Prestressed concrete thermal behaviour

Aslani, Farhad

doi:10.1680/macr.12.00037

Cited by 29 publications

(13 citation statements)

References 24 publications

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“…Second, the slow rate of heating restricted obvious spalling. Third, the ITZs between fibers and surrounding fresh paste provided sufficient pathway for the vapor, contributing to mirror spalling behavior …”

Section: Resultsmentioning

confidence: 99%

“…Third, the ITZs between fibers and surrounding fresh paste provided sufficient pathway for the vapor, contributing to mirror spalling behavior. 21,[54][55][56][57][58][59][60][61][62][63][64][65][66] Figure 7 presented that mass loss for PP fiber-reinforced LWSCC increased by higher fiber ratio especially higher than 600 C. The mass losses were less than 0.1% of selfweight at 100 C for all the mixes, which suggested that at 100 C minimal free water was lost due to dehydration of the cement paste. For the 300 C heating treatment, the mass loss LWSCC mixes with various fiber ratios raised dramatically to 4.6% of self-weight.…”

Section: Hardened Mechanical Propertiesmentioning

confidence: 99%

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Fiber‐reinforced lightweight self‐compacting concrete incorporating scoria aggregates at elevated temperatures

Aslani

Sun

Bromley

et al. 2019

Structural Concrete

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Self‐compacting concrete (SCC) has developed rapidly in modern concrete structures to accommodate the need of high deformability and considerable resistance to segregation. The lightweight aggregate called scoria is also utilized to manufacture lightweight self‐compacting concrete (LWSCC) to improve the strength‐to‐weight ratio with considerable cost beneficial. Meanwhile, the LWSCC employs fibers (polypropylene [PP] and steel) equipping different replacement ratios of traditional aggregates, the SCC will be invented to reveal balanced fresh property, spalling behavior, mechanical performance especially at elevated temperatures. In this study, eight LWSCC mix designs were explored with varying fiber ratios by volume of PP fiber (0.1, 0.15, 0.20, and 0.25%) and steel fiber (0.25, 0.5, 0.75, and 1.0%). The effects of different fiber types and ratios are tested with fresh properties (slump flow and J‐ring), hardened mechanical performance (compressive and tensile strength at 20°C) and high temperature resistance (compressive and tensile strength, mass loss and spalling) after 28‐day curing at 100, 300, 600, and 900°C. The 0.25% optimum fiber ratio for PP fiber mix and 0.75% for steel fiber mix are determined with balanced fresh properties as well as high‐temperature resistance for the hardened properties.

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Section: Resultsmentioning

confidence: 99%

Section: Hardened Mechanical Propertiesmentioning

confidence: 99%

Fiber‐reinforced lightweight self‐compacting concrete incorporating scoria aggregates at elevated temperatures

Aslani

Sun

Bromley

et al. 2019

Structural Concrete

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“…In the stressed test, the concrete specimen is subjected to preload before and throughout the heating process [ 18 ], and the most obvious difference between the stressed and unstressed concrete is that the compressive strength is higher when the specimen is stressed during heating than that of unstressed concrete during heating, which was first reported by Malhotra [ 19 , 20 ]. In order to investigate the effect of high temperature on stressed concrete, Abram [ 21 ], Khoury [ 22 ], and Schneider [ 23 ] conducted experimental tests on the stressed and unstressed concrete and came to the same conclusion as Malhotra [ 19 , 20 ].…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Residual Mechanical and Porosity Properties of Cement Mortar under Axial Stress during Heating

2021

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The preload load on concrete during heating is considered to cause a ‘densification’ of cement mortar which led to the increased compressive strength. In order to assess the influence of coupled load and heating effects on porosity characteristics of concrete, the porosity of mortar after mechanical and thermal loading was measured by X-ray computed tomography (X-ray CT). The preload at pre-stress ratios of 0, 0.2, 0.4, and 0.6 (ratio of stress applied to the specimen to its compressive strength at room temperature) were applied on mortar specimens during heating. The residual compressive strengths of the heated and stressed mortar specimens were tested after cooling to room temperature. Combined analyses of the residual compressive strength test results and porosity test results, it shows that the porosity of the specimens under the coupled stressing and heating conditions were slightly lower than that under the unstressed conditions; however, the conclusion that the increase of compressive strength of stressed mortar was caused by the ‘densification’ of cement paste was insufficient. The preload reduced the cracks in the mortar, especially the crack induced due to the thermal mismatch in aggregates and hardened cement paste (HCP), and this may account for the increased compressive strength of stressed mortar.

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“…It can however be argued that HSC is more prone to spalling due to its lower porosity, thereby contributing to the increased likelihood of high pressure developing within the concrete structure [8]. On another hand, the effect of high temperature on the reinforcing steel was by others [9,10]. Youssef and Moftah [2] reported reinforcing steel is much more sensitive to high temperatures than concrete.…”

Section: Introductionmentioning

confidence: 99%

Performance of Post-Fire Composite Prestressed Concrete Beam Topped with Reinforced Concrete Flange

Harbi

Izzet

2018

CivileJournal

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The performance of composite prestressed concrete beam topped with reinforced concrete flange structures in fire depends upon several factors, including the change in properties of the two different materials due to fire exposure and temperature distribution within the composition of the composite members of the structure. The present experimental work included casting of 12 identical simply supported prestressed concrete beams grouped into 3 categories, depending on the strength of the top reinforced concrete deck slab (20, 30, and 40 MPa). They were connected together by using shear connector reinforcements. To simulate the real practical fire disasters, 3 composite prestressed concrete beams from each group were exposed to high temperature flame of 300, 500, and 700°C, and the remaining beams were left without burning as reference specimens. Then, the burned beams were cooled gradually by leaving them at an ambient lab condition, after which the specimens were loaded until failure to study the effect of temperature on the residual beams serviceability, to determine the ultimate load-carrying capacity of each specimen in comparison with unburned reference beam, and to find the limit of the temperature for a full composite section to remain composite. It was found that the exposure to fire temperature increased the camber of composite beam at all periods of the burning and cooling cycle as well as the residual camber, along with reduction in beam stiffness and the modulus of elasticity of concrete in addition to decrease in the load-carrying capacity.

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Prestressed concrete thermal behaviour

Cited by 29 publications

References 24 publications

Fiber‐reinforced lightweight self‐compacting concrete incorporating scoria aggregates at elevated temperatures

Fiber‐reinforced lightweight self‐compacting concrete incorporating scoria aggregates at elevated temperatures

Investigation of the Residual Mechanical and Porosity Properties of Cement Mortar under Axial Stress during Heating

Performance of Post-Fire Composite Prestressed Concrete Beam Topped with Reinforced Concrete Flange

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