• 한국재료학회지
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• 제34권2호
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• pp.72-78
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• 2024

The lightweight and high strength characteristics of aluminum alloy materials make them have promising prospects in the field of construction engineering. This paper primarily focuses on aluminum alloy materials. Aluminum alloy was combined with concrete, wood and carbon fiber reinforced plastic (CFRP) cloth to create a composite column. The axial compression test was then conducted to understand the mechanical properties of different composite structures. It was found that the pure aluminum tube exhibited poor performance in the axial compression test, with an ultimate load of only 302.56 kN. However, the performance of the various composite columns showed varying degrees of improvement. With the increase of the load, the displacement and strain of each specimen rapidly increased, and after reaching the ultimate load, both load and strain gradually decreased. In comparison, the aluminum alloy-concrete composite column performed better than the aluminum alloy-wood composite column, while the aluminum alloy-wood-CFRP cloth composite column demonstrated superior performance. These results highlight excellent performance potential for aluminum alloy-wood-CFRP composite columns in practical applications.

• 한국축산시설환경학회지
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• 제4권1호
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• pp.29-36
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• 1998

Sawdust is commonly used as a bulking agent for livestock manure composting. Nowadays, demand of sawdust for composting is increasing, so its price is very high and not easy to obtain. In this study in order to examine the effect of autoclaved lightweight concrete (ALC, one of the industrial wastes) on composting of swine manure, ALC (each size of 2, 4, an 8mm) was used as a bulking agent. Swine manure was mixed with each of sawdust and 8mm of ALC in a 1:1 ratio by volume and 2, 4mm of ALC was mixed in a 2:1 ratio by volume. The total period lasted 50 days and was divided into two periods. After mixing bulking agent with swine manure, they were left undisturbed to compost with aeration for an initial period of 20 days. At the end of this period, they were decomposed and mixed to effect a homogenization and then a second period of composting (without aeration) was conducted for 30 days. Temperature during the initial period of swine manure composting were above 70$^{\circ}C$ in all piles and maintained above 55$^{\circ}C$ for 5 days. Temperatures during the second period were relatively lower than the initial period. pH of the compost was increased during the initial period and after 50 days it reached 9.08 in sawdust pile and 9.03 in ALC pile ( 2mm). In nitrogen content of final compost, sawdust pile was higher than ALC piles by 21∼29%.

• KIEAE Journal
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• 제8권3호
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• pp.77-83
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• 2008

The effective mixture of structural laminated timber and other materials is expected to extend the potentials of building structures because of the potentials to realize high performance in structural safety. The classical joint types using drift pin and bolts are occurred local failures due to the small bearing area. In result, new joints using H shaped steel were suggested in this research. The objective of this study is to evaluate elasto-plastic behaviors by strengthening types of wood frames with new joints connecting structural laminated timber with H shaped steel. A total of five specimens of about one-second scale were tested. Specimens had columns with 1,050 height and $84mm{\times}100mm$ section, and a beams with 1,950mm length and $130mm{\times}100mm$ section. Also, the specimens were stiffened by brace, hwang-toh brick, and autoclaved lightweight concrete. The results of the test showed that the specimen stiffened with autoclaved lightweight concrete was characterized by fairly good strength and stiffness than those of the other specimens. Initial stiffness of H-2.0D-NS specimen with 2 times inserting length of beam height showed 1.33 times than that of H-1.5D-NS specimen. However, the strength of H-2.0D-NS specimen has not improved too much than H-1.5D-NS specimen.

• 한국건설순환자원학회논문집
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• 제1권3호
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• pp.219-224
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• 2013

본 연구에서는 규석, 시멘트, 생석회 및 소량의 무수석고를 사용하여 미네랄 하이드레이트 단열소재를 제조하였다. 슬러리의 특성 분석을 선행한 후, $CaO/SiO_2$ 몰비 변화에 따른 배합설계를 통해 최적 배합비를 도출하였다. 도출된 배합 설계비를 기준으로 혼합수 함량 및 수열합성 조건에 따른 소재의 특성을 측정, 평가하였다. 초적 조건으로 제조된 미네랄 하이드레이트 소재의 특성은 각각 밀도 $0.26g/cm^3$, 압축강도 0.4MPa, 열전도율 0.064W/mK로 나타났다. 이는 기존의 ALC(Autoclaved Lightweight Concrete) 소재의 성능을 한층 개선한 결과로서, 향후 지속적인 열적특성 개선 연구를 수행하여 유기 및 무기 단열재를 대체하여 새로운 개념의 무기계 단열재로 사용 가능할 것이라 판단된다.

• 콘크리트학회지
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• 제3권3호
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• pp.101-110
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• 1991

이 연구는 피치계 탄소섬유 보강 플라이애쉬.시멘트 복합체의 여러 가지 특성을 실험적으로 구명하고, 그 제조방법을 제시한 것이다. 복합체는 조강시멘트, 시리카 분말, 스티렌 부타디엔 러버 라텍스, 기포제와 탄소섬유 및 플라이애쉬를 사용하여 제조하였고, 배합조건별로 그 특성을 검토하였다. 연구결과, 경량 탄소섬유 보강 플라이애쉬.시멘트 복합체의 압축강도, 인장강도, 휨강도, 흡수성 및 특수성 그리고 건조수축과 같은 물리적.역학적 성질은 스티렌 부타디엔 러버 라텍스를 첨가하므로써 현저히 개선되었으며, 아울러 복합체를 제조하는데는 기건양생보다 오토클래브 양생이 유리한 것으로 나타났다. 이결과, 앞으로 경량 탄소섬유 보강 플라이애쉬.시멘트 복합체를 이용한 프리캐스트 제품의 개발에 크게 기여할 수 있을 것으로 기대된다.

