Functional evaluation of road surfaces has traditionally been based on the safety and comfort of traveling vehicles. However, the influence of road surface condition to unconscious mental fatigue while driving is also significant for drivers. This study examines a new evaluation method of surface unevenness based on heart rate variability analysis in terms of “passive fatigue” that is defined as mental fatigue caused by road surface condition. For this purpose we conduct a driving experiment by use of a sophisticated driving simulator to diagnose the passive fatigue induced by repeated traveling over specific surface conditions. The frequency analysis of heart rate variability signals measured by pulse waves is employed to monitor the behavior of high frequency (HF) and low frequency (LF) components of the signals, which reflects mental stress of humans. According to the result a multiple regression model of the International Roughness Index (IRI) on the HF and LF/HF contributes to evaluate surface unevenness considering the passive fatigue. This study also suggests an IRI value of 5.2mm/m as an acceptable level for highways in respect of the passive fatigue.

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 In recent years a number of road profilers has been developed against the background of a rise in needs for the inspection of road infrastructures. To the effective and efficient inspection of pavement surfaces, however, it is necessary to associate measurement results by different profilers with each other. The Pavement Diagnosis Researchers Group conducted the experiment to compare and harmonize testing methods of International Roughness Index (IRI) under actual road environment. In this study we provide the verification of profilers and its procedures in terms of multiplicity, repeatability, reproducibility, and portability based on the experiment results. This paper also illustrates profile agreement corresponding to IRI disagreement based on the cross-correlation function of profiles.

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 International roughness index is globally accepted among road operators. However, the roughness value tends to be lower evaluated on road surface containing impulsive and spotted distress types. In this study, by distributing longitudinal road profiles into nine octave bands and focusing on maximum profile height of each band, an appropriate assessment length detectable to such sporadic uncomfortable spots was clarified. A subjective rating study using a driving simulator specially designed for road-surface impulse was then conducted. As a result, a new repair criterion indicating discomforts for road users was proposed as 8 mm/m in terms of 10-meter-based IRI. Finally the proposed criterion was validated as appropriate after examining the relation between users' opinions regarding surface defects and the newly defined IRI values obtained on Japanese nationwide expressways.

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 Visual inspection to evaluate pavement surface conditions is employed for guideline of full check project notified by ministry of Land, Infrastructure, Transport and Tourism. Almost all local governments employ not the visual inspection but high cost conventional method, because there were few case studies using visual inspection. Walking inspection and travelling vehicle inspection are proposed for the visual inspection in this study, both are executed on the pavements which surface condition have been measured by road surface measuring device and accuracy of the visual inspection is discussed. Rate of correct answers in the walking inspection was about 80% for crack and rut, 60% for roughness and it improved in accordance with inspector's accumulated experiences. In travelling inspection, the rate of correct answers was about 60% for crack and rut, 70% for roughness. As inspector's experience enlarges, that for crack increased in severe cracking sections.

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 For appropriate road maintenance and management of the road, detection and evaluation of the asphalt distress is very important. In Japan, crack ratio, amount of rutting, and flatness are investigated to evaluate the damage. This research focuses on the crack ratio. Because there is no established method to detect cracks automatically, drawing and counting cracks manually from the photo of the road surface are required though enormous effort and time are needed. To solve the problem, there exist several automatic crack detection methods, but all of them suffer from the error including false detection. Therefore this research has developed the semi-automatic method which enables us to modify the automatic crack detection result manually. The developed method is tested using the photos of asphalt pavements, and it is found that the method can detect cracks with very high accuracy.

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 Toward the application of anti-skid materials to rough-textured pavement, this study analyzed how these materials affect pavement performance and how effective is their application in mitigating skidding. Based on the analysis results, the scope of application of anti-skid materials and application methods were examined. The effect of repeated application of anti-skid materials on pavement performance was determined in laboratory tests, with particular attention given to the major features of rough-textured pavement (i.e., surface texture and permeability). The effectiveness of anti-skid materials applied to rough-textured pavement was examined in indoor driving tests that simulated driving on an actual highway. These tests helped to determine the scope of application, based on how anti-skid materials affect pavement performance. The effectiveness of anti-skid materials by pavement type was also clarified.

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 The applicability of a method for estimating the surface friction of roads paved with stone mastic asphalt and porous asphalt was improved by new indoor experiments, and the efficacy of deicing salt spreading was evaluated by simulations based on the method in this study.
 The results were as follows. (1) Formulas were derived from the relation between the amount of water applied and the mean thickness of ice film on the dense-graded, stone mastic and porous asphalt pavements. (2) Formulas were also derived from the relation between the proportion of salt lost to penetration and the mean thickness of ice film on the stone mastic and porous asphalt pavements. (3) This study has enabled to estimate the road friction after deicing salt spreading considering weather, road conditions, pavement type and traffic. (4) The influence of pavement type, air or road temperature, amount of water and deicing agents applied, and hourly traffic volume on the road friction after deicing agent application was clarified.

