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The prediction of long-term performance is a crucial step in the effective structural design of adhesively bonded connections. A lack of knowledge on the durability of the FRP-to-concrete bonded connections compromises structural safety and requires employing higher safety factors in design. This study examines the capability of machine learning techniques in studying the long-term performance of FRP-to-concrete bonded connections under moisture conditions. A comprehensive database of 429 durability test results is built and used to develop various machine learning models. A Bayesian optimisation method is employed during the model development to tune the machine learning hyperparameters. Based on the detailed evaluation of prediction results, artificial neural networks (ANN) and ensemble models are proposed to study the bond strength and the failure mode of the connections. The ANN model is used to evaluate the impact of various moisture conditioning regimes on bond strength. The contribution of environmental factors in identifying the failure mode is studied by the ensemble method. Moreover, a practical equation is proposed by the M5P model tree method to predict the bond strength. The prediction results in this study indicate the capability of machine learning in predicting the durability of FRP-bonded concrete connections under moisture conditions.
K. Aghabalaei Baghaei; S.A. Hadigheh. Durability assessment of FRP-to-concrete bonded connections under moisture condition using data-driven machine learning-based approaches. Composite Structures 2021, 114576 .
AMA StyleK. Aghabalaei Baghaei, S.A. Hadigheh. Durability assessment of FRP-to-concrete bonded connections under moisture condition using data-driven machine learning-based approaches. Composite Structures. 2021; ():114576.
Chicago/Turabian StyleK. Aghabalaei Baghaei; S.A. Hadigheh. 2021. "Durability assessment of FRP-to-concrete bonded connections under moisture condition using data-driven machine learning-based approaches." Composite Structures , no. : 114576.
Geopolymer is a sustainable binding material which can be produced from industrial by-products, such as fly ash and ground granulated blast furnace slag. Despite having higher mechanical strengths and durability properties than conventional ordinary Portland cement (OPC) concrete, geopolymer concrete has not been widely used in structural grade concrete, so far. The safety hazards in mixing and handling of concrete due to the use of liquid sodium hydroxide in geopolymer binder is one of the barriers to the adaptation of geopolymer in the concrete industry. This study aims to use sodium hydroxide-free one-part geopolymer binder for structural concrete applications, such as prestressed concrete beams. In this study, the mechanical and serviceability properties of grade 50 MPa geopolymer concrete cured at ambient temperature are investigated and compared against same grade OPC concrete. The effects of tensile strength of concrete in load–deflection behaviours of prestressed concrete beams of different spans and sizes are investigated using finite element analysis for short-term and long-term durations. This study finds that geopolymer concrete has around 27% higher indirect-tensile and flexural strengths than OPC concrete of same strength grade which contributes to geopolymer prestressed concrete beams to withstand around 20% higher first-crack load than OPC concrete beams of same span. In addition, geopolymer prestressed concrete beams show a relatively smaller loss in prestressing stress which results in a smaller loss in flexural capacity of beams over the service life of the structure.
Kamal Neupane; S. Ali Hadigheh. Sodium hydroxide-free geopolymer binder for prestressed concrete applications. Construction and Building Materials 2021, 293, 123397 .
AMA StyleKamal Neupane, S. Ali Hadigheh. Sodium hydroxide-free geopolymer binder for prestressed concrete applications. Construction and Building Materials. 2021; 293 ():123397.
Chicago/Turabian StyleKamal Neupane; S. Ali Hadigheh. 2021. "Sodium hydroxide-free geopolymer binder for prestressed concrete applications." Construction and Building Materials 293, no. : 123397.
This research studies the properties of mortars incorporating waste materials including red mud (RM), ground granulated blast furnace slag (GGBFS), and electric arc furnace dust (EAFD). Ordinary Portland cement (OPC) was partially replaced with equal contents of RM, GGBFS, and EAFD at different ratios by weight (0, 5, 10, 15, 20, 30, 40, and 50%). Slump, compressive strength, splitting tensile strength, electrical resistivity, water absorption, resistance to freeze–thaw cycles, and durability under sodium sulphate and sulphuric acid attacks were investigated. Moreover, the microstructure of mortars cured in tap water and exposed to sulphuric acid was examined using scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDX). Cement replacement up to 20% led to a slight increase in compressive strength at 7, 28, and 120 days, while the results of durability tests showed that only up to 10% cement substitution could improve the durability of the mortar. A microstructural analysis showed that small waste grain portions in the matrix improved the whole mix density and the interfacial transition zone (ITZ) between aggregates and paste. The results of this study showed that there is an optimum replacement ratio of about 10%, beyond which the incorporation of these waste powders can cause degradation of concrete properties.
