This paper provides the flexural test results of steel fiber reinforced concrete (SFRC) prisms with different aspect ratios of steel fibers (60 and 67). All mixtures have specific compressive strength of 40 MPa and steel fiber volume fraction of 0.75%. According to ASTM C 1609 and EN-14651, SFRC prisms with 150×150×550 mm were made and tested under bending loading. Test results indicated that the aspect ratio of hooked-end steel fibers has insignificant effect on the first-cracking strength and flexural behavior of SFRC prisms.

This paper presents the flexural test results of steel fiber reinforced concrete (SFRC) prisms with different lengths of steel fibers. The specified compressive strength of SFRC is 40 MPa. Two types of steel fiber used in this study have lengths (0.5 and 0.9mm). Test results indicated that steel fibers with longer length is more effective to improve the flexural performance of concrete prisms than steel fibers with shorter length.

이 연구에서는 순환굵은골재를 사용하여 31∼38 MPa 범주의 압축강도를 갖는 콘크리트의 보의 휨강도 실험연구를 수행하였다. 천 연굵은골재에 대한 순환굵은골재의 치환률과 철근비를 실험변수로 고려하였다. 순환굵은골재의 치환률로써 0, 30, 50 및 100%를 고려하였으 며, 주철근의 철근비로써 0.50, 0.79 및 1.14%를 고려하였다. 4점 하중재하 시험방법을 통하여 순환골재 콘크리트 보의 균열 및 파괴거동, 하중- 처짐 관계 특성을 파악하였다. 천연굵은골재 보와 순환굵은골재 보의 휨균열 형상은 거의 유사하며, 전반적으로 순환굵은골재 보의 균열간격 이 천연굵은골재 보의 균열간격보다 작다. 순환골재치환률에 따른 균열폭 크기는 뚜렷한 차이를 나타내지 않는다. 또한, 설계기준에 의한 예측 식을 이용하여 실험 부재의 휨강도를 산정하였다.현행 설계기준에 의한 순환골재 콘크리트 보의 휨강도 예측결과는 실제의 휨강도를 과소평 가하여 보수적인 설계를 제공하는 것으로 나타난다.

The purpose of this paper is to evaluate the flexural strength and deflections developed of FRC beam with tensile bars composed of two layers combinations of steel bar, GFRP bar, and CFRP bar. As a test result, specimen with CFRP bars had the greatest maximum flexural strength. Specimens with FRP bars had more brittle failure behavior than only steel bars.

The minimum reinforced in RC flexural members is prescribed to avoid sudden and brittle in overload. The minimum reinforced depends on the geometrical and materials parameter of RC members. In this paper ,the influence of the geometrical and materials parameter on the minimum reinforcing steel beam has been investigated.

The ultimate load of beam reinforced with polymer cement slurry(PCS)-coated rebar is a little lower than that of un-coated rebar, and almost the same as that epoxy-coated rebar. In special, that using EVA 50% with is in range of 97.0% of un-coated rebar. In this study, it is also apparent that PCS-coated rebar can replace epoxy-coated rebar to solve the corrosion problem in marine construction field.

This paper presents an experimental study on the improvement of ductile and flexural strength for high performance fiber reinforced cementitous composites (HPFRCC). The test was evaluated by compressive and flexural behavior of HPFRCC(compressive strength : 180 MPa) according to aspect ratio and volume contents of steel fiber. The flexural strength was increased by aspect ratio near 100 or increasing volume contents of steel fiber while there is no clearly result on the compressive strength.

In this study, We evaluated the applicability of high performance fiber reinforced cementitious composite (HPFRCC) with compressive strength of 180, 140 and 100 MPa and identical contents in steel fiber. The analysis of the flexure tensile behavior showed that HPRFCC presents deflection hardening after the initiation of cracks and exhibits higher energy absorbing capacity with high compressive strength.

The purpose of this research is to evaluate the standard deviation and coefficient of variation for flexural strength of lathe scrap reinforced cementitious composites. For this purpose, the cementitious composites containing lathe scrap were repeatedly made 5 times for water-binder ratio of 30%, 2mm width and 40mm length of lathe scrap, and then the standard deviation and coefficient of variation of the cementitious composites were estimated. It was observed from the test results that the standard deviation and coefficient of variation of the cementitious composites were slightly larger than plain mortar but did not matter much.

This study was evaluated of flexure strength and ductility of a V-tie arrangement method in reinforced concrete columns under a variable axial force. The axial load level varied to be 0.25, 0.4, and 0.55 for columns with V-ties or crossties. As compared with displacement ductility ratio and the work damage indicator of the companion crosstie columns, the V-tie columns had higher value as much as 1.5 times, 5.2 times for the axial load level of 0.55, respectively.

This study presents the results of an experimental program carried out for estimating the variation of the flexural rigidity of reinforced concrete beams with different shear span-to-depth ratios. The specimens are designed to have identical sectional dimension, tension and compression reinforcement ratios, and material properties, except shear span-to-depth ratio. Experimental results showed that the flexural rigidity of reinforced concrete beams was affected by the shear span-to-depth ratio of specimens.

