• 한국세라믹학회지
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• 제47권5호
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• pp.357-364
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• 2010

This study was performed to get basic information about properties of high blaine slag cement(HSC) to use shotcrete(or sprayed concrete and mortar). Particle size distribution, setting time and compressive strength test, analysis like as SEM, DSC thermal analysis, XRD was carried out to investigate principle properties of HSC. Setting time of HSC was delayed slightly, but influence of accelerators was more bigger than ordinary portland cement(OPC). Compressive strength of HSC at 28 days was more higher than OPC regardless of using accelerators. Results of analysis showed early period hydration products of HSC is more small and located widely, because of the interface of between cement particle and water is increased as specific surface of cement increase. From the SEM observation and analysis of DSC and XRD results, aluminates accelerators bring on some hydration products like as calcium aluminium hydrates, alkali free accelerators increases ettringite and monosulfates. Aluminates accelerators has a advantage of setting time and early strength, alkali free accelerators increases strength after 7 days.

• 한국구조물진단유지관리공학회 논문집
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• 제23권1호
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• pp.163-170
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• 2019

최근 들어, 첨단산업의 발전으로 다양한 종류의 산업폐기물이 빠르게 발생하고 있다. 특히, 산업폐기물 중 중금속을 함유한 고밀도의 폐 브라운관 유리는 재처리 비용과 환경오염 문제로 인해 전량 매립 처분되고 있다. 따라서 이러한 폐자원을 재활용하기 위한 기초 연구가 필요한 실정이다. 이에 본 연구에서는 중금속이 함유된 CRT 폐유리를 잔골재로 대체한 모르타르 시험체의 기초 물성과 방사선 차폐 성능을 분석하여 차폐 재료로의 활용성을 평가하였다. 연구 결과에 따르면 중금속을 함유한 CRT 폐유리를 잔골재로 대체한 시험체의 겉보기 밀도가 상승하였으며, 압축강도와 휨강도는 저하되는 현상을 나타냈다. 또한, 납 성분이 다량 함유된 폐유리 대체 시험체는 일반 모르타르 시험체보다 저에너지의 차폐 성능이 상승하는 효과를 보였으며, $122KeV{\cdot}^{57}Co$ 방사선원에 대해서는 일반 모르타르 시험체보다 2.5배 높은 선형감쇠계수를 나타냈다.

• 한국건축시공학회지
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• 제12권5호
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• pp.490-502
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• 2012

The use of recycled aggregate, even for low-performance concrete, has been very limited because recycled aggregate, which contains a large amount of old mortar, is very low in quality. To produce a high-quality recycled aggregate, removing the paste that adheres to the recycled aggregate is very important. We have conducted research on a complex abrasion method, which removes the component of cement paste from recycled fine aggregate by using both a low-speed wet abrasion crusher as a mechanical process and neutralization as chemical processes, and well as research on the optimal manufacturing condition of recycled fine aggregates. Subsequently, we evaluated the quality of recycled fine aggregate manufactured using these methods, and tested the specimen made by this aggregate. As a result, it was found that recycled fine aggregates produced by considering the aforementioned optimal abrasion condition with the use of sulfuric acid as reactant showed excellent quality, recording a dry density of 2.4 and an absorption ratio of 2.94. Furthermore, it was discovered that gypsum, which is a reaction product occurring in the process, did not significantly affect the quality of aggregates. Furthermore, the test of mortar using this aggregate, when gypsum was included as a reaction product, showed no obvious retarding effect. However, the test sample containing gypsum recorded a long-term strength of 25.7MPa, whereas the test sample that did not contain gypsum posted a long-term strength of 29.4MPa. Thus, it is thought to be necessary to conduct additional research into the soundness and durability because it showed a clear reduction of strength.

• 한국건축시공학회지
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• 제21권3호
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• pp.189-194
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• 2021

본 연구에서는 Lab. 스케일 LIBS 장치를 제작하여 모르타르 내 염화물 분석에서의 LIBS 적용성과 재현성 검토를 수행하였다. 염화물 함량을 조절한 모르타르를 대상으로 기존의 분석방법(XRF, 전위차 적정법)과 LIBS 분석을 동시에 진행하였다. LIBS 분석 결과, 염소이온은 837.59nm 파장에서 검출되었고, 다양한 농도 구간에서의 정밀도를 향상시키기 위하여 전기장 강화를 통한 약 50배의 LIBS 신호증폭을 구현하였다. 수용액 기반의 재현성을 검증을 통하여 LIBS 신호 강도와 Cl농도 사이의 높은 상관관계를 확인할수 있었으며, 콘크리트 염해 내구성 진단에 LIBS적용 가능성을 확인하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 추계 학술논문 발표대회
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• pp.137-140
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• 2009

Nowadays, the high performance composite materials are famous for the new construction materials as the construction buildings are bigger and higher. Out of them of all, the fiber reinforced concrete and mortar have been studied to develop and strengthen the performances of concrete, such as tensile strength, durability and the resistibility of crack. Also, it is considered that precast concrete is important alternatives of dry process for saving time, upgrading the material's quality and the productivity. Thus, PC panel is being produced for the use of dry wall as well as exterior finishing materials and it requires lots of tests and studies to be conducted to meet the various functional conditions. According to this study, it is considered that PVA fiber might be more effective than nylon fiber for developing the exterior PC panels.