Javad Sabzi; Elyas Asadi Shamsabadi; Mansour Ghalehnovi; S. Hadigheh; Ali Khodabakhshian; Jorge Brito. Mechanical and Durability Properties of Mortars Incorporating Red Mud, Ground Granulated Blast Furnace Slag, and Electric Arc Furnace Dust. Applied Sciences 2021, 11, 4110 .
AMA StyleJavad Sabzi, Elyas Asadi Shamsabadi, Mansour Ghalehnovi, S. Hadigheh, Ali Khodabakhshian, Jorge Brito. Mechanical and Durability Properties of Mortars Incorporating Red Mud, Ground Granulated Blast Furnace Slag, and Electric Arc Furnace Dust. Applied Sciences. 2021; 11 (9):4110.
Chicago/Turabian StyleJavad Sabzi; Elyas Asadi Shamsabadi; Mansour Ghalehnovi; S. Hadigheh; Ali Khodabakhshian; Jorge Brito. 2021. "Mechanical and Durability Properties of Mortars Incorporating Red Mud, Ground Granulated Blast Furnace Slag, and Electric Arc Furnace Dust." Applied Sciences 11, no. 9: 4110.
This research proposes new types of shear connectors made of carbon fibre reinforced polymer (CFRP) composites for effective stress transfer between the timber and concrete sections in cross laminated timber (CLT)-concrete composite beams. New shear connectors are designed and made of bidirectional carbon fibre reinforced polymer (CFRP) composite plates and crossed CFRP reinforcing bars. The mechanical performance, bending stiffness, ductility, and interfacial slippage and strain of timber-concrete composite (TCC) beams with CFRP connectors are compared with those with steel plate and screw systems through four-point flexure testing. Local slip, interfacial slip and strain behaviour are comparatively analysed for connections with equivalent axial stiffness using a Digital Image Correlation (DIC) based technique, so that relative composite behaviour could be determined. Furthermore, a cost evaluation is undertaken to compare the feasibility of proposed shear connectors for construction of TCC systems. Results from flexural tests demonstrate that CFRP rod specimens experience higher ultimate load and bending stiffness in elastic loading stage and ductility in failure while slippage at serviceability and ultimate load is minimal. These results demonstrate that CFRP reinforcing bars can be used as an alternative to existing steel plate/screw systems. Although CFRP plate connectors show lower ultimate strength, bending stiffness and ductility, the performance of the system can be further improved by using sufficient anchorage systems at the end of CFRP plate within the concrete.
S.A. Hadigheh; R. McDougall; C. Wiseman; L. Reid. Evaluation of composite action in cross laminated timber-concrete composite beams with CFRP reinforcing bar and plate connectors using Digital Image Correlation (DIC). Engineering Structures 2021, 232, 111791 .
AMA StyleS.A. Hadigheh, R. McDougall, C. Wiseman, L. Reid. Evaluation of composite action in cross laminated timber-concrete composite beams with CFRP reinforcing bar and plate connectors using Digital Image Correlation (DIC). Engineering Structures. 2021; 232 ():111791.
Chicago/Turabian StyleS.A. Hadigheh; R. McDougall; C. Wiseman; L. Reid. 2021. "Evaluation of composite action in cross laminated timber-concrete composite beams with CFRP reinforcing bar and plate connectors using Digital Image Correlation (DIC)." Engineering Structures 232, no. : 111791.
