A road profile estimation method based on vehicle responses measured by a smartphone is proposed. A half-car model, which can represent vehicle bouncing and pitching motions, is employed; the road profiles at the tire locations are included as state variables in the augmented state vector; these variables are estimated by the combination of a Kalman filter, the RTS smoothing, and the Robbins-Monro algorithm. Because the estimation accuracy depends on the vehicle modeling accuracy, an algorithm to calibrate the model is also proposed. The algorithm optimizes the vehicle parameters by minimizing the difference between identified road profiles at the front and rear tire locations. The rationale is that the two profiles are estimates of one physical profile while they are dealt with as two independent state variables. Through numerical simulation, the accuracy of the profile estimation and parameter identification are clarified. Drive tests with three rental cars showed that the proposed algorithm can compensate for the vehicle and drive speed differences; the estimated IRI values are consistent among the three vehicles and with reference profiler.

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 The importance of bicycle transportation is rapidly increasing. However, to evaluate long-distance bicycle lanes, existing pavement surface monitoring techniques are not applicable, quantitative, or efficient. In this paper, a simple and accurate road profile estimation system was developed using a bicycle and a smartphone. A Kalman filter algorithm integrates multiple sensor data to estimate the profile. The accuracy of the proposed algorithm was experimentally evaluated on test courses. As a result, the coefficient of the determination of the estimated profile with the measured profile by a road profiler was above 0.81 and IRI error was below 14%. The estimated profile was highly accurate in the wide spatial frequency range; the proposed algorithm can thus accurately evaluate pavement condition of a variety of scale.

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 The authors constructed a test section of concrete pavement with various size voids underneath the concrete slabs and monitored deflections and strains generated by FWD load and an aircraft gear that was repeatedly applied to the section. Cracks were found at the bottom of the slab with an 1m by 1m size void after the loading. FEM analysis revealed that the combined stress due to the load and temperature gradient of the slab with the void would exceed the bending strength of concrete, which was speculated to cause the cracks. Based on the results, the simulations of loading stress in the airport concrete pavement with various size voids forming at various pavement conditions were performed to evaluate the possibility of the bending failure of the slab.

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 Development of the seismic design and the seismic countermeasures of the structures supporting railroad ballasted tracks are progressing; development of them for ballasted tracks is also required. In this study, we conducted small-scale model tests to evaluate the mechanism of reduction of the lateral ballast resistance during shaking. The deformation behavior inside the ballast during shaking was photographed and image analysis by PIV was performed; then it was found out that a shear plane was generated in the loading direction from the depth of the bottom of the sleeper. Large shaking table tests were also conducted using a full-scale model to investigate the effect of the seismic countermeasures for ballasted tracks. It was confirmed that both the buckling prevention plates and the ballast retaining wall had high seismic countermeasure effect.

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 In Japan, the recycling of asphalt mixture has a long history and it seems that recycling asphalt mixture regenerated several times already is also used. The usage rate of the recycled asphalt mixture is increasing year by year and it is necessary to establish a recycling method that is adapted to recycling repeatedly for sustainable recycling. For the purpose of establishing sustainable asphalt recycling technology, repeated recycling was carried out using several types of rejuvenator having different SARA (Saturate, Aromatic, Resin, Asphaltene) fraction, and the properties of the recycled asphalt and the recycled asphalt mixture were tested. As a result, the following was clarified. The softening point tended to rise due to repeated recycling. Recycled asphalt mixtures using recycled asphalt having a high softening point tended to occur cracking easily at high temperature. Rejuvenators containing a high aromatic tended to suppress an increase in softening point.

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 A formula of pavement thickness index that concisely relates to design CBR of subgrade and wheel load passing over the pavement has been used as a basis of Japan’s structural design method of pavement, since its essence was distributed in 1966. The relationship has long been used so far, despite the fact that there is still unknown part of the process in developing the formula. This study tries to unlock some of the unknown part after reaching a conclusion through mathematical validation with reasonable results. The job was made when technical history of the nation’s expressway pavements was compiled. The currently used Japanese formula relating pavement thickness index, subgrade’s design CBR and wheel loading of traffic was developed over 50 years ago by combining Japanese national highway survey by relating pavement thickness index and its subgrade CBR and the AASHO Road Test’s successfully obtained relationship between pavement thickness index and more than a million wheel loadings passing on the test field. Through trial assumptions and calculations, it was finally inferred that some modification was made to the AASHO’s original formula.

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