• Advances in concrete construction
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• v.9 no.4
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• pp.387-395
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• 2020

This study has been carried out in two-phases to develop Fiber Reinforced Self-Compacting Concrete (FRSCC) performance. In the first phase, the composition of the quaternary composite binder compromised CEM I 42.5N (58-70%), Rice Husk Ash (25-37%), quartz sand (2.5-7.5%) and limestone crushing waste (2.5-7.5%) were optimized. And in the second phase, the effect of two fiber types (steel brass-plated and basalt) was investigated on the SCC optimized with the optimum CB as disperse reinforcement at 6 different ratios of 1, 1.2, 1.4, 1.6, 1.8, and 2.0% by weight of mix for each type. In this study, the theoretical principles of the synthesis of self-compacting dispersion-reinforced concrete have been developed which consists of optimizing structure-formation processes through the use of a mineral modifier, together with ground crushed cement in a vario-planetary mill to a specific surface area of 550 m2 / kg. The amorphous silica in the modifier composition intensifies the binding of calcium hydroxide formed during the hydration of C3S, helps reduce the basicity of the cement-composite, while reducing the growth of portlandite crystals. Limestone particles contribute to the formation of calcium hydrocarbonate and, together with fine ground quartz sand; act as microfiller, clogging the pores of the cement. Furthermore, the results revealed that the effect of fiber addition improves the mechanical properties of FRSCC. It was found that the steel fiber performed better than basalt fiber on tensile strength and modulus of elasticity; however, both fibers have the same performance on the first crack strength and sample destruction of FRSCC. It also illustrates that there will be an optimum percentage of fiber addition.

• Composites Research
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• v.13 no.4
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• pp.54-66
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• 2000

Interfacial and microfailure properties of carbon fiber/epoxy matrix composites were evaluated using both tensile fragmentation and compressive Broutman tests with an aid of acoustic emission (AE) monitoring. A polymeric maleic anhydride coupling agent and a monomeric amino-silane coupling agent were used via the electrodeposition (ED) and the dipping applications, respectively. Both coupling agents exhibited significant improvements in interfacial shear strength (IFSS) compared to the untreated case under tensile and compressive tests. The typical microfailure modes including fiber break of cone-shape, matrix cracking, and partial interlayer failure were observed during tensile test, whereas the diagonal slippage in fiber ends was observed under compressive test. For both loading types, fiber breaks occurred around just before and after yielding point. In both the untreated and treated cases AE amplitudes were separately distributed for the tensile testing, whereas they were closely distributed for the compressive tests. It is because of the difference in failure energies of carbon fiber between tensile and compressive loading. The maximum AE voltage for the waveform of carbon or basalt fiber breakages under tensile tests exhibited much larger than those under compressive tests, which can provide the difference in the failure energy of the individual failure processes.

• Advances in aircraft and spacecraft science
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• v.4 no.5
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• pp.515-528
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• 2017

Since composite structures are widely used in structural engineering, delamination in such structures is an important issue of research. Delamination is one of a principal cause of failure in composites. In This study the electrical potential (EP) technique is applied to detect and locate delamination in basalt fiber reinforced polymer (FRP) laminate composite pipe by using electrical capacitance sensor (ECS). The proposed EP method is able to identify and localize hidden delamination inside composite layers without overlapping with other method data accumulated to achieve an overall identification of the delamination location/size in a composite, with high accuracy, easy and low-cost. Twelve electrodes are mounted on the outer surface of the pipe. Afterwards, the delamination is introduced into between the three layers (0º/90º/0º)s laminates pipe, split into twelve scenarios. The dielectric properties change in basalt FRP pipe is measured before and after delamination occurred using arrays of electrical contacts and the variation in capacitance values, capacitance change and node potential distribution are analyzed. Using these changes in electrical potential due to delamination, a finite element simulation model for delamination location/size detection is generated by ANSYS and MATLAB, which are combined to simulate sensor characteristic. Response surfaces method (RSM) are adopted as a tool for solving inverse problems to estimate delamination location/size from the measured electrical potential changes of all segments between electrodes. The results show good convergence between the finite element model (FEM) and estimated results. Also the results indicate that the proposed method successfully assesses the delamination location/size for basalt FRP laminate composite pipes. The illustrated results are in excellent agreement with the experimental results available in the literature, thus validating the accuracy and reliability of the proposed technique.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.656-659
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• 1993

The failure phenomenon of Dual Basalt Fibers Reinforced Epoxy Composites(DFC) under tensile load was studied using acoustic emission(AE) technique. AE amplitude and AE energy were mainly associated with the internal microscopic failure mechanism of DFC specimen, such as fiber fracture, matrix cracking, and fiber/matrix debonding. Fiber failures in the DFC specimens were distinguishable by showing the highest AE energy amplitude. They were dependant on the fiber diameters. Matrix cracking was determined from the relatively lower AE amplitude and AE energy, whereas fiber/matrix debonding could not be successfully isolated. AE method, however, can be applicable to the fragmentation method for interfacial strength(IFSS) in DFC specimens with adjusting the threshold to isolate fiber breaks from matrix crack and debonding.

• Proceedings of the Korean Fiber Society Conference
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• 2007.11a
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• pp.139-142
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• 2007

• Earthquakes and Structures
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• v.14 no.5
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• pp.379-388
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• 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.

• Structural Monitoring and Maintenance
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• v.4 no.1
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• pp.69-84
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• 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.

• Advances in nano research
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• v.5 no.4
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• pp.337-357
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• 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.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.76-79
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• 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.

• Structural Monitoring and Maintenance
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• v.10 no.4
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• pp.299-314
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• 2023

Long-gauge carbon fiber line (CFL) sensors have received considerable attention in the past decade. However, there is still a need for an in-depth investigation of their measuring accuracy. This study investigates the accuracy of carbon fiber line sensors to monitor and differentiate the flexural behavior of two beams, one reinforced with steel bars alone and the other reinforced with steel and basalt fiber-reinforced polymer bars. A distributed set of long-gauge carbon fiber line, Fiber Bragg Grating (FBG), and traditional strain gauge sensors was mounted on the tensile concrete surface of the studied beams to compare the results and assess the accuracies of the proposed sensors. The test beams were loaded monotonically under four-point bending loading until failure. Results indicated the importance of using long-gauge sensors in providing useful, accurate, and reliable information regarding global structural behavior, while point sensors are affected by local damage and strain concentrations. Furthermore, long-gauge carbon fiber line sensors demonstrated good agreement with the corresponding Fiber Bragg Grating sensors with acceptable accuracy, thereby exhibiting potential for application in monitoring the health of large-scale structures.