International Journal of Highway Engineering (한국도로학회논문집)

Korean Society of Road Engineers (한국도로학회)
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Evaluation of NOx Removal Efficiency of Photocatalytic Concrete for Road Structure

도로구조물 적용을 위한 광촉매 콘크리트의 질소산화물(NOx) 제거효율 평가

  • 김영규 (강릉원주대학교 방재연구소) ;
  • 홍성재 (강릉원주대학교 토목공학과) ;
  • 이경배 (한국도로공사 도로교통연구원) ;
  • 이승우 (강릉원주대학교 토목공학과)
  • Received : 2014.07.18
  • Accepted : 2014.10.01
  • Published : 2014.10.16
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Abstract

PURPOSES : In areas of high traffic volume, such as expressway across large cities, the amount of nitrogen oxides (NOx) emitted into the atmosphere as air pollution can be significant since NOx gases are the major cause of smog and acid rain. Recently, the importance of NOx removal has arisen in the world. Titanium dioxide ($TiO_2$), that is one of photocatalytic reaction material, is very efficient for removing NOx. The NOx removing mechanism of $TiO_2$ is the reaction of solar photocatalysis. Therefore, $TiO_2$ in road structure concrete need to be contacted with ultraviolet rays (UV) to be activated. In general, $TiO_2$ concretes are produced by replacement of $TiO_2$ as a part of concrete binder. However, considerable portion of $TiO_2$ in concrete cannot contact with the pollutant in the air and UV. Therefore, $TiO_2$ penetration method using the surface penetration agents is attempted as an alternative in order to locate $TiO_2$ to the surface of concrete structure. METHODS : This study aimed to evaluate the NOx removal efficiency of photocatalytic concrete due to various $TiO_2$ application method such as mix with $TiO_2$, surface spray($TiO_2$ penetration method) on hardened concrete and fresh concrete using surface penetration agents. The NOx removal efficiency of $TiO_2$ concrete was confirmed by NOx Analyzing System based on the specification of ISO 22197-1. RESULTS : The NOx removal efficiency of mix with $TiO_2$ increased from 11 to 25% with increasing of replacement ratio from 3 to 7%. In case of surface spray on hardened concrete, the NOx removal efficiency was about 50% due to application amount of $TiO_2$ with surface penetration agents as 300, 500 and 700g/m2. The NOx removal efficiency of surface spray on fresh concrete due to all experimental conditions, on the other hand, which was very low within 10%. CONCLUSIONS : It was known that the $TiO_2$ penetration method as surface spray on hardened concrete was a good alternative in order to remove the NOx gases for concrete road structures.

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References

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