Effect of patch repair and strengthening with EBR and NSM CFRP laminates for RC beams with low, medium and heavy corrosion

Triantafyllou, Garyfalia G.; Rousakis, Theodoros; Karabinis, Athanasios I.

doi:10.1016/j.compositesb.2017.09.029

Cited by 74 publications

(26 citation statements)

References 28 publications

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“…This issue leads to the growth and development of micro-or macro-cracks, resulting in a decreased service life and/or durability due to the increased in water penetration, chloride ions, or carbonation. At this time and age, RC structure deterioration has caused the development of new and innovative materials and methods for structural rehabilitation and strengthening, as replacement of structures would be very costly and is thus prohibitive [9,10]. Employing fibers in concrete and cement-based composites, in order to increase toughness and ductility in post-crack regions, have seen considerable growth.…”

Section: Introductionmentioning

confidence: 99%

Restrained Shrinkage Cracking of Fiber-Reinforced High-Strength Concrete

Saradar

Tahmouresi

Mohseni

et al. 2018

Fibers

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Concrete shrinkage and volume reduction happens due to the loss of moisture, which eventually results in cracks and more concrete deformation. In this study, the effect of polypropylene (PP), steel, glass, basalt, and polyolefin fibers on compressive and flexural strength, drying shrinkage, and cracking potential, using the ring test at early ages of high-strength concrete mixtures, was investigated. The restrained shrinkage test was performed on concrete ring specimens according to the ASTM C1581 standard. The crack width and age of restrained shrinkage cracking were the main parameters studied in this research. The results indicated that the addition of fiber increases the compressive strength by 16%, 20%, and 3% at the age of 3, 7, and 28 days, respectively, and increases the flexural toughness index up to 7.7 times. Steel and glass fibers had a better performance in flexural strength, but relatively poor action in the velocity reduction and cracking time of the restrained shrinkage. Additionally, cracks in all concrete ring specimens except for the polypropylene-containing mixture, was developed to a full depth crack. The mixture with polypropylene fiber indicated a reduction in crack width up to 62% and an increasing age cracking up to 84%.

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Section: Introductionmentioning

confidence: 99%

Restrained Shrinkage Cracking of Fiber-Reinforced High-Strength Concrete

Saradar

Tahmouresi

Mohseni

et al. 2018

Fibers

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“…The vast majority of the existing research on the durability of FRP based strengthening systems is mostly dedicated to the study of the externally bonded reinforcement (EBR), e.g. [19][20][21][22]. Given the lack of numerous studies focussing NSM, an overall perspective of the degradation mechanisms and factors affecting the durability, as well as the strategies used to characterize it, may be found in the literature regarding EBR.…”

Section: Introductionmentioning

confidence: 99%

Durability of bond in NSM CFRP-concrete systems under different environmental conditions

Fernandes

Sena-Cruz

Xavier

et al. 2018

Composites Part B: Engineering

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This paper addresses the durability of bond between concrete and carbon fibre reinforced polymer (CFRP) strips installed according to the near-surface mounted (NSM) technique (NSM CFRP-concrete systems) under the effects of two main groups of environmental conditions: (i) laboratory-based ageing conditions; (ii) real outdoor ageing conditions. The bond degradation was evaluated by carrying out direct pullout tests on aged specimens that were previously subjected to distinct environmental conditions for different periods of exposure. Moreover, the degradation of the mechanical properties of the involved materials was investigated. The digital image correlation (DIC) method was used to document the evolution of the deformation fields at the surface over the whole region of interest consisting of concrete and epoxy adhesive at the ligament region. This information supported the discussion about the evolution of the bond resistant mechanism developed in NSM CFRP-concrete specimens during testing, as well as the assessment of the bond quality of the system. In general, the results obtained from the durability tests conducted have shown that the different exposure environments, which may be considered as quite severe, did not result in significant damage on NSM CFRP-concrete system. The maximum decrease of about 12% on bond strength was obtained for real outdoor environments. Conversely, a maximum increase of 8% on bond strength was obtained on the specimens exposed to the temperature cycles between -15 °C and +60 °C. DIC allowed to document the stress transfer mechanisms established between the CFRP and the concrete substrate, revealing the crack patterns and the influence widths of the CFRP reinforcement strips, which were shown to be important for avoiding group effect when using multiple parallel strengthening CFRP strips.

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“…Samples were submerged in calcium hydroxide solution for the chosen curing time and then transferred to a saline solution tank, with a 3.5% sodium chloride (NaCl) solution. Alternate dry and wet cycles were performed to accelerate the corrosion process of embedded steel rebar, previously used in other corrosion studies 10,[24][25][26][27][28][29] . One cycle consisted of 5 days under drying condition (exposed in air, laboratory environment) and 2 days under wetting condition (tank with NaCl solution).…”

Section: Compressive Strengthmentioning

confidence: 99%

Investigating the Effect of Curing in the Chloride Diffusion Coefficient of Conventional Concrete

et al. 2019

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Concrete is the most used material in the construction industry worldwide. Built concrete infrastructure is exposed to specific environments conditions during the asset's life, which impose chemical and physical actions that may lead to premature deterioration. Poor concrete durability and corrosion of reinforcement bars are the primary cause of structural deterioration and reduced service life. Most concrete deterioration mechanisms are driven by transport properties, in particular, the chloride diffusion coefficient. In this paper, the effect of curing in the chloride diffusion coefficient of conventional concrete is investigated through Electrochemical Impedance Spectroscopy (EIS). Reinforced concrete samples cured for 3, 7 and 28 days were exposed to accelerated chloride testing for 300 days (40 wet-dry cycles). Results indicate that the chloride diffusion coefficient reduces significantly with curing time, evidencing that prolonged curing may decrease the likelihood of corrosion in reinforced concrete structure when combined with appropriate design and construction processes.

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Effect of patch repair and strengthening with EBR and NSM CFRP laminates for RC beams with low, medium and heavy corrosion

Cited by 74 publications

References 28 publications

Restrained Shrinkage Cracking of Fiber-Reinforced High-Strength Concrete

Restrained Shrinkage Cracking of Fiber-Reinforced High-Strength Concrete

Durability of bond in NSM CFRP-concrete systems under different environmental conditions

Investigating the Effect of Curing in the Chloride Diffusion Coefficient of Conventional Concrete

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