A Study on the Optimum Mix Proportion of the Mass Concrete Designed as Massive and Deep Structure

Title & Authors
A Study on the Optimum Mix Proportion of the Mass Concrete Designed as Massive and Deep Structure
Kwon Yeong-Ho; Lee Hwa-Jin;

Abstract
This study describes data from determination of the optimum mix proportion and site application of the mass concrete placed in bottom slab and side wall having a large depth and section as main structures of LNG in-ground tank. This concrete requires low heat hydration, excellent balance between workability and consistency because concreting work of LNG in-ground tank is usually classified by under-pumping, adaptation of longer vertical and horizontal pumping line than ordinary pumping condition. For this purpose, low heat Portland cement and lime stone powder as cementitious materials are selected and design factors including unit cement and water content, water-binder ratio, fine aggregate ratio and adiabatic temperature rising are tested in the laboratory and batch plant. As experimental results, the optimum unit cement and water content are selected under $\small{270kg/m^3}$ and $\small{l55{\~}l60 kg/m^3}$ separately to control adiabatic temperature rising below $\small{30^{\circ}C}$ and to improve properties of the fresh and hardened concrete. Also, considering test results of the confined water ratio($\small{\beta}$p) and deformable coefficient(Ep), $\small{30\%}$ of lime stone powder by cement weight is selected as the optimum replacement ratio. After mix proportions of 5cases are tested and compared the adiabatic temperature rising($\small{Q^{\infty}}$, r), tensile and compressive strength, modulus of elasticity, teases satisfied with the required performances are chosen as the optimum mix design proportions of the side wall and bottom slab concrete. $\small{Q^{\infty}}$ and r are proved smaller than those of another project. Before application in the site, properties of the fresh concrete and actual mixing time by its ampere load are checked in the batch plant. Based on the results of this study, the optimum mix proportions of the massive concrete are applied successfully to the bottom slab and side wall in LNG in-ground tank.
Keywords
high belite cement;lime stone powder;adiabatic temperature;confined water ratio;mixing time;
Language
English
Cited by
1.
지하식 LNG 저장탱크 구조물의 온도균열 제어에 관한 연구,권영호;

한국콘크리트학회논문집, 2011. vol.23. 6, pp.773-780
2.
지하식 LNG 저장탱크의 지붕 콘크리트의 요구성능에 관한 실험적 연구,권영호;

한국콘크리트학회논문집, 2013. vol.25. 3, pp.339-345
1.
Evaluation on the durability of low heat concrete using ternary blended cement, Computers and Concrete, 2016, 18, 4, 527
2.
An Experimental Study on the Required Performances of Roof Concrete Placed in the In-ground LNG Storage Tank, Journal of the Korea Concrete Institute, 2013, 25, 3, 339
3.
A Study on the Thermal Crack Control of the In-Ground LNG Storage Tank as Super Massive Structures, Journal of the Korea Concrete Institute, 2011, 23, 6, 773
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