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Eugen Bruhwiler - One of the best experts on this subject based on the ideXlab platform.

  • tensile fatigue behaviour of ultra high performance fibre reinforced concrete combined with Steel Rebars r uhpfrc
    International Journal of Fatigue, 2014
    Co-Authors: Tohru Makita, Eugen Bruhwiler
    Abstract:

    Ultra-High Performance Fibre Reinforced Concrete (UHPFRC) combined with Steel Rebars, subsequently called R-UHPFRC, is a promising building material implying a novel technology for the improvement of concrete structures. Steel Rebars enhance effectively the resistance of UHPFRC while reducing variability in the tensile behaviour of monolithic UHPFRC due to variation in fibre distribution and orientation. When a thin layer of R-UHPFRC is overlaid on top of a concrete bridge deck slab, it is subjected to repeating wheel loads and fatigue limit state needs to be considered. This paper presents the results of tensile fatigue tests on R-UHPFRC elements for the determination of its fatigue behaviour. Experimental results show a fatigue endurance limit at 10 million cycles at a solicitation level of S = 0.54 for S being the ratio between the maximum fatigue force and the ultimate strength. Over the fatigue life of the specimens, stress was transferred from UHPFRC to Steel Rebars. Fatigue resistance of R-UHPFRC shows that it has a significant potential for fatigue strengthening of reinforced concrete structural elements like bridge deck slabs.

  • tensile fatigue behaviour of ultra high performance fibre reinforced concrete combined with Steel Rebars r uhpfrc
    International Journal of Fatigue, 2014
    Co-Authors: Tohru Makita, Eugen Bruhwiler
    Abstract:

    Ultra-High Performance Fibre Reinforced Concrete (UHPFRC) combined with Steel Rebars, subsequently called R-UHPFRC, is a promising building material implying a novel technology for the improvement of concrete structures. Steel Rebars enhance effectively the resistance of UHPFRC while reducing variability in the tensile behaviour of monolithic UHPFRC due to variation in fibre distribution and orientation. When a thin layer of R-UHPFRC is overlaid on top of a concrete bridge deck slab, it is subjected to repeating wheel loads and fatigue limit state needs to be considered. This paper presents the results of tensile fatigue tests on R-UHPFRC elements for the determination of its fatigue behaviour. Experimental results show a fatigue endurance limit at 10 million cycles at a solicitation level of S = 0.54 for S being the ratio between the maximum fatigue force and the ultimate strength. Over the fatigue life of the specimens, stress was transferred from UHPFRC to Steel Rebars. Fatigue resistance of R-UHPFRC shows that it has a significant potential for fatigue strengthening of reinforced concrete structural elements like bridge deck slabs.

Tohru Makita - One of the best experts on this subject based on the ideXlab platform.

  • tensile fatigue behaviour of ultra high performance fibre reinforced concrete combined with Steel Rebars r uhpfrc
    International Journal of Fatigue, 2014
    Co-Authors: Tohru Makita, Eugen Bruhwiler
    Abstract:

    Ultra-High Performance Fibre Reinforced Concrete (UHPFRC) combined with Steel Rebars, subsequently called R-UHPFRC, is a promising building material implying a novel technology for the improvement of concrete structures. Steel Rebars enhance effectively the resistance of UHPFRC while reducing variability in the tensile behaviour of monolithic UHPFRC due to variation in fibre distribution and orientation. When a thin layer of R-UHPFRC is overlaid on top of a concrete bridge deck slab, it is subjected to repeating wheel loads and fatigue limit state needs to be considered. This paper presents the results of tensile fatigue tests on R-UHPFRC elements for the determination of its fatigue behaviour. Experimental results show a fatigue endurance limit at 10 million cycles at a solicitation level of S = 0.54 for S being the ratio between the maximum fatigue force and the ultimate strength. Over the fatigue life of the specimens, stress was transferred from UHPFRC to Steel Rebars. Fatigue resistance of R-UHPFRC shows that it has a significant potential for fatigue strengthening of reinforced concrete structural elements like bridge deck slabs.

