본 연구는 순환골재를 사용한 콘크리트의 활용증대 방안으로 철근콘크리트 구조물의 노후화와 내구성 저하 시 보수 보강으로 사용되는 FRP (AFRP, CFRP) 판으로 보강된 순환골재 고강도콘크리트(40MPa, 60MPa) 보를 제작하여 순환골재 철근콘크리트 보의 휨 보강에 대한 적용성을 평가하고자 한다 기존의 표면매입보강에 따른 에폭시와 FRP 판의 부착력을 고려하지 않기 위해 콘크리트 타설 전 FRP 보강판을 거푸집에 미리 설치하였으며, 순환골재 치환율(30%), 콘크리트 강도(40MPa, 60MPa), 이형철근(D10, D13), FRP 판의 종류(AFRP 판, CFRP 판)를 변수로 12개 실험체를 제작하여, FRP 판과 순환골재 치환율에 따른 휨 성능을 분석하였다. 그 결과 FRP 판으로 보강한 실험체는 무보강 실험체에 비해 최대 17% 증가하는 경향을 나타내었으며 AFRP 판에 비해 CFRP 판의 보강 성능이 우수한 것으로 나타났다. 또한 순환골재 치환율에 따른 보강 성능의 차이는 없는 것으로 나타났다. 실험에 의해 측정된 균열모멘트는 파괴계수를 이용한 결과 기준식과 비슷한 값을 나타났으며 휨 모멘트는 FRP 판을 보강한 일부 시험체가 KCI 2012와 ACI 440-2R에서 제시한 기준을 만족하지 못하는 것으로 나타났다.
본 연구는 순환골재를 사용한 콘크리트의 활용증대 방안으로 철근콘크리트 구조물의 노후화와 내구성 저하 시 보수 보강으로 사용되는 FRP (AFRP, CFRP) 판으로 보강된 순환골재 고강도콘크리트(40MPa, 60MPa) 보를 제작하여 순환골재 철근콘크리트 보의 휨 보강에 대한 적용성을 평가하고자 한다 기존의 표면매입보강에 따른 에폭시와 FRP 판의 부착력을 고려하지 않기 위해 콘크리트 타설 전 FRP 보강판을 거푸집에 미리 설치하였으며, 순환골재 치환율(30%), 콘크리트 강도(40MPa, 60MPa), 이형철근(D10, D13), FRP 판의 종류(AFRP 판, CFRP 판)를 변수로 12개 실험체를 제작하여, FRP 판과 순환골재 치환율에 따른 휨 성능을 분석하였다. 그 결과 FRP 판으로 보강한 실험체는 무보강 실험체에 비해 최대 17% 증가하는 경향을 나타내었으며 AFRP 판에 비해 CFRP 판의 보강 성능이 우수한 것으로 나타났다. 또한 순환골재 치환율에 따른 보강 성능의 차이는 없는 것으로 나타났다. 실험에 의해 측정된 균열모멘트는 파괴계수를 이용한 결과 기준식과 비슷한 값을 나타났으며 휨 모멘트는 FRP 판을 보강한 일부 시험체가 KCI 2012와 ACI 440-2R에서 제시한 기준을 만족하지 못하는 것으로 나타났다.
As means to increase the use of concrete with recycled coarse aggregate (RCA), this study aims to evaluate the applicability for flexural strengthening of reinforced concrete beam with high-strength concretes and RCA on which FRP plates, used for repair and strengthening of old and low-durability re...
As means to increase the use of concrete with recycled coarse aggregate (RCA), this study aims to evaluate the applicability for flexural strengthening of reinforced concrete beam with high-strength concretes and RCA on which FRP plates, used for repair and strengthening of old and low-durability reinforced concrete structures, is applied. In order to increase the adhesive force of epoxy and FRP plate, FRP plate was installed according to Near-Surface-Mounted (NSM) method. 12 specimens were manufactured using substitution rate of RCA (30%), concrete strengths (40MPa, 60MPa), diameters of deformed bar (D10, D13), and types of FRP plate (AFRP, CFRP) as variables to analyse flexural performance according to FRP plate and substitution rate of recycled aggregate. As a result, in all specimens, specimens strengthened by FRP plate showed a maximum of 17% increase in performance compared to specimens without FRP plate and strengthening performance of CFRP was found to be higher than AFRP. When modulus of rupture was used, the value of cracking moment was similar to that of the reference equation. As bending moment of some specimens strengthened by FRP plate failed to satisfy the criteria of KCI 2012 and ACI 440-2R, additional experiment is deemed as necessary.
As means to increase the use of concrete with recycled coarse aggregate (RCA), this study aims to evaluate the applicability for flexural strengthening of reinforced concrete beam with high-strength concretes and RCA on which FRP plates, used for repair and strengthening of old and low-durability reinforced concrete structures, is applied. In order to increase the adhesive force of epoxy and FRP plate, FRP plate was installed according to Near-Surface-Mounted (NSM) method. 12 specimens were manufactured using substitution rate of RCA (30%), concrete strengths (40MPa, 60MPa), diameters of deformed bar (D10, D13), and types of FRP plate (AFRP, CFRP) as variables to analyse flexural performance according to FRP plate and substitution rate of recycled aggregate. As a result, in all specimens, specimens strengthened by FRP plate showed a maximum of 17% increase in performance compared to specimens without FRP plate and strengthening performance of CFRP was found to be higher than AFRP. When modulus of rupture was used, the value of cracking moment was similar to that of the reference equation. As bending moment of some specimens strengthened by FRP plate failed to satisfy the criteria of KCI 2012 and ACI 440-2R, additional experiment is deemed as necessary.
