For appropriate road maintenance and management of the road, detection and evaluation of the asphalt distress is very important. Standard test method for asphalt pavement in Japan have defined that crack ratio, amount of rutting, and flatness are main damage indices for the evaluation. Though the amount of rutting and the flatness can be obtained automatically from the pavement condition survey vehicles, the crack ratio is not automatically derived. Since this process requires to draw and count cracks manually from the photo of the road surface taken by the vehicle, enormous effort and time are required. In addition, the accuracy of the evaluation is doubt because the manual method does not evaluate the important information including the crack width. To solve these problems, this paper have developed automated asphalt pavement crack detection method using image processing technique and naïve Bayes based machine learning approach. The developed method is tested using the photos of various types of asphalt pavements, and it is found that the method can detect cracks with very high accuracy.

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 In this study, image processing was applied to photographs of the road surface taken from a traveling vehicle using a simple and inexpensive photographing unit, and method for automatic detection of pavement crack was developed. In comparison of the automatic detection and visual detection, the concordance rate of the crack detection by both methods became more than 80%. Furthermore, we calculated crack progress level (small, middle, large) using the automatically detecting method and compared it with the result of road surface measuring vehicle. It was revealed that the concordance rate of the crack detection by the both methods became more than 90%.

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 With an aim to grasp the damage progress on porous asphalt pavement, those data has been measured every other month using the high-accuracy pavement-condition measuring vehicle at the sites. Afterwards, it is confirmed that the cracks have progressed to potholes in a short time at the concerned place. Such the damages could not be detected and forecasted at their early stage with the traditional evaluation indicators (cracks, rutting, and surface roughness) and the conventional frequency of investigations. This paper is to propose (i) the new evaluation factors, the partial settlement values specific to porous asphalt pavement, based on the analysis of the high-accuracy surface profile, and (ii) the forecasting method of potholes occurrence, introducing the growth curve models for the damage progresses specific to the damage factors.

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 In “Overhaul Procedures for Pavement” issued to the local governments from the Ministry of Land, Infrastructure and Transport, a visual inspection for pavement is used. Minokamo city is carrying forward a plan by senior human resources to introduce a visual inspection of community road pavement maintenance in which road surface texture measuring vehicle is difficult to apply. The purpose of this study, is to conduct verification tests of visual inspection in Minokamo roads and to examine the method for training inspectors in order to improve accuracy of visual inspection. In conclusion, we found that ever though senior human resources do not have knowledge of pavement the accuracy of the visual inspection can be improved significantly by adopting pavement engineer led training method evaluation points in the field. Furthermore, we have developed a visual inspection support system that has function required upon introduction to practice.

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 We push forward examination about the effective road surface property investigation technique that utilized MMS (Mobile Mapping System). We made improved model MMS equipped with a high-density laser scanner and made a figure of contour from the three-dimensional point group data which we acquired in improved model MMS in yard road. And we confirmed the irregularity of the road surface in a figure of contour. In addition, we suggested a new evaluation index. By the main subject, we report an examination result of the road surface evaluation technique using three-dimensional point group data for true ways. Furthermore, we report an inspection result about the grasp possibility of the minute transformation of the road surface after the service of about a half year.

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 In recent years, expressway authorities require an effective method for monitoring and measuring surface characteristics of their pavements. This study examines an estimation method of a longitudinal true profile by an accelerometer-based mobile profilometer (MPM) for express way pavements. One of the advantages of the MPM is to capture the information from profile measurements. However, since the measurement algorithm of the MPM is optimized to compute the IRI in real-time, the back-calculated profile is distorted by the natural frequencies of suspension components. In this study, we examine an estimation technique of a true profile by developing a reconstruction filter to attenuate the distortion in the spatial frequency domain by the Fast Fourier Transform (FFT) method. As the result of a validation experiment, the MPM with reconstruction filters satisfies practical requirements as a profiler that is within 30% error compared with a rod & level survey. The result also indicates that the MPM basically has a capacity to measure the IRI in real-time, and the back-calculated profile is appropriate for the purpose.

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 In the past study that a research group of Tokyo University of Agriculture, Ishikawa National College of Technology, Public Works Research Institute and Japan Cement Association carried out, design curves of the crusher-run base, the mechanical stabilized base and the cement treated base considering reliability were proposed 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. However the two layered base course design method was not examined. Consequently in this study, change of bearing capacity of the two layered base course surface was examined using the Monte-Carlo simulation when the reliability level of design curves were changed, and as a result a simple reliability calculation method was proposed.