  • tensile fatigue behaviour of ultra high performance fibre reinforced concrete combined with Steel Rebars r uhpfrc
    International Journal of Fatigue, 2014
    Co-Authors: Tohru Makita, Eugen Bruhwiler
    Abstract:

    Ultra-High Performance Fibre Reinforced Concrete (UHPFRC) combined with Steel Rebars, subsequently called R-UHPFRC, is a promising building material implying a novel technology for the improvement of concrete structures. Steel Rebars enhance effectively the resistance of UHPFRC while reducing variability in the tensile behaviour of monolithic UHPFRC due to variation in fibre distribution and orientation. When a thin layer of R-UHPFRC is overlaid on top of a concrete bridge deck slab, it is subjected to repeating wheel loads and fatigue limit state needs to be considered. This paper presents the results of tensile fatigue tests on R-UHPFRC elements for the determination of its fatigue behaviour. Experimental results show a fatigue endurance limit at 10 million cycles at a solicitation level of S = 0.54 for S being the ratio between the maximum fatigue force and the ultimate strength. Over the fatigue life of the specimens, stress was transferred from UHPFRC to Steel Rebars. Fatigue resistance of R-UHPFRC shows that it has a significant potential for fatigue strengthening of reinforced concrete structural elements like bridge deck slabs.

D D N Singh - One of the best experts on this subject based on the ideXlab platform.

  • time dependent variation of the electrochemical impedance for thermo mechanically treated versus plain low alloy Steel Rebars in contact with simulated concrete pore solution
    Construction and Building Materials, 2014
    Co-Authors: Raja Rizwan Hussain, Abdulrahman Alhozaimy, Abdulaziz I Alnegheimish, D D N Singh
    Abstract:

    Electrochemical studies (AC impedance and DC polarization) have been used to study the protective properties of passive films that form on reinforced Steel embedded in concrete as a function of time and space. Experiments have been performed on passive/oxide films grown on the surface of Steel reinforcement bars exposed to chloride-contaminated simulated concrete pore solution (SPS) prepared by dissolving a representative amount of sodium hydroxide and potassium hydroxide in distilled water and saturated with lime. A common type of locally available concrete reinforcement TMT (thermo-mechanically treated) mild Steel with TM (tempered martensitic) and PF (pearlite ferrite) rings (source “A”) was investigated in comparison to a type of hot rolled low-alloy Steel without thermo-mechanical treatment (source “B”). The results of the elemental analysis and metallographic microstructure coupled with electrochemical studies indicate that the coupled surface and sub-surface composition of TMT rebar has a time-dependent reversing effect on the protective properties of the passive oxide films that provide durability and protection to the Steel Rebars against corrosion in concrete. Steel with TM–PF rings has a better initial corrosion resistance in comparison to low alloyed Steel. However, with the passage of time, its corrosion resistance decreases, and alloyed Steel finally dominates over the TMT rebar.

  • fluoride induced corrosion of Steel Rebars in contact with alkaline solutions cement slurry and concrete mortars
    Corrosion Science, 2002
    Co-Authors: D D N Singh, R C Ghosh, B K Singh
    Abstract:

    Abstract Corrosion behaviour of mild Steel Rebars has been studied in contact with 0.01 N NaOH, saturated lime water, cement slurry and embedded mortars having different concentrations of fluoride ions. Weight-loss, electrochemical DC cyclic polarisation and polarisation resistance, surface topographic and X-ray diffraction (XRD) techniques have been used to investigate the effects of fluoride ion on the corrosion behaviour of the material. Under all the conditions of the exposure it is observed that a low content of fluoride (⩽25 ppm) in the corrodent has deleterious action on the performance of the Steel, where as at its higher content (⩾100 ppm) the ion has rather an inhibiting effect on corrosion rate. XRD studies of the corrosion product accumulated on the Steel surface in the presence of fluoride ion indicate the predominance of magnetite oxide phase. Accelerating effect of the ion is observed to be due to depolarisation of cathodic reaction of the corrosion process. Observations show that in accelerating range of fluoride (⩽25 ppm) it has almost double corrosive effect than noted for equal concentration of chloride ion.

  • Corrosion performance of hot-dip galvanized zinc-aluminum coated Steel Rebars in comparison to the conventional pure zinc coated Rebars in concrete environment
    Construction and Building Materials, 1
    Co-Authors: Abdulaziz I. Al-negheimish, Raja Rizwan Hussain, Abdulrahman Alhozaimy, D D N Singh
    Abstract:

    Abstract In this investigation zinc was alloyed with aluminum in order to improve the corrosion resistance of hot-dip galvanized coated Steel Rebars in contact with chloride-contaminated concrete. To rapidly assess the role of aluminum alloying in zinc, test panels in sheet form containing 10%, 15%, 20%, and 30% aluminum in zinc were prepared and evaluated in terms of their corrosion resistance via salt spray exposure tests. It was found that 10%Al-90%Zn (10AZ) provided the best results. Mild Steel Rebars were galvanized in 90%Zn-10%Al and 100%Zn (100Z) baths and their corrosion resistance performances when they were exposed to simulated concrete pore solution and embedded in mortars were examined. The10AZ-coated rebar showed superior corrosion resistance performance to the 100Z-coated rebar. Electrochemical impedance spectroscopy, DC polarization, scanning electron microscopy, Raman spectroscopy, and X-ray diffraction techniques were used to study the kinetics and corrosion mechanism of the coated Rebars.

