• Title/Summary/Keyword: Basalt fiber

Search Result 81, Processing Time 0.027 seconds

Restoration of pre-damaged RC bridge columns using basalt FRP composites

  • Fahmy, Mohamed F.M.;Wu, Zhishen
    • Earthquakes and Structures
    • /
    • v.14 no.5
    • /
    • pp.379-388
    • /
    • 2018
  • This study aims to identify the effect of both longitudinal reinforcement details and damage level on making a decision of repairing pre-damaged bridge columns using basalt fiber reinforced polymer (BFRP) jackets. Two RC bridge columns with improper details of the longitudinal and/or transverse reinforcement were tested under the effect of a constant axial load and increasing lateral cyclic loading. Test results showed that the lap-splice column exhibited an inferior performance where it showed rapid degradation of strength before achieving the theoretical strength and its deformation capacity was limited; however, quick restoration is possible through a suitable rehabilitation technique. On the other hand, expensive repair or even complete replacement could be the decision for the column with the confinement failure mode. After that, a rehabilitation technique using external BFRP jacket was adopted. Performance-based design details guaranteeing the enhancement in the inelastic performance of both damaged columns were addressed and defined. Test results of the repaired columns confirmed that both reparability and the required repairing time of damage structures are dependent on the reinforcement details at the plastic hinge zone. Furthermore, lap-splice of longitudinal reinforcement could be applied as a key design-tool controlling reparability and restorability of RC structures after massive actions.

EPC method for delamination assessment of basalt FRP pipe: electrodes number effect

  • Altabey, Wael A.
    • Structural Monitoring and Maintenance
    • /
    • v.4 no.1
    • /
    • pp.69-84
    • /
    • 2017
  • Delamination is the most common failure mode in layered composite materials. The author have found that the electrical potential change (EPC) technique using response surfaces method is very effective in assessment delamination in basalt fiber reinforced polymer (FRP) laminate composite pipe by using electrical capacitance sensor (ECS). In the present study, the effect of the electrodes number on the method is investigated using FEM analyses for delamination location/size detection by ANSYS and MATLAB, which are combined to simulate sensor characteristic. Three cases of electrodes number are analyzed here are eight, twelve and sixteen electrodes, afterwards, the delamination is introduced into between the three layers [$0^{\circ}/90^{\circ}/0^{\circ}$]s laminates pipe, split into eight, twelve and sixteen scenarios for cases of eight, twelve and sixteen electrodes respectively. Response surfaces are adopted as a tool for solving inverse problems to estimate delamination location/size from the measured EPC of all segments between electrodes. As a result, it was revealed that the estimation performances of delamination location/size depends on the electrodes number. For ECS, the high number of electrodes is required to obtain high estimation performances of delamination location/size. The illustrated results are in excellent agreement with solutions available in the literature, thus validating the accuracy and reliability of the proposed technique.

An exact solution for mechanical behavior of BFRP Nano-thin films embedded in NEMS

  • Altabey, Wael A.
    • Advances in nano research
    • /
    • v.5 no.4
    • /
    • pp.337-357
    • /
    • 2017
  • Knowledge of thin films mechanical properties is strongly associated to the reliability and the performances of Nano Electro Mechanical Systems (NEMS). In the literature, there are several methods for micro materials characterization. Bulge test is an established nondestructive technique for studying the mechanical properties of thin films. This study improve the performances of NEMS by investigating the mechanical behavior of Nano rectangular thin film (NRTF) made of new material embedded in Nano Electro Mechanical Systems (NEMS) by developing the bulge test technique. The NRTF built from adhesively-bonded layers of basalt fiber reinforced polymer (BFRP) laminate composite materials in Nano size at room temperature and were used for plane-strain bulging. The NRTF is first pre-stressed to ensure that is no initial deflection before applied the loads on NRTF and then clamped between two plates. A differential pressure is applying to a deformation of the laminated composite NRTF. This makes the plane-strain bulge test idea for studying the mechanical behavior of laminated composite NRTF in both the elastic and plastic regimes. An exact solution of governing equations for symmetric cross-ply BFRP laminated composite NRTF was established with taking in-to account the effect of the residual strength from pre-stressed loading. The stress-strain relationship of the BFRP laminated composite NRTF was determined by hydraulic bulging test. The NRTF thickness gradation in different points of hemisphere formed in bulge test was analysed.

