Influence of Frost Heaving on Korean Pavement Structure

Jung-Hoon Jin, Senior researcher   

ITS RC University Incheon,

177 Dowha-dong Nam-gu Incheon 402-749, Republic of Korea

email: jinrino@kornet.net

Young-Kug Nam, Emeritus Professor/ Director

Department of Civil and Environment system Engineering

University Incheon, 177 Dowha-dong Nam-gu Incheon 402-749, Republic of Korea

email: yknam@incheon.ac.kr

Kwang-Ho Lee, Pavement Group Director

the Korea Road Technology  Transfer Center(KRTTC)University Incheon, 177 Dowha-dong Nam-gu Incheon 402-749, Republic of Korea

email: yknam@incheon.ac.kr

Abstract:

 The Korea peninsular located from the north latitude 33°0′35″ to 43°6′40″. Therefore, almost all areas in Korea except parts of the Southern-coastal region and the Che-ju island are known to be seasonal freezing areas because of geographical and climatic conditions.  For that reason, we consider that design of pavement thickness before the frost heaving damage. So, anti-frost layers have been constructed in pavements to avoid damages occurred from frost heave. But, our anti-frost design methods are the joint use of American and Japanese methods. Cause, we haven’t pavement structure design methods of individual development. Although characteristics of Korean subgrade soil are different from those of foreign countries, the identical methods have been adopted without any change.

In this study, we investigated a few general subgrade soil properties of national highways in Korea. We considering  frost heave to be the factors consist of  water content, soil size and low temperature . So, we measured seasonal changes of moisture content in the field and temperature changes in the pavement sub structure. This measurement includes   outdoor measuring of the field and indoor experiments of field samples, to verify whether the present frost layer in Korea is correct or not.

Through analyzing measured data we verified the relationship between temperature and moisture content during the freezing to the melting duration for 8 sites. And we certified if there's frost heave damage using moisture content, fine particles sizes of subgrade soil and temperature of pavement sub structure.  

As the result, we found out that there is no frost heaving in those sites. Cause, frost heave factors have overlap during the winter season.  Also we suggested to a new equation is account for no frost heaving. To verify the new equation the other known equations and 107 pavements the design data of Korean national highways are used. It turns out that the new equation predicts 15cm less thickness of frost penetration compared to other equations, and reliability of the new equation is higher than the other ones. More data and verification will be needed in the future for practical use.