Nanocarbon materials such as carbon nanotubes are well known for their superior performances in thermal, mechanical, electrical and optical properties. The purpose of this study is to prepare new asphalt composites improved by adding nanocarbons and to find new features that reflect the characteristics of nanocarbons in the asphalt composites. Such composites were prepared using several types of asphalt emulsions as a source of asphalt. Both nonionic and anionic emulsions maintained dispersed state well, when combined with nanocarbons. Cationic emulsion, however, failed to keep dispersed state. After several systematic experiments, it was found that cationic emulsion also succeeded in maintaining well-dispersed state, when combined with acid solution-pretreated nanocarbons. Asphalt-nanocarbons composites showed higher performances in both penetration and microwave-absorption tests than asphalt composites including carbon black powder instead of nanocarbons, when the mass percentage of both carbon materials was the same.

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 This study proposes a methodology to nd the optimal inspection policy for road pavement with uncertain deterioration processes. Since the deterioration progresses are characterized by a lot of uncertainty, the pavement conditions cannot be deterministically evaluated unless the inspection or repair activities are carried out. The road administrators have to make the decisions of whether repair should be implemented based upon the results of inspection. In this paper, the value of the inspection is evaluated by use of real option theory, and the optimal inspection and repair model is formulated to investigate the optimal inspection frequencies and repair policy which may minimize the expected life cycle costs. Finally, the validity of the methodology presented in the paper is investigated by a case study dealing with the expressway in the real world.

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 The deterioration of pavement structure is a complex phenomenon that follows the deterioration of both pavement surface and pavement sub-surface. In addition, the deterioration progress of pavement sub-surface affects the deterioration speed of pavement surface. The road pavement management is important to determine the optimal repair strategy which considers the deterioration of both pavement surface and sub-surface (hereafter call "pavement structure"). This study proposes pavement repair planning and strategies of 1) extraction of key management section of relative evaluation based on road inspection survey results, and 2) determination of decision-making repair methodologies based on pavement structural soundness survey by FWD (Falling Weight Deflectometer) in key management sections. In addition, the National Highway Route 9 is the target area as empirical study to verify the methodology proposed in this study.

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 In this study, reliability of the base-course thickness design curves in Japan were examined based on bearing capacity research results of an actual size concrete pavement / base course yard constructed in the Public Works Research Institute and the past researches. As the results, it was found that the degree of reliability of design curve of the crusher-run base and the mechanically stabilized base is 80%, 70% respectively. And it was also found that different design curve of cement-treated base would be required for each base course thickness. In addition, based on these results, the design curve of each base course materials considering reliability was proposed in this study.

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 In order to evaluate the rainwate r storage and infiltration properties of the permeable pavement by unsaturated seepage analysis or gas-liquid two-phase flow analysis, it is important to know the unsaturated hydraulic properties of materials wh ich constitute the pavement. For this reason, we showed the unsaturated hydraulic properties of porous asphalt material s but we have not clarified the relation between the performance of the permeable pavement and the properties of all constituti on materials. In this paper, we try to determine the unsaturated hydraulic properties of subbase course and subgrade materials that greatly affect the rainwater storage and infiltration properties of the permeable pavement. We show from experiments that water retention characteristic and the un saturated hydraulic properties of subbase course and subgrade materials well match the van Genuchten model and the Irmay model.

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