In the modern construction industry, some methods for enhancing the quality of a building have been sought in various ways. Accordingly, this research team intends to mutually compare the overall kinds of quality of products, such as, the temperature characteristics of PE films and the exposed surface, etc., by applying the single-layered bubble sheet that was developed as a surface curing material for summer to the construction site for a wall-type Apartment which is under construction.

In this study, it is intended to find out clearly whether there are any initial damages by frost by analyzing the temperature characteristics of the reinforcing bars of each area depending on the changes of surface curing methods for the exposed areas of some reinforcing bars by modelling the wall reinforcing bar areas of a wall-type apartment.

This study presents the results of experiments to investigate the effect of polymer type and curing temperature on the mechanical properties of polymer mortar. The flexural strength, compressive strength of RHP mortar at the curing temperature of 20℃, 0℃, and –20℃ at the curing age of 24hr were 93%, 93%, and 91%, respectively, relative to those at the curing age of 168hr. On the other hand, The flexural strength, compressive strength of HDP mortar at the curing temperature of 20℃, 0℃, and –20℃ at the curing age of 72hr were 91%, 81%, and 80%, respectively, relative to those at the curing age of 168hr.

Quality control of concrete during its curing process is crucial when it comes to reaching the ideal strength. This paper presents the basic study of optimizing concrete curing process by using Arduino platform based on the maturity method. The research has suggested a quality control of curing process by visualizing the curing temperature and its strength from web. The maturity method was coded into the web which allows managers to monitor regardless their locations.

In this study, high strength concrete with satuated artificial lightweight aggregate(SLWA) produced by domestic for reducing autogenous shrinkage, which provides additional water to the hydratin cement particles, is applied to be the internal curing. This paper presents the test result of basic property of SLWA and autogenous shrinkage with volumes of SLWA.

The aim of the research is suggesting the curing method and selection of surface-covered curing materials with the goal of achieving non-cracking concrete by applying on the actually constructed top slab of the apartment and comparing the surface covering method using single-layered white bubble sheet with the surface covering method using polyethylene film.

섬유보강콘크리트의 균열발생 평가는 보통 인장강도나 휨강도가 지표가 되지만 시험체 제작 과정 시에 이루어지는 양생의 영향도 좌우된다. 일반적으로 콘크리트 시험체는 20±3°C의 온도에서 수중양생을 실시한 후 강도 평가를 수행하나 실구조물은 습윤양생을 소정의 기 간 동안 실시한 후 건조 상태로 된다. 이러한 기술적인 진보가 이루어지고 있는 경향과는 달리 양생방법의 차이가 균열발생 강도에 미치는 영향 은 아직 명확하지 않고 있는 실정이다. 따라서 본 연구에서는 섬유보강콘크리트의 역학적 특성, 특히 균열발생강도에 미치는 양생방법의 영향 에 대해서 검토하였다.

Effects of recycled fine aggregate on the behavior of cement-based concrete were evaluated with different compressive strengths through experiments. It can be observed that recycled fine aggregate can be useful to fabricate precast concrete products in terms of having of concrete strength equivalent to natural aggregate.

In order to identify the nature of recycled fine aggregates, an experiment was conducted by mixing recycled fine aggregates. Then, comparative analysis was carried out throughout compressive strengths obtained from steam curing and water curing methods. The concrete mixed with recycled fine aggregate has low strength gain compared to the conventional concrete. But in case that concrete produced in dry process is applied to precast concrete prod

The study is compressive strength of 110MPa PHC pile using ground granulated blast furnace slag to NAC, AC curing method. In the result, 20% of ground granulated blast furnace slag could be substituted for cement in PHC pile concrete.

In experimental results, the prediction equation for 28 day-strength of GGBF slag concrete could be produced through the linear regression analysis of early strength and 28 day-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 day-strength of GGBF slag concrete by 1 day strength won the good reliability.

