• 한국농공학회지
• /
• 제37권3_4호
• /
• pp.72-81
• /
• 1995

This study was performed to evaluate the mechanical properties of high performance lightweight polymer concrete using fillers and synthetic lightweight coarse aggregate. The following conclusions were drawn. 1. The unit weight of the G3, G4 and G5 concrete was 1.500t/m$^3$, 1.506t/m$^3$ and 1.535t/m$^3$, respectively. Specially, the unit weights of those concrete were decreased 33~35% than that of the normal cement concrete. 2. The highest strength was achieved by heavy calcium carbonate, it was increased 27% by compressive, 95% by tensile and 195% by bending strength than that of the normal cement concrete, respectively. 3. The elastic modulus was in the range of 8.0 x 104~ 10.4 x lO4kg/cm2, which was approximately 35~42% of that of the normal cement concrete. Normal cement concrete was showed relatively higher elastic modulus. 4. The ultrasonic pulse velocity of fillers was in the range of 2, 900m/sec, which was showed about the same compared to that of the normal cement concrete. Heavy calcium carbonate was showed higher pulse velocity. 5. The compressive, tensile, bending strength and ultrasonic pulse velocity were largely showed with the increase of unit weight.

• Computers and Concrete
• /
• 제8권4호
• /
• pp.465-472
• /
• 2011

This paper investigates bond behavior of structural lightweight concrete (SLWC) and ordinary concrete (OC) comparatively using bending test called Standard Belgium Hinged Beam Test (SBHBT). For this purpose the experiments were carried out as three series on 36 beam specimens (12 specimens of SLWC and OC with $20{\phi}$ development length, 12 specimens of SLWC with $25{\phi}$ development length). For each series bond behavior of steel rebars with 8, 10, 12, 14 mm diameters were tested. The results indicate that bond strength of SLWC is considerable lower than OC and $20{\phi}$ development length is insufficient for steel rebars with 12 mm and 14 mm diameters. Therefore development length of SLWC was extended to $25{\phi}$, even if 8 and 10 mm steel rebars provided acceptable bond strength. In this way, bond strength between SLWC and 8 and 10 mm steel rebars was developed. In addition, adequate bond behavior was achieved for 12 mm rebar but the beam in which 14 mm rebar used exceeded their bearing capacity by shear forces before yield stress. This result shows that SBHBT is more convenient for small sized steel rebars.

• Computers and Concrete
• /
• 제21권2호
• /
• pp.199-207
• /
• 2018

With the development of concrete technology, producing concrete products that have the ability to flow under their own weights and do not need internal or external vibrations is an important achievement. In this study, assessments are made on using travertine, marble and limestone rock flours in self-compacting lightweight concrete (SCLC). In fact, the effects of these powders on plastic and hardened phases of SCLC are studied. To address this issue, concrete mixtures with water to cementitious materials ratios of 0.42 and 0.45 were used. These mixtures were made with 0 and 10% silica fume (SF) replacement levels by cement weight. To achieve lightweight concrete, lightweight expanded clay aggregate (Leca) with the bulk density of about $520kg/m^3 $was utilized. Also two kinds of water were consumed involving tap water and magnetic water (MW) for investigating the possible interaction of MW and rock flour type. In this study, 12 mixtures were studied, and their specific weights were in the range of $1660-1692kg/m^3$. To study the mixtures in plastic phase, tests such as slump flow, J-ring, V-funnel and U-box were performed. By using marble and travertine powders instead of limestone flour, the plastic viscosities and rheology were not changed considerably and they remained in the range of regulations. Moreover, SCLC showed better compressive strength with travertine, and then with marble rock flours compared to limestone powders. According to the results of the conducted study, MW showed better performance in both fresh and hardened phases in all the mixes, and there was no interaction between MW and rock flour type.

• 자원리싸이클링
• /
• 제8권4호
• /
• pp.3-10
• /
• 1999

생활하수처리장에서 발생하는 슬러지연소재(SA)에 정유공장의 폐촉매(RFCC)를 첨가시켜 제조하려는 실험.연구를 행하였다. SA만의 경우에는 $1250^{\circ}C$에서 열처리하였을 때 비중이 1.67인 골재를 얻을 수 있었으며, 부피팽창률은 승온속도에 큰 영향이 없었고 소성시간에 따라서는 다소 저하하는 경향을 보였다. SA에 RFCC를 10 wt% 첨가한 경우에 $1250^{\circ}C$에서 비중이 1.07인 경량골재를 얻을 수 있었으며 소성시간에 따라 부피팽창율이 다소 증가하였다. 경량골재를 제조하기 위한 최적 RFCC 첨가량은 10 wt%이었으며 최대 부피팽창율을 보인 조건은 승온속도; $20^{\circ}C/min$, 소성온도; $1250^{\circ}C$, 유지시간; 50분의 경우였다. RFCC의 첨가량에 따라 제조된 시편의 압축강도는 30 wt% RFCC>SA>20 wt% RFCC>10 wt% RFCC의 경향을 보였다.

