strength, but also can greatly enhance the soil's compressibility and fluidity, which is significant for the smooth dumping and excavation face stability maintenance.

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