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 Many back-calculation programs have been developed to interpolate the FWD data, including both static and dynamic assumptions. However, the most of popular back-calculation programs are based on the static assumption, though the FWD loading on pavement is a dynamic load. On the other hand, the contact pressure distribution is one of the key influence factors for dynamic back-calculation program of portable FWD. While soil types are affecting the contact pressure distribution of loading plate, there are very few devices to investigate the contact pressure. In this study, the process of a dynamic back-calculation program was clarified and the types of contact pressure distribution were examined by a prototype of device to investigate the contact pressure. The results of the examinations of contact pressure distribution were revealed the highly accurate estimation for the dynamic back-calculation analysis.

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 This study proposes two kinds of estimation methods for the frost heave ratio of unsaturated frost-susceptible soils under low overburden pressure such as subgrade soils at the pavement structure in cold regions. One is the modified Takashi's equation in contemplation of matric suction of soils under low overburden pressure. The other is the simple frost heave model which evaluates the effects of initial water content, Bishop's effective stress and water absorption during freezing on the frost heave ratio. In addition, the applicability and the usefulness of both methods were discussed based on the results of frost susceptibility tests. As the results, it was revealed that the estimation methods proposed in this study have an excellent applicability to the precise prediction for the frost-heave phenomenon of unsaturated subsurface ground in cold regions.

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 A limit equilibrium method was focused to evaluate the lateral resistance of ballasted tracks. The method can be easily applied to canted tracks or tracks under seismic condition. In this study, the lateral resistances of ballasted tracks for various shapes of sleepers were estimated based on the method. Lateral resistances under track-panel pull-out loadings were also estimated. The estimated lateral resistances were compared with those obtained from model tests. It was found that the proposed method could well predict the lateral resistance not only for a rectangular parallelepiped-shape sleeper but also for winged-shape sleepers having rectangular or trapezoid sections. It was also found that the lateral resistance under track panel conditions could be reasonably predicted by the method.

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 To evaluate charateristies of ballasted tracks under seicmic conditions, small-scale tilting tests and full-scale shaking table tests were conducted. The results showed that lateral resistances under seismic conditions were significantly lower those before or after seismic conditions. It was also revealed that lateral resistance of canted track was little different from that of non-canted track. However, significant difference was observed between the lateral resistance obtained from single sleeper conditions and that from track-panel conditions.

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 Recently in Japan, railway ballasts have been flown out several times by heavy or intense rainfalls. However, the mechanism has not yet been investigated in detail, so that the risk and the countermeasures cannot be reasonably proposed. Therefore, in this research, model tests and numerical analyses were conducted to investigate the flow-out mechanism. It was found that the permeability characteristics of ballast track-beds can be expressed based on Forchheimer' law not on Darcy' law. Progressive failure was also observed in the model tests. It was also found that the stability of the ballast track-beds can be reasonably explained by the proposed micro-model.

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 The effect of the structure below the base course of the asphalt pavement on the behavior of the asphalt mixture has been investigated by the authors. In those studies the asphalt mixture is modeled using the Burger's model and linear viscoelastic analyses are carried out using the Laplace transformation based on the Elastic-Viscoelastic Analogy. It is feared that dynamic effect is neglected in the method using the Laplace transformation where the equations of motion are not solved. In this paper, dynamic effect on linear viscoelastic analyses for asphalt mixture of pavement was investigated through the comparison between the semi-static analyses using Laplace transformation and the time history response analyses using Newmark-beta method. As a result no dynamic effect on linear viscoelastic analyses could be seen under the condition of the base structure of asphalt pavement with ordinary mass and stiffness.

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 The warm-mix asphalt technics have been applied to the hot asphalt pavements to improve the quality of constructions and to reduce CO₂ emission. Although many studies have reported that the warm-mix additives affected the physical characteristics of asphalt mixtures, the basic characteristics of the warm-mix asphalt binder has not been revealed. In this investigation, we measure the differential scanning calorimetry (DSC) and the viscoelastic property of the warm-mix asphalt binder in a wide range of temperature. Also, we discuss the validity of the thermal analysis to detect the physical change of the asphalt binder.