Pyrolysis is a thermo-chemical method to recover clean fibres from carbon fibre reinforced polymer (CFRP) composite waste under oxygen-free conditions. To ensure the recovery quality and economic efficiency of reclaimed fibres, thermal decomposition of CFRP needs to be guided by the kinetic analysis. This paper investigates the kinetic behaviour of CFRP thermal decomposition at temperatures of up to 800 °C. A thermo-gravimetric method is used to monitor the thermal decomposition of CFRP samples during the pyrolysis process. The activation energies (E) required for different conversion fractions (α) are evaluated based on five different kinetic models: four Arrhenius-type model-free methods (Friedman, OFW, KAS and Starink) and one curve fitting method (Coats-Redfern). Pyrolysis of CFRP composite wastes show that the process consists of two stages, where majority of the polymer matrix (55%) is removed in the first stage of reaction. During stage one and up to 425 °C, lower heating rates successfully lead to higher conversion fractions with lower activation energies. Moreover, by investigating physical characteristics of the recycled fibres using scanning electron microscopy (SEM) and conversion kinetics of the recycling process, it is shown that pyrolysis of the composite remains efficient until 425 °C and an oxidation process up to 550 °C is required to achieve high quality recycled carbon fibre (rCF) products. The outcomes of this research contribute to optimisation of process variables and development of highly efficient and cost effective CFRP recycling method using pyrolysis technique.
S.A. Hadigheh; Y. Wei; S. Kashi. Optimisation of CFRP composite recycling process based on energy consumption, kinetic behaviour and thermal degradation mechanism of recycled carbon fibre. Journal of Cleaner Production 2021, 292, 125994 .
AMA StyleS.A. Hadigheh, Y. Wei, S. Kashi. Optimisation of CFRP composite recycling process based on energy consumption, kinetic behaviour and thermal degradation mechanism of recycled carbon fibre. Journal of Cleaner Production. 2021; 292 ():125994.
Chicago/Turabian StyleS.A. Hadigheh; Y. Wei; S. Kashi. 2021. "Optimisation of CFRP composite recycling process based on energy consumption, kinetic behaviour and thermal degradation mechanism of recycled carbon fibre." Journal of Cleaner Production 292, no. : 125994.
Fibre-reinforced polymer (FRP) composites have been utilised as promising and popular solutions to strengthen existing reinforced concrete (RC) structures. Due to the increasing industrial activities, growing population and climate change, corrosive environments (e.g. acid rains) that diminish the durability of FRP-strengthened RC structures are becoming more common. The long-term durability of structures in these corrosive environments is central to the success of any strengthening technique. Despite this urgency, very limited research data is available regarding the degradation of RC structures strengthened with the FRP in acidic environments. This paper evaluates the impact of sulphuric acid on the performance of externally bonded FRP-strengthened RC structures and investigates the long-term behaviour of concrete, FRP composite, and the FRP-concrete interface. The acid diffusion mechanism within the FRP-concrete bond system is studied with the establishment of both one-dimensional (1D) and three-dimensional (3D) models. Moreover, a reduction factor (βα) accounting for the degrading effect of acid, is proposed to predict the retained bond strength at the FRP-concrete interface. The proposed models provide a theoretical basis for the durability design and the service life prediction of FRP-strengthened RC structures when subjected to acid attack.
S. Ali Hadigheh; Feihu Ke; Sima Kashi. 3D acid diffusion model for FRP-strengthened reinforced concrete structures: Long-term durability prediction. Construction and Building Materials 2020, 261, 120548 .
AMA StyleS. Ali Hadigheh, Feihu Ke, Sima Kashi. 3D acid diffusion model for FRP-strengthened reinforced concrete structures: Long-term durability prediction. Construction and Building Materials. 2020; 261 ():120548.
Chicago/Turabian StyleS. Ali Hadigheh; Feihu Ke; Sima Kashi. 2020. "3D acid diffusion model for FRP-strengthened reinforced concrete structures: Long-term durability prediction." Construction and Building Materials 261, no. : 120548.
