Development of rough-surface-type retroreflective materials as countermeasures to urban heat islands

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K06444
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Civil engineering materials/Construction/Construction management
• Research Institution: Osaka City University
• Principal Investigator: Sakai Hideki 大阪市立大学, 大学院生活科学研究科, 准教授 (90277830)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 再帰反射 / 環境材料 / ヒートアイランド / 都市環境 / 日射反射率

Outline of Final Research Achievements

Retroreflection is a unique optical property in which the incident light returns back in the direction of its source. Up to the present, two main optic structures have been used to achieve this property: ball lens optics constructed using glass beads, and corner cube optics constructed using prisms. In this study, we proposed another completely different retroreflective structure called the rough-surface-type. Its retroreflectivity is caused by a combination of surface roughness and its diffuse reflection. Therefore, it can withstand distortion and is suited for road surfaces.

Free Research Field

建築・土木材料

Academic Significance and Societal Importance of the Research Achievements

近年，世界各地で夏季のヒートアイランド現象が顕在化しており，その対策が求められているが，本研究成果の導入による直接的効果として，夏季の日中晴天時の舗装路面の表面温度低下（現行の遮熱性舗装と同等以上），道路面からの照り返し日射量の低減（新規効果）が，さらに，間接的効果として，ヒートアイランド現象の緩和（日中の最高気温の抑制，熱帯夜日数の減少），道路周辺の光・熱環境の改善，歩行空間の快適性向上（新規効果），が見込まれる。