• 한국농공학회논문집
• /
• 제52권5호
• /
• pp.53-60
• /
• 2010

The effects of blast furnace slag, hwang-toh, and reinforcing fiber on the physical and mechanical properties of porous concrete using blast furnace slag coarse aggregates have been evaluated in this study. The effect of the depending on replacement ratio of blast furnace slag to cement was investigated such that the replacement ratio was varied to 0 %, 25 % and 50 %. Also, the replacement ratios of hwang-toh were 0, 20 and 30 %. The polyvinyl alcohol fiber was used for the reinforcing fiber. A series of pH, unit mass, and void ratio tests have been performed to study the physical properties of the porous concrete using blast furnace slag coarse aggregates with the polyvinyl alcohol fiber and the replacement ratios of blast furnace slag, hwang-toh, while a series of compressive tests have been performed to evaluate the strength property depending on polyvinyl alcohol fiber and the replacement ratios of blast furnace slag, hwang-toh. The test results indicated that the physical and mechanical properties of porous concrete using blast furnace slag coarse aggregates is affected by the replacement ratio of blast furnace slag, and the fiber contents. According to the tests with polyvinyl alcohol fiber contents, the void ratio was decreased and the compressive strength was upgraded.

• Advances in concrete construction
• /
• 제16권1호
• /
• pp.1-20
• /
• 2023

This study presents the experimental results performed to evaluate the effects of Polyvinyl-alcohol (PVA) and Polypropylene (PP) fibers on the fresh and residual mechanical properties of the hybrid fiber reinforced SCC before and after the exposure of 250℃, 500℃ and 750℃ temperatures. The compressive and splitting tensile strength, modulus of rupture (MOR), ultrasonic pulse velocity (UPV) as well as toughness and weight loss were investigated at different temperatures. PVA and PP fibers were added into SCC mixtures having only macro steel fiber and also having binary hybridization of both macro and micro steel fiber. The results showed that the use of micro steel fiber replaced by macro steel fiber improved the fresh and hardened properties compared to the use of only macro steel fiber. Moreover, it was emphasized that PVA or PP enhanced the residual flexural performance of SCC, generally, while it negatively influenced the workability, weight loss, UPV and the residual strengths with regards to the use of single steel fiber and binary steel fiber hybridization. Compared to the effect of synthetic fibers, PP had slightly more positive effect in the view of workability while PVA enhanced the residual mechanical properties more.

• Advances in Computational Design
• /
• 제8권2호
• /
• pp.113-131
• /
• 2023

The use of fibers has been commonly considered in engineered cementitious composites, but their behavior with coarse aggregate in concrete has not been studied significantly, which is needed to meet structural performance objectives for design, such as ductility. This research analyzes the behavior of fiber-reinforced concrete with coarse aggregate with 0.62%, 1.23%, and 2% PVA (Polyvinyl-alcohol) content, varying the maximum aggregate size. Tensile (direct and indirect) and compressive concrete tests were performed. The PVA fiber addition in coarse aggregate concrete increased the ductility in compression, especially for the fiber with a larger aspect ratio, with a minor impact on strength. In addition, the tensile tests showed that the PVA fiber increased the tensile strength of concrete with coarse aggregate and, more significantly, improved the ductility. A selected mixture was used to build short and slender reinforced concrete beams to assess the behavior of structural members. PVA fiber addition in short beams changed the failure mode from shear to flexure, increasing the deflection capacity. On the other hand, the slender beam tests revealed negligible impact with the use of PVA.

• 한국섬유공학회:학술대회논문집
• /
• 한국섬유공학회 2003년도 봄 학술발표회 논문집
• /
• pp.87-90
• /
• 2003

Polyvinyl Alcohol(PVA)와 같이 분자간 결합력이 큰 극성고분자에 극성의 가소제를 도입하여 가역적 가소화기법을 이용하여 비결정영역뿐만 아니라 결정영역까지도 가소화시켜 연신성을 개선시키고자하는 연구가 일부 이루어져 왔다. 특히 요드는 극성고분자의 비결정 영역뿐만 아니라 결정영역까지 침투한다는 사실이 밝혀지면서 PVA의 요드 처리에 대한 연구가 많이 이루어져왔다[1-3]. 그러나 지금까지의 연구에서는 대부분 필름이나 섬유와 같이 성형가공된 상태에서, 즉 결정화가 이루어진 후에 요드화를 시켰기 때문에 그 응용범위나 연구에 있어서 한계를 지니고 있다고 할 수 있다. (중략)

• 콘크리트학회논문집
• /
• 제23권4호
• /
• pp.461-469
• /
• 2011

이 연구에서는 하이브리드 구조용 합성 섬유와 폴리비닐알코올(PVA)섬유 보강 시멘트 복합 재료에 정착된 구조용 합성 섬유의 인발 거동에 미치는 PVA 섬유 혼입률의 효과를 제시하였다. 구조용 합성 섬유와 하이브리드 섬유보강 시멘트 복합 재료와의 인발 거동은 Dog-bone 부착 시험에 의해서 결정하였다. 시험 결과 PVA 섬유의 혼입은 구조용 합성 섬유와 시멘트 복합 재료와의 인발 거동 특히, 섬유 계면인성을 강화하는 효과가 있었다. 구조용 합성 섬유의 인발 시험 결과 구조용 합성 섬유와 시멘트 복합 재료와의 계면인성은 PVA 섬유의 혼입률이 증가할수록 증가하였다. 미세 구조 분석 결과 PVA 섬유의 혼합은 구조용 합성 섬유와 PVA 섬유 보강 시멘트 복합 재료의 계면인성 메커니즘을 강화시키는데 효과적이라는 것을 확인할 수 있었다.

