• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.159-160
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• 2009

본 연구에서는 고강도 콘크리트의 교량 구조물 적용의 일환으로 현재 27MPa로 적용되고 있는 교각구조물에, 단면축소와 내구성 향상을 목적으로 40MPa 고강도 콘크리트를 시험적용하였다. 고강도 콘크리트 적용에 따라 교각의 단면을 재설계한 결과, 기둥단면은 0.6m, 코핑높이는 0.4m 감소되었고, 고강도 콘크리트를 시공한 결과, 철저한 품질관리와 양생관리를 통해 당초 우려되었던 수화열에 의한 온도균열이 발생하지 않는 고품질의 콘크리트 시공이 가능하였다.

• 콘크리트학회논문집
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• 제12권6호
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• pp.23-34
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• 2000

This paper reports the effects of curing temperature and aging on the strength and the modulus of elasticity. In oder to determine the strength and the modulus of elasticity with curing temperature and aging, experimental and analytical methods are adopted. The tests of 480 cylinders are carried out for type I, V and V with 15 percent replacement of fly ash cement concretes, which are cured at isothermal conditions of 10, 23, 35 and 5$0^{\circ}C$. and the concrete cylinders are tested at the ages of 1, 3, 7 and 28 days. According to the experimental results, the concrete subjected to high temperature at early ages attaines higher early-age compressive and splitting tensile strength but eventually attaines lower later-age compressive and splitting tensile strength. Even if modulus of elasticity has the same tendency, the variation of modulus of elasticity with curing temperature is smaller than that of compressive strength. Based on these experimental results, the relationships among compressive strength, modulus of elasticity and splitting tensile strength are proposed considering the effects of curing temperature, aging and cement type.

• 한국세라믹학회지
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• 제48권6호
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• pp.610-616
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• 2011

The effect of curing temperature on basic geopolymeric reactivity and hardening behaviour of blast furnace slag were investigated using the mixture of pulverized slag and several alkaline solutions of relatively high concentration. For the pastes prepared at several different temperatures between 20$^{\circ}C$ and 90$^{\circ}C$, setting time and heat of reaction were examined while mineralogical and morphological examinations were performed for the hardened paste after curing period at same temperature. The geopolymeric reaction of slag was revealed to be accelerated strongly according to the curing temperature regardless of the sort and concentration of the alkaline solution. The increase of concentration of the alkaline solution within 9M and the existence of silicic ion in the solution also promoted the reaction severely. The mineral component and their ratio of the hardened paste were revealed to be influenced by the chemical species and silicic ion contained in alkaline solution rather than by the curing temperature. The higher temperature and longer period of curing stage were effective for the sustained formation of geopolymer and succeed improvement of density and uniformity of morphology of the final hardened body.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2005년도 추계 학술논문 발표대회
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• pp.75-78
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• 2005

This raper investigates the effect of curing temperature on strength development of concrete incorporating cement kiln dust(CKD) and blast furnace slag (BS) quantitatively. Estimation of compressive strength of concrete was conducted using equivalent age equation and rate constant model. An increasing curing temperature results in an increase in strength at early age, but with the elapse of age, strength development at high curing temperature decreases compared with that at low curing temperature. Especially, the use of 35 has a remarkable strength development at early age and even at later age, high strength is maintained due to accelerated pozzolanic activity resulting from high temperature. Whereas, at low curing temperature, the use of BS leads to a decrease in compressive strength. Accordingly, much attention should be paid to prevent strength loss at low temperature. Based on the strength development estimation using equivalent age equation, good agreements between measured strength and calculated strength are obtained.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문발표회
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• pp.19-22
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• 2003

The purpose of this study is to analyze the curing effect of planar surface heater for concreting in cold weather. Some experiments were conducted to evaluate the temperature history of concrete structures cured with heating sheets. Results are as follows ; (1) The temperature of concrete showed continuously rising trend with the heating by planar surface heater under the cold environmental condition of 3~-12$^{\circ}C$. And after about 24 hours the maximum temperature of concrete was reached at 25~3$0^{\circ}C$. (2) The temperature of slab concrete heated by planar surface heater of 130W/$m^2$ was at least $25^{\circ}C$ higher than that of an exterior air, and the curing performance was much more effective than heating by hot wind machine. (3) Through the curing by planar surface heater for 48 hours, the concrete maturity of about 1.5 times to heating by hot wind machine was acquired.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.47-48
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• 2018

The aim of the research is to suggest the compensating strength values depending on various managing periods of concrete based on the strength development model calculated with equivalent age method for OPC 100 % concrete. As a result, for 28 days of managing period, 6, and 3 MPa of compensating strength values were suggested when the temperatures were from 4 to 9℃, from 9 to 17℃, respectively. Additionally, for 42 days of managing period, 3MPa of compensating strength value was suggested when the temperature was from 4 to 10℃, and for 56 days of managing period, 3 MPa of compensating strength value was suggested when the temperature was from 4 to 5℃. Furthermore, for 28, 42, 56, and 91 days of managing periods, any compensating strength values were needed when the temperature were higher than 17, 10, 5, and 4℃, respectively.

