JZUS - Journal of Zhejiang University SCIENCE

Journal of Zhejiang University SCIENCE A 2019 Vol.20 No.12 P.948-960

http://doi.org/10.1631/jzus.A1900300

Influence of wet-dry cycles on vertical cutoff walls made of reactive magnesia-slag-bentonite-soil mixtures

Author(s): Hao-liang Wu, Fei Jin, Yan-jun Du
Affiliation(s): Jiangsu Key Laboratory of Urban Underground Engineering & Environmental Safety, Institute of Geotechnical Engineering, Southeast University, Nanjing 210096, China; more
Corresponding email(s): duyanjun@seu.edu.cn
Key Words: Cutoff wall, Reactive MgO-activated ground granulated blast furnace slag (GGBS), Durability, Wet-dry cycles, Carbonation

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Abstract: The strength and hydraulic conductivity of vertical cutoff walls consisting of reactive magnesia-activated ground granulated blast furnace slag (GGBS), bentonite, and soil (MSB) have been investigated in previous studies. However, there has been little comprehensive study of the influence of wet-dry cycles on the mechanical and microstructural properties of MSB backfills. In this paper, the durability of MSB backfills when exposed to wet-dry cycles is investigated. The variations in mass change, dry density, pH value, pore size distribution, and mineralogy are discussed. The results show that the mass change of ordinary Portland cement (OPC)-based and MSB backfills increases with respect to wet-dry cycles. The MSB backfills exhibit up to 8.2% higher mass change than OPC-based ones after 10 wet-dry cycles. The dry density, pH value, and unconfined compressive strength of MSB backfill decrease with the increasing number of wet-dry cycles. Increasing the GGBS-MgO content from 5% to 10% in MSB backfills results in 2.1–2.3 times higher strength, corresponding to a reduction of 2%–12% in cumulative pore volume; while increasing the bentonite content slightly reduces the strength of MSB mixtures, corresponding to an increase of cumulative pore volume by 4.6%–7.9%. The hydrotalcite-like phases and calcium silicate hydrate (C-S-H) are the primary hydration products in MSB backfills. Moreover, the continuous wet-dry cycles result in the precipitation of calcite and nesquehonite.

Cut-off wall is a useful technology to control the risks of contaminated source in soil. The idea in this work that using cement-bentonite-soil as backfill materials is novel and of practical significance. To replace OPC with more sustainable MgO-GGBS is also a novel approach. Adequate experiments were conducted with very nice and clear figures to support the discussions. More discussions are needed to elaborate the interesting findings and their implications in this work.

干湿循环作用下氧化镁激发矿渣-膨润土竖向隔离墙耐久特性研究

目的:1. 研究干湿循环作用下氧化镁激发矿渣-膨润土(MSB)竖向隔离墙的耐久特性. 2. 探讨干湿循环过程中循环级数对隔离墙的质量变化、干密度、pH值、无侧限抗压强度、孔隙结构和微观产物等的影响,并探究MSB的服役性能.
创新点:1. 通过干湿循环作用,揭示新型MSB隔离墙与传统水泥基(OPC)隔离墙的耐久性差异; 2. 通过微观分析,成功测定新型MSB隔离墙干湿循环后形成的水化产物.
方法:1. 通过宏观实验分析,在干湿循环作用下比较MSB隔离墙和OPC隔离墙的质量、干密度、pH值和无侧限抗压强度等参数的变化情况(图2和4~6); 2. 通过微观分析,研究MSB隔离墙中氧化镁激发高炉矿渣(GGBS-MgO)和膨润土的掺量对空隙结构的影响(图8),并探讨干湿循环作用如何影响碳酸钙和碳酸镁等水化产物的形成(图9).
结论:1. MSB隔离墙的质量损失比OPC隔离墙高1.1%~2.1%; 2. MSB和OPC隔离墙的干密度和pH值均随干湿循环级数的增长而减小; 3. MSB和OPC隔离墙的无侧限抗压强度随干湿循环级数的增长而降低; 4. 增加GGBS-MgO的掺量可减少2%~12%的累计进汞量,而增加膨润土的掺量会增加4.6%~7.9%的进汞量; 5. 干湿循环可加速碳酸钙和碳酸镁等水化产物的形成.
关键词：竖向隔离墙; 氧化镁激发矿渣; 耐久特性; 干湿循环; 碳化

Reference

[1]Arulrajah A, Kua TA, Suksiripattanapong C, et al., 2017a. Compressive strength and microstructural properties of spent coffee grounds-bagasse ash based geopolymers with slag supplements. Journal of Cleaner Production, 162:1491-1501.

