• Explosives and Blasting
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• v.14 no.1
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• pp.22-30
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• 1996

• 레미콘
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• s.78
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• pp.27-37
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• 2004

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.218-219
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• 2015

Precast concrete produced in the industry is advantage that easy to manage, and it save construction period in the field. The specimens according to the type of activator for AAS(Alkali-Activated Slag) mortar cured in an autoclave. The specimens of AAS mortar with sodium was shown the high rate of increase of the compressive strength.

• The Journal of the Korea Contents Association
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• v.16 no.1
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• pp.52-59
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• 2016

For almost of concrete structures by placing in cold weather, it is very important that the selection of curing method at early aged construction stage. The Exothermic curing method with hot wire and rapid hardening cement is used mostly to prevent the initial cracks and the strength decrease. Most of the construction sites, however, have not been applied to the optimal curing method caused by the simple approaches and the empirical judgements. Therefore, this paper has proposed a evaluation algorithm of the exothermic curing method for representing heating temperature, period, position of hot wire by analyzing the transient heat transfer solution. This has been implemented, moreover, using an object oriented programming language to develop structural analysis system taking account risk parameters. This system is composed of input module, database module, database store module, analysis module, and result generation module. Linkage interface between the central database and each of the related module is implemented by the visual c# concept. Graphic user interface and the relational database table are supported for user's convenience.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.1
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• pp.53-60
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• 2024

Compressive strength in concrete has many affecting parameters and varies with exposure conditions. Although the concrete has same mix proportions, its properties are different with exposure conditions, and sea-environment can be classified into three groups such as tidal, atmospheric, and sea submerged region particularly. In this study, compressive strength was evaluated on 7-year-cured concrete and the results from previous equations (KDS, ACI, CEB, and JSCE) were compared with them. Furthermore the strength and carbonation progress were evaluated on concrete cured for 7 years exposed to three different sea environment. Three levels of w/c (water to cement) ratio (0.37, 0.42, and 0.47) and three different exposure conditions (tidal, atmospheric, and submerged) were considered. The results from wet-cured condition are all higher than those from the previously proposed equations, and the results from different sea exposure conditions (tidal, atmospheric, and submerged region) were lower than those from wet-cured condition. A reduction of strength was evaluated with increasing w/c ratio and the minimum strength was evaluated in the sea-submerged conditions. Several experimental constants applicable to the previous equations were obtained from regression analysis since the strength change with w/c ratios were not considered in those equations. Regarding carbonation depth with different exposure conditions, higher carbonation depth clearly was observed with increasing w/c ratios, and evaluated in the order of atmospheric, submerged, and tidal region. Considerable carbonation depth was observed in submerged and tidal region due to sulfate ion and dissloved carbon dioxide as well.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.77-78
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• 2017

In this study, the effect of insulation curing for mass concrete wall according to thickness and curing period was evaluated by thermal analysis.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 1994.03a
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• pp.75-80
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• 1994

지반의 진동은 크게 지진과 같은 자연적인 진동과 발파, 항타(piling) 및 중장비의 가동 등에 따른 건설진동 등 인공진동으로 나눌 수 있는데 이들 지반진동은 지상 구조물의 안전도에 큰 영향을 미친다. 특히 양생(養生)중인 모르타르 및 콘크리트의 강도 및 물리적 성질에 큰 영향을 미치기 때문에 선진국에서는 엄격히 제한하고 있다. (중략)

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.4
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• pp.91-98
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• 2009

Recently, production cost of ready mixed concrete has been increased due to the rising cost of raw materials such as cement and aggregate etc. cause by the upturn of oil price and increase of shipping charge. The delivery cost of ready mixed concrete companies, however, has been decreased owing to their excessive competition in sale. Consequently, ready mixed concrete companies began to manufacture the concrete by mixing ground granulated blast furnace slag(GGBF) and fly-ash in order to lower the production cost. Therefore, the objective of this study was to predict 28 days strength of GGBF slag concrete by early strength(warm and hot water curing method) for the sake of managing with ease the quality of ready mixed concrete. In experimental results, the prediction equation for 28 days compressive strength of GGBF slag concrete could be produced through the linear regression analysis of early strength and 28 days strength. In order to acquire the reliability, all mixture were repeated as 3 times and each mixture order was carried out by random sampling. The prediction equation for 28 days strength of GGBF slag concrete by 1 day compressive strength(accelerated testing) according to warm and hot water curing method won the good reliability.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.1
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• pp.74-80
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• 2009

This study analysis the fundamental properties of temperature-dependence corresponding the change of curing temperature classified by the replacement ratio of BS, and the results are summarized as following. As the properties of flow, plain satisfied with the target slump, and as the replacement ratio of BS increased, the flow increased, but the air content slightly decreased. The time of set delayed as the replacement ratio of BS increased, but the curing temperature $35^{\circ}C$, even with 80% BS replaced concrete, the time of set was faster than $5^{\circ}C$, $20^{\circ}C$ plain, so the temperature-dependence was much greater. The compressive strength was decreased as the replacement ratio of BS increased, especially as the curing temperature lower, the compressive strength was lower comparatively. Also as the age increased, the plain developed more strength, therefore it show the temperature-dependence is much larger.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.275-276
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• 2010

In this study, using experimental results on the autogenous expansion of concrete containing MgO, autogenous expansion model which considers water-binder ratio, amount of MgO and curing temperature was suggested. The results predicted by autogenous expansion model agreed well with experiment results.