TY - GEN
T1 - Heat island impact of chip seals
AU - Sen, Sushobhan
AU - Roesler, Jeffery
N1 - Funding for this study was provided by the US Department of Transportation (USDOT) through the University Transportation Center for Highway Pavement Preservation (UTCHPP) at Michigan State University with Contract Number DTR13-G-UTC44. Part of the study was carried out in the Frederick Seitz Materials Research Laboratory Central Facilities, University of Illinois. The authors would like to thank Dr. Karim Chatti, Yogesh Kumbargeri, and Shabnam Rajaei for providing the chip seal specimens.
PY - 2021
Y1 - 2021
N2 - Chip seals are a common pavement preservation technique for maintaining an acceptable roadway condition for vehicles. Chip seals applied in urban areas can alter the optical and thermal properties of the pavement, which affects the Urban Heat Island (UHI). Four field cores were extracted from chip seal roadways that were 6-12 months old and their thermal and optical properties were measured to quantify the impact on UHI. The thermal properties were measured using a transient plane source (TPS) technique for the asphalt substrate layer as well as the combined asphalt and chip seal structure, with similar values found for both sets. Measurements with the combined structure had a higher standard deviation as compared to the asphalt only condition, indicating a higher percentage of air voids in the chip seals. The optical properties were measured only for the chip seal surface. The albedo of the chip seal ranged from 0.04 to 0.06, as compared to 0.15 to 0.20 for typical asphalt that is at least a year old. The emissivity of the chip seal averaged 0.92, as compared to 0.83 for asphalt concrete reported in literature. The UHI impact was quantified in terms of the global warming potential (GWP) as well as the hourly average net surface heat flux and surface temperature. Given the measured optical and thermal properties of field cores, chip seals were found to increase the UHI effect of flexible pavements by a small amount.
AB - Chip seals are a common pavement preservation technique for maintaining an acceptable roadway condition for vehicles. Chip seals applied in urban areas can alter the optical and thermal properties of the pavement, which affects the Urban Heat Island (UHI). Four field cores were extracted from chip seal roadways that were 6-12 months old and their thermal and optical properties were measured to quantify the impact on UHI. The thermal properties were measured using a transient plane source (TPS) technique for the asphalt substrate layer as well as the combined asphalt and chip seal structure, with similar values found for both sets. Measurements with the combined structure had a higher standard deviation as compared to the asphalt only condition, indicating a higher percentage of air voids in the chip seals. The optical properties were measured only for the chip seal surface. The albedo of the chip seal ranged from 0.04 to 0.06, as compared to 0.15 to 0.20 for typical asphalt that is at least a year old. The emissivity of the chip seal averaged 0.92, as compared to 0.83 for asphalt concrete reported in literature. The UHI impact was quantified in terms of the global warming potential (GWP) as well as the hourly average net surface heat flux and surface temperature. Given the measured optical and thermal properties of field cores, chip seals were found to increase the UHI effect of flexible pavements by a small amount.
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U2 - 10.1061/9780784483510.029
DO - 10.1061/9780784483510.029
M3 - Conference contribution
AN - SCOPUS:85108056075
T3 - Airfield and Highway Pavements 2021: Pavement Materials and Sustainability - Selected Papers from the International Airfield and Highway Pavements Conference 2021
SP - 320
EP - 331
BT - Airfield and Highway Pavements 2021
A2 - Ozer, Hasan
A2 - Rushing, John F.
A2 - Leng, Zhen
PB - American Society of Civil Engineers
T2 - International Airfield and Highway Pavements 2021: Pavement Materials and Sustainability
Y2 - 8 June 2021 through 10 June 2021
ER -