[2]Arulrajah A, Kua TA, Horpibulsuk S, et al., 2017b. Recycled glass as a supplementary filler material in spent coffee grounds geopolymers. Construction and Building Materials, 151:18-27.

[3]ASTM, 2008. Standard Test Method for Unconfined Compressive Strength Index of Chemical-grouted Soils, ASTM D4219-08. National Standards of USA.

[4]ASTM, 2010a. Standard Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass, ASTM D2216-2010. National Standards of USA.

[5]ASTM, 2010b. Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils, ASTM D4318. National Standards of USA.

[6]ASTM, 2010c. Standard Test Method for Determination of Pore Volume and Pore Volume Distribution of Soil and Rock by Mercury Intrusion Porosimetry, ASTM D4404-10. National Standards of USA.

[7]ASTM, 2010d. Standard Test Method for Measuring the Exchange Complex and Cation Exchange Capacity of Inorganic Fine-grained Soils, ASTM D7503. National Standards of USA.

[8]ASTM, 2014. Standard Test Methods for Specific Gravity of Soil Solids by Water Pycnometer, ASTM D854-14. National Standards of USA.

[9]ASTM, 2017. Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System), ASTM D2487-17. National Standards of USA.

[10]ASTM, 2018a. Standard Test Methods for pH of Soils, ASTM D4972-18. National Standards of USA.

[11]ASTM, 2018b. Standard Test Methods for Laboratory Determination of Density (Unit Weight) of Soil Specimens, ASTM D7263-09(2018)e2. National Standards of USA.

[12]Benhelal E, Zahedi G, Shamsaei E, et al., 2013. Global strategies and potentials to curb CO₂ emissions in cement industry. Journal of Cleaner Production, 51:142-161.

[13]Cerato AB, Lutenegger AJ, 2002. Determination of surface area of fine-grained soils by the ethylene glycol monoethyl ether (EGME) method. Geotechnical Testing Journal, 25(3):315-321.

[14]Collins F, Sanjayan JG, 2000. Effect of pore size distribution on drying shrinking of alkali-activated slag concrete. Cement and Concrete Research, 30(9):1401-1406.

[15]Du YJ, Jiang NJ, Liu SY, et al., 2014. Engineering properties and microstructural characteristics of cement-stabilized zinc-contaminated kaolin. Canadian Geotechnical Journal, 51(3):289-302.

[16]Du YJ, Fan RD, Liu SY, et al., 2015. Workability, compressibility and hydraulic conductivity of zeolite-amended clayey soil/calcium-bentonite backfills for slurry-trench cutoff walls. Engineering Geology, 195:258-268.

[17]Du YJ, Bo YL, Jin F, et al., 2016. Durability of reactive magnesia-activated slag-stabilized low plasticity clay subjected to drying–wetting cycle. European Journal of Environmental and Civil Engineering, 20(2):215-230.

[18]Du YJ, Wu J, Bo YL, et al., 2019. Effects of acid rain on physical, mechanical and chemical properties of GGBS-MgO-solidified/stabilized Pb-contaminated clayey soil. Acta Geotechnica, in press.

[19]Evans JC, 1991. Geotechnics of hazardous waste control systems. In: Fang HY (Ed.), Foundation Engineering Handbook, 2nd Edition. Springer, Boston, USA, p.750-777.

[20]Horpibulsuk S, Rachan R, Chinkulkijniwat A, et al., 2010. Analysis of strength development in cement-stabilized silty clay from microstructural considerations. Construction and Building Materials, 24(10):2011-2021.