• 한국구조물진단유지관리공학회 논문집
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• 제25권6호
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• pp.27-32
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• 2021

본 연구는 시멘트계 건설재료의 작업성 증진을 위하여 나노버블수의 사용을 시도하였다. 사용된 나노버블수는 약 750 nm의 입경을 지닌 나노버블이 7% 포함된 배합수를 사용하였다. 초고성능콘크리트, 경량시멘트 복합체, 고강도 모르타르 등 다양한 시멘트 복합체에 나노버블수가 배합수로서 사용될 때 미치는 영향을 실험하였다. 작업성을 대표할 수 있는 플로우 값이 시편에 따라 3-22%정도 증진됨을 확인하였다. 하지만 압축강도에는 큰 영향을 미치지 않는 것으로 확인되었다. 따라서 재료의 굳은 성질에 큰 영향 없이 시멘트 복합체의 작업성을 증진시킬 수 있는 새로운 방법으로 나노버블수의 사용이 다양한 시멘트 복합체에 활용될 수 있음을 제시하였다.

• 대한건축학회논문집:구조계
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• 제34권1호
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• pp.79-87
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• 2018

The purpose of this study was to analyze factors influencing insulation performance of inorganic Autoclaved Lightweight Concrete(ALC) sandwich wall panels with the application of shear connectors. To analyze the effect of shear connectors on the thermal performance of sandwich wall panels, heat transfer analysis was conducted by using the three-dimensional heat transfer simulation software. Four types of shear connector such as Pin, Clip, Grid, and Truss were selected for insulation performance analysis. Thermal bridge coefficient was calculated by varying typical panel thickness and shear connector thickness and materials such as steel, aluminum, and stainless steel. The results showed that Grid and Truss type widely distributed along the section of sandwich wall panel had a great influence on the thermal bridge coefficient by changing the influence factors. Based on the results of thermal and structural performance analysis, effective heat transmission coefficient of the sandwich wall panel satisfying the passive house insulation criteria was calculated. As a result, it was found that heat transmission coefficient was increased from $0.132W/m^2{\cdot}K$ to $0.141{\sim}0.306W/m^2{\cdot}K$ depending on the shear connector types and materials. In the majority of cases, the passive house insulation criteria was not satisfied after using shear connectors. The results of this study were likely to vary according to how influence factors were set, but it is important to apply the methods that reduce the thermal bridge when there would be a possibility of greatly affecting the insulation performance.

• 한국건설순환자원학회논문집
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• 제10권4호
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• pp.411-419
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• 2022

본 연구에서는 탄소나노튜브를 혼입한 경량·고강도 시멘트 독합체의 유해성을 평가하기 위해 급성경구독성시험 및 급성경피 독성시험을 실시하고, 이를 재령 28일 압축강도 50 MPa 수준의 탄소나노튜브를 혼입하지 않은 일반 콘크리트의 유해성과 비교하였다. 일반 콘크리트 및 탄소나노튜브를 혼입한 경량·고강도 시멘트 복합체 모두 급성경구독성시험결과 GHS category 5인 것으로 조사되었다. 또한, 모든 시편에서 급성경피독성시험에서 독성증상은 관찰되지 않았으며, GHS category 5/미분류(unclassified)에 해당하는 것으로 판단된다.

• 환경영향평가
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• 제20권6호
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• pp.815-821
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• 2011

This study aims to estimate the biological decomposition capacity of MPC(Microorganism Porous-Concrete). MPC has specific surface area formed by inside pores, and bio compound was added to those pores to reduce pollutants loading. To evaluate the water purification capacity of MPC, we carried out the comparative studies using different media types [GPC(General Porous-concrete), CPC(Compound porous-concrete), LPC(Lightweight aggregate porous-concrete)] under the condition of CFSTR, and different retention times (30, 60 and 120 min). We also estimated the purification capacity of MPC under different concentrations of pollutant loadings. The MPC showed higher efficiency in water purification function than other conventional porous concretes with efficient decrease rates of SS, BOD, COD, and nutrient concentrations. In the comparison experiment for different retention times, MPC showed the highest removal efficiency for all tested pollutants in the longest retention time(120 min). In the long period test, the removal efficiencies of MPC concrete were high until 100 days after the set up of the operation, but began to decrease. Outflow flux was invariable compared with inflow flux so that extra detention time for media fouling such as back washing is not needed. But the results suggested that appropriate management is necessary for long-term operation of MPC. As the final outcome, MPC using bio organisms is considered to be efficient for stream water purification when they used as substrates for artificial river structure.

• Computers and Concrete
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• 제15권6호
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• pp.951-972
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• 2015

The focus of the present study is to investigate both local and global behaviour of a precast concrete sandwich panel. The selected prototype consists of two reinforced concrete layers coupled by a system of cold-drawn steel profiles and one intermediate layer of insulating material. High-definition nonlinear finite element (FE) models, based on 3D brick and 2D interface elements, are used to assess the capacity of this technology under shear, tension and compression. Geometrical nonlinearities are accounted via large displacement-large strain formulation, whilst material nonlinearities are included, in the series of simulations, by means of Von Mises yielding criterion for steel elements and a classical total strain crack model for concrete; a bond-slip constitutive law is additionally adopted to reproduce steel profile-concrete layer interaction. First, constitutive models are calibrated on the basis of preliminary pull and pull-out tests for steel and concrete, respectively. Geometrically and materially nonlinear FE simulations are performed, in compliance with experimental tests, to validate the proposed modeling approach and characterize shear, compressive and tensile response of this system, in terms of global capacity curves and local stress/strain distributions. Based on these experimental and numerical data, the structural performance is then quantified under various loading conditions, aimed to reproduce the behaviour of this solution during production, transport, construction and service conditions.