In this study, we developed a 3DFEM model for analysis of crack development and mechanical responses of steel bar and concrete slab in a continuously reinforced concrete pavement. An incremental method was adopted to consider variation of material properties of concrete in the early stage after placement. A model of interaction between steel and concrete was developed. The model was validated by comparing calculated responses and measured ones. Effects of asphalt interlayer between concrete slab and base course on the early age cracking were investigated with 3DFEM simulations. From the simulations, it was found that secondary cracks might occur near the first crack that were observed in the test pavement.

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 This paper describes the reinforcing effect of the newly proposed reinforcing method using SFRC paving with ordinary Portland cement and low shrinkage type mixture material for orthotropic steel decks of highway bridges, which have been suffering from fatigue cracking due to heavy traffic loading. To examine the fatigue performance of paving material and steel deck slab, a running wheel fatigue test was conducted using a scale model of the typical orthotropic steel deck without and with SFRC paving. The test results showed that the proposed SFRC paving material was verified to have all the required performance of the specifications for highway bridges in Japan, and the proposed stiffening method effectively improves the fatigue endurance of steel decks.

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 Deterioration process of a pavement is a complex one composed of the deterioration of road surface and the decrease in the load bearing capacity of pavement. Decrease in the load bearing capacity and the deterioration of road surface influence each other. In this study, such a deterioration process of a pavement is expressed by using a composite Markov deterioration model. The soundness level of road surface is observed through road condition surveys. On the other hand, the decline in the load bearing capacity can be detected with a falling weight deflectometer (FWD) or the like. In actual cases of road maintenance and repair, these two kinds of inspections are not conducted at the same time, and so these two kinds of inspection data cannot be obtained concurrently. This study proposes a method for estimating a composite hidden Markov deterioration model considering such systematic sample dropping, and also discusses the effectiveness of the proposed methodology by applying it to a case of the expressway managed by NEXCO.

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 A method of estimating the post-salting road surface skid resistance considering salt scattered by the passage of vehicles on the road ice film (simplified prediction method) was developed in this study. In order to develop this method, a numerical model was developed to calculate the amount of de-icing salt that is scattered beyond the roadway due to the passage of vehicles. And then, the ratio of scattered salt to spread salt was evaluated by simulations based on the numerical model. Moreover, the relation between the road ice film thickness and HFN was clarified by field tests. Additionally, the simplified prediction method was verified through comparison between estimated HFN and measured HFN.
 It became possible to estimate the post-salting HFN for a road ice film considering the influence of vehicle passage.

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 In recent years, owing to heavy or intense rainfalls, railway tracks have been damaged in Japan. Some involves the cases where railroad ballast beds were washed away. Thus, accurate prediction methods and efficient countermeasures against the ballast flow-outs are now required. Therefore, in this study, to focus the railroad ballast bed flow-outs under inundation flow, simulations of ballast bed slope collapse were carried out using SPH (Smoothed Particle Hydrodynamics) method. The simulation considered the progressive slope failure and seepage characteristics observed in model experiments. The seepage characteristics of the ballast beds were expressed by introducing the Forchheimer law into the SPH simulation. The progressive slope failure process involved the slip-out of several ballast particles. The slip-out was reproduced in the SPH simulation by considering critical pore water velocities which could be obtained by a micro-mechanic model.

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