• International Journal of Concrete Structures and Materials
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• 제8권2호
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• pp.165-172
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• 2014

Recycled coarse aggregate (RCA) made from waste concrete is not a suitable structural material as it has high absorption of cement mortar, which adheres on the aggregate surface and on the tiny cracks thereon. Therefore, when using RCA made from waste concrete, much water must be added with the concrete, and slump loss occurs when transporting. Hence, its workability is significantly worse than that of other materials. In this study, surface of RCA was coated with water-soluble polycarboxylate (PC) dispersant so that its characteristics improved. Each possibility was evaluated: whether its slump loss can be controlled, by measuring its workability based on the elapsed time; and whether it can be used as a structural material, by measuring its strength. Moreover, the carbonation due to cement mortar adhesion was measured through a carbonation test. As a result, RCA coated with PC dispersant was found to be better than crushed coarse aggregate and RCA when the physical properties of the fresh concrete and the mechanical, durability of the hardened concrete were tested.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 가을 학술발표회 논문집
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• pp.508-513
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• 1996

The purpose of this paper, having chosen the connection method, filled by High-strength mortar, in conncetion of PC member, is to study the mechanical behaviour and practical usage of the method. The paper estimates the connection ability of Reinforced-bar, that is, Sleeve considering the effect of Reinforced-bar's dimeter. Sleeve's length and diameter in the structural behaviour of mortar-filled connection, therefore the behaviour of Splice-Sleeve exists in concrete practically. This paper discusses the effect of the concrete in Splice-Sleeve. Also, to estimate structural behaviour in a practical wall panel, the upper and bottom wall panels are produced and the behaviour of Splice-Sleeve is discussed. And then Vertical Tie Bar being designed by using Precast method, this paper presents the various application and the practicable method using Splice-Sleeve.

• 콘크리트학회논문집
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• 제17권6호
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• pp.1085-1090
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• 2005

Rod-type fiber reinforced polymer plastics(FRPs) similar to reinforcing steel bars have rarely been considered. In this study, an experiment was performed using beams strengthened with rod-type CFRPs and high-strength mortar overlay. The test results show that the strengthened beams not only had improved endurance limits but also improved load carrying capacities, stiffness values, and cracking loads as compared to a non-strengthened beam. Strengthened beams anchored with bolts throughout their entire span had more efficient structural behaviors, including composite behavior on the interface between the concrete and mortar, and load carrying capacity, than a strengthened beam anchored only on the end block.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.46-47
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• 2015

This study has analyzed the engineering characteristics of resource-cycling mortar according to the variation of fine aggregate type using illite with high development potentials by setting the goal as developing eco-friendly construction materials. As a result, while flow has increased if recycled fine aggregate and waste refractory are used separately or mixing them adequately in case of flow and compressive strength, the flow had somewhat declined followed by illite replacement. However, the possibility of such usage is determined to be adequate if used by mixing illite, recycled fine aggregate and waste refractory properly due to the dry shrinkage effect.

• 자원리싸이클링
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• 제28권6호
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• pp.64-72
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• 2019

플라이애시는 발전소의 탄종 및 품질에 따라 화학조성이 다르고 품질 변화가 크며 탄소함량과 입경에 따라 분류하며, 폐유리분말은 파유리를 분쇄하여 제조하고 분쇄정도에 따라 분류한다. 건축물의 외단열 공법은 경제적이면서 단열성능이 우수한 폴리스티렌 폼 단열재를 활용한 공법이 일반적이다. 하지만 유기계 단열재는 단열성능이 우수하나 화재에 취약하고 다수의 문제점이 지적되었다. 본 연구에서는 플라이애시와 폐유리분말을 사용하여 고온에서 안정한 외단열용 마감모르타르를 제작하고 고온 강도 및 난연 특성을 검토하였다. 실험 결과, 플라이애시와 폐유리분말을 이용한 마감모르타르는 고온에서의 안전성이 높았다. 하지만 강도감소의 폭이 크므로 적절한 배합조건의 선정이 필요하다.