A systematic review on photocatalytic concrete for pavement applications: an innovative solution to reduce air pollution

摘要

Air pollution is one of the major health threats for urban dwellers due to increased concentration of pollutants and vehiculartraffic. Approximately 7.0 million premature deaths in the world are associated with air pollution. Although stringentemission standards have been introduced, no significant reduction in air quality index in metro cities has been reported.Alternative solutions such as photocatalytic materials can be utilized as an innovative strategy to reduce the concentrationof pollutants. Photocatalytic materials can be used in photocatalytic concrete pavements, which decrease the concentrationof NO_xby photocatalytic activity. A systematic review of photocatalytic materials and its application in concrete pavementshas been introduced. The laboratory and field investigations of photocatalytic concrete pavements have been discussed. Itwas found that NOxreduction up to 60 and 31%, respectively, was observed in laboratory and field conditions. Titaniumdioxide (TiO_2) is the mostly commonly used photocatalytic additive in the range of 3–10% by cement weight. The reviewfound that the photocatalytic concrete pavements have not gained significant attention unlike other pavement materials. Thedemerits of TiO_2for field application and research lacunae in this domain have been discussed and based on which, futurescope of research is proposed. It is envisaged that photocatalytic concrete pavements can play a significant role in reducingair pollutant concentration in urban areas.