Experimental study on compacted steel slag-bentonite mixtures as hydraulic barrier material of cover

被引：1

作者：

Ni J.-Q. ^{[1
,2
]}

Zhan L.-T. ^{[1
,2
]}

Feng S. ^{[1
,2
,3
]}

Kong L.-G. ^{[1
,2
]}

Feng T. ^{[1
,2
]}

机构：

[1] Geotechnical Engineering Department, Zhejiang University, Hangzhou

[2] Key Laboratory of Soft Soils and Geoenvironmental Engineering of Ministry of Education, Zhejiang University, Hangzhou

[3] College of Civil Engineering, Fuzhou University, Fuzhou

来源：

Zhejiang Daxue Xuebao (Gongxue Ban)/Journal of Zhejiang University (Engineering Science) | 2022年 / 56卷 / 12期

关键词：

bentonite; hydraulic barrier; microscopic characteristic; saturated hydraulic conductivity; steel slag;

D O I：

10.3785/j.issn.1008-973X.2022.12.017

中图分类号：

学科分类号：

摘要：

Bentonite was used to modify steel slag to improve impermeability of steel slag in cover liner of solid waste landfills. The saturated hydraulic conductivity of the compacted steel slag-bentonite mixtures ks was investigated through the flexible-wall permeation tests. Then, the pore size distributions, interlayer spacing of montmorillonite and mineral morphology were investigated through mercury intrusion porosimetry tests, X-ray diffraction tests and scanning electron microscopy tests, in order to analyse the impact mechanism of the ks at the microscopic scale. Thereafter, a formula and a preparation method were proposed, which meets the permeability requirement of the hydraulic barrier (ks≤10−9 m/s). Results showed that the ks of the specimen, treated by prehydration of bentonite, was reduced to 1/2 of that of the untreated one. After improving the gradation of steel slag, the content of macropores between the steel slag particles was decreased, reducing the ks of the specimens to 1/5 of that of the specimen with poorly graded steel slag. The ks and pore size distribution of the specimens mixed steel slag with Wyoming were similar to those of sodium-activated calcium bentonite. The high salt content leachate of steel slag results in the increase of the interlayer spacing and the decrease of the bound water of montmorillonite. Subsequently, the osmotic swelling of bentonite is suppressed. Water-washing treatment of steel slag can alleviate the suppression effect and the formation of montmorillonite clusters, and reduce the ks of specimens to 1/10 of that of the untreated one. © 2022 Zhejiang University. All rights reserved.

引用

页码：2478 / 2486

页数：8

共 28 条

[1]

GUO J, BAO Y, WANG M., Steel slag in China: treatment, recycling, and management [J], Waste Management, 78, pp. 318-330, (2018)

[2]

DIENER S, ANDREAS L, HERRMANN T, Et al., Accelerated carbonation of steel slags in a landfill cover construction [J], Waste Management, 30, 1, pp. 132-139, (2010)

[3]

ZHAN Liang-tong, JIAO Wei-guo, KONG Ling-gang, Et al., Feasibility analysis of using loess as soil cover material for landfills in Northwest China and its analysis of design thickness [J], Rock and Soil Mechanics, 35, 12, pp. 3361-3369, (2014)

[4]

(2013)

[5]

HERRMANN I, ANDREAS L, DIENER S., Steel slag used in landfill cover liners: laboratory and field tests [J], Waste Management and Research, 28, 12, pp. 1114-1121, (2010)

[6]

KENNEY T C, VEEN W A V, SWALLOW M A, Et al., Hydraulic conductivity of compacted bentonite-sand mixtures [J], Canadian Geotechnical Journal, 29, 3, pp. 364-374, (1992)

[7]

TONG S, SHACKELFORD C D., Standardized hydraulic conductivity testing of compacted sand-bentonite mixtures [J], Geotechnical Testing Journal, 39, 6, pp. 1015-1029, (2016)

[8]

SCALIA LV J, BENSON C H., Polymer fouling and hydraulic conductivity of mixtures of sodium bentonite and a bentonite-polymer composite, Journal of Geotechnical and Geoenvironmental Engineering, 143, 4, (2017)

[9]

SCALIA J, BENSON C H, BOHNHOFF G L, Et al., Long-term hydraulic conductivity of a bentonite-polymer composite permeated with aggressive inorganic solutions, Journal of Geotechnical and Geoenvironmental Engineering, 140, 3, (2014)

[10]

ZHU Wei, XU Hao-qing, WANG Sheng-wei, Et al., Influence of CaCl<sub>2</sub> solution on the permeability of different clay-based cutoff walls [J], Rock and Soil Mechanics, 37, 5, pp. 1224-1230, (2016)

← 1 2 3 →