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 The life cycle cost of concrete pavement is superior to it's of asphalt pavement, because of high durability of concrete pavement. Therefore the concrete pavement is must be spread from the viewpoint of social overhead capital maintenance cost reduction. Recently, the natural aggregate dries up, and the mainstream aggregate moves to crushed stone, and the use of the slag aggregate is demanded from the viewpoint of effective utilization of resources, too. Consequently in this study, the characteristics of strength and abrasion resistance of pavement concrete with various kind of coarse aggregate were examined. In the examination, flexural, compression, tensile strength test and abrasion test were carried out for twelve kinds of pavement concrete with aggregate such as, river gravel, two kinds of hard sandstone, andesite, four kinds of limestone, three kinds of blast-furnace slag, electric arc furnace oxidizing slag. As a result, it was cleared that each strength of examined pavement concrete shows strong correlation and there is a possibility to estimate the flexural strength of pavement concrete by compression and tensile strength even if the kind of coarse aggregate were different. And it was showed that abrasion resistance of concrete and crushing value of coarse aggregate has better correlation than abrasion resistance and Los Angeles abrasion loss.

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 This paper presents the reasons of interface bond failures on National Highway-5 (N5) and remedial measures to counter those failures. Based on field investigation and assumptions, the pavement was analysed by General Analysis of Multi-layered Elastic System (GAMES) software. Different interface conditions ranging from full bond to full slip were analysed by GAMES. Results indicate that combination of interface bond condition and overloading can reduce pavement life significantly. Analysis also suggests that interface bonding condition between two asphalt layers can be improved by converting lower asphalt layer into granular base layer or combining two asphalt layers into single asphalt layer. These measures were found to be applicable for N5 in Bangladesh.

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 The field excavation of asphalt pavement was conducted in the expressways where East Nippon Expressway Company manage, to investigate how the aging effects from surface to subgrade layer. From the result of this investigations, it is evidenced that the aging of asphalt has attained to not only the surface but also the asphalt stabilization subgrade, and the penetration of asphalt in porous asphalt mixture decreased more rapidly than that of dense-graded asphalt mixture. As a result of further laboratory test based on the aforementioned investigation results, it is indicated that conducting accelerated aging test considering mixture type is necessary to simulate the aging ofthe asphalt arising on the actual road.

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 In order to rationally select the mechanical test for evaluation of stripping resistance of asphalt mixture, the authors evaluated change of mechanical properties in the process of moisture damage of asphalt mixture. Then, the authors investigated influence of void ratio of asphalt mixture on the stripping resistance index by using Marshall compaction specimens and asphalt cores sampled from airport pavement for the purpose of discussing criteria on the index. As a result, it was shown that the change ratio of indirect tensile strength in the process of moisture damage was higher than Marshall stability and resilient modulus. And, there was a possibility that the void ratio showed no consistent relationship to stripping resistance index.

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 In the asphalt pavement of Japan , porous asphalt pavement has increased certainly with highway etc. However, the porous asphalt pavement has a main problem that pot holes occur by aggregate scattering. The author focused on the particle size of 9.5 mm of the aggregate that are used with the porous asphalt mixtures and investigated about the fluctuation of aggregate scattering.
 As a result, this research confirms that the difference of aggregate particle size are influencing aggregate scattering by the method of Cantabro test. Furthermore, it was inspected that the difference of the contact of aggregate is influencing the scattering of aggregate by two-dimension image analysis software (iPas).

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 In this study, structural lives of repaired pavements with large stone mastic asphalt mixture or in situ restored base course was estimated based on structural analysis using elastic moduli obtained with back analysis of FWD data. Two back analysis methods were employed in this study, static and dynamic analyses. The numbers of loads to fatigue and permanent deformation failure were estimated applying tensile strain in asphalt layer and compressive strain in subgrade to failure criterions. The numbers are converted to structural service life in years. The lives of the repaired pavements based on the static analysis were compared with the ones from dynamic analysis. It was found that the permanent deformation failure are more highly possible to occur in the repaired pavements.

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 In this study, the full scale pavement was constructed, in which vertical stresses at the top of the base course and subgrade were measured under a large number of repetitive loads without any rainwater on the pavement surface. From the results of measurements, it was re-confirmed that the water intrusion significantly affects fatigue damage development. It was also observed that elastic moduli of asphalt layer and base course rapidly declined in the early stage of loading but become steady at a certain level in the later stage, which suggests a long term durability of the pavement unless the water intrudes into the base course or subgrade.

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 To optimize the budget allocation for rehabilitation work, the Airport Pavement Optimal Rehabilitation Timing System (AirPORTS) was developed for application to airport pavements. AirPORTS is composed of four subsystems: a database subsystem; an optimal rehabilitation method selection subsystem; a yearly rehabilitation expense prediction subsystem; and a budget equalization subsystem.
 As example applications of AirPORTS, the optimal rehabilitation strategy of a major local airport is described. Extensive data on the construction, rehabilitation and surface conditions of asphalt pavements at the airport for a period of at least 20 years has been collected. Through a sensitivity analysis on several variables, the optimal rehabilitation strategy was determined.
 In order to provide the versatility to AirPORTS, the following three major points will be required to improve; pavement serviceability evaluation, quantification of serviceability change and estimation of traffic volume and aircraft in the future.