The Spalling Properties of High-Performance Concrete with the Kinds of Aggregates and Polypropylene Fiber Contents (골재종류 및 폴리프로필렌 섬유 혼입률 변화에 따른 고성능콘리트의 폭열 성상)

  • 이병렬;황인성;윤기원;양성환;한천구
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 1999.04a
    • /
    • pp.76-79
    • /
    • 1999
  • The purpose of this study is to investigate the spalling properties of high-performance concrete with the kinds of aggregates and polypropylene(below PP) fiber contents. According to the experimental results, concrete contained no PP fiber take place in the form of the surface spalling and the failure of specimens after fire test regardless of the kinds of aggregates. Concrete contained more than 0.05% of PP fiber with the kinds of aggregates does not take place the spalling. Concrete using basalt has better performance in spalling resistance that concrete using granite and limestone. It is found that residual compressive strength has 50~60% of their original strength. Although specimens after exposed at high temperature are cured at water for 28days, they do not recover their original strength.

  • PDF

A Study on the Physical Properties of Heat resistance and Cut resistance of Coating Gloves for Work

  • Pyo, Kyeong-Deok;Jung, Eugene;Park, Cha-Cheol
    • Elastomers and Composites
    • /
    • v.54 no.2
    • /
    • pp.91-96
    • /
    • 2019
  • The purpose of this study was to examine the effect of different yarn twisting methods on physical properties. Plain single jersey structured fabrics were knitted from Kevlar yarn, and from Kevlar/HPPE, and from Kevlar/Basalt fiber, and from Kevlar/Glass fiber and Kevlar/Stainless steel fiber blended and core-spun yarns. and then, The fabrics were coated NBR Latex. The physical properties, including tear strength, modulus, degree of penetration, heat resistance, and cut resistance of the knitted fabrics were investigated and compared. Kevlar/HPPE blended yarn fabrics recorded the highest heat resistance (13 Sec.). and Kevlar/HPPE blended yarn fabrics had good cut resistance (Cut Level 4).

Microfailure Mechanisms of Single-Fiber Composites Using Tensile/Compressive Fragmentation Techniques and Acoustic Emission (인장/압축 Fragmentation시험법과 음향방출을 이용한 단 섬유 복합재료의 미세파괴 메커니즘)

  • 김진원;박종만;윤동진
    • Proceedings of the Korean Society For Composite Materials Conference
    • /
    • 2000.04a
    • /
    • pp.159-162
    • /
    • 2000
  • Interfacial and microfailure properties of carbon fiber/epoxy matrix composites were evaluated using both tensile fragmentation and compressive Broutman tests with acoustic emission (AE). Amino-silane and maleic anhydride polymeric coupling agents were used via the dipping and electrodeposition (ED), respectively. Both coupling agents exhibited higher improvements in interfacial shear strength (IFSS) under tensile tests than compressive cases. However, ED treatment showed higher IFSS improvement than dipping case under both tensile and compressive test. The typical microfailure modes including fiber break, matrix cracking, and interlayer failure were observed during tensile test, whereas the diagonal slippage in fiber ends was observed during compressive test. For both the untreated and treated cases AE distributions were separated well under tensile testing. On the other hand, AE distributions were rather closer under compressive tests because of the difference in failure energies between tensile and compressive loading. Under both loading conditions, fiber breaks occurred around just before and after yielding point. Maximum AE voltage fur the waveform of carbon or basalt fiber breakage under tensile tests exhibited much larger than those under compressive tests.

  • PDF

A Study on the Spalling Properties of High-Performance Concrete with the Kinds of Aggregate and Polypropylene Fiber Contents (골재종류 및 폴리프로필렌 섬유 혼입률 변화에 따른 고성능 콘크리트의 폭열 특성에 관한 연구)

  • 한천구;양성환;이병렬;황인성
    • Journal of the Korea Concrete Institute
    • /
    • v.11 no.5
    • /
    • pp.69-77
    • /
    • 1999
  • A spalling is defined as the damages of concrete exposed to high temperature during the fire by causing cracks and localized bursting of small pieces of concrete. It is reported that spalling is caused by the vapor pressure and polypropylene(PP) fiber has an important role in protecting from spalling. This paper is a study on the properties and spalling resistance of high-performance concrete with the kinds of aggregate and the contents of PP fiber. According to the experimental results, concrete contained no PP fiber take place in the form of the surface spalling and the failure of specimenns after fire test regardless of the kinds of aggregate. Concrete contained more than 0.05% of PP fiber with the aggregate of basalt does not take place the spalling, while the concrete using granite and limestone does the surface spalling. It is found that residual compressive strength after exposed at high temperature has 50~60% of its original strength. Although specimens after exposed at high temperature is cured at water for 28days, they do not recover their original strength.

