Damage Evolution and NOx Photocatalytic Degradation Performance of Nano-TiO<sub>2</sub> Concrete Under Freeze–Thaw Cycles

The internal pore structure of nano-TiO<sub>2</sub> concrete deteriorates gradually during freeze–thaw (F–T) cycles. The deterioration process can reveal the F–T damage mechanism and the deterioration law of photocatalytic performance. The evolution law of the pore structure of nano-TiO&...

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Main Authors: Zongming Jia, Yanru Zhao, Hengmao Niu
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Buildings
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Online Access:https://www.mdpi.com/2075-5309/14/12/3763
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author Zongming Jia
Yanru Zhao
Hengmao Niu
author_facet Zongming Jia
Yanru Zhao
Hengmao Niu
author_sort Zongming Jia
collection DOAJ
description The internal pore structure of nano-TiO<sub>2</sub> concrete deteriorates gradually during freeze–thaw (F–T) cycles. The deterioration process can reveal the F–T damage mechanism and the deterioration law of photocatalytic performance. The evolution law of the pore structure of nano-TiO<sub>2</sub> concrete during F–T damage was investigated. Moreover, this paper defined the microscopic F–T damage factor based on porosity and fractal dimension. The results showed that a 2% dosage of nano–TiO<sub>2</sub> concrete had better frost resistance and lower porosity in this experiment. Its porosity only increased by 13.3% after 200 F–T cycles, which was much smaller than that of ordinary concrete. Furthermore, the presence of nano-TiO<sub>2</sub> enhanced the volume fractal dimension of concrete pores larger than 100 nm, increasing the complexity of the pore structure and contributing to improved frost resistance. F–T damage led to a decrease in the photocatalytic performance of nano–TiO<sub>2</sub> concrete. Still, it helped the nitrate on the surface of the concrete to dissolve and disappear more quickly under rainwater washout. Finally, a thermodynamic theory-based concrete F–T damage correction model was constructed, and the model was used to predict F–T damage values for some scholars. The results showed that the correlation between the model values and the experimental values was more than 0.95, which could accurately reflect the degree of F–T damage of concrete. In addition, a prediction model of photocatalytic NO reduction by nano-TiO<sub>2</sub> concrete based on microscopic damage factor was established. It provides a theoretical basis for the application of nano-TiO<sub>2</sub> concrete in the field of gas pollutant treatment.
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spelling doaj-art-317b13d0d5364a05ab7cc9ff9d5b50292024-12-27T14:15:15ZengMDPI AGBuildings2075-53092024-11-011412376310.3390/buildings14123763Damage Evolution and NOx Photocatalytic Degradation Performance of Nano-TiO<sub>2</sub> Concrete Under Freeze–Thaw CyclesZongming Jia0Yanru Zhao1Hengmao Niu2College of Science, Inner Mongolia University of Technology, Hohhot 010051, ChinaCollege of Civil Engineering, Inner Mongolia University of Technology, Hohhot 010051, ChinaSchool of Architectural Engineering and Surveying and Mapping, Inner Mongolia Technical College of Construction, Hohhot 010070, ChinaThe internal pore structure of nano-TiO<sub>2</sub> concrete deteriorates gradually during freeze–thaw (F–T) cycles. The deterioration process can reveal the F–T damage mechanism and the deterioration law of photocatalytic performance. The evolution law of the pore structure of nano-TiO<sub>2</sub> concrete during F–T damage was investigated. Moreover, this paper defined the microscopic F–T damage factor based on porosity and fractal dimension. The results showed that a 2% dosage of nano–TiO<sub>2</sub> concrete had better frost resistance and lower porosity in this experiment. Its porosity only increased by 13.3% after 200 F–T cycles, which was much smaller than that of ordinary concrete. Furthermore, the presence of nano-TiO<sub>2</sub> enhanced the volume fractal dimension of concrete pores larger than 100 nm, increasing the complexity of the pore structure and contributing to improved frost resistance. F–T damage led to a decrease in the photocatalytic performance of nano–TiO<sub>2</sub> concrete. Still, it helped the nitrate on the surface of the concrete to dissolve and disappear more quickly under rainwater washout. Finally, a thermodynamic theory-based concrete F–T damage correction model was constructed, and the model was used to predict F–T damage values for some scholars. The results showed that the correlation between the model values and the experimental values was more than 0.95, which could accurately reflect the degree of F–T damage of concrete. In addition, a prediction model of photocatalytic NO reduction by nano-TiO<sub>2</sub> concrete based on microscopic damage factor was established. It provides a theoretical basis for the application of nano-TiO<sub>2</sub> concrete in the field of gas pollutant treatment.https://www.mdpi.com/2075-5309/14/12/3763nano-TiO<sub>2</sub> concretefreeze–thaw (F–T)photocatalysisdamagemodel
spellingShingle Zongming Jia
Yanru Zhao
Hengmao Niu
Damage Evolution and NOx Photocatalytic Degradation Performance of Nano-TiO<sub>2</sub> Concrete Under Freeze–Thaw Cycles
Buildings
nano-TiO<sub>2</sub> concrete
freeze–thaw (F–T)
photocatalysis
damage
model
title Damage Evolution and NOx Photocatalytic Degradation Performance of Nano-TiO<sub>2</sub> Concrete Under Freeze–Thaw Cycles
title_full Damage Evolution and NOx Photocatalytic Degradation Performance of Nano-TiO<sub>2</sub> Concrete Under Freeze–Thaw Cycles
title_fullStr Damage Evolution and NOx Photocatalytic Degradation Performance of Nano-TiO<sub>2</sub> Concrete Under Freeze–Thaw Cycles
title_full_unstemmed Damage Evolution and NOx Photocatalytic Degradation Performance of Nano-TiO<sub>2</sub> Concrete Under Freeze–Thaw Cycles
title_short Damage Evolution and NOx Photocatalytic Degradation Performance of Nano-TiO<sub>2</sub> Concrete Under Freeze–Thaw Cycles
title_sort damage evolution and nox photocatalytic degradation performance of nano tio sub 2 sub concrete under freeze thaw cycles
topic nano-TiO<sub>2</sub> concrete
freeze–thaw (F–T)
photocatalysis
damage
model
url https://www.mdpi.com/2075-5309/14/12/3763
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AT yanruzhao damageevolutionandnoxphotocatalyticdegradationperformanceofnanotiosub2subconcreteunderfreezethawcycles
AT hengmaoniu damageevolutionandnoxphotocatalyticdegradationperformanceofnanotiosub2subconcreteunderfreezethawcycles