Chloride-based deicing material is excellent to dissolve ice and snow in economical but they accelerate deterioration of concrete or corrosion steel reinforced concrete. Chlorine ions contained in the chloride-based deicing material currently used act as catalysts for accelerating corrosion when the air-void level is above a concentration level, even if the airvoid retain the proper alkali level. Environment-friendly CMA based deicing material has been difficult to use due to high unit prices in the past, but recently prices have stabilized. As an environment-friendly deicing material agent citric acid, which is a typical organic acid in citrus fruits, plays a role of controlling pH and preventing oxidation. This is effective against reducing steel corrosion and concrete deterioration. In the long term, environment-friendly deicing material is economical considering the damages of structures due to existing chloride-based deicing material. Although environmnet-friendly deicing material has these various advantages, they are inferior in performance to existing chloride-based deicing material. This study suggests proper utilization methods through analyzing the effects of existing chloride-based and environmentfriendly deicing material. Experimental results show that some environment-friendly products a similar level of ice-melting effects of existing chloride, but the effect of chloride-based deicing material is relatively good. This suggests that the performance of ice-melting is inferior only with the use of the environment-friendly deicing material. Therefore, it is necessary to improve deicing methods using with environment-friendly deicing material such as sand and other friction material. Further, it is considered that if the frozen area is predicted in advance and spraying is possible, the environment-friendly deicing material can be used more effectively.

▪ About Heat island? In the city, there are many concrete and asphalt structures easily heated by solar heat. Also, while the fuel of factories, homes and cars in the city is burned, it generates heat at the same time. Due to these, there is the phenomenon called the heat island effect that the temperature of the city is 2 to 5 ℃ as high as of the suburb. As for widely known isolation-heat technology, there are reflection-paint coating(structure and pavement), heat-reduction pavement(water retention). Applying reflection paint to a building and pavement can reduce the surface temperature of the building up to 30 ℃, and 15 ℃ over the pavement. In summer, heat-reduction pavement(water retention) has the effect of reducing the pavement surface temperature to 10~20 ℃ ▪ Solution We can consider ways about applying heat-reduction pavement(water retention) to main section of expressway, spraying water using dirt wagon and applying reflection paint to office and tollgate.