Subsurface cavities in the asphalt pavement which can cause road depression and cave-in accidents influence on the safety of pedestrians and vehicle drivers in the urban area. The existence of subsurface cavity can increase the tensile strain at the bottom of asphalt layer which is an indicator of fatigue cracking potential, and leads to the weakening of the pavement structural capacity. In this study, the finite element (FE) analysis was conducted to examine the relationship between the critical pavement responses and influencing factors, such as cavity depth and size, asphalt layer thickness, and asphalt concrete modulus. The surface deflections and tensile strains calculated from the ABAQUS FE program were compared to those from ILLIPAVE. It is found from this comparison that there are a good relationship between two analysis results. A three dimensional finite element model which is essential to simulate the hexahedral cavity were used to generate the synthetic database of critical pavement responses. To validate the developed model, the deflection data obtained from field Falling Weight Deflectometer (FWD) testing in four different locations were compared to FE deflections. It is found that the center deflections obtained from the FWD testing and FE analysis are similar to each other with an error values of 2.7, 4.4, 5.5, and 11.9 % respectively. The FE model developed in this study seems to be acceptable in simulating actual field cavity condition. On the basis of the data in the database, various analyses were conducted to estimate the effect of influencing factors on the critical pavement responses. It was found that the tensile strain at the bottom of asphalt layer is affected by all the factors but the most affected by the cavity depth and asphalt concrete modulus. Further studies are recommended to properly account for the effect of cavity’s geometry to pavement response.

Ondol is the unique traditional heating system of Korea, which is excellent in thermal comfort. Whereas it has several merits as a wet construction method, its work process is complicated and disadvantageous in protecting noise and has concrete heat storage layer. So it is necessary to develop a new material to cover these demerits. In this research the material that can resolve the problems of construction and noise prevention while keeping heating function of existing wet floor structure has been developed through manufacturing artificial wooden floor panel utilizing waste tires. The developing tendency of existing floor structure companies was studied for experimental contents, and through testing of manufactured materials' degree of strength of bending and pressure the function and similarity of natural wooden material could be confirmed. These floor structure can be shortened of its construction period through simple method which results in saving construction cost and convenience of maintenance, and especially it can be said that as 70~80% of its material is powder of waste tires, it has excellent function against floor impact noise and it utilizes recycling material more than anything. It is likely that through more tests and research, the construction method for linking part between panels which hasn't been dealt with in this research will be improved.