Characteristics of thermally-enhanced bentonite grouts for geothermal heat exchanger in South Korea  

作　　者：Chulho LEE Kangja LEE Hangseok CHOI Hyo-Pum CHOI 

机构地区：[1]School of Civil,Environmental and Architectural Engineering,Korea University,Anam-dong,Seongbuk-gu,Seoul 136-701,Republic of Korea [2]Research & Development Institute,KUNHWA Co.,LTD.,Yeoksam-dong,Gangnam-gu,Seoul 135-513,Republic of Korea

出　　处：《Science China(Technological Sciences)》2010年第1期123-128,共6页中国科学（技术科学英文版）

基　　金：supported by a Korea University Grant and by Construction Technology Innovation Program (Grant No.06CTIPD04) from KICTEP,the Ministry of Land,Transport and Maritime Affairs of Korea

摘　　要：The thermal conductivity and viscosity of bentonite grouts have been evaluated and compared each other to determine the suitability of these materials for backfilling vertical boreholes of ground heat exchangers.Seven bentonite grouts from different product sources were considered in this paper.Two additives,silica sand and graphite were added in bentonite grouts to enhance thermal performance.The bentonite grouts indicate that both the thermal conductivity and the viscosity increase with the content of silica sand and graphite.Therefore,it is recommended to select cautiously the amount of silica sand and graphite considering not only thermal conductivity but also viscosity for the optimum condition of backfilling.Finally,the effect of salinity in the pore water on the change of swelling potential of the bentonite-based grouts has been quantitatively evaluated to show the feasibility of bentonite grouts in the coastal area.The thermal conductivity and viscosity of bentonite grouts have been evaluated and compared each other to determine the suitability of these materials for backfilling vertical boreholes of ground heat exchangers.Seven bentonite grouts from different product sources were considered in this paper.Two additives,silica sand and graphite were added in bentonite grouts to enhance thermal performance.The bentonite grouts indicate that both the thermal conductivity and the viscosity increase with the content of silica sand and graphite.Therefore,it is recommended to select cautiously the amount of silica sand and graphite considering not only thermal conductivity but also viscosity for the optimum condition of backfilling.Finally,the effect of salinity in the pore water on the change of swelling potential of the bentonite-based grouts has been quantitatively evaluated to show the feasibility of bentonite grouts in the coastal area.

关 键 词：ground heat EXCHANGER BENTONITE GROUT thermal conductivity viscosity silica SAND and GRAPHITE 

分 类 号：TK523[动力工程及工程热物理—热能工程]