Airport concrete slabs behave by combined loads including environmental loads and traffic loads. To analyze the behavior of concrete slabs by combined load, the dynamic strain gages were embedded at 2 depths(50mm, 450mm) and 3 locations(corner, Center and Mid-Edge). And the thermometers were embedded at 5 depths(50mm, 150mm, 250mm, 350mm, 450mm) in actual airport concrete slabs. HWD(Heavy Weight Deflectometer) is a device to measure the deflection by applying an impact load. The values calculated by the HWD test are deflection, ISM(Impact Stiffness Modulus), LTE(Load Transfer Efficiency). Concrete slabs tend to expand during the summer when the temperature is high, and contract during the winter when the temperature is low. In addition, the drying shrinkage occurs as age increases. Field HWD test were conducted in March, May, August, and November to examine seasonal and age-specific changes. Furthermore, the temperature difference between top and bottom of concrete slabs causes the curl-up and curl-down behavior. The test was conducted 3 times at 12o`clock, 16o`clock, 21o`clock, 3o`clock, 7o`clock to examine temporal changes. The strain of the slab at HWD strike was measured 500 times per second because the strain occurred instantaneously, and the temperature was measure 1 times per 10 minutes. The calculated values and the measured values varied according to environmental loads. In order to examine these values in various angles, the equivalent linear temperature difference obtained by converting the temperature by depth into the uppermost lowermost temperature difference, the temperature of the slab which changes seasonally as a whole, and the drying shrinkage which occurs as the age increases are considered. Therefore, the purpose of this study is to clarify the behavior of concrete slabs by combined load considering long - term drying shrinkage, annual variation of temperature, and daily variations. This study was supported by Incheon International Airport Corporation(BEX00625) and Korea Airports Corporation.