• 한국건축시공학회지
• /
• 제23권5호
• /
• pp.527-536
• /
• 2023

본 연구에서는 라멘식 모듈러 건축물의 비내력 벽체 적용성 검토를 목적으로 국가건설기준센터 KCS 14 20 20 경량골재 콘크리트에서 규정하는 성능을 기준으로 바텀애시와 코팅된 발포폴리스티렌 비드를 활용하여 경량 콘크리트 실험을 진행하였다. 코팅된 발포폴리스티렌 비드를 사용할 경우, 경량 콘크리트 강도 성능에 부정적인 영향을 주는 것으로 나타났다. 하지만 단위 질량의 감소와 단열성능에 긍정적인 영향을 주는 것으로 나타났고, 바텀애시의 경우 기존 연구와 마찬가지로 내부 공극 특성으로 인하여 열전도율 값이 낮게 나타났다. 이를 통하여 발포폴리스티렌 비드 50%와 10~20mm의 바텀애시 50%를 굵은 골재로 대체하는 배합이 표준시방서의 단위 질량과 설계기준 강도를 만족하며 가장 열전도율이 낮은 배합으로 나타났다.

• Steel and Composite Structures
• /
• 제50권6호
• /
• pp.675-688
• /
• 2024

Cold-formed steel (CFS) is prone to buckling failure under loading. Lightweight concrete (LC) made of lightweight aggregate has light weight and excellent thermal insulation performance. However, concrete is brittle in nature which is why different materials have been used to improve this inherent behavior of concrete. The distortional buckling (DB) performance of cold-formed steel-lightweight concrete (CFS-LC) composite columns was investigated in this paper. Firstly, the compressive strength test of foam concrete (FC) and ceramsite concrete (CC) was carried out. The performance of the CFS-LC members was investigated. The test results indicated that the concrete-filled can effectively control the DB of the members. Secondly, finite element (FE) models of each test specimen were developed and validated with the experimental tests followed by extensive parametric studies using numerical analysis based on the validated FE models. The results show that the thickness of the steel and the strength of the concrete-filled were the main factors on the DB and bearing capacity of the members. Finally, the bearing capacity of the test specimens was calculated by using current codes. The results showed that the design results of the AIJ-1997 specification were closer to the experimental and FE values, while other results of specifications were conservative.

• 한국산학기술학회논문지
• /
• 제19권12호
• /
• pp.363-373
• /
• 2018

오늘날 다변화된 사회에서 어떤 스타일의 건물이 동시대를 대표하는 건축적 양식인지 알기 어렵다. 그 중에서 모놀리스적 스타일의 건물에서 드러나는 단순함은 현대의 지극히 복잡한 사회구조와 대칭점을 이루며 그 가치를 인정받을 수 있다. 본 논문에서는 21세기 초반 단열경량골재콘크리트가 사용된 건물의 분석을 통해서 모놀리스적 표현에 대한 개념정의와 그 특징들이 공간 및 형태 그리고 건축구법에서 어떻게 표현되고 있는지에 대해 연구하였다. 여러 재료가 층을 이루어 구성되는 다층적 방식의 외벽시스템과는 달리, 단열경량골재콘크리트에 의한 외벽은 단일재료로서 콘크리트를 사용하여 거푸집을 빈틈없이 채워서 만들어진 덩어리 형태이며 그 자체로 모놀리스적이다. 이러한 점은 동일한 재료에 의한 내외부공간의 동질성, 고형(固形)으로서 표면의 연속성, 스테레오토믹적(stereotomic) 구축방식의 공간적 특성, 노출콘크리트사용에 의한 물질성의 표현, 덩어리와 공간 사이의 대비적 특성을 가진 공간을 만들어 낸다. 그리고 현대건축의 다층적 외벽 방식의 모놀리스적 건축에 대한 담론을 외부로 드러나는 형상적 특징과 더불어 구조와 재료, 그리고 그것이 공간에 끼치는 영향에 까지 논의의 범위를 넓힐 수 있는 기회를 제공한다.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
• /
• pp.92-93
• /
• 2014

This study was carried out to process the shape of dry bottom ash using the impact crusher and gravity crusher, which are identified as most effective in improving grain shape through the preceding research, and a comparison was made between concrete that utilized the processed dry bottom ash as aggregate and concrete containing dry bottom ash before processing to understand properties of the new concrete.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2017년도 춘계 학술논문 발표대회
• /
• pp.71-72
• /
• 2017

The oyster shell is lightweight and exhibits strength characteristics similar to sand. In this study, mortar specimens were fabricated by crushing them and processed to 5mm or less of the fine aggregate standard, and examined the fire resistance of the mortar according to changes in particle size distribution. In this experiment, seven particle size distribution conditions were tested. In addition, the mixing ratio was fixed at 1: 3, and the experiment was conducted in terms of the volume ratio because the densities of sand and oyster shells were different.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
• /
• pp.405-408
• /
• 2006

In this study it compares a Japanese standards which is most similar contents with domestic standards related with the light weight aggregate concrete and derives the fundamental data from the results so that it will be able to refer at maintenance of standards or specifications in future. The case of domestic is the actual more insufficient condition which is described in the standards and the specifications than Japanese standards. For the production of he domestic light weight concrete the development of general standards and construction guides and control of water content ratio of the light weight aggregates become accomplished rightly in quality of construction site.