This study explores the effect of sulphuric acid (H2SO4) on the physical and mechanical properties of carbon fibre-reinforced polymer (CFRP) and its constituent elements including epoxy resin and fibrous reinforcement. Specimens are exposed to decreasing pH levels through an accelerated aging regime and subsequently tested by mechanical and non-destructive methods. Active infrared thermography is applied to develop a quantitative framework for material degradation. The effect of acid exposure is subsequently assessed through a performance criterion based on thermal energy variation. Microscopic analyses through scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) reveal the material degradation and impact of acid at the fibre-epoxy interface. Tensile testing on FRP and epoxy resin coupons indicate up to 25% reduction in strength. An acid attack model is developed for the environmental reduction factor (CE) that is shown to compare well with experimental data. The performance-based environmental reduction factor presented expands our understanding of the FRP material response to aggressive environments and its effectiveness during the in-service life of structure.
Munawar Sarker; S. Ali Hadigheh; Daniel Dias-Da-Costa. A performance-based characterisation of CFRP composite deterioration using active infrared thermography. Composite Structures 2020, 241, 112134 .
AMA StyleMunawar Sarker, S. Ali Hadigheh, Daniel Dias-Da-Costa. A performance-based characterisation of CFRP composite deterioration using active infrared thermography. Composite Structures. 2020; 241 ():112134.
Chicago/Turabian StyleMunawar Sarker; S. Ali Hadigheh; Daniel Dias-Da-Costa. 2020. "A performance-based characterisation of CFRP composite deterioration using active infrared thermography." Composite Structures 241, no. : 112134.
This paper provides a framework for the calibration of partial safety factors in prestressed concrete (PC) girders strengthened in flexure with carbon fiber–reinforced polymer (CFRP) laminates. A hybrid approach was proposed to take advantage of comprehensive nonlinear numerical models in reliability analysis using a first-order reliability method (FORM) in conjunction with the response surface method (RSM). The PC girders selected for analyses were taken from real structures designed and built in the 1980s based on old standards that now require strengthening and upgrade due to partial corrosion of the prestressing strands. Using the proposed approach, a sensitivity analysis was performed to identify the most relevant variables and assess the area of CFRP laminates needed to restore capacity up to new design standards. A partial safety factor was proposed for strengthening PC girders using CFRP laminates. Sensitivity analysis showed that traffic loads and model uncertainties are the most important variables for calibration.
Daniel Dias-Da-Costa; L. A. C. Neves; S. Gomes; Rui Graça-E-Costa; Seyed Ali Hadigheh; Paulo Fernandes. Partial Safety Factors for Prestressed Concrete Girders Strengthened with CFRP Laminates. Journal of Composites for Construction 2020, 24, 04019060 .
AMA StyleDaniel Dias-Da-Costa, L. A. C. Neves, S. Gomes, Rui Graça-E-Costa, Seyed Ali Hadigheh, Paulo Fernandes. Partial Safety Factors for Prestressed Concrete Girders Strengthened with CFRP Laminates. Journal of Composites for Construction. 2020; 24 (1):04019060.
Chicago/Turabian StyleDaniel Dias-Da-Costa; L. A. C. Neves; S. Gomes; Rui Graça-E-Costa; Seyed Ali Hadigheh; Paulo Fernandes. 2020. "Partial Safety Factors for Prestressed Concrete Girders Strengthened with CFRP Laminates." Journal of Composites for Construction 24, no. 1: 04019060.
The detection and measurement of surface properties, such as cracks and roughness, on concrete structures have been of significant interest in recent years. Crack formation, width and propagation as well as surface roughness are important indicators of the structural integrity and condition of a concrete pavement that can determine the need for an upgrade or maintenance in roads and bridges. The use of non-destructive testing techniques for development of analytical and numerical processing tools that enable the efficient measurement of surface properties is the aim of this work. In the proposed framework, a stereo camera set-up is utilised to map and register surface roughness of a concrete pavement. The benefit of using a depth image to create a surface map lies in its low-cost and ability to provide depth changes at a highly-refined level with approximately 0.05 mm accuracy. Concrete samples of different roughness are used to assess the viability of such technique in enhancing inspection ability and the effectiveness of robust structural health monitoring and assessment. The focus is placed on: the acquisition of spatial and visual data and creating a 3D point cloud mesh using XYZ and RGB data; an efficient algorithm for the registration and analysis of XYZ-RGB data; and accuracy assessment of stereo cameras in detection and measurement. The investigation herein outlined capitalises on the potential for stereo cameras in developing a pipeline for data acquisition, detection and measurement of cracks and surface roughness in concrete structures.