M F Montemor - One of the best experts on this subject based on the ideXlab platform.

  • corrosion behavior of stainless Steel Rebars embedded in concrete an electrochemical impedance spectroscopy study
    Electrochimica Acta, 2014
    Co-Authors: L Freire, R G Duarte, A S Castela, R Neves, M F Montemor
    Abstract:

    Abstract This work aims at studying the electrochemical behavior, by Electrochemical Impedance Spectroscopy (EIS), of austenitic (AISI 304 and AISI 316) and duplex (SAF 2205 and SAF 2304) stainless Steels, when embedded in concrete specimens. Concrete specimens were exposed to chloride containing solutions simulating the aggressive conditions found in sweater environments. Samples were fully immersed and submitted to periodic immersion/emersion cycles. EIS and open circuit potential (OCP) were monitored in a monthly basis. Samples containing carbon Steel (C-Steel) Rebars were also prepared for comparison of the corrosion rates between the different materials. The results showed that the austenitic and duplex SAF 2205 stainless Steels were passive for all the testing period, due to the formation of protective oxide layer, with the AISI 316 presenting the higher corrosion resistance value. The EIS results suggest an increase of more than one order of magnitude in the corrosion resistance of the duplex Steels and AISI 316 comparatively to C-Steel Rebars.

  • chloride induced corrosion behavior of reinforcing Steel in spent fluid cracking catalyst modified mortars
    Cement and Concrete Research, 2013
    Co-Authors: Y Morozov, A S Castela, Ana Paula Soares Dias, M F Montemor
    Abstract:

    Abstract Concrete properties can be improved by various additives. Nowadays there is a strong interest concerning the use of spent fluid catalytic cracking catalyst (SFCC) as an admixture to improve mechanical properties of concrete. This work aims at studying the corrosion resistance of Steel Rebars in SFCC modified mortar specimens. Results of physicochemical characterization indicate the acceleration of cement hydration due to pozzolanic activity of SFCC. Electrochemical measurements show that the addition of the SFCC enhances corrosion resistance by delaying its corrosion onset and decreasing the corrosion rate. These benefits can be attributed to the reduction of the mortar permeability.

  • the corrosion potential of stainless Steel Rebars in concrete temperature effect
    Corrosion Science, 2012
    Co-Authors: J M Deus, L Freire, M F Montemor, X R Novoa
    Abstract:

    Abstract This work reports the temperature dependence of the corrosion potential of passive stainless Steel Rebars embedded in concrete or in alkaline media. The corrosion potential mirrored the temperature variations and the coefficient (mV/°C) increased as the average temperature range increased. These variations were observed in the long time-scale domain (several hours) and were interpreted based on temperature-induced changes in the chemistry of the passive layer. This behaviour and its interpretation have not been reported before and are of great importance from the point of view of understanding the electrochemical behaviour of stainless Steel Rebars and the inspection and durability of reinforced concrete structures.

Bastidas, David M. - One of the best experts on this subject based on the ideXlab platform.

  • Corrosion Fatigue Numerical Model for Austenitic and Lean-Duplex Stainless-Steel Rebars Exposed to Marine Environments
    'MDPI AG', 2020
    Co-Authors: Calderón-uríszar-aldaca Iñigo, Briz Estibaliz, Matanza Amaia, Martin Ulises, Bastidas, David M.
    Abstract:

