Effects of high temperature and post-fire-curing on compressive strength and microstructure of calcium carbonate whisker-fly ash-cement system

Cao, Mingli; Cao, Mingli; Lv, Xuewei; Yin, Hui; Li, L.; Liu, Zixing

doi:10.1016/j.conbuildmat.2020.118333

Cited by 35 publications

(17 citation statements)

References 40 publications

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“…Based on the aforementioned experimental results and previous findings (Akca and Özyurt 2020;Ming et al 2020;Suh et al 2020), a dynamic model for the conversion of quick lime to Portlandite was established as follows.…”

Section: Modeling Of Expansion Due To Production Of Ca(oh)mentioning

confidence: 99%

Remaining Shear Capacity of Fire-Damaged High Strength RC Beams after Moist Curing

Higuchi

Iwama

Maekawa

2021

ACT

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This study presents an analytical method for estimating the remaining shear capacity of reinforced concrete (RC) beams subjected to high temperature heating and verifies it by experiments. We focused on the mechanism by which the remaining shear capacity of members self-recovers in a humid environment after slow cooling. The authors confirmed that the infiltration of water vapor in the air into concrete after heating caused rehydration of quicklime (CaO) produced by high-temperature heating and self-recovery of material strength. Based upon material experiments, the mechanical model of calcium hydroxide formation by rehydration of quicklime was incorporated into the multi-scale analysis. Using the proposed model of this study, the effect of damage on the remaining strength of damaged members was also investigated. It was confirmed that the series of high temperature heating, slow cooling, moisture absorption, selfhealing, and remaining shear capacity could be reproduced by the multi-scale analysis.

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Section: Modeling Of Expansion Due To Production Of Ca(oh)mentioning

confidence: 99%

Remaining Shear Capacity of Fire-Damaged High Strength RC Beams after Moist Curing

Higuchi

Iwama

Maekawa

2021

ACT

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“…The third peak at 600-740 °C can be the indicator for the dehydration of CaCO 3 content. Finely the fourth peak at 740-900 °C may indicate the second peak for CSH decomposition [28][29][30].…”

Section: Thermo-gravimetric Resultsmentioning

confidence: 99%

“…Less loss of mass was observed by the inclusion of SF, FA, or MK corresponds to the second peak, in which SCM decreases the Ca(OH) 2 content and producing additional strength. Finally, the last peak indicates that SF, FA, or MK decreases the loss of mass due to the CaCO 3 decomposition [30].…”

Section: Thermo-gravimetric Resultsmentioning

confidence: 99%

Flexural strength of silica fume, fly ash, and metakaolin of hardened cement paste after exposure to elevated temperatures

Abdelmelek

Lublóy

2021

J Therm Anal Calorim

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The mechanical properties of concrete based mainly on flexural and compressive bearing capacity. Generally, researchers have an interest in the evaluation of compression property through the importance of the flexural performance of the material in the constructions, namely the significance of each mechanical property based upon the position of the structural element. The present experimentally work is directed toward improving the flexural strengths performance of ordinary hardened cement paste (HCP) at ambient and after elevated temperatures exposure. The used parameters were different pozzolanic materials with different replacements ratios to cement mass and different levels of temperature. Results proved the significant contribution of pozzolanic material to enhance the flexural properties of HCP after being exposed to elevated temperatures. The low content of CaO, the high grinding fineness, and the physical morphology of the used pozzolanic materials, made their adoption effective to HCP after exposure to elevated temperatures. Using 3%, 12%, and 15% of silica fume (SF), metakaolin (MK), and fly ash (FA), respectively, showed the highest heat endurance among the other replacements. However, the optimum replacement of MK has shown a better heat endurance than the optimum replacements of SF and FA. On the other hand, the spalling has occurred at high replacements of SF. Finally, the results are supported by means of thermo-gravimetric, SEM, and computed tomography investigations.

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“…In contrast, there has been relatively little research on the role that fire plays in rock weathering. Numerous studies have examined the impact of temperature on rocks by using laboratory heating and cooling cycles, mainly to assess the basic properties of materials suitable for construction and infrastructures [34][35][36][37]. Additional information on the fire-related behaviour of carbonate rock is available from archaeological sites [38,39].…”

Section: The Influence Of Fires On Rock Weatheringmentioning

confidence: 99%

Wildfires as a Weathering Agent of Carbonate Rocks

Shtober‐Zisu

Wittenberg

2021

Minerals

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While most of the scientific effort regarding wildfires has predominantly focused on fire effects on vegetation and soils, the role of fire as an essential weathering agent has been largely overlooked. This study aims to evaluate rock decay processes during wildfires, in relation to ground temperatures and rock morphologies of limestone, dolomite, and chalk. In 2010, a major forest fire in Israel caused massive destruction of the exposed rocks and accelerated rock weathering over the burned slopes. While a detailed description of the bedrock exfoliation phenomenon was previously reported, here, we conducted an experimental open fire to determine the temperature and gradients responsible for boulder shattering. The results show ground temperatures of 700 °C after 5 min from ignition, while the peak temperature (880 °C) was reached after 9 min. Temperature gradients show a rapid increase during the first 5 min (136 °C/min), moderate increase during the next 4 min (43 °C/min), and slow decrease for the next 9 min (25 °C/min). After 12 min, all boulders of all formations were cracked or completely shattered. The behaviour of carbonate rocks upon heating was studied to identify the erosive effects of fire, namely the formation of new cracks and matrix deterioration.

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Effects of high temperature and post-fire-curing on compressive strength and microstructure of calcium carbonate whisker-fly ash-cement system

Cited by 35 publications

References 40 publications

Remaining Shear Capacity of Fire-Damaged High Strength RC Beams after Moist Curing

Remaining Shear Capacity of Fire-Damaged High Strength RC Beams after Moist Curing

Flexural strength of silica fume, fly ash, and metakaolin of hardened cement paste after exposure to elevated temperatures

Wildfires as a Weathering Agent of Carbonate Rocks

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