M. M. Sarker; S. A. Hadigheh; D. Dias-Da-Costa. Stereoscopic Modelling and Monitoring of Roughness in Concrete Pavements. Lecture Notes in Civil Engineering 2019, 635 -644.
AMA StyleM. M. Sarker, S. A. Hadigheh, D. Dias-Da-Costa. Stereoscopic Modelling and Monitoring of Roughness in Concrete Pavements. Lecture Notes in Civil Engineering. 2019; ():635-644.
Chicago/Turabian StyleM. M. Sarker; S. A. Hadigheh; D. Dias-Da-Costa. 2019. "Stereoscopic Modelling and Monitoring of Roughness in Concrete Pavements." Lecture Notes in Civil Engineering , no. : 635-644.
This paper presents an experimental study on the mechanical behaviour of four different timber concrete composite (TCC) connections. Experimental shear tests were conducted to assess the strength and stiffness of the composite connection system. A new type of connection based on carbon fibre reinforced polymer (CFRP) was also proposed to achieve enhanced performance at the cross laminated timber. The stiffness and strength for each type of connection were identified by assessing the load-slip behaviour and load capacity. In addition, the relationship between applied force and slip characteristic of each type of connecting system was also established. Results showed that the addition of CFRP to the connection can effectively improve the maximum shear capacity and stiffness of the connection.
S. A. Hadigheh; Daniel Dias-Da-Costa. Shear Strength of Cross Laminated Timber-Concrete Connections Reinforced With Carbon Fibre Polymer Composites. Proceedings of EECE 2020 2019, 179 -185.
AMA StyleS. A. Hadigheh, Daniel Dias-Da-Costa. Shear Strength of Cross Laminated Timber-Concrete Connections Reinforced With Carbon Fibre Polymer Composites. Proceedings of EECE 2020. 2019; ():179-185.
Chicago/Turabian StyleS. A. Hadigheh; Daniel Dias-Da-Costa. 2019. "Shear Strength of Cross Laminated Timber-Concrete Connections Reinforced With Carbon Fibre Polymer Composites." Proceedings of EECE 2020 , no. : 179-185.
The quantification of the surface roughness of concrete pavements is important for upgrading and maintenance operations. This paper explores the application of stereoscopy in the morphology assessment of surfaces with exposed aggregates. The approach herein proposed is based on a single camera to avoid the need for multiple view points and calibration of multiple cameras. An application example is used to address the issues related to the point cloud reconstruction and filtering of the surface points acquired, whilst keeping computational costs reduced. The accuracy of the technique is evaluated by a detailed comparison with a scan using several roughness quantification statistical parameters. Kurtosis is shown to better compare surface profiles and overcome limitations found in standard parameters. A good match between techniques is achieved, with global mean errors of less than 3% in the surface roughness, and local mean errors below 5%. The proposed technique is low-cost and has the potential to be used for the automatic acquisition and characterisation of concrete surfaces.
Munawar Sarker; Daniel Dias-Da-Costa; S. Ali Hadigheh. Multi-scale 3D roughness quantification of concrete interfaces and pavement surfaces with a single-camera set-up. Construction and Building Materials 2019, 222, 511 -521.
AMA StyleMunawar Sarker, Daniel Dias-Da-Costa, S. Ali Hadigheh. Multi-scale 3D roughness quantification of concrete interfaces and pavement surfaces with a single-camera set-up. Construction and Building Materials. 2019; 222 ():511-521.
Chicago/Turabian StyleMunawar Sarker; Daniel Dias-Da-Costa; S. Ali Hadigheh. 2019. "Multi-scale 3D roughness quantification of concrete interfaces and pavement surfaces with a single-camera set-up." Construction and Building Materials 222, no. : 511-521.