    Steel Rebars of structures exposed to cyclic loadings and marine environments su_er an accelerated deterioration process by corrosion fatigue, causing catastrophic failure before service life ends. Hence, stainless Steel Rebars have been emerging as a way of mitigating pitting corrosion contribution to fatigue, despite the increased cost. The present study proposes a corrosion fatigue semiempirical model. Di_erent samples of Rebars made of carbon Steel, 304L austenitic (ASS), 316L ASS, 2205 duplex (DSS), 2304 lean duplex stainless Steels (LDSS), and 2001 LDSS have been embedded in concrete and exposed to a tidal marine environment for 6 months. Corrosion rates of each Steel rebar have been obtained from direct measurement and, considering rebar standard requirements for fatigue and fracture mechanics, an iterative numerical model has been developed to derive the cycles to failure for each stress range level. The model resulted in a corrosion pushing factor for each material, able to be used as an accelerating coe_cient for the Palmgren-Miner linear rule and as a performance indicator. Carbon Steel showed the worst performance, while 2001 LDSS performed 1.5 times better with the best cost-performance ratio, and finally 2205 DSS performed 1.5 times better than 2001 LDSS.The authors would like to acknowledge funding support from Centre for Industrial Technological Development CDTI and ACERINOX EUROPA, that funded the materials and experiments through the grant of IISIS project: IPT-20111023 and UPV/EHU PPGA19/61 contract. Besides, they would also like to acknowledge the University of Akron, Fellowship Program FRC-207367, the IT1314-19 (Basque Government) and GIU19/029 (UPV/EHU) research groupsand the Laboratoire des ciencies de l’ingenieur appliquées, Fédération IPRA-EA4581, from the Université de Pau et Pays de l’Adour, for their support setting a cooperation framework for this research

  • Corrosion Behavior of AISI 304 Stainless Steel Reinforcements in SCBA-SF Ternary Ecological Concrete Exposed to MgSO4
    Multidisciplinary Digital Publishing Institute, 2020
    Co-Authors: Ariza-figueroa, Hilda A., Bosch Juan, Baltazar-zamora, Miguel Angel, Croche René, Santiago-hurtado Griselda, Landa-ruiz Laura, Mendoza-rangel, José M., Bastidas, José M., Almeraya-calderón Facundo, Bastidas, David M.
    Abstract:

    In this study, ternary ecological concrete (TEC) mixtures were produced with partial substitution of the ordinary Portland cement (OPC) by 10%, 20%, and 30% of sugar cane bagasse ash (SCBA) and silica fume (SF); a control mixture (100% OPC) was prepared according to ACI 211.1 standard. The studied TEC specimens were reinforced with AISI 304 stainless Steel and AISI 1018 carbon Steel Rebars. TEC reinforced specimens were immersed in two different electrolytes, a control (DI-water) and 3.5 wt.% MgSO4 solution, for 180 days. The electrochemical corrosion was monitored by corrosion potential (Ecorr) according to ASTM C-876-15 standard, and the linear polarization resistance (LPR) technique using ASTM G59 standard. The Ecorr and current density icorr results show that AISI 304 stainless Steel Rebars have a high corrosion resistance, with icorr values below 0.1 µA/cm2, which is interpreted as a level of negligible corrosion. The best corrosion performance was found for the TEC mixture made with a 20% addition of blend of sugar cane bagasse ash-silica fume (SCBA-SF) to the OPC

  • Corrosion behavior of AISI 304 stainless Steel reinforcements in SCBA-SF ternary ecological concrete exposed to MgSO4
    'MDPI AG', 2020
    Co-Authors: Ariza-figueroa, Hilda A., Bosch Juan, Baltazar-zamora, Miguel Angel, Croche René, Santiago-hurtado Griselda, Landa-ruiz Laura, Mendoza-rangel, José M., Almeraya-calderón Facundo, Bastidas Rull, José María, Bastidas, David M.
    Abstract:

    In this study, ternary ecological concrete (TEC) mixtures were produced with partial substitution of the ordinary Portland cement (OPC) by 10%, 20%, and 30% of sugar cane bagasse ash (SCBA) and silica fume (SF); a control mixture (100% OPC) was prepared according to ACI 211.1 standard. The studied TEC specimens were reinforced with AISI 304 stainless Steel and AISI 1018 carbon Steel Rebars. TEC reinforced specimens were immersed in two different electrolytes, a control (DI-water) and 3.5 wt.% MgSO4 solution, for 180 days. The electrochemical corrosion was monitored by corrosion potential (Ecorr) according to ASTM C-876-15 standard, and the linear polarization resistance (LPR) technique using ASTM G59 standard. The Ecorr and current density icorr results show that AISI 304 stainless Steel Rebars have a high corrosion resistance, with icorr values below 0.1 µA/cm2, which is interpreted as a level of negligible corrosion. The best corrosion performance was found for the TEC mixture made with a 20% addition of blend of sugar cane bagasse ash-silica fume (SCBA-SF) to the OPC.This research was funded by PRODEP for the support granted by the SEP, to the Academic Body UV-CA-458 “Sustainability and Durability of Materials for Civil Infrastructure”, within the framework of the 2018 Call for the Strengthening of Academic Bodies with IDCA 28593. Funding support from The University of Akron, Fellowship Program FRC–207367