[21]ICE (Institution of Civil Engineers), 1999. Specification for the Construction of Slurry Trench Cut-off Walls: As Barriers to Pollution Migration. Thomas Telford, London, UK.

[22]Jefferis S, 2012. Cement-bentonite slurry systems. In: Johnsen LF, Bruce DA, Byle MJ (Eds.), Grouting and Deep Mixing. ASCE, Reston, USA, p.1-24.

[23]Jin F, Al-Tabbaa A, 2014a. Characterisation of different commercial reactive magnesia. Advances in Cement Research, 26(2):101-113.

[24]Jin F, Al-Tabbaa A, 2014b. Evaluation of novel reactive MgO activated slag binder for the immobilisation of lead and zinc. Chemosphere, 117:285-294.

[25]Jin F, Gu K, Al-Tabbaa A, 2014. Strength and drying shrinkage of reactive MgO modified alkali-activated slag paste. Construction and Building Materials, 51:395-404.

[26]Jin F, Gu K, Al-Tabbaa A, 2015. Strength and hydration properties of reactive MgO-activated ground granulated blastfurnace slag paste. Cement and Concrete Composites, 57:8-16.

[27]Joshi K, Soga K, Ng MYA, et al., 2008. Durability study of eleven years old cement-bentonite cut-off wall material. In: Khire MV, Alshawabkeh AN, Reddy KR (Eds.), GeoCongress 2008: Geotechnics of Waste Management and Remediation. ASCE, New Orleans, USA, p.620-627.

[28]Joshi K, Kechavarzi C, Sutherland K, et al., 2010. Laboratory and in situ tests for long-term hydraulic conductivity of a cement-bentonite cutoff wall. Journal of Geotechnical and Geoenvironmental Engineering, 136(4):562-572.

[29]Kamon M, Nontananandh S, Katsumi T, 1993. Utilization of stainless-steel slag by cement hardening. Soils and Foundations, 33(3):118-129.

[30]Lam C, Jefferis SA, 2017. Polymer Support Fluids in Civil Engineering. ICE Publishing, London, UK.

[31]Li YC, Tong X, Chen Y, et al., 2018. Non-monotonic piezocone dissipation curves of backfills in a soil-bentonite slurry trench cutoff wall. Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 19(4):277-288.

[32]Malusis MA, Yeom S, Evans JC, 2011. Hydraulic conductivity of model soil–bentonite backfills subjected to wet–dry cycling. Canadian Geotechnical Journal, 48(8):1198-1211.

[33]Nahlawi H, Kodikara JK, 2006. Laboratory experiments on desiccation cracking of thin soil layers. Geotechnical and Geological Engineering, 24(6):1641-1664.

[34]National Research Council, 2007. Assessment of the Performance of Engineered Waste Containment Barriers. The National Academies Press, Washington, USA.

[35]Opdyke SM, Evans JC, 2005. Slag-cement-bentonite slurry walls. Journal of Geotechnical and Geoenvironmental Engineering, 131(6):673-681.

[36]Ross RR, Beljin MS, 1998. Evaluation of containment systems using hydraulic head data. Journal of Environmental Engineering, 124(6):575-578.

[37]Rowe RK, Bostwick LE, Take WA, 2011. Effect of GCL properties on shrinkage when subjected to wet-dry cycles. Journal of Geotechnical and Geoenvironmental Engineering, 137(11):1019-1027.

[38]Ruan SQ, Qiu JS, Weng YW, et al., 2019. The use of microbial induced carbonate precipitation in healing cracks within reactive magnesia cement-based blends. Cement and Concrete Research, 115:176-188.

[39]Ruffing DG, Evans JC, 2014. Case study: construction and in situ hydraulic conductivity evaluation of a deep soil-cement-bentonite cutoff wall. Proceedings of Geo-Congress 2014, p.1836-1848.

[40]Ryan CR, Day SR, 2002. Soil-cement-bentonite slurry walls. In: O’Neill MW, Townsend FC (Eds.), Deep Foundations 2002: an International Perspective on Theory, Design, Construction, and Performance. Geotechnical Special Publication, New York, USA, p.713-727.

[41]Shand MA, 2006. The Chemistry and Technology of Magnesia. John Wiley & Sons, Hoboken, USA.

