## 3 Results and Discussion
### When an Aircraft Load Acts on the Slab  
The stress distribution of the pavement slab with and without the dowel bar is shown in Figure 6a,b, when the aircraft wheel load operates on the center location of the slab. At the wheel load, the bending tensile stress of the paving slab is the greatest. With and without a dowel bar, the top surface of the pavement slab experiences the maximum vertical stress of 0.218 MPa and 0.289 MPa, increasing by 24.56% in each case. As the range is extended, the force continuously lowers, whereas the bending tensile stress at the loaded concrete slab's (LS and unloaded concrete slab-ULS) edge marginally rises. Moreover, there is no discernible difference between the vertical stress at the connection points of adjacent slabs with and without a dowel bar. In the transverse direction of the pavement slab, the maximum vertical stress is approximately 0.005 MPa for the wheel impression. In the transverse direction of the laden slab, there is a tiny variation between the vertical stress at the axle with and without a dowel bar. There is significant bending tensile stress at the slab's edge along the transverse direction, and this is what causes the dowel bar's vertical stress to be compressive at the wheel load of the pavement slab. Additionally, there is compressive stress and bending tensile stress at the wheel load of the pavement without a dowel bar, which vertically reduces to the edge of the slab along the wheel load until it disappears.  
Figure 5: Diagram of an aircraft’s wheel load acting on different positions of the pavement slab.  
As depicted in Figure 6(a),b, the displacement of the pavement slab progressively diminishes from the wheel load to the surrounding area, thus exhibiting a displacement diffusion circle, and the longitudinal and transverse displacement of the pavement slab decreases in a parabolic fashion. The slab's vertical displacement at the longitudinal half of the laden slab, the slab's edge, and the attenuation coefficient, are all affected when a wheel load is applied to it. These measurements are 1.06 mm, 0.25 mm, and 76.42%, respectively.  
The vertical displacement at the center of the laden slab's longitudinal edge is 0.31 mm, whereas the edge of the slab is 0.17 mm. The attenuation coefficient is 45.16%. Here, in the transverse direction of the loaded slab, the vertical displacement between the wheel load and slab edge increases by 0.28 mm. Figure 7 shows that there is an upward warping deformation along the slab's edge, and Figure 6(c,d) also demonstrate that there is an upward warping deformation at the joint between the adjacent slabs. The warping deformation displacement of the loaded slab's edge is 0.28 mm, and that of the empty slab is 0.05 mm when there is no dowel bar. The displacement caused by warping when a dowel bar is present is 0.28 mm for the loaded slab's edge and 0.15 mm for the unloaded slab's edge. Hence, we may conclude that when the dowel bar is introduced, the adjacent slabs share a portion of the load, the deformation of the laden slab occurs on the opposite side, and the deflection load transfer coefficient of the dowel bar is 56.03%.  
Figure 6: Stress distribution of pavement slabs under the aircraft’s wheel load.