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Title |
An Experimental Study on the Optimum Mix Design and Constructability Evaluation of Mass Concrete used in Super Massive Structures
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DOI |
https://doi.org/10.4334/JKCI.2018.30.4.365 |
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Keywords |
경시변화 90분 ; 저열 시멘트 ; 석회석 미분말 ; 단열온도 상승량 ; 시공성 elapsed time 90 minutes ; low heat cement ; lime stone powder ; adiabatic temperature rising ; constructability |
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Abstract |
The purpose of this study is to investigate experimentally the optimum mix proportions of low heat mass concrete placed in bottom slab (BS) and side wall (SW) as super massive structures of LNG in-ground tanks and to evaluate site constructability and economical evaluation of mass concrete in actual work. Low heat portland cement and lime stone powder (LSP) as cementitious materials are used. Unit cement quantity for adiabatic temperature rising test and unit water quantity, replacement ratio of LSP are tested for the required performances. Test items for mix design factors including water-binder ratio (W/B) and fine aggregates ratio (S/a) are as followings ; (1) Slump, air contents and compressive strength (2) Setting time, bleeding and adiabatic temperature rising (3) Mixing time in plant, constructability and cost evaluation in actual site work. As test results, (1) Unit cement quantity, below 270 kg/m3 and unit water 155 kg/㎥, replacement ratio of LSP 30 % (2) Optimum mix proportions ; W/B 47.1 % and S/a 40 % in case of BS, W/B 43.4 % and S/a 41 % in case of SW (3) Mixing time in batcher plant is 60 seconds and concrete productive capacity is about 95∼105 ㎥/hr. (4) Actual data in site construction are satisfied with the required performance as slump, air contents and compressive strength in the low standard deviations. total concrete quantity compared with design quantity are saved in the rang of 3.16∼3.46 % BS and 1.89∼2.18 % SW.
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