The present study evaluated resistance effects of fatigue cracking and subsequent reflection cracking of the basalt fiber geogrid reinforcement for asphalt mixture layers. The following findings were obtained. The stress distribution to the grid is a major factor for fatigue cracking suppression. This effect is reduced when the grid greatly inhibits the interlocking of aggregate particles between layers. There is a significant difference in the effect of reflection cracking suppression depending on the tensile strength of the grid until crack appears on the lower surface of the surface course. However, the suppression effect is not found while the crack grows and reaches to the upper surface.

 Dynamic wireless power transfer has been proposed to solve the issue of performance problem of electric vehicles, which is a short cruising range. There is the eddy current loss in the conductors which is in the magnetic field by wireless power transfer system. Since road structures contain conductors such as metals, the effects of road structures on the power supply efficiency were verified by actual measurement. The results show that the surface and base materials do not affect the proposed dynamic wireless power transfer system. However the reinforcing steel in the structure reduces the efficiency by 4.8%. The magnetic shield made of aluminum reduces the influence of the steel bars by half, while the use of the shield reduces the efficiency by 0.4% in the case of the granularity-adjusted crushed stone in the roadbed.

 In Japan, the time to repair and renew a vast stock of aging roads is approaching. Road administrators need to establish a pavement maintenance cycle that allows for efficient maintenance and repair in the face of difficulties such as fiscal constraints and a shortage of engineers. In this study, with the aim of providing a pavement diagnostic support tool for road administrators, we developed a method to determine the cause of cracks in pavement using an explainable AI (XAI) based on road surface images from vehicle-mounted cameras and basic data on pavement characteristics. As a result, we found that using a composite model incorporating a convolutional neural network and random forest improved the accuracy of determining the cause of cracks, and that it was possible to visualize the basis of the results. Furthermore, we applied this method to pavement over a wide area in Hokkaido and demonstrated that it is possible to map the causes of cracks along a route (project-level evaluation) and to analyze the regional characteristics of cracks (network-level evaluation).

 In this study, test sections of concrete pavement were constructed on the circular accelerated pavement testing (APT) facility and subjected to 5.2 million of 49kN equivalent standard wheel loads (ESWL). The test pavement has sections with and without steel mesh in concrete slab and asphalt interlayer under the slab to investigate the effect of these devices. During the loading, FWD tests were conducted periodically and the structural changes were evaluated with FWD back-analysis, which considers the degradation process simulated with 3DFEM models. The analysis revealed that interior parts of the slabs did not significantly degrade, while transverse cracks exhibited severe degradation. In spite of those severe degrading conditions, the stress at the slab bottom of joints did not significantly increased and the slabs have kept sound for more than 3 million of ESWLs.

 The authors investigate influence of grooving pattern to skid resistance and grooving stability for the purpose of increasing skid resistance of runway by changing the grooving pattern. The investigation indicates skid resistance increases by widening groove of the grooving. Even after repeated loading test, the skid resistance of the grooving whose groove width is three times of the present one stays high. Moreover, residual volume of the widened groove after repeated loading tends to be large.