Effect of temperature on uni-axial compressive behavior of confined concrete

Zaidi, Kaleem A.; Sharma, Umesh Kumar; Bhandari, N. M.

doi:10.1016/j.firesaf.2011.12.001

Cited by 16 publications

(9 citation statements)

References 15 publications

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“…Most of recent research works have reported an improvement in thermal resistance of confined concrete, lead to sustain the strength, and increase the deformability of confined concrete owing to the exposure to high temperature. Further residual behavior after thermal cycles of confined concrete in higher residual compressive strength, ductility, and toughness were more as compared to unconfined concrete studied by Zaidi et al Thus, the available confinement models developed under ambient room temperature conditions overestimate the strength and underestimate the strain, if applied to heated confined concrete. The published data on the stress‐strain modeling of confined concrete columns exposed to high temperatures are negligible.…”

Section: Introductionmentioning

confidence: 87%

An empirical model for confined concrete after exposure to high temperature

et al. 2017

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Summary In this study, constitutive relationships have been developed for confined concrete subjected to elevated temperature to specify the fire‐performance criteria for concrete structures after exposé to fire. This study extends over a total of 63 circular hoop confined concrete specimens that were casted and tested under concentric compression loading after exposure to high temperature. The test variables studied are the yield strength of transverse reinforcement, spacing of the hoop, and exposure to temperatures from ambient to 800°C. It is shown that all of these variables have significant influence on concrete behavior at different temperatures and further an improvement in the thermal resistance of concrete when confined using transverse steel reinforcement. On the basis of experimental results, a model for confined concrete after exposed to high temperature is proposed to predict the results of residual behavior after thermal cycles. The proposed empirical stress‐strain equations are suitable to predict the postfire behavior of confined normal strength concrete in compression. The predictions were found to be in good agreement and well fit with experimental results.

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Section: Introductionmentioning

confidence: 87%

An empirical model for confined concrete after exposure to high temperature

et al. 2017

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“…Therefore, a maximum target temperature of 900°C inside the specimens was considered to be reasonable for testing. The lower limit of the exposure temperature was 300°C, because generally no significant effects on the properties of concrete are found when it is heated below this temperature (Mohamedbhai, 1986;Zaidi et al, 2012). All the prisms were heated without any preloading.…”

Section: Thermal Testingmentioning

confidence: 99%

“…However, no serious spalling was observed in the concrete specimens at any exposure temperature. When exposed to elevated temperatures, concrete becomes loose because of the pore During the cooling stage, the ionised CaO formed by the decomposition of Ca(OH) 2 absorbs water and becomes Ca (OH) 2 again, which results in the expansion of the concrete volume (Karakoc, 2013;Zaidi et al, 2012). The damage accumulated during the cooling process further reduces the residual strength, which leads to further expansion of any cracks day by day (see Figure 5).…”

Section: Observations After Heatingmentioning

confidence: 99%

“…With the increasing use of confined concrete in the potential plastic-hinge regions of RC structures, concern has developed regarding the post-fire behaviour of such confined concrete zones. The literature indicates that the effectiveness of transverse reinforcement in confining the core concrete decreases on exposure to elevated temperatures (Zaidi et al, 2012). In view of this, it is important to design and provide confinement strengthening to RC elements after a fire accident in order to restore the original room-temperature strength and deformability.…”

Section: Practical Implicationsmentioning

confidence: 99%

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Confinement strengthening of heat-damaged reinforced concrete columns

Roy

Sharma

Bhargava

2016

Magazine of Concrete Research

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The effectiveness of different strengthening techniques in restoring heat-damaged concrete short columns was evaluated experimentally. Four confinement strengthening systems were employed: high-strength fibre-reinforced concrete (HSFRC), ferrocement (FC), glass-fibre-reinforced polymer (GFRP) and steel plate (SP) jacketing. Fifty-one reinforced concrete prisms of size 150 Â 150 Â 450 mm were first subjected to different elevated temperatures. Heated specimens were strengthened using one of the chosen techniques. Thereafter, all specimens were tested under monotonic loading to determine the axial ultimate strength, stiffness, ductility, energy absorption and peak stressstrain behaviour. It was observed that the GFRP jacketing was effective in restoring the compressive strength and energy dissipation, but was not capable of restoring the stiffness. However, FC and HSFRC jacketing were effective mainly in restoring the stiffness of heat-damaged concrete. SP jacketing was not effective in improving the strength or the stiffness properties. GFRP jacketing was found to be the most effective method for strengthening of fire-or heat-damaged concrete structures.

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“…Several tests on reinforced concrete columns with different geometries have been reported in the literature [17], [18], [20]- [25]. In general, tests are performed using standard ISO 834 fire curves [26] and losses in strength and stiffness and failure modes are usually presented.…”

Section: Introductionmentioning

confidence: 99%

Residual strength of reinforced concrete stub columns subject to moderate temperatures

Lima¹,

Cardoso²

2021

Rev. IBRACON Estrut. Mater.

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This work aims to evaluate the residual strength of reinforced concrete stub columns subjected to moderate temperatures. To accomplish this task, an experimental program was carried out including compression tests on plain concrete specimens exposed to temperatures up to 600 ºC and on reinforced concrete stub columns with two different tie configurations heated at a constant rate for up to 120 min. The results show a loss of residual compressive strength with temperature and the beneficial influence of ties to prevent the spalling phenomenon, although samples with more ties exhibited lower capacity. Finally, the results were compared to the analytical prediction using a cross-sectional approach with idealized stress-strain relations, showing a good correlation. The applicability of the Isotherm 500 ºC method is discussed for moderate temperatures.

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Effect of temperature on uni-axial compressive behavior of confined concrete

Cited by 16 publications

References 15 publications

An empirical model for confined concrete after exposure to high temperature

An empirical model for confined concrete after exposure to high temperature

Confinement strengthening of heat-damaged reinforced concrete columns

Residual strength of reinforced concrete stub columns subject to moderate temperatures

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