Spalling Properties of High Performance Concrete Designed with the Various Types of Coarse Aggregate (굵은골재 종류 변화에 따른 고성능 콘크리트의 폭렬특성)

  • Heo, Young-Sun;Park, Yong-Kyu;Jin, Hu-Lin;Jee, Suk-Won;Yang, Seong-Hwan;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2006.11a
    • /
    • pp.95-98
    • /
    • 2006
  • This study investigates spalling properties of high performance concrete, 60MPa clan, made with the various types of coarse aggregate and adding ratio of polypropylene(PP) fiber. As experimental parameters, totally sixteen specimens of ${\phi}100{\times}200mm$ in size are prepared: one specimen for control without fiber, ten specimens with different coarse aggregate types, along with 0.05, 0.1, 0.15 percent of PP fiber in each. 1 hour fire test is conducted and then spalling appearance, spalling degree and residual compressive strength are examined. In addition, sit specimens made with two types of coarse aggregate site, along with same adding ratio of fiber are supplementally done, and only spalling properties is examined. Test results showed that control concrete and most specimens containing 0.05% of PP fiber exhibited 4 to 3 level of spalling degree, resulting severe explosive spalling, except for the specimen using basalt aggregate(Bc) showing 2 to 3 level of that. Especially, the Bc specimen containing 0.1% of the fiber exhibited that residual compressive strength value was 32%, which is 10% higher than other specimens using limestone or granite. Spalling resistance performance was also effective as aggregate size increase.

  • PDF

Flame Resistance Performance of Architectural Membrane According to Woven Fabrics and Coating Materials (직포 및 코팅재 타입에 따른 건축용 막재의 난연성능)

  • Kim, Ji Hyeon;Song, Hun
    • Journal of the Korea Institute of Building Construction
    • /
    • v.16 no.6
    • /
    • pp.545-551
    • /
    • 2016
  • Membrane structures which can be used large spatial structure are being expanded because of various advantages. However, despite the diverse membrane structure buildings and materials, the standard for membrane material performance that considering fire safety is still inadequate. Therefore, this study applied basalt or glass woven fabric with flame resistance on architectural membrane, and report the fire safety for architectural membrane using the strength properties, flammability and incombustibility. From the test result, the architectural membrane using basalt or glass woven fabric showed a low heat release rate and total heat release. Therefore, it was confirmed that the fire safety is relatively high.

Performance of FRP confined and unconfined geopolymer concrete exposed to sulfate attacks

  • Alzeebaree, Radhwan;Gulsan, Mehmet Eren;Nis, Anil;Mohammedameen, Alaa;Cevik, Abdulkadir
    • Steel and Composite Structures
    • /
    • v.29 no.2
    • /
    • pp.201-218
    • /
    • 2018
  • In this study, the effects of magnesium sulfate on the mechanical performance and the durability of confined and unconfined geopolymer concrete (GPC) specimens were investigated. The carbon and basalt fiber reinforced polymer (FRP) fabrics with 1-layer and 3-layers were used to evaluate the performances of the specimens under static and cyclic loading in the ambient and magnesium sulfate environments. In addition, the use of FRP materials as a rehabilitation technique was also studied. For the geopolymerization process of GPC specimens, the alkaline activator has selected a mixture of sodium silicate solution ($Na_2SiO_3$) and sodium hydroxide solution (NaOH) with a ratio ($Na_2SiO_3/NaOH$) of 2.5. In addition to GPC specimens, an ordinary concrete (NC) specimens were also produced as a reference specimens and some of the GPC and NC specimens were immersed in 5% magnesium sulfate solutions. The mechanical performance and the durability of the specimens were evaluated by visual appearance, weight change, static and cyclic loading, and failure modes of the specimens under magnesium sulfate and ambient environments. In addition, the microscopic changes of the specimens due to sulfate attack were also assessed by scanning electron microscopy (SEM) to understand the macroscale behavior of the specimens. Results indicated that geopolymer specimens produced with nano-silica and fly ash showed superior performance than the NC specimens in the sulfate environment. In addition, confined specimens with FRP fabrics significantly improved the compressive strength, ductility and durability resistance of the specimens and the improvement was found higher with the increased number of FRP layers. Specimens wrapped with carbon FRP fabrics showed better mechanical performance and durability properties than the specimens wrapped with basalt FRP fabrics. Both FRP materials can be used as a rehabilitation material in the sulfate environment.