현재 전 세계적으로 자연적, 인위적 요인으로 인하여 이상기후가 나타나고 있다. 이상기후의 대표적인 것으로 슈퍼태풍, 극한폭설, 폭염과 같은 극한 기후현상이 초래된다. 1970년대 산업화 시대 이후 급격하게 지구의 온도가 상승하는 것을 알 수 있으며, 이로 인하여 발생하는 가장 큰 문제점은 지구 온난화이다. 지구 온난화에 영향을 미치는 온실가스의 종류로는 이산화탄소, 과불화탄소, 아산화질소, 메탄과 같은 다양한 종류의 화학성분이 존재하며 특히 이산화탄소가 약 90%의 비중을 차지하는 것을 알 수 있다. 콘크리트의 경우 건설재료로써 탁월한 내구성능을 지니고 있으며, 사회기반시설물 건설 재료로 70%이상 사용되고 있다. 그러나 콘크리트는 타설직후 물리·화학적으로 다양한 환경조건으로부터 성능저하 현상이 발생하기도 한다. 특히 대기중의 이산화탄소는 콘크리트 알칼리도 저하에 따른 철근을 부식시키고 내구성 저하를 초래하게 된다. 따라서 본 연구에서는 풍속, 일조시간에 관하여 양생 한 후 콘크리트의 탄산화 실험을 접목시켜 탄산화 깊이와 탄산화 속도 계수를 측정하고 이를 바탕으로 만족도 확률 곡선을 통하여 성능중심평가(Performance Based Evaluation(PBE))를 수행 할 것이다.

본 연구는 폴리머 기반 보수모르타르에 미분쇄된 플라이애시 치환율의 영향을 평가하였다. 주요변수는 양생온도와 미분쇄된 플라이애시의 치환율이다. 양생온도는 40℃, 20℃ 및 5℃로, 미분쇄된 플라이애시 치환율은 결합재 대비 0~35%로 변화하였다. 굳지 않은 모르타르에서는 플로우를, 굳은 모르타르에서는 재령별 압축강도, 응력-변형률 관계 및 탄성계수, 파괴계수를 측정하고, 주사전자현미경 및 엑스선회절기 분석을 수행하였다. 실험결과 보수모르타르의 플로우, 탄성계수 및 파괴계수는 미분쇄된 플라이애시 치환율 20~30%에서 가장 높은 성능을 발휘하였다. 또한 재령별 압축강도는 미분쇄된 플라이애시 치환율과 양생온도에 현저한 영향을 받았는데, 미분쇄된 플라이애시 치환율 20%에서 초기강도 발현율이 가장 높았다. ACI 209에서 제시하고 있는 콘크리트 재령별 압축강도예측모델에서 초기 및 장기재령 강도발현 계수는 미분쇄된 플라이애시 치환율과 양생온도의 함수로 일반화할 수 있었다. 미분쇄된 플라이애시가 첨가된 페이스트는 수화생성물을 나타내는 피크(peak)의 수와 강도(intensity)가 증가되고 플라이애시 입자주변에 CSH 겔이 형성되었다.

Nowadays, we are witnessing all the industrial structures being reorganized on the axis of the carbon dioxide technology to solve the problem of global warming. Therefore, there is need for various approaches even in the construction material industry to realization of the reduction of greenhouse gases and the recycling. Thus, this study sought to apply low energy binder material manufactured with industrial by-products to the extruded panels and develop a composite panel through the modularization of the insulator and the extruded panel. Results are as follows. Regarding the physical properties, the LEC panel had a lower flexural strength with 1.0 N/mm2 than the plain panel, while showing no less absorption rate, percentage of water content, density and compression strength than the plain panel. Panels and insulation attachment was found suitable for B Bond's XPS. It is found that B's glue for XPS is appropriate for putting together the panel and the insulator. As for the thermal transmission coefficient, the LEC panel was lower with 0.384 W/mK than the plain panel but the difference with the composite panel was a mere 0.047 W/mK indicating a similar thermal property to that of the plain composite panel.

이 연구에서는 초고성능 콘크리트 (UHPC)와 보통 콘크리트 (NSC)간 계면부착강도에 관한 연구를 수행하였다. UHPC를 보수⋅보강재 로 활용하기 위한 기존의 부착강도에 관한 연구와 달리, UHPC를 프리캐스트 합성부재로 활용하기 위한 연구에 초점을 맞추었으며, 여기 에 영향을 미칠 수 있는 다양한 요인에 대하여 검토하였다. 기존 연구들을 분석한 결과, UHPC-NSC 계면 부착강도에 영향을 미칠 수 있는 요인으로는 계면의 형상, 합성 전 UHPC의 경화 진행상태, 합성 전 UHPC의 수분 흡수상태, 그리고 합성 후 양생장소와 같이 크게 4가지 로 구분되었다. 계면의 형상을 변수로 한 실험에서는 형상에 따라 각기 다른 파괴모드가 나타났으며, 기존 연구에서 확인되지 않았던 거칠 게 처리한 UHPC 계면 일부가 파괴되는 새로운 파괴모드가 발견되었다. 합성 전 UHPC의 경화진행 상태가 부착강도에 영향을 미치는 것 으로 나타났으며, 이러한 영향은 부착 파괴모드에 따라 다르게 나타났다. 또한, 합성 전 UHPC의 수분상태가 부착강도에 영향을 주었으며, UHPC의 양생방법에 따라 서로 상반되는 결과를 보였다. 마지막으로, 합성한 시편의 양생조건 역시 계면 부착강도에 영향을 미친다는 것 을 확인하였다.