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문제 정의
Problems about reduced durability and strength during the use of RCA need to be supplemented. Therefore, as means to increase the use of concrete with RCA, the aim of this study is to evaluate the applicability for flexural strengthening of high strength reinforced concrete member with RCA by experimental works. For flexural strengthening, FRP plates (AFRP plate, CFRP plate) were applied.
This study was an evaluation on flexural performance of high-strength reinforced concrete beam according to substitution rate of RCA strengthened by FRP plate. 12 specimens were manufactured to conduct an experiment on applicability of the current standards and practicality of RCA concrete.
제안 방법
Shapes of reinforced concrete beams strengthened by FRP plate and specimens are listed in Fig. 1 and Table 1. FRP plate was installed on the form prior to casting of concrete in this experiment in order to exclude bonding strength of epoxy and NSM FRP plate from consideration. To evaluate flexural behaviour of high strength reinforced concrete beam with RCA strengthened by FRP plate, Series 1-Series 4 were manufactured.
성능/효과
, 2004). As a result, there was no difference in flexural performance of high-strength reinforced concrete beam according to substitution rate of RCA, and all specimens substituted with RCA concrete of 60MPa showed higher performance than specimens with 0% substitution of RCA. Song conducted experiment using material characteristics and substitution rate of recycled coarse aggregate and recycled fine aggregate as variables (S.
As result of comparing cracking moment measured by the experiment to the reference value in design, all specimens other than Series 3, Series 4 and C-D13-40 specimen showed higher cracking moment than the reference. Overall range of cracking moment was 0.
참고문헌 (15)
A. Nami. (2010), FRP Reinforcement for Bridge Structures, Proceedings, Structural Engineering Conference Beams, Journal of Composites for Construction, 5(1), 12-17.
ACI Committee 440. (2002), Guide for the Design and Construction of Concrete Reinforced with FRP Bars. (ACI440.2R-02), American Concrete Institute, 41.
D. H. Lim. (2008), An Experimental Study on the Flexural Behavior of RC Beams Strengthened with Near-Surface-Mounted CFRP Strips, Journal of the Korea Institute for Structural Maintenance and Inspection, 12(6), 89-96.
D. J. Oehlers, R. Rashid and R. Seracino. (2007), IC debonding resistance of group of FRP NSM strips in reinforced concrete beams, ELSEVIER.
I. Maruyma, M. Sogo, T. Sogabe, R. Sato and K. Kawai. (2004), Flexural Properties of Reinforced Recycled Concrete Beams, Proceedings RILENM Symp. International RILEM Conference on the Use of Recycled Materials in Buildings and Structures, 525-535.
J. R. Yost, S. P. Gross, D. W. Dinehart and J. J. Mildenberg. (2007), Flexural Behavior of Concrete Beams Strengthened with Near-Surface Mounted CFRP Strips, ACI Structural Journal, 104(4), 430-437.
L. De Lorenzis and J. G. Teng. (2007), Near-surface mounted FRP reinforcement: An emerging technique for strengthening structures, Composite Part B, 38, 119-143.
L. De Lorenzis, A. Nanni and A. La Tegola. (2000), Flexural and Shear Strengthening of Reinforced Concrete Structures with Near Surface Mounted FRP Rods, Proceedings ACMBS III Symp. The 3rd International Conference on Advanced Composite Materials in Bridges and Structures (ACMBS III), 521-528.
Ministry of Environment. (2010), Construction Waste Recycling Promotion Act.
R. EI-Hacha and S. H. Rizkalla. (2004), Near-Surface-Mounted Fiber-Reinforced Polymer Reinforcements for Flexural Strengthening of concrete Structures, ACI Structural Journal, 101(5), 717-726.
R. Seracino, M. R Raizal Saifulnaz and D. J. Oehlers. (2007), Generic intermediate crack debonding resistance of EB and NSM plate-to-concrete joints, Composite Construction Journal, 11(1), 62-70.
S. H. Song, K. S Choi, Y. C. You, K. H. Kim and H. D. Yun. (2009), Flexural Behavior of Reinforced Recycled Aggregate Concrete Beams, Journal of the Korea Concrete Institute, 21(4), 431-439.
S. Rizkalla and R. EI-Hacha. (2004), Near-Surface-Fiber-Reinforced Polymer Reinforcements for Flexural Strengthening of Concrete Structures, ACI Structural Journal, 101(5), 717-726.
S. Y. Seo, K. B. Choi and Y. S. Kwon. (2012), Retrofit Capacity of Near-Surface-Mounted RC Beam by using FRP Plate, Journal of the Korea Institute for Structural Maintenance and Inspection, 16(1),18-26.
Y. T. Lee, S. U. Hong, S. H. Kim, S. K. Baek and Y. S. Cho. (2014), Flexural Behavior of High Strength Reinforced Concrete Beams by Replacement Ratios of Recycled Coarse Aggregate, Journal of the Korea Institute for Structural Maintenance and Inspection, 18(1), 1-9.
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