This paper presents a time-dependent reliability analysis of prestressed concrete girders subjected to degradation caused by pitting corrosion. The procedure presented includes the effects of both spatial and temporal pitting corrosions on prestressing steel, as well as the degradation of the strengthening CFRP laminate used for the rehabilitation of the member. Results indicate that the correlation of corrosion in different segments of the prestressing tendons impacts on the computed safety index for the deteriorated structure. Ditlevsen bounds are proposed for a better approximation of the correlation between failure modes in the spatial discretisation. Results show that such approach produces adequate estimates of the reliability index over the full range of analysis in comparison with other tested models. It is also observed that the degradation of the CFRP laminates does not affect the reliability as significantly as corrosion, and that traffic loads, models uncertainties, corrosion error and corrosion rate are the most relevant variables in the analysis, followed by prestressing strength and concrete cover. The significance of the variables changes with time: the corrosion rate, corrosion model error and concrete cover increase in importance with the development of corrosion, whereas traffic loads become gradually less important.
D. Dias-Da-Costa; Luis Neves; S. Gomes; Seyed Ali Hadigheh; Paulo Fernandes. Time-dependent reliability analyses of prestressed concrete girders strengthened with CFRP laminates. Engineering Structures 2019, 196, 109297 .
AMA StyleD. Dias-Da-Costa, Luis Neves, S. Gomes, Seyed Ali Hadigheh, Paulo Fernandes. Time-dependent reliability analyses of prestressed concrete girders strengthened with CFRP laminates. Engineering Structures. 2019; 196 ():109297.
Chicago/Turabian StyleD. Dias-Da-Costa; Luis Neves; S. Gomes; Seyed Ali Hadigheh; Paulo Fernandes. 2019. "Time-dependent reliability analyses of prestressed concrete girders strengthened with CFRP laminates." Engineering Structures 196, no. : 109297.
With the growing popularity of fibre reinforced polymer (FRP) composites in strengthening of structures, new FRP processing methods are required to achieve reliable repairing systems. Application of vacuum resulted in production of components with sound mechanical properties, lower porosity level and accurate fibre management. While the application of automated composite processing techniques is fairly well developed in the aeronautics and marine industry for production of high performance composites, review of the literature reveals that civil infrastructure has still not been benefitted well from the advantages of these methods. This highlights the potential for a comprehensive research program to evaluate efficiency of automated processing techniques in strengthening of infrastructures. This paper will examine interface behaviour of various FRP-concrete connections processed with automated vacuum consolidated techniques as well as wet lay-up and pultrusion. Local and global interfacial characteristics of connections are investigated through series of single lap shear tests and the analytical formulation of governing equations are presented. In addition, the morphology of the composites is examined through scanning electron microscope (SEM). This research reveals the potential of automated FRP processing methods in achieving high level of bond characteristics for structural applications and provides recommendations for future research.
S.A. Hadigheh; S. Kashi. Effectiveness of vacuum consolidation in bonding fibre reinforced polymer (FRP) composites onto concrete surfaces. Construction and Building Materials 2018, 187, 854 -864.
AMA StyleS.A. Hadigheh, S. Kashi. Effectiveness of vacuum consolidation in bonding fibre reinforced polymer (FRP) composites onto concrete surfaces. Construction and Building Materials. 2018; 187 ():854-864.
Chicago/Turabian StyleS.A. Hadigheh; S. Kashi. 2018. "Effectiveness of vacuum consolidation in bonding fibre reinforced polymer (FRP) composites onto concrete surfaces." Construction and Building Materials 187, no. : 854-864.
Sima Kashi; Rahul K. Gupta; Nhol Kao; Seyed Ali Hadigheh; Sati N. Bhattacharya. Influence of graphene nanoplatelet incorporation and dispersion state on thermal, mechanical and electrical properties of biodegradable matrices. Journal of Materials Science & Technology 2018, 34, 1026 -1034.
AMA StyleSima Kashi, Rahul K. Gupta, Nhol Kao, Seyed Ali Hadigheh, Sati N. Bhattacharya. Influence of graphene nanoplatelet incorporation and dispersion state on thermal, mechanical and electrical properties of biodegradable matrices. Journal of Materials Science & Technology. 2018; 34 (6):1026-1034.
