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김성운 ( Sungun Kim ),최창정 ( Changjeong Choi ),안재규 ( Jaekye Ahn ),( Youngsam Kim ),김광우 ( Kwang W. Kim ) 한국농공학회 2019 한국농공학회 학술대회초록집 Vol.2019 No.-
아스팔트 혼합물은 생산, 시공 및 유지보수가 용이하고, 비용이 저렴하여 차도, 보도, 광장, 산책로, 농로, 시골길 등 광범위하게 적용되는 도로 포장용 재료이다. 일반적으로 차도용 아스팔트 혼합물은 굵은 골재, 잔골재, 채움재 등이 규정된 합성입도 기준을 만족하는 적절한 비율로 혼합되어 차량의 하중을 지지하는 구조적 안정성과 내구성, 주행 안전을 위한 미끄럼 저항성을 확보하여 차량의 운행을 가능하게 하는 표장면을 제공한다. 또한, 잔골재만을 사용하여 제조한 샌드 아스팔트 혼합물(sand asphalt mixture: SAM)은 시공 후 포장 표면이 부드럽고 고운 평탄성을 제공하므로 보도, 산책로, 농촌 소도로 등에 적용이 유리하다. 아스팔트 혼합물은 생산온도 범위에 따라서 가열아스팔트 혼합물(hot mix asphalt: HMA), 준고온 아스팔트 혼합물(warm mix asphalt: WMA), 상온 아스팔트 혼합물(cold mix asphalt: CMA)로 구분할 수 있다. 준고온 아스팔트 혼합물은 가열 아스팔트 혼합물과 비교하여 30∼40℃ 낮은 온도에서 생산하므로 골재가열에 소모하는 화석연료 저감, 이로 인한 온실가스 배출저감 등 환경적, 경제적 효과가 있으며, HMA와 비교하여 낮은 온도에서 시공되므로 작업안전에 유리하여 유럽, 미국 등 해외 여러 나라에서 널리 적용되고 있다. 본 연구에서는 준고온 방식으로 SAM을 제조하기 위해서 준고온 아스팔트 바인더를 개발하고, 5mm 이하의 잔골재, 채움재, CRM(crum rubber modifier), 소석회(hydrated lime)를 사용하여 준고온 샌드 아스팔트 혼합물(warm mix sand asphalt mixture: WSAM) 배합설계를 수행하여 최적 아스팔트 함량(optimum asphalt content: OAC)을 결정하였다. OAC로 실험용 공시체를 제조하여 내구성, 변형저항성, 균열저항성, 충격흡수 특성 평가를 위한 변형강도(deformation strength: SD), 간접인장강도(indirect tensile strength: ITS), 인장강도비(tensile strength ratio: TSR), 변형강도비(deformation strength ratio: SDR), 낙구(drop boll) 실험을 수행하였다. 더불어 가열방식으로 제조한 샌드아스팔트 혼합믈 (hot mix sand asphalt mixture: HSAM)과 제반 특성을 비교하여 성능을 평가하였다. 연구결과 WSAM은 HSAM과 비교하여 변형저항성, 균열저항성, 수분민감성, 충흡수 특성이 유사하게 평가되었고, 이는 준고온 아스팔트 바인더 제조 시 사용된 다양한 첨가제 및 개질재의 영향으로 판단되었다.
김광우 ( Kim Kwang W ),도영수 ( Young S Doh ),이상범 ( Xiang Fan Li ) 한국농공학회 2001 韓國農工學會誌 : 전원과 자원 Vol.43 No.2
This study deals with coal-mine waste (CMW) for use in concrete as a replacement of normal aggregates. The CMW was collected from Sabuk region. Ganwon-do. Fine and coarse aggregates from CMW were prepared by using a crusher and separating debris with #4 sieve. CMW aggregates showed good physical and mechanical properties with having specific gravity over 2.65, absorption less than 1%, and abrasion ratio below 20%. However, particle shape of CMW was poor because of non-isotropic nature of matrix which cause particles to be long or flat. Since irregular particles caused a poor workability, to make workability better, a 1/4 of coarse aggregate was replaced with normal aggregate together with a superplasticizer. Compressive strength and other mechanical properties of CMW concrete were very good. Color of the concrete was darker than normal concrete due to black color of CMW. In conclusion, characteristics of CMW concrete was acceptable for use as a structural concrete material.