• 섬유기술과 산업
• /
• 제6권1_2호
• /
• pp.83-95
• /
• 2002

• 전기전자학회논문지
• /
• 제13권2호
• /
• pp.216-219
• /
• 2009

$V_2O_5$ 나노선/폴리비닐 알코올(PVA) 고분자 복합체를 나일론 제조법을 응용하여 제작하였고 전기적 특성을 연구하였다. PVA가 아세톤, 에탄올, 메탄올 등의 벤젠기와 반응하여 얇은 막을 형성하는 것을 이용하여 나일론 섬유 제작방법과 유사하게 실타래를 감아올려 나노선 섬유가 섞인 폴리머 섬유를 만들었다. 폴리머-나노선 복합체는 내부에서 전도성이 있는 $V_2O_5$나노선 다발이 네트워크를 형성하기 때문에 전자기장을 차폐할 수 있는 고분자 섬유 등에 적용할 수 있다.

• Structural Engineering and Mechanics
• /
• 제87권4호
• /
• pp.333-346
• /
• 2023

This paper presents findings from an experimental study that was focused on evaluating the use of Forta-Ferro (FF) and Polyvinyl Alcohol (PVA) fibers on the response of moderate and special ductility beams under load cycles. For this reason, eight full-scale specimens, identical in geometry, were subjected to gradual cyclic loading. The specimens included two plain concrete beams with medium and special ductility, three beams with medium ductility and stirrup spacing of one-quarter the effective depth (d/4) and three beams with special ductility, and stirrup spacing of one-half the effective depth (d/2), strengthened with FF and PVA fibers separately. The use of fibers was aimed at reducing the amount of shear reinforcement in flexural members. Here, the variation of parameters including the maximum strength, ultimate strength, stiffness, ductility, damage index, energy dissipation, and equivalent damping was studied. Utilizing FF and PVA fibers improved the performance in beams with moderate ductility when compared to those beams with special ductility. Therefore, in special ductility beams, fibers can be used instead of crossties and in moderate ductility beams, fibers can be added to reduce the ratio of shear reinforcement. Furthermore, increasing the stirrup spacing in the moderate ductility beams from d/4 to d/2 and adding 0.6% FF or 1.5% PVA fibers resulted in behavior similar to those of the moderate ductility beam.

• International Journal of Concrete Structures and Materials
• /
• 제11권1호
• /
• pp.29-43
• /
• 2017

This study investigates the blast resistance of fiber-reinforced cementitious composite (FRCC) panels, with fiber volume fractions of 2%, subjected to contact explosions using an emulsion explosive. A number of FRCC panels with five different fiber mixtures (i.e., micro polyvinyl alcohol fiber, micro polyethylene fiber, macro hooked-end steel fiber, micro polyvinyl alcohol fiber with macro hooked-end steel fiber, and micro polyethylene fiber with macro hooked-end steel fiber) were fabricated and tested. In addition, the blast resistance of plain panels (i.e., non-fiber-reinforced high strength concrete, and non-fiber-reinforced cementitious composites) were examined for comparison with those of the FRCC panels. The resistance of the panels to spall failure improved with the addition of micro synthetic fibers and/or macro hooked-end steel fibers as compared to those of the plain panels. The fracture energy of the FRCC panels was significantly higher than that of the plain panels, which reduced the local damage experienced by the FRCCs. The cracks on the back side of the micro synthetic fiber-reinforced panel due to contact explosions were greatly controlled compared to the macro hooked-end steel fiber-reinforced panel. However, the blast resistance of the macro hooked-end steel fiber-reinforced panel was improved by hybrid with micro synthetic fibers.

• 복합신소재구조학회 논문집
• /
• 제6권4호
• /
• pp.58-63
• /
• 2015

The purpose of this experimental research is to evaluate the workability and strength properties of hybrid fiber reinforced concrete containing amorphous steel fiber and organic fiber. For this purpose, the hybrid fiber reinforced concrete containing amorphous steel fiber(ASF) with polyamide(PA) and polyvinyl alcohol(PVA) fiber, respectively were made according to their total volume fraction of 0.5% for water-binder ratio of 33%, and then the characteristics such as the workability, compressive strength, and flexural strength of those were investigated. It was observed from the test results that the workability and compressive strength at 7 and 28 days were decreased and the flexural strength at 7 and 28 days was increased with increasing ASF and decreasing organic fiber.