Chicago/Turabian StyleSima Kashi; Rahul K. Gupta; Nhol Kao; Seyed Ali Hadigheh; Sati N. Bhattacharya. 2018. "Influence of graphene nanoplatelet incorporation and dispersion state on thermal, mechanical and electrical properties of biodegradable matrices." Journal of Materials Science & Technology 34, no. 6: 1026-1034.
With the widespread development and use of electronics and telecommunication devices, electromagnetic radiation has emerged as a new pollution. In this study, we fabricated flexible multifunctional nanocomposites by incorporating graphene nanoplatelets into a soft thermoplastic matrix and investigated its performance in attenuating electromagnetic radiation over frequency ranges of C (5.85–8.2 GHz), X (8.2–12.4 GHz), and Ku bands (12.4–18 GHz). Effects of nanofiller loading, sample thickness, and radiation frequency on the nanocomposites shielding effectiveness (SE) were investigated via experimental measurements and simulation. The highest rate of increase in SE was observed near percolation threshold of graphene. Comparison of reflectivity and absorptivity revealed that reflection played a major role in nanocomposites shielding potential for all frequencies while the low absorptivity was due to high power reflection at nanocomposite surface and thin thickness. Subsequently, effective absorbance calculations revealed the great potential of nanocomposites for absorbing microwaves, reaching more than 80%. Simulations confirmed the observed nanocomposites SE behaviours versus frequency. Depending on thickness, different frequency dependency behaviours were observed; for thin samples, SE remained unchanged, while for thicker samples it exhibited either increasing or decreasing trends with increasing frequency. At any fixed frequency, increasing the thickness resulted in sine-wave periodic changes in SE with a general increasing trend.
Sima Kashi; S. Ali Hadigheh; Russell Varley. Microwave Attenuation of Graphene Modified Thermoplastic Poly(Butylene adipate-co-terephthalate) Nanocomposites. Polymers 2018, 10, 582 .
AMA StyleSima Kashi, S. Ali Hadigheh, Russell Varley. Microwave Attenuation of Graphene Modified Thermoplastic Poly(Butylene adipate-co-terephthalate) Nanocomposites. Polymers. 2018; 10 (6):582.
Chicago/Turabian StyleSima Kashi; S. Ali Hadigheh; Russell Varley. 2018. "Microwave Attenuation of Graphene Modified Thermoplastic Poly(Butylene adipate-co-terephthalate) Nanocomposites." Polymers 10, no. 6: 582.
Fibre reinforced polymer (FRP) composites have been increasingly used worldwide in the strengthening of civil engineering structures. As FRP becomes more common in structural strengthening, the development of probability-based limit state design codes will require accurate models for the prediction of the mechanical properties of the FRPs. Existing models, however, are based on small sample sizes and ignore the importance of the tail region for analyses and design. Addressing these limitations, this paper presents a probabilistic-based characterisation of the mechanical properties of carbon FRP (CFRP) laminates using a large batch of tension tests. The analysed specimens were pre-cured laminates of carbon fibres embedded in epoxy matrices, which is the most commonly used laminate for the strengthening concrete beams and slabs. Based on the existing data, probabilistic models and correlations were established for the Young's modulus, ultimate strain and tensile strength. Analyses demonstrate the suitability of the Weibull distribution for the estimation of CFRP properties. Results also show that the statistical characterisation of the mechanical properties should be performed with a focus on the tail region. The proposed distributions constitute a set of validated probabilistic models that can be used for performing reliability analyses of structures strengthened with CFRP laminates.
S. Gomes; D. Dias-Da-Costa; L.A.C. Neves; S.A. Hadigheh; Paulo Fernandes; E. Júlio. Probabilistic-based characterisation of the mechanical properties of CFRP laminates. Construction and Building Materials 2018, 169, 132 -141.
AMA StyleS. Gomes, D. Dias-Da-Costa, L.A.C. Neves, S.A. Hadigheh, Paulo Fernandes, E. Júlio. Probabilistic-based characterisation of the mechanical properties of CFRP laminates. Construction and Building Materials. 2018; 169 ():132-141.
Chicago/Turabian StyleS. Gomes; D. Dias-Da-Costa; L.A.C. Neves; S.A. Hadigheh; Paulo Fernandes; E. Júlio. 2018. "Probabilistic-based characterisation of the mechanical properties of CFRP laminates." Construction and Building Materials 169, no. : 132-141.