이 연구의 목표는 학교 건물과 같은 저층 보－기둥 철근콘크리트 구조 건물에서 프리캐스트 벽패널을 사용한 새로운 내진보강 방법을 개발하는 것이다. 1개의 무 보강 보－기둥 실험체와 U형 PC 벽패널로 보강한 2개의 보강 보－기둥 실험체에 대한 정적 이력 하중실험을 진행하였다. 앵커접합 PR1-UA 실험체와 철판접합 PR1-UP 실험체는 무 보강 실험체보다 평균 2.8배(평균 591.8 kN)의 강도 증가를 보여 주었다. 최대 변위비도 1.4%에서 2.7%사이 값을 보여주었다. RC 골조 우측 상단에서 좌측방향으로 가력 할 때 우측에 있는 RC 기둥과 보강 PC 패널의 수직 요소는 완전 합성상태로 가정하였고, 좌측에 있는 RC 기둥과 PC 패널은 완전 비 합성 거동하는 것으로 가정하여 해석한 결과 전체적인 휨 거동은 실험 결과와 대체적으로 부합하는 것으로 판단되었다.

본 연구는 SIFCON 형태의 고성능 강섬유보강 시멘트 복합체의 섬유혼입률에 따른 휨실험을 수행하였고, 실험결과를 바탕으로 휨성능을 평가하였다. 슬러리를 충전하는 형태로 일반 섬유보강시멘트와 달리 높은 섬유혼입률을 확보할 수 있는 장점을 가지고 있다. 주요 실험변수는 섬유혼입률 8.0%, 7.5%, 7.0%, 6.5% 및 6.0% 이며, 각 변수에 대한 휨강도 및 휨인성 특성을 분석하였다. 그 결과, 높은 섬유혼입률로 인하여 초기균열 발생 이후에도 계속적으로 하중이 증가하였으며, 최대강도 이후 충분한 잔류강도를 확보하였다. 또한 최대 50MPa 수준의 높은 휨강도를 발현하였으며, 섬유혼입률에 따른 휨강도 및 휨인성은 비례하여 증가하는 경향으로 나타났다.

The ultimate load of beam reinforced with polymer cement slurry(PCS)-coated rebar that is developed to replace the epoxy coated rebar having many defects is almost the same as that using plain rebar, and is higher than that of epoxy-coated rebar. In special, that using EVA 100% with ultra high early strength cement is a little bigger than that using plain rebar. In this study, it is also apparent that PCS-coated rebar can replace epoxy-coated rebar to solve the corrosion problem in marine construction field.

This study is to determine the flexural reinforcement performance of the RC beam through the NSM reinforcement experiment. To do this, to produce non-reinforced specimen and reinforced specimens were performed the experimental study. As the results of this study, the tension reinforcing steel has been confirmed between the FRP bar and filled material integrated behavior before yielding. Compared with non-reinforced specimen the reinforced specimens showed that the rigidity of the reinforced specimens is higher than that of the non-reinforced specimen about 16.7%, and increases 8.3%~20.0% and 33.3%~52.7% for yielding strength and ultimate strength respectively. It appears an excellent bending reinforcing effect.

The objective of this study is to understand the flexural reinforcement effects of RC slab reinforced with HFRP plate. To this end, an experiment was conducted by fabricated five RC slabs with the variables such as the number of anchors, epoxy injection amount and position. The Strength formula calculation on the specimens, was calculated to apply the ACI 440.2R-08(10.2.10). The results of this study, the stiffness, strength and structural performance of reinforced specimens are appeared very high compared with non-reinforced specimen, so the flexural reinforcement effects were very good. And the flexural reinforcement effects depending on the number of anchors and epoxy injection method was confirmed to differ greatly. Additionally, it is possible to predict the required number of anchors to the structure through the strength formula calculation.

This study was performed to analyze the flexural performance of large diameter PHC Pile reinforced with transveres and longitudinal rebar and in-filled concrete. From the flexural test result, it was found that the initial cracking strength and maximum flexural strength of composite PHC pile were approximately 400% and 345% higher than that of the conventional PHC pile.

This study investigated the flexural performance of high performance fiber reinforced cementitious composite (HPFRCC), which used high strength steel fibers with volume fraction 8%. Under the third-point loading using a closed-loop, servo-controlled testing system (ASTM 1609), load-deflection curves were obtained. The major test variables include silica fume replacement ratio 15% and exposure termperature, ambient and 400°C. The flexural strength was similar to the compressive strength and the absorbed fracture energy was relatively greater than other typical HPFRCC materials. This may be a composite reaction of the strong bonding between steel fiber and matrix and high compressive strength of the matrix itself. Once the specimens were exposed to high temperature 400°C the flexural strength decreased.

Recently, studies of eco-friendly construction materials have been increased. For this reason, this paper presents the material properties of steel fiber reinforced slag concrete. Direct shear, flexural, and CMOD tests were conducted to determine the shear and flexural contribution of steel fiber.

In this study, it was developed eco-friendly alkali-activated slag fiber reinforced concrete using ground granulated blast furnace slag, alkali activator (water glass, sodium hydroxides), and steel fiber. Eight reinforced concrete beam using alkali-activated slag concrete were constructed and tested under monotonic loading. The major variables were mixture ratio of alkali activator, mixed/without of steel fiber. Experimental programs were carried out to improve and evaluate the flexural performance of such test specimens, such as the load-displacement, the failure mode, the maximum load carrying capacity, and ductility capacity. All the specimens were modeled in scale-down size. The reinforced concrete beams using the eco-friendly alkali-activated slag fiber reinforced concrete was failed by the flexure or flexure-shear in general. In addition, the maximum strength increased with the adding the mol of sodium hydroxide, and the specimen reinforced the steel fiber showed the value of maximum strength which is increased by 15.8% through 25.9%. It is thought that eco-friendly alkali-activated slag fiber reinforced concrete can be used with construction material and product to replace normal concrete. If there is applied to structures such as precast concrete member and production of 2nd concrete product, it could be improved the productivity and reduction of construction duration etc.