• 콘크리트학회지
• /
• 제2권1호
• /
• pp.14-17
• /
• 1990

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1993년도 봄 학술발표회 논문집
• /
• pp.93-98
• /
• 1993

In order to discuss the mechanical properties of fiber reinforced composites with fly ash, lime, gypsum and polymer emulsion-Stylene Butadiene Rubber Latex (SBR) , experimental studies on FRC were carried out. The kinds of fiber used in FRC are PAN-dervied and Pitch-derived carbon fiver, alkali-resistance glass fiber. As a test results, the flexural strength and tougthness of fiber reinforced fly ash. lime.gypsum cement composites are remarkably increased by fiber contents ,but compressive strength of the composites are influenced by kinds of fiber more than by fiber contents. Also, addition of a polymer emulsion (SBR) to the composites decreased the bulk specific gravity, but compressive and flexural strengths, toughness of the composites are not influenced by it, are considerably improved by increasing fiber contents.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
• /
• pp.292-295
• /
• 2004

Recently, polymer-clay hybrid materials have received considerable attention from both a fundamental research and application point of view. This organ-inorganic hybrid, which contains a nanoscale dispersion of the layered silicates, is a material with greatly improved thermal and mechanical characteristics. Two classes of nanocomposites were synthesized using an unsaturated polyester resin as the matrix and sodium montmorillonite as well as an organically modified montmorillonite as the reinforcing agents. X -ray diffraction pattern of the composites showed that the interlayer spacing of the modified montmorillonite were exfoliated in polymer matrix. The mechanical properties also supported these findings, since in general, tensile strength, modulus with modified montmorillonite were higher than the corresponding properties of the composites with unmodified montmorillonite. Adding organically modified clay improved the tensile strength of unsaturated polyester by $22\%$ and the tensile modulus of unsaturated polyester was also improved by $34\%$.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
• /
• pp.371-374
• /
• 2005

The research reported in this paper provides the test results of eleven reinforced concrete beams strengthened with FRP composites. Three parameters were considered in this investigation: the amount of FRP composites, the types of bonding schemes(continuous sheets or strips), and the material types of FRP composites (Carbon or Glass). The experimental results indicated that because the rupture strain of FRP composites was relatively higher that the yield strain of steel bars, the RC beams strengthened with FRP composites failed due to concrete crushing before the FRP composites arrived at its rupture strain. The compatibility-aided truss model showed reasonable agreement between the predicted and experimental shear stress-strain curves of the beams throughout the entire loading history.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1995년도 가을 학술발표회 논문집
• /
• pp.350-354
• /
• 1995

Deteriorated concrete components are repaired using various repair materials for preventing functional deficiencies. However, the durability performance of these materials is not very well investigate. This study aims to examine the dynamic behavior of R/C beams repaired by Polymer, Polymer-Cement and Cemtitious material through dynamic test. Totally 18repaired R/C beams were tested, and the results from dynamic test of beams repaired with various materials were compared.

• 한국구조물진단유지관리공학회 논문집
• /
• 제15권5호
• /
• pp.169-177
• /
• 2011

본 연구에서는 충격하중에 유리한 층 구조를 갖는 패각의 구조를 채용한 콘크리트 분절 복합체의 충격하중 성능을 평가하였다. 콘크리트 분절 복합체의 성능을 향상시키기 위해서는 콘크리트 블록 사이의 모르타르의 부착강도가 개선되어야 한다. 따라서 본 연구에서는 모르타르의 부착강도를 향상시키기 위해 폴리머 모르타르를 적용하였다. 부착강도 실험에 따라 15% 라텍스 모르타르를 선정하였고, 일반 모르타르와 라텍스 모르타르를 적용한 부재에 대한 정하중 및 저속 충격하중 실험을 수행하였다. 실험 결과 모르타르의 부착력이 향상된 분절복합체가 높은 충격하중 저항 능력을 보였다. 불연속 균열 모델을 이용한 비선형 유한요소해석과 충격하중 실험의 결과와 충격에너지 소산도가 유사하게 나타났다. 따라서 분절복합체 해석 모델의 개선을 통해 다양한 변수의 충격 저항 능력의 예상과 평가가 가능할 것으로 판단된다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1996년도 봄 학술발표회 논문집
• /
• pp.340-347
• /
• 1996