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 The object of this paper is to study the method to estimate the pavement conditions on the road network using sampling theory. The content of our proposed method is as follows. Firstly, number of sampling links is determined and MCI (Maintenance Control Index) of these links are measured by monitoring car. Secondly, future MCI of sampling links are estimated based on past experience and maintenance & repair cost is calculated. In this study, validity of the proposed method is confirmed using the pavement conditions survey data for all links conducted by local government in the past.

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 The thickness of ice film and the road surface friction coefficient (μ) on dense-graded, porous and stone mastic asphalt pavement surfaces after the spreading of deicing agents were evaluated from indoor experiments. Based on the experimental results, a method for estimating μ on these pavement surfaces after deicing-agent application was proposed in this paper. Moreover, the changes in μ with temperature after deicing-agent application were compared between pavements from results simulated using the proposed method.
 The results were as follows. (1) The mean thickness of ice film on these pavement surfaces after water decreased linearly with increase in the amount of deicing agent spread. (2) μ decreases exponentially with increase in the mean thickness of ice film. (3) The ratios of the amount of deicing agents not acting on the melting ice to the amount of deicing agents sprayed tend to decrease with increase in the amount of water applied in the case of the porous and stone mastic asphalt pavements.
 It was shown that the value of μ after deicing agents were spread differs depending on pavement type, even though the road surface temperatures, the amounts of water and deicing agents applied were all the same.

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 Rough-textured pavements are constructed to improve the roadside environment and driving safety. In addition, many are constructed in snowy cold regions as a measure against road icing. The authors have conducted research to elucidate the effectiveness of rough-textured pavement alone and the effectiveness of such pavement in combination with salting in terms of mitigating slipperiness. Research results to date have mainly been obtained through laboratory tests; thus, experiments on roads in service or under similar circumstances are needed. Further, large amounts of data should be accumulated, such as traffic conditions, weather conditions and pavement conditions. In this study, outdoor tests at the Tomakomai Winter Test Track and a skid resistance monitoring survey on a section of National Highway 230 near the urbanized area of Sapporo were done. The results were examined in terms of the effectiveness of rough-textured pavement in mitigating road icing, considering the effectiveness of anti-freezing agent application and the impact of road weather conditions.

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 After investigating early distress on bridge pavements that had been laid on high performance waterproofing for protecting the bridge deck, the authors reported last year that the problem is due to small air voids named "cavity", caused by point contacts between a leveling layer of SMA and the waterproofing membrane at low temperatures. It was revealed that the cavity is easily created beneath SMA-like gap-graded AC mix type in which bituminous mortars are massively filled with its aggregates structure, while less created under continuous grade type. Based on the tendency, a new leveling layer type of mix was developed, by conducting simulation tests at laboratory as well as full-scale accelerated pavement tests.

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 On-site surveys on skid resistance were performed on concrete pavements of the expressways operated by NEXCO. As a result, it became clear that the decrease in skid resistance in tunnel sections is caused by the polishing action by passing vehicles' tires. It was considered that the polishing especially reduces micro-texture, while macro-texture also needs to be enlarged to keep the skid resistance higher on concrete pavement under a tunnel. It was further confirmed that the shape of macro-texture also affects skid resistance; angular-shaped positive macro-texture assures higher skid. According to the experiments on surface roughening methods for the purpose of recovering skid resistance for concrete road surface, shot-blast method was proved to be the most cost-effective by arranging bigger steel balls.

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 The permeation type repairing method is one of the most effective repairing methods to the porous asphalt mixtures. When the permeation type repair material is penetrated from the surface of the porous asphalt mixture, the effect of the water interception layer and the effect of the adhesion enhancing of coarse aggregate are exerted internally. However, it has been very difficult to evaluate the filling situation of repair materials in the porous asphalt mixture nondestructively. Inthisstudy, weproposeanewevaluationmethodofafillingsituationofthepermeationtyperepairmaterialtotheporous asphalt mixture by the X-ray computed tomography (CT). The proposed method is applied to the experiments of filling situation of the permeation type repairing of the porous asphalt mixtures. In the proposed method, the CT value distribution of each material and the porous asphalt mixture are estimated by the least-square method. As the result, we can supposed the CT value distribution of each material to be the Gaussian distribution. The results also show the proposed method can estimate the materials composition ratio in the test specimen with 5% of differences and can estimate the filling rate and adhesion quantity to coarse aggregate at each depth.

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