Influence of cover thickness on the mechanical properties of steel bar in mortar exposed to high temperatures

Topçu, İ̇lker Bekir; Boğa, Ahmet Raif; Demi̇r, Abdullah

doi:10.1002/fam.1042

Cited by 6 publications

(4 citation statements)

References 19 publications

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“…The stress-strain curve of plain steel only experienced a rapid drop in resistance when exposed to 800°C. A similar finding was reported by Topcu et al (2011). This observation was inconsistent with the steel behaviour; steel can withstand high temperatures up to 700°C with only a slight decrease in yield strength of up to 15 per cent, as reported by Felicetti et al (2009).…”

Section: Tensile Test Of Steel Bar After Being Exposed To Elevated Temperaturessupporting

confidence: 67%

“…The limestone aggregates are stable up to 600°C (Hager, 2013). However, at 700°C and above, CaCO 3 turns into CaO and CO 2 and expands with temperature (Topcu et al, 2011). The decomposition of CaCO 3 causes a volume change in concrete, thereby resulting in shrinkage and destruction (Yüzer et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

“…Literature on the effects of concrete cover on various material properties when exposed to elevated temperatures is limited. Topcu et al (2011) studied the effects of 30 and 50 mm concrete covers on the mechanical properties of steel bar in mortar under the exposure to elevated temperatures. At 800°C, the yield strength of steel bar drops more rapidly in concrete with 30 mm cover than in steel bar in concrete with 50 mm cover.…”

Section: Introductionmentioning

confidence: 99%

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Performance of spent garnet as a sand replacement in high-strength concrete exposed to high temperature

Kadir

Khiyon

Sam

et al. 2019

JSFE

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Purpose The purpose of this paper is to examine the mechanical properties, material composition of spent garnet as a sand replacement in high-strength concrete at room and elevated temperatures. Bonding of the concrete containing spent garnet and reinforcing rebar is investigated. Moreover, the optimum thickness of concrete cover subjected to elevated temperatures is investigated. Design/methodology/approach First, the plain spent garnet was physically, chemically and thermally studied. Then, a series of concrete specimens with 0, 20, 40, 60, 80 and 100 per cent of spent garnet were prepared to determine the optimum percentage of spent garnet. Finally, the physical and mechanical behaviours of concrete specimens and effects of cover thickness on steel rebar when subjected to elevated temperature of 200°C, 400°C, 600°C and 800°C for 1 h were studied. It was observed that spent garnet was thermally stable compared to river sand. Findings Mechanical properties were found to be optimal for concrete with 40% spent garnet replacement. Physically, spent garnet concrete changed colour to brown at 400°C, and to whitish grey at 600°C. The residual compressive strength of spent garnet concrete was also found slightly higher than that for control specimens. At various high temperatures, the reduction in ultimate tensile stress for steel bar inside concrete cover of 30 mm was the lowest compared to that of 20 mm. Research limitations/implications Spalling effect it not considered in this study. Practical implications The optimum concrete cover is important issues in reinforced concrete design. This can be used as a guideline by structural designers when using a different type of concrete material in the construction. Social implications Utilization of the waste spent garnet reduces usage of natural aggregates in concrete production and enhances its performance at elevated temperatures. Natural aggregates are normally taken from sand and rock. The new innovation in concrete perhaps can produce light concrete, reduce the cost of concrete production and at the same time also mitigates environmental problems affect from waste material such as minimizing disposal area. Originality/value Utilization of spent garnet in ordinary Portland cement (OPC) concrete at high temperature is a new innovation. It shows that the concrete cover of the concrete element reduced as compared to the OPC concrete. Reduce in weight concrete however the strength of concrete is similar to conventional concrete. This study at elevated temperature has never been performed by any previous researcher.

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Section: Tensile Test Of Steel Bar After Being Exposed To Elevated Temperaturessupporting

confidence: 67%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Performance of spent garnet as a sand replacement in high-strength concrete exposed to high temperature

Kadir

Khiyon

Sam

et al. 2019

JSFE

View full text Add to dashboard Cite

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“…Also remarkable chemical changes take place in the cement paste. Generally over 900°C, a complete decomposition takes place in the concrete and thereby concrete losses its strength as reported by Topcu et al (2011). The reduction in strength is because of the dehydration of absorbed water and chemically bound water (Arioz, 2007).…”

Section: Compressive Strengthmentioning

confidence: 94%

Strength and microstructure characteristics of concrete with different grade exposed to standard fire

Thanaraj

Anand

Arulraj

2020

JSFE

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Purpose The purpose of this study is to investigate the effect of standard fire on the strength and microstructure properties of concrete with different strength grades. Design/methodology/approach Different strength grades of concrete used for the investigation are M20, M30, M40 and M50. An electrical bogie hearth furnace was developed to simulate the International Standards Organization 834 standard fire curve.Concrete samples were subjected to high temperatures of 925, 1,029, 1,090 and 1,133°C for the duration of 1, 2, 3 and 4 h, respectively, as per standard fire curve. Compressive strength, tensile strength, thermal crack pattern and spalling of heated concrete specimens were evaluated by experimental investigation. Scanning electron microscopy and thermo-gravimetric analysis were performed to investigate the microstructure properties of heated concrete specimens. Findings Test results indicated reduction in the strength and changes in the microstructure properties of concrete exposed to elevated temperature. The degree of weight and the strength loss were found to be higher for concrete with higher grades. An empirical relation is proposed to determine the residual strength of concrete with different strength grade using regression analysis. Social implications Results of this research will be useful for the design engineers to understand the behavior of concrete exposed to elevated temperature as per standard fire. Originality/value When concrete is exposed to elevated temperature, its internal microstructure changes, thereby strength and durability of concrete deteriorates. The performance of concrete with different strength grade exposed to standard fire is well understood. This research’s findings will be useful for the designers to understand more about fire resistance of concrete. A simple relationship is proposed to determine the residual strength of concrete exposed to various durations of heating.

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Study of the structural safety assessment of steel bridge subjected in post-fire

Chi

Peng

2020

Construction and Building Materials

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Influence of cover thickness on the mechanical properties of steel bar in mortar exposed to high temperatures

Cited by 6 publications

References 19 publications

Performance of spent garnet as a sand replacement in high-strength concrete exposed to high temperature

Performance of spent garnet as a sand replacement in high-strength concrete exposed to high temperature

Strength and microstructure characteristics of concrete with different grade exposed to standard fire

Study of the structural safety assessment of steel bridge subjected in post-fire

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