Sealing performance of compacted block joints backfilled with bentonite paste or a particle-powder mixture

doi:10.1016/j.sandf.2021.01.005

IR > 土木工程学院

	Sealing performance of compacted block joints backfilled with bentonite paste or a particle-powder mixture
	Wang, Ying1,2 ; Zhang, Huyuan 1,3; Tan, Yu 1; Zhu, Jianghong 1
	2021-04
发表期刊	Soils and Foundations
ISSN	0038-0806
卷号	61 期号:2 页码:496-505
摘要	Technology gaps are inevitable parts of the buffer barriers in the high-level radioactive waste (HLW) repositories. The mechanical properties, permeability and water-solute-radionuclide migration of buffer barrier are different when considering the gaps. The present study was designed to investigate the sealing effect of joint between the compacted blocks with two types of sealing materials, a bentonite paste (P) and a bentonite particles and powder mixture (P/P) both from the macro- and micro-aspects. A series of laboratory test was conducted to study the hydro-mechanical properties of bentonite blocks after backfilling the joint between blocks. Both the intake and outflow water volume, and the pressure on radial and axial direction were monitored during the hydration. Following the permeability test, the joint's sealing was evaluated by a final dry density, water content distribution and microstructure evolution. The results showed that the axial and radial pressure of blocks backfilled with bentonite P and bentonite P/P mixture were higher than that of blocks with a blank joint. Pressure preferentially increased in the low-stress areas (the joint areas), contributing to sealing of the joint. The hydraulic conductivities for backfilled bentonite blocks were almost on the same order of magnitude as to intact bentonite blocks, revealing a clear sealed hydraulic behavior. The final dry density decreased in the block area and increased in the joint area after hydration, forming a transition zone with a certain width. A smaller difference was found between the block and joint area in the backfilled block. The mercury intrusion porosimetry (MIP) test and scanning electron microscope (SEM) test showed that backfill decreased the numbers of inter-aggregates pores ranged between 8 and 15 μm compared with that in the blank joint. The comprehensive data showed that a joint backfilled with a bentonite P/P mixture has a higher swelling capacity, lower permeability, and denser structure compared with joint backfilled with bentonite P. The results suggested that joint backfilling improved the integrity of the blocks and enhanced the swelling property and impermeability compared with that of the non-backfilled blocks. Both bentonite P and bentonite P/P has satisfactory sealing performance of compacted block joints, with better effect of the later. © 2021
关键词	Bentonite Hydration Mechanical permeability Mixtures Powders Scanning electron microscopy Swelling Content distribution High level radioactive waste repositories Mercury intrusion porosimetry Micro-structure evolutions Radionuclide migration Sealing performance Swelling capacities Swelling properties
DOI	10.1016/j.sandf.2021.01.005
收录类别	EI ; SCIE
语种	英语
WOS研究方向	Engineering ; Geology
WOS类目	Engineering, Geological ; Geosciences, Multidisciplinary
WOS记录号	WOS:000634817700017
出版者	Elsevier B.V.
EI入藏号	20210809972252
EI主题词	Seals
EI分类号	482.2 Minerals ; 619.1.1 Pipe Accessories ; 951 Materials Science
来源库	WOS
引用统计	被引频次：10[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	https://ir.lut.edu.cn/handle/2XXMBERH/147737
专题	土木工程学院
通讯作者	Zhang, Huyuan
作者单位	1.Lanzhou Univ, Sch Civil Engn & Mech, Lanzhou 730000, Gansu, Peoples R China; 2.Lanzhou Univ Technol, Sch Civil Engn, Lanzhou 730050, Gansu, Peoples R China; 3.Minist Educ China, Key Lab Mech Disaster & Environm Western China, Beijing, Peoples R China
第一作者单位	兰州理工大学
推荐引用方式 GB/T 7714	Wang, Ying,Zhang, Huyuan,Tan, Yu,et al. Sealing performance of compacted block joints backfilled with bentonite paste or a particle-powder mixture[J]. Soils and Foundations,2021,61(2):496-505.
APA	Wang, Ying,Zhang, Huyuan,Tan, Yu,&Zhu, Jianghong.(2021).Sealing performance of compacted block joints backfilled with bentonite paste or a particle-powder mixture.Soils and Foundations,61(2),496-505.
MLA	Wang, Ying,et al."Sealing performance of compacted block joints backfilled with bentonite paste or a particle-powder mixture".Soils and Foundations 61.2(2021):496-505.