In the cement industry, a large amount of CO2 is emitted from the first production step, and moreover the most of secondary products go through a variety of curing processes in which fossil fuels are used, causing additional CO2 emissions. Thus there is need for developing technology so that the secondary cement products are to be processed with no or less frequent curing in the manufacturing stage, helping not only reduce CO2 emissions but also improve the economical efficiency. Thus, this study seeks to make a comparative analysis of the engineering characteristics of extruded panels which are manufactured using CSA, calcined kaolins and CAMC inorganic binder, and those of traditional extruded cement panels, and then to use the results as basic data for developing LEC extruded panels. The experiment results showed that unit weight and density of extruded panels were similar to those of the traditional mix of ordinary Portland cement, and that the ratios of the former’s water content and water absorption were 2~3% higher than those of the latter. On a material age basis of 28 days, the compressive strength was shown to be about 4.5 N/mm² more with 64.6 N/mm² for the 35 mm thickness, and 24.9 N/mm² more with 84.2 N/mm² for thr 50mm thickness, while the flexural strength was shown to be 2.4 N/mm² less with 14.1 N/mm² for the 35 mm thickness and 1 N/mm² less with 13.9 N/mm² for the 50 mm thickness compared to the traditional mix. These conflicting results in the cases of the compressive and flexural strength are though to have been due to the fact that the LEC binder had caused the greater volume expansion of the hydration products resulting from the hydration of the binder under the closely-knit structures thanks to the vacuum extrusion, necessitating future observation of the length changes and the fine structure. In addition, there were some cases where the 35 mm thickness had 1.0 N/mm² more than the 50mm thickness depending on the thickness of the panel. This is thought to be due to the difference in the hydration ratios incurred by the different caloric values per unit area depending on the thickness of the panel when going through a short period of curing process.

To improve the quality of polyurea paints, the conventional polyurea heat resistance and wear resistance performance was confirmed with the test method of KS F 4922 and KS M 6080. The test results showed that the enhanced polyurea paints increase the applicability of concrete and asphalt concrete.

In experimental results, the prediction equation for 28 day-strength of GGBF slag concrete could be produced through the linear regression analysis of early strength and 28 day-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 day-strength of GGBF slag concrete by 1-day strength won the good reliability.

현재 전 세계적으로 석탄, 석유 등 화석연료의 사용으로 지구 온난화가 진행되고 있다. 이러한 원인으로 폭염, 폭설, 폭우 및 슈퍼태풍 등과 같은 이상기후, 극한기후 현상이 지속적으로 증가 하고 있다. 또한 심각한 자연재해로 콘크리트 구조물 및 사회기반시설의 심각한 손상과 붕괴가 발생한다. 이러한 문제들을 해결하기 위해서는 기후변화에 적합한 기준 및 시공 기술 등이 필요한 실정이므로 본 연구에서는다양한 온도와 습도 양생조건이 콘크리트 배합에 미치는 영향을 검토해 보았다. 다양한 온도와 습도 조건에서 양생된 콘크리트의 압축강도와 할렬인장강도 실험을 수행하였다. 또한 성능중심평가 (performance based evaluation (PBE))방법을 사용하여 다양한 양생조건에서 경화된 콘크리트 강도의 만족도확률을 평가하였다. 또한 콘크리트의 성능중심평가로부터 얻는 결과 값을 바탕으로 기후변화가 배합에 미치는영향을 고려하여 배합설계에 적용할 수 있다.

Carbon dioxide generated from construction materials and construction material industry among the fields ofconstruction is approximately 67million tons. It is about 30% of the carbon dioxide generated in the fields of construction.In order to reduce carbon dioxide in the fields of construction, it is necessary to control the use of fossil fuel consumedand decrease carbon emission by reducing the secondary and tertiary curing generating carbon dioxide in constructionmaterial industry. Therefore, this study produced an extrusion panel by using cement as the base materials and substitutingbinding materials up to 40% to analyze strength characteristics. According to the results of strength characteristics bythe replacement binder (Low energy curing Admixture) showed an apparent active strength improvement. In particular,specimens substituting binder as 45% indicated the greatest strength improvement. When binding materials was used withsubstitution, it showed strength characteristics similar or higher than specimens made from tertiary autoclave curing assecondary steam curing.