• 한국산업융합학회 논문집
• /
• 제6권2호
• /
• pp.115-122
• /
• 2003

This experimental study on high strength lightweight concrete using compound materials has been performed. In which, expanded clay was used as coarse aggregate, and silica fume and fly ash as admixtures varying by 0, 10% and 0, 5, 10, 15, 20% of cement amount respectively were added. Thus, the properties of fresh and hardened concrete have been investigated. The results of this study can be summarized as follows ; Each slump loss of mixtures replaced fly ash has been decreased by increasing replacement rate. The compressive strength have shown 465, 428 and $401kgf/cm^2$ at 30, 40 and 50% of W/B in 28days respectively, all of which have satisfied the criterion $270kgf/cm^2$ of high strength lightweight concrete. The unit volume weight of hardened concrete has been decreased by increasing replacement rate of silica fume and fly ash, values of which have satisfied the criterion $2000kgf/cm^3$of light weight concrete.

• 한국환경복원기술학회지
• /
• 제5권6호
• /
• pp.9-13
• /
• 2002

This study has been performed to investigate the physical and mechanical characteristics of compaction, volume change and compressive strength for reinforced soil mixed with cement. And confirm the reinforcing effects with admixture such as cement. To this end, a series of compaction test and compression test was conducted for clayey soil(CL) and cement reinforced soil. In order to determine proper moisture content and mixing ratio, pilot test was carried out for soil and cement reinforced soil. And the mixing ratio of cement admixture was fixed 3%, 6%, 9% and 12% by the weight of dry soil. As the experimental results, the maximum dry unit weight(${\gamma}_{dmax}$) was increased with the mixing ratio and then shown the peak at 10% reinforced soil, but the optimum moisture content(OMC) and the volume change was decreased with the ratio increase. And the compressive strength volume change was decreased with mixing ratio increased.

• 한국건축시공학회지
• /
• 제17권5호
• /
• pp.393-401
• /
• 2017

본 논문에서는 발포폴리스티렌 비드 (EPB)와 폐 발포폴리스티렌 (WEP)의 대체율에 따른 경량 모르타르의 기초 특성을 평가였다. EPB 및 WEP를 이용한 경량 모르타르의 기초 특성으로서 단위용적중량, 압축 강도, 휨강도, 흡수율, 열전도율 및 폴리스티렌 (EPB 및 WEP) 분포를 분석하였다. 그 결과 경량 모르타르는 WEP의 대체율이 증가할수록 단위용적중량, 압축 강도, 휨강도, 흡수율 및 열전도율은 증가하고, 폴리스틸렌 면적 분포는 감소하였다.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2005년도 춘계 학술기술논문발표대회 논문집
• /
• pp.93-98
• /
• 2005

The purpose of this study was to analyze the compression strength research by aerated concrete as mixing ratio This Study used foaming-agent and produced aerated concrete by pre-foam way that is used in construction site. An experiment changes unit cement amount, w/c and the glass fiber mixing rate and 'measured capacity change, unit capacity weight and compressive strength. The results obtained from experimental study are as following; Research to reduce unit capacity weight in condition more than unit cement amount 500kgf is considered should be gone side by side. The highest compressive strength result appeared in aerated concrete that cement amount 600kgf and w/c ratio $45\%$, $50\%$. compressive strength was increased maximum $34%$ when glass fiber $0.7\%$ addition cause by coherence enlargement to enlargement of cement paste and glass fiber addition per unit volume

• 한국환경복원기술학회지
• /
• 제5권6호
• /
• pp.37-42
• /
• 2002

This study has been performed to investigate the physical and mechanical characteristics of compaction, volume change and compressive strength for reinforced soil mixed with polypropylene fiber, and to confirm the reinforcing effects with admixture such as polypropylene fiber. To this end, a series of compaction test and compression test was conducted for clayey soil(CL) and polypropylene fiber reinforced soil. In order to determine proper moisture contents and mixing ratio, pilot test was carried out for natural soil and PFRS(polypropylene fiber reinforced soil). And the mixing ratio of mono-filament fiber and fibrillated polypropylene fiber admixture was 0.1%, 0.3%, 0.5% and 1.0% by the weight of dry soil. From the experimental results, it was found that the optimum moisture contents(OMC) increased with the mixing ratio of fiber, but the maximum dry unit weight and the volume change was decreased with the mixing ratio. It means that the improvement of the workability and the reduction of the weight of embankment was done by the addition of the polypropylene fiber. And, from the compression test results, it was found that the addition of the polypropylene fiber remarkably improved the compressive strength of PFRS. And it was observed in the viewpoint of strength that the fibrillated polypropylene fiber reinforced soil was more effective than the mono-filament polypropylene fiber reinforced soil.