Recent years, many items in construction industry are produced by precasting from factories. Among the precasting items which are cost effective by virtue of standardization of size and reduction of construction time is the load bearing wall. However, due to many reasons inherent in concrete materials, often it was found that the member did not meet the designed strength after construction. In this case, the wall had to be ether replaced or reinforced somehow. Since replacement is almost impossible due to budget and schedule, reinforcement is a preferred choice in many cases. Therefore, objective of this study was to evaluate reinforcement of the wall using polymer composites. Flexural strength and axial compressive strength were evaluate for the wall before and after reinforcement. The polymer composite reinforcement was found to be very effective in improving these strengths.

• Structural Engineering and Mechanics
• /
• 제58권5호
• /
• pp.825-845
• /
• 2016

The Turkish Earthquake Code was revised in 1998 and 2007. Before these Codes, especially 1998, reinforced concrete (RC) beams with low flexural and shear strength were widely used in the building. In this study, the RC specimens have been produced by taking into consideration the RC beams with insufficient shear and tensile reinforcement having been manufactured with the use of concrete with low strength. The performance of the RC specimens strengthened with different wrapping methods by using of Carbon Fibre Reinforced Polymer (CFRP) and Glass Fibre Reinforced Polymer (GFRP) composites have been examined in terms of flexural strength, ductility and energy absorption capacity. In the strengthening of the RC elements, the use of GFRP composites instead of CFRP composites has also been examined. For this purpose, the experimental results of the RC specimens strengthened by wrapping with CFRP and GFRP are presented and discussed. It has been concluded that although the flexural and shear strengths of the RC beams strengthened with GFRP composites are lower than those of beams reinforced with CFRP, their ductility and energy absorption capacities are very high. Moreover, the RC beams strengthened with CFRP fracture are more brittle when compared to GFRP.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
• /
• pp.165-168
• /
• 2005

Carbon Fiber Reinforced Polymer(CFRP) composites are widely applied to strengthen deteriorated concrete structures. This paper presents the experimental results of the performance of reinforced concrete(RC) decks strengthened with CFRP composites. Simple span decks with 2m span length were tested to investigate the effect of CFRP reinforcement types on the flexural behavior of strengthened RC beams. The test results were analyzed with the special emphasis on the failure mode and the maximum load.

• Steel and Composite Structures
• /
• 제44권6호
• /
• pp.803-816
• /
• 2022

Composite materials are effective in forming externally bonded reinforcements which find applications related to existing structures repair, attributed to their high strength-to-weight ratio and ease of installation. Among various composites, fibre reinforced polymers (FRP) have somewhat been largely accepted as a commonly utilized composite for such purposes. It is only recently that steel fibres have been considered as additional members of the FRP fibre family, intuitively termed as steel reinforced polymer (SRP). Owing to its low cost and permissibility of fibre bending at sharp corners, SRP is rapidly becoming a viable contender to other FRP systems. This paper investigates the bond behaviour of SRP-concrete joints with different bonded lengths (50, 75, 100, 150 and 300 mm) and widths (15, 30, 40, 50, and 75 mm) using single-lap shear tests. The experimental specimens contain SRP strips with a fixed density of steel fibres (0.472 cords/mm) bonded to the face of concrete prisms. The load responses were obtained and compared in terms of corresponding load and slip boundaries of the constant region and the peak loads. The failure modes of SRP composites are discussed, and the range of effective bonded length is evaluated herein. In the end, a new analytical model was proposed to estimate the SRP-concrete bond strength using a genetic algorithm, which outperforms 22 existing FRP-concrete bond strength models.