• 한국구조물진단유지관리공학회 논문집
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• 제16권3호
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• pp.109-116
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• 2012

본 연구는 수산화나트륨(NaOH)으로 활성화된 슬래그 모르타르에 석고를 혼합하여 플로우, 응결시간 및 압축강도에 미치는 영향을 알아보고자 하였다. 실험에는 석고를 슬래그 중량에 대해 0~50%까지 혼합하고, 활성화제의 농도는 3M와 6M, 양생온도는 $20{\pm}2^{\circ}C$와 $35{\pm}2^{\circ}C$의 경우에 대해 실시하였다. 플로우와 응결시간시험결과는 석고의 혼합률이 증가할수록 증가하였다. 그러나 압축강도는 일정 혼합률까지 석고의 첨가량이 증가하면 증가하지만 그 이후로는 감소하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 추계 학술논문 발표대회
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• pp.133-136
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• 2007

This study investigates mechanical properties of the concrete using fine particle cement which is manufactured by the pulverizing process. The variable factors are 3 types of W/C such as 40, 50, and 60%, 3 types of curing temperature such as 5, 20, and $35^{\circ}C$, and 5types of the replacement of the fine particle cement such as 0, 25, 50, 75, and 100%. The unit water content, S/a and amount of the SP and AE agents to secure the slump and air content is gradually increased in accordance with amount of replacement. It can be confirmed that the delay of the setting time depending on FC content is decreased corresponding to FC content, so the effect of the acceleration to the setting time is expected. The compressive strength corresponding to FC content is proportionally increased, and the growth is confirmed about $30{\sim}40%$ at a day in 50% of FC contents. However, the increase of the strength is gradually decreased in accordance with increasing age.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 춘계 학술논문 발표대회 학계
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• pp.119-122
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• 2009

As architectures have recently become high-risers and mega-structured, stable high strength products have been ensured. Accordingly, use of precast concrete accouplement has been increased in order to facilitate air compression and rationalize construction. Since not only external heating but a1so internal temperature rise caused by the accumulation of cement hydration heat in manufacturing process, precast concrete members with large cross-section used for high-rise mega-structure's columns and beams may exhibit different temperature history compared to the precast concrete members for wall and sub-floor with relatively small cross-sections. Therefore, this study aims to elucidate the characteristics of temperature history of mass concrete members cast with high-strength concrete fur precast concrete application. In this study, large cross-sectional precast concrete mock-up, unit cement quantity, and temperature histories in manufacturing precast concrete member under different curing condition were inclusively investigated.

• 콘크리트학회논문집
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• 제20권5호
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• pp.549-555
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• 2008

본 연구는 비활성 황토결합재로 시멘트를 대체함으로써 시멘트의 수화 반응 등에 의한 콘크리트 내부 발열과 수축 특성을 연구하였다. 먼저 재료의 분석을 토대로 압축강도, 슬럼프, 공기량을 살펴보았다. 소형시편과 대형시편을 제작하였고, 보통콘크리트 (OPC)와 황토콘크리트 (HBC)의 수화열, 수축을 측정하여 비교 평가하였다. 황토결합재는 압축강도가 $18{\sim}33\;MPa$로 보통강도 콘크리트의 강도를 발현하였고, 유동성도 확보되는 결과를 보였다. 소형시편에서는 HPC는 OPC에 비해 양생시 내부의 최고온도가 약 1/4 정도로 낮게 나타나고 수축 역시 HBC는 OPC에 비하여 감소하였다. 대형시편에서도 HBC는 OPC에 비해 내부온도가 낮게 나타났으며 수축 역시 60일 기점으로 OPC의 상대적으로 매우 낮은 수축률을 보였다. 따라서 비활성 황토 결합재는 일정강도와 유동성을 확보할 수 있는 재료이며 친환경적 재료이다. 수화열과 수축에 있어 내구성능을 확보하는데 긍정적으로 사료된다.