Mechanical performances and microstructures of metakaolin contained UHPC matrix under steam curing conditions

Mo, Zongyun; Gao, Xiaojian; Su, Anshuang

doi:10.1016/j.conbuildmat.2020.121112

Cited by 152 publications

(41 citation statements)

References 45 publications

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“…Due to the presence of BFS (containing aluminum phase) in the mixture, it reacts with LF to form Mc and Hc [25]. The formation of Hc can be observed at 3 days, but as the hydration reaction proceeds, the Hc content decreases, and Mc is formed [52,53]. The presence of LF prevents the decomposition of ettringite to monosulfate, and the formation of Hc and Mc indirectly stabilizes ettringite [49,54].…”

Section: Xrdmentioning

confidence: 99%

The Hydration, Mechanical, Autogenous Shrinkage, Durability, and Sustainability Properties of Cement–Limestone–Slag Ternary Composites

2021

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This study examines the hydration–mechanical–autogenous shrinkage–durability–sustainability properties of ternary composites with limestone filler (LF) and ground-granulated blast furnace slag (BFS). Four mixtures were prepared with a water/binder ratio of 0.3 and different replacement ratios varying from 0 to 45%. Multiple experimental studies were performed at various ages. The experimental results are summarized as follows: (1) As the replacement levels increased, compressive strength and autogenous shrinkage (AS) decreased, and this relationship was linear. (2) As the replacement levels increased, cumulative hydration heat decreased. At the age of 3 and 7 days, there was a linear relationship between compressive strength and cumulative hydration heat. (3) Out of all mixtures, the ultrasonic pulse velocity (UPV) and electrical resistivity exhibited a rapid increase in the early stages and tended to slow down in the latter stages. There was a crossover of UPV among various specimens. In the later stages, the electrical resistivity of ternary composite specimens was higher than plain specimens. (4) X-ray diffraction (XRD) results showed that LF and BFS have a synergistic effect. (5) With increasing replacement ratios, the CO2 emissions per unit strength reduced, indicating the sustainability of ternary composites.

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Section: Xrdmentioning

confidence: 99%

The Hydration, Mechanical, Autogenous Shrinkage, Durability, and Sustainability Properties of Cement–Limestone–Slag Ternary Composites

2021

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“…(2) The weight loss percentage of the specimen exposed to 300–550 °C decreased with the increase in the biochar content. The weight loss at 300–550 °C was mainly the dehydration of CH (Calcium hydroxide) [ 17 , 18 ], and the CH content of CB2 and CB5 decreased with the addition of biochar [ 19 ]. (3) The weight loss percentage with exposure to 550–900 °C increased with the increase in the biochar content.…”

Section: Resultsmentioning

confidence: 99%

Behavior of Biochar-Modified Cementitious Composites Exposed to High Temperatures

et al. 2021

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In this study, the effect of biochar on the high temperature resistance of cementitious paste was investigated using multiple experimental methods. The weight loss, cracks, residual compressive strength, and ultrasonic pulse velocity (UPV) of biochar cementitious paste with 2% and 5% biochar exposed to 300, 550 and 900 °C were measured. The products and microstructures of biochar cementitious paste exposed to high temperatures were analyzed by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. The results showed that the cracks of specimens exposed to high temperatures decreased with increasing biochar content. The addition of 2% and 5% biochar increased the residual compressive strength of the specimens exposed to 300 °C and the relative residual compressive strength at 550 °C. As the exposure temperature increased, the addition of biochar compensated for the decreasing ultrasonic pulse velocity. The addition of biochar contributed to the release of free water and bound water, and reduced the vapor pressure of the specimen. The addition of biochar did not change the types of functional groups and crystalline phases of the products of cementitious materials exposed to high temperatures. Biochar particles were difficult to observe at 900 °C in scanning electron microscopy images. In summary, because biochar has internal pores, it can improve the high-temperature resistance of cement paste.

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“…Different supplementary cementitious materials, such as fly ash (FA), ground granulated blast furnace slag, calcined clay, etc., were used as replacements for cement. Mo et al, 2021 investigated the microscopic performances of metakaolin (MK) containing a UHPC matrix using steam curing. They have reported that MK reaction kinetics increased with higher curing temperature; however, cement hydration rate reduced.…”

Section: Introductionmentioning

confidence: 99%

Impact of Silica Nanoparticles on the Durability of fly Ash Concrete

Ali

Sharma

Singh³

et al. 2021

Front. Built Environ.

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In the present study, the mechanical and durability properties of silica nanoparticle (SNP)-incorporated fly ash (FA) concrete mix were examined after 365 days of exposure. The dosages of FA replaced by cement in the present study were 30%, 40%, and 50%, while 3% SNPs were added by the weight of cement in the FA incorporated mix. For a comparison of SNPs with silica fume (SF), 6% SF was added (by the weight of cement) and entire casting was performed at a constant water to binder (w/b) ratio of 0.29. The present work is the extension of a previous study wherein durability properties of the same mixes were reported for up to 180 days of exposure. Compressive strength results show that in the presence of SNPs, the enhancement in compressive strength was in the range of 10–14%, while, in presence of SF, 8–10% of the enhancement was observed as compared to control. However, exposed samples in a carbonation environment showed that the compressive strength of the control and SF incorporated mix increased, while SNP-incorporated samples showed negligible enhancement. Further, sulphate exposed mix show that compressive strength decreases, however, the SNP-incorporated mix showed the lowest reduction compared to other mixes. Therefore, the study shows that the SNP-incorporated mix has higher mechanical properties and more durability compared to other mixes in a severe environment.

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Mechanical performances and microstructures of metakaolin contained UHPC matrix under steam curing conditions

Cited by 152 publications

References 45 publications

The Hydration, Mechanical, Autogenous Shrinkage, Durability, and Sustainability Properties of Cement–Limestone–Slag Ternary Composites

The Hydration, Mechanical, Autogenous Shrinkage, Durability, and Sustainability Properties of Cement–Limestone–Slag Ternary Composites

Behavior of Biochar-Modified Cementitious Composites Exposed to High Temperatures

Impact of Silica Nanoparticles on the Durability of fly Ash Concrete

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