[42]Shen SL, Han J, Du YJ, 2008. Deep mixing induced property changes in surrounding sensitive marine clays. Journal of Geotechnical and Geoenvironmental Engineering, 134(6):845-854.

[43]Shen ZT, Hou DY, Xu WD, et al., 2018. Assessing long-term stability of cadmium and lead in a soil washing residue amended with MgO-based binders using quantitative accelerated ageing. Science of the Total Environment, 643:1571-1578.

[44]Shen ZT, Pan SZ, Hou DY, et al., 2019. Temporal effect of MgO reactivity on the stabilization of lead contaminated soil. Environment International, 131:104990.

[45]Soga K, Joshi K, Evans JC, 2013. Cement bentonite cutoff walls for polluted sites. Proceedings of Coupled Phenomena in Environmental Geotechnics, p.149-165.

[46]Tang CS, Shi B, Liu C, et al., 2011. Experimental characterization of shrinkage and desiccation cracking in thin clay layer. Applied Clay Science, 52(1-2):69-77.

[47]Wang F, Jin F, Shen ZT, et al., 2016. Three-year performance of in-situ mass stabilised contaminated site soils using MgO-bearing binders. Journal of Hazardous Materials, 318:302-307.

[48]Wu HL, Du YJ, Wang F, et al., 2016. Workability and strength characteristics of alkali-activated slag-bentonite backfills for vertical slurry cutoff wall. Journal of Southeast University (Natural Science Edition), 46(S1):25-30 (in Chinese).

[49]Wu HL, Jin F, Bo YL, et al., 2018a. Leaching and microstructural properties of lead contaminated kaolin stabilized by GGBS-MgO in semi-dynamic leaching tests. Construction and Building Materials, 172:626-634.

[50]Wu HL, Zhang D, Ellis BR, et al., 2018b. Development of reactive MgO-based engineered cementitious composite (ECC) through accelerated carbonation curing. Construction and Building Materials, 191:23-31.

[51]Wu HL, Jin F, Ni J, et al., 2019. Engineering properties of vertical cutoff walls consisting of reactive magnesia-activated slag and bentonite: workability, strength, and hydraulic conductivity. Journal of Materials in Civil Engineering, 31(11):04019263.

[52]Xia WY, Du YJ, Li FS, et al., 2019a. Field evaluation of a new hydroxyapatite based binder for ex-situ solidification/ stabilization of a heavy metal contaminated site soil around a Pb-Zn smelter. Construction and Building Materials, 210:278-288.

[53]Xia WY, Du YJ, Li FS, et al., 2019b. In-situ solidification/ stabilization of heavy metals contaminated site soil using a dry jet mixing method and new hydroxyapatite based binder. Journal of Hazardous Materials, 369:353-361.

[54]Yang YL, Reddy KR, Du YJ, et al., 2018a. Short-term hydraulic conductivity and consolidation properties of soil-bentonite backfills exposed to CCR-impacted groundwater. Journal of Geotechnical and Geoenvironmental Engineering, 144(6):04018025.

[55]Yang YL, Reddy KR, Du YJ, et al., 2018b. Sodium hexametaphosphate (SHMP)-amended calcium bentonite for slurry trench cutoff walls: workability and microstructure characteristics. Canadian Geotechnical Journal, 55(4):528-537.

[56]Yang YL, Reddy KR, Du YJ, et al., 2019. Retention of Pb and Cr(VI) onto slurry trench vertical cutoff wall backfill containing phosphate dispersant amended Ca-bentonite. Applied Clay Science, 168:355-365.

[57]Yi YL, Liska M, Al-Tabbaa A, 2014. Properties of two model soils stabilized with different blends and contents of GGBS, MgO, lime, and PC. Journal of Materials in Civil Engineering, 26(2):267-274.

[58]Zhang WB, Rao WB, Li L, et al., 2019. Compressibility and hydraulic conductivity of sand-attapulgite cut-off wall backfills. Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 20(3):218-228.

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干湿循环作用下氧化镁激发矿渣-膨润土竖向隔离墙耐久特性研究

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