공시체 구속 상태에서 정하중 시험에 의한 SMA 혼합물의 소성변형 저항성평가 가능성
김성운 ( Kim Sunguna ),최창정 ( Choi Chang-jeongb ),김광우 ( Kim Kwang W. ) 한국농공학회 2019 한국농공학회논문집 Vol.61 No.3
It is well-known fact that the stone-mastic asphalt (SMA) mixture has shown superior rut resistance, compared with the dense-graded asphalt (DGA) mixture in highway pavements. However, the SMA is measured to be inferior to DGA mixes when tested by well-known high-temperature test methods, such as the wheel tracking (WT), asphalt pavement analyzer, the Marshall Stability and Kim Test. Therefore, this study examined the reasons why it was measured to be inferior, and devised a potential procedure by which the superiority of SMA could be measured at 60℃. The strength against deformation (S<sub>D</sub>), which was known to show very high correlation with WT results for DGA mixes, was measured by the Kim Test on the specimen confined in the compacted mold. In standard Kim Test, which used the specimen without confinement, the DGA was measured to show higher S<sub>D</sub> than the SMA. But by confining specimen, it was found that the S<sub>D</sub> of SMA was measured to be higher than that of DGA. Therefore, the confined static test protocol devised in this study was found to be feasible for evaluating rut resistance of SMA mix.
최동춘 ( Dong Choon Choi ),( Javeed A. Munsh ),김광우 ( Kwang W. Kim ) 한국농공학회 2001 韓國農工學會誌 : 전원과 자원 Vol.43 No.5
This paper represents results of an effort to seismically rehabilitate a 12-story nonductile reinforced concrete frame building. The frame located in the most severe seismic area, zone 4, is assumed to be designed and detailed for gravity load requirements only. Both pushover and nonlinear time-history analyses are carried out to determine strength, deformation capacity and the vulnerability of the building. The analysis strength. Deformation capacity and the vulnerability of the building. The analysis indicates a drift concentration at the 1<sup>st</sup> floor level due to inadequate strength and ductility capacity of the ground floor columns. The capacity curve of the structure, when superimposed on the average demand response spectrum for the ensemble of scaled earthquakes indicates that the structure is extremely weak and requires a major retrofit. The retrofit of the building is attempted using viscoelastic (VE) dampers. The dampers at each floor level are sized in order to reduce the elastic story drift ratios to within 1%. It is found that this requires substantially large dampers that are not practically feasible. With practical size dampers, the analyses of the viscoelastically damped building indicates that the damper sizes provided are not sufficient enough to remove the biased response and drift concentration of the building. The results indicate that VE-dampers alone are not sufficient to rehabilitate such a concrete frame. Concrete buildings, in general. Being stiffer require larger dampers. The second rehabilitation strategy uses concrete shearwalls. Shearwalls increased stiffness and strength of the building, which resulted in reducing the drift significantly. The effectiveness of VE-dampers in conjunction with stiff shearwalls was also studied. Considering the economy and effectiveness, it is concluded that shearwalls were the most feasible solution for seismic rehabilitation of such buildings.
다짐온도에 따른 변형강도 변화를 통한 아스팔트 콘크리트의 철도노반 적용성 평가
박지용(Ji-Yong Park),최광수(Kwang-Soo Choi),이성진(Sung-Jin Lee),김성운(Sungun Kim),나일호(Ilho Na),김광우(Kwang W. Kim) 한국철도학회 2012 한국철도학회 학술발표대회논문집 Vol.2012 No.10
아스팔트 콘크리트 철도노반은 여러 가지 장점 때문에 선진국에서는 많이 적용되고 있어 국내에서도 철도에 적용성 연구가 필요하다. 아스팔트 포장은 소성변형 발생의 우려가 커 사전에 강도시험 등을 통해 공용성 확인이 필요하며, 철도용 아스팔트 콘크리트도 같은 맥락에서 소성변형에 대한 평가가 필요하다. 이에 본 연구에서는 변형강도(SD)를 사용하여 가열 아스팔트(HMA) 콘크리트와 준고온 아스팔트(WMA) 콘크리트의 소성변형 저항성을 평가하여 적정다짐온도를 추정하였다. 연구 결과 일반 아스팔트 혼합물은 HMA 135℃, WMA 105℃ 이상, PMA에서는 HMA155℃, WMA 125℃ 이상이 적정 다짐온도로 확인되었다. Since asphalt concrete is widely used for railroad base in advanced countries due to many advantages, the preliminary research for its applicability is necessary in Korea. Asphalt concrete is prone to deform (rut) in hot environment, and therefore, the rut resistance of asphalt concrete for railroad is also need to be evaluate. The rut resistance of hot-mix asphalt (HMA) concrete and warm-mix asphalt (WMA) concrete was evaluated to determine optimum compaction temperature (OCT) using deformation strength (SD). The results showed that OCT values of normal asphalt HMA and WMA were 135℃ and 105℃ , respectively, and those of polymer-modified HMA and WMA were 155℃ and 125℃, respectively.