Seyed Ali Hadigheh; R.J. Gravina; Scott Smith. Effect of acid attack on FRP-to-concrete bonded interfaces. Construction and Building Materials 2017, 152, 285 -303.
AMA StyleSeyed Ali Hadigheh, R.J. Gravina, Scott Smith. Effect of acid attack on FRP-to-concrete bonded interfaces. Construction and Building Materials. 2017; 152 ():285-303.
Chicago/Turabian StyleSeyed Ali Hadigheh; R.J. Gravina; Scott Smith. 2017. "Effect of acid attack on FRP-to-concrete bonded interfaces." Construction and Building Materials 152, no. : 285-303.
Seyed Ali Hadigheh; S. Saeed Mahini; Sujeeva Setunge; Stephen A. Mahin. A preliminary case study of resilience and performance of rehabilitated buildings subjected to earthquakes. Earthquakes and Structures 2016, 11, 967 -982.
AMA StyleSeyed Ali Hadigheh, S. Saeed Mahini, Sujeeva Setunge, Stephen A. Mahin. A preliminary case study of resilience and performance of rehabilitated buildings subjected to earthquakes. Earthquakes and Structures. 2016; 11 (6):967-982.
Chicago/Turabian StyleSeyed Ali Hadigheh; S. Saeed Mahini; Sujeeva Setunge; Stephen A. Mahin. 2016. "A preliminary case study of resilience and performance of rehabilitated buildings subjected to earthquakes." Earthquakes and Structures 11, no. 6: 967-982.
Rebecca Gravina; Hasret Aydin; Seyed Ali Hadigheh; Phillip Visintin. Durability of FRP strengthened reinforced concrete flexural members for bridge structures. Maintenance, Monitoring, Safety, Risk and Resilience of Bridges and Bridge Networks 2016, 205 -205.
AMA StyleRebecca Gravina, Hasret Aydin, Seyed Ali Hadigheh, Phillip Visintin. Durability of FRP strengthened reinforced concrete flexural members for bridge structures. Maintenance, Monitoring, Safety, Risk and Resilience of Bridges and Bridge Networks. 2016; ():205-205.
Chicago/Turabian StyleRebecca Gravina; Hasret Aydin; Seyed Ali Hadigheh; Phillip Visintin. 2016. "Durability of FRP strengthened reinforced concrete flexural members for bridge structures." Maintenance, Monitoring, Safety, Risk and Resilience of Bridges and Bridge Networks , no. : 205-205.
This paper investigates the bond characteristics between the concrete substrate and fiber-reinforced polymer (FRP) material processed with advanced manufacturing techniques. Tests provide further understanding regarding the interface behavior of the joints manufactured with a heated vacuum bag only (HVBO), vacuum-assisted resin infusion (VARI), wet lay-up, and pultrusion techniques. A specific criterion, the equalization of the processing techniques, is proposed to compare the characteristics of the joints. Based on the outcomes, the advanced processing techniques such as HVBO and VARI can be successfully applied to achieve a high-quality bond in strengthening of the reinforced concrete structures. Furthermore, a new analytical approach is presented to determine the interface behavior, which can be applied to any type of the FRP processing technique.
Seyed Ali Hadigheh; Rebecca Gravina; Sujeeva Setunge. Influence of the Processing Techniques on the Bond Characteristics in Externally Bonded Joints: Experimental and Analytical Investigations. Journal of Composites for Construction 2016, 20, 04015081 .
AMA StyleSeyed Ali Hadigheh, Rebecca Gravina, Sujeeva Setunge. Influence of the Processing Techniques on the Bond Characteristics in Externally Bonded Joints: Experimental and Analytical Investigations. Journal of Composites for Construction. 2016; 20 (3):04015081.
Chicago/Turabian StyleSeyed Ali Hadigheh; Rebecca Gravina; Sujeeva Setunge. 2016. "Influence of the Processing Techniques on the Bond Characteristics in Externally Bonded Joints: Experimental and Analytical Investigations." Journal of Composites for Construction 20, no. 3: 04015081.