• 한국환경복원기술학회지
• /
• 제9권3호
• /
• pp.17-25
• /
• 2006

To increase freeze-thaw resistance of porous concrete, this study examined physical properties of polymer by replacing paste used as a binding material with polymer, using unsaturated polyester and epoxy resin, and changing the mixing ratio of polymer. According to the result of this study, when the mixing ratio of resin paste to aggregates was 11 to 16%, voids volume was 33 to 37% and unit weight was about 1620 to 1720kg/$m^3$. In comparison with previous studies using cement paste, voids volume increased by about 7 to 16%, while unit weight decreased by about 100 to 300kg/$m^3$. Compressive strength was 90 to 155kg/$cm^2$ at the age of 7 days, which was 5-40kg/$cm^2$ bigger than porous concrete using cement paste. From a viewpoint of freeze-thaw resistance, it was identified that pluse velocity fell by 0.23km/sec, about 7% of the original velocity, when the cycle of freeze-thaw was repeated 300 times. In spite of 300 repetitions of the cycle, relative dynamic modulus of elasticity was more than 60%, which suggested that its freeze-thaw resistance was more excellent compared with the result that relative dynamic modulus of elasticity of porous concrete using cement paste was 60 % or less under the condition of 80 repetitions of freeze-thaw cycle.

• KIEAE Journal
• /
• 제13권6호
• /
• pp.137-143
• /
• 2013

The purpose of this study is to suggest optimum micro-filler experiment method to select the optimal particle size of earth for using in earth construction works and test this suggestion through compressive strength measurement. According to the results of selecting the method to choose the optimum micro-filler mixing of earth and sand, three-stage filling(plate tamping) showed relatively high results and so was estimated to be the proper filling method. According to the results of optimum micro-filler experiment of earth and sand by the maximal sizes of sand, between 80% and 90% showed the highest result values. The larger the maximum size of sand was, the lower the addition ratio of sand was in optimum micro-filler mixing. According to the results of compressive strength experiment by the particle sizes of earth and sand, 90% in the addition ratio of sand showed the highest results, and so tended to be similar to the results of unit volume weight experiment.

• 한국건축시공학회지
• /
• 제7권2호통권24호
• /
• pp.77-83
• /
• 2007

This study investigated the fundamental properties of the lightweight foamed concrete depending on various admixtures, and the results were summarized as following. When 20% of cement kiln dust(CKD) and 0.002% of stabilizing agent were mixed to lightweight foamed concrete, it was necessary to use a superplasticizer because flowability was decreased. However, it could reduce sinking depth which were the extensive trouble of lightweight foamed concrete. Bulk density was divided into '0.4' and '0.5' grades on KS according to unit volume weight. The compressive strength was less than that of plain concrete when admixtures were applied, but the results exceeded the minimum strength of the each grades on KS. Totally, it is found that the combination of 20% of CKD and 0.002% of stabilizing agent makes it possible to reduce a sinking depth, recycle resources, and save cost when were mixed.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2009년도 추계 학술논문 발표대회
• /
• pp.69-72
• /
• 2009

This research is focused on the applying of the foaming agent which can make the independent pore in the concrete structure in order to make a lightweight concrete structure. This lightweight foamed concrete can satisfy both the required strength and the mechanical properties as structural members. In addition, anti freezing-thawing properties also required. As a result of the unit volume-weight measurement, when the foaming agent mixed at 0.5% to 1%, the lightweight foamed concrete can be applied for the structural member. Also the density and compressive strength measurement results reveals that it will be suitable as structural member with 21MPa strength, when the density is betweenity8 to 1.9 and foaming agent quantities are 0.5% to 1%. Finally the result of freezing-thawing experiment, the effect freezing-thawing damage reduced according to adding foaming agent because those foaming agent make micro-pores in the structure which are not seen in the ordinary concrete structure.

• 한국터널지하공간학회 논문집
• /
• 제21권1호
• /
• pp.49-59
• /
• 2019

본 연구는 로터리드럼커터에 적용된 두 종류의 코니컬 픽커터에 대한 현장시험을 통해 시험 전과 후의 육안조사와 중량감소 및 마모부피를 측정하여 코니컬 픽커터의 내구성을 비교 분석하였다. 육안조사를 통해 슬림 타입 코니컬 픽커터에서만 총 9개의 삽입재 손실이 나타남을 확인하였고 삽입재 보호를 위해 두부의 두께가 중요함을 알 수 있었다. 시험 전과 후의 픽커터의 중량손실과 마모부피는 헤비타입이 슬림타입에 비해 반이하로 작게 나타나 경암반에서 헤비타입이 더 유용함을 확인할 수 있었다. 픽커터의 마모손실을 판단할 때, 중량측정과 마모부피 측정결과의 상호 비교는 재료의 단위중량과 굴착에 의한 스폴링에 의해 차이가 나타날 수 있으므로 주의해야 할 것으로 판단된다.