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 Warm-mix asphalt technology helps reduce CO2 emissions. In snowy cold regions, however, it is unclear what times of year it is feasible to use warm-mix asphalt for paving to help reduce CO2 emissions, and quality control techniques for warm-mix asphalt have not been established. In light of the above, a test pavement was installed by using warm-mix asphalt technology in the cold-weather period, in order to contribute to CO2 emissions reduction. Toward applying this technology, the asphalt mixing temperature was kept lower than the conventional asphalt mixing temperature. The test pavement was used for evaluating the conditions under which warm-mix technology is applicable. It was confirmed that warm-mix asphalt was unsuitable for the cold-weather period, because the degree of compaction was reduced due to the drops in asphalt mixture temperature during transport, laying, leveling and compaction. However, it was found that applying warm-mix asphalt materials at a temperature that is typically used for conventional asphalt materials improves the work efficiency and the quality of pavement compared with warm-mix asphalt.

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 In Japan, it has been passed more than 30 years since reclaimed asphalt pavement (RAP) was started to use as recycling material. More than the half of asphalt pavements in service may have been executed recycling in the past. If considering a maintenance cycle of asphalt pavements, RAP which has experienced recycling repetitively is concerned to increase in the future.
 Authors evaluated the behavior of hot mix asphalt and asphalt binder after aging and recovering processes repetitively in a laboratory, using rejuvenator which is applied widely in Japan.
 As a result, it is found that the physical properties of recovered asphalt binder, using rejuvenator, become lower gradually depending on recycling counts. From chemical analysis, such as bitumen components, oxidation and molecular weight distribution of recycled asphalt binder, it becomes clear that the oxides accumulated through the aging and recovering processes are affecting the property deterioration. The characteristic degradation of recycled asphalt binder was remarkable as the blending ratio of RAP is large.

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 Aseries of laboratory tests were conducted to confirm the aging property of repetitive recycled asphalt and mixture. In this study, rejuvenator which consists of different component, and high penetration asphalt were applied to recycling procedure.
 As a result, the differences of the aging were occurred in physical and chemical properties of recycled asphalt mixture and recycled asphalt, according to difference in composition of rejuvenator. The rejuvenator, which composed of low saturates and high aromatics could constrain the aging of properties in recycled asphalt mixture and recycled asphalt.

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 “NEXCO East”, although studying the applicability of reuse asphalt mixture, it has not been standardized for application to the pavement in highway. However, in the 2004 off Niigata Prefecture Chuetsu Earthquake and the 2011 off Pacific coast of Tohoku Earthquake, to be limited to the restoration work of the affected were route, the reuse pavement It was re-used in the base layer and asphalt stabilization processing roadbed. In order to verify the regeneration pavement to welcome these 10th year in service from the Niigata Prefecture Chuetsu Earthquake, road surface properties investigation, FWD investigation, is carried out laboratory tests by the core collection, the result, it was confirmed that there was no damage to be a hindrance to the running at the moment.

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 The solutions against the problems found as a result of applying Airport Pavement Optimal Rehabilitation Timing System (AirPORTS) to the asphalt pavements of some airports being studied, advanced version of AirPORTS has been being developed. The points taken into consideration this time were the following three. As the items for pavement performance evaluation, cracking, rutting and roughness are included in addition to PRI, and the fatigue damages of both asphalt mixtures and subgrade are also included. For quantifying the change of pavement performance, various kinds of curve models other than a straight line model are introduced. Furthermore, prolongation of the planning period and types and number of operations of aircraft are arbitrarily selected.

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 This project is launched to identify the specific deterioration of asphalt pavement, and detect the real cause of each damage occurred in field. The study was conducted with comparison of in-situ status in damaged and non-damaged sections after almost twenty years under traffics. Specimens for lab tests were taken by block sampling of both asphalt layers and granular subbase course. Based on the field observation of the damaged part and various testing results, several important key factors were found out for long term durability of asphalt pavement. Those points, such as total thickness of asphalt layers, durability of asphalt stabilized (third) layer and bonding property of each layers are vitally important to prevent fatigue cracking. Well graded in good compaction of granular subbase and subgrade are also key issue to support traffics in long period without permanent deformation. Preventing water penetration through the pavement into its base is another important factor to avoid severe deterioration in field.

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 Hokkaido-type Stone Mastic Asphalt (SMA) is used for Arterial high-standard highway in Hokkaido. It is important to make rough surface texture in terms of functionality and to increase compaction degree in terms of durability. However, optimal method of roller compaction to provide both has not cleared yet. In this study, transition of the texture and the durability of the SMA are measured in laboratory simulating roller compaction in situ. The compaction degree of the SMA is not influenced by the type of roller, but the texture was decreased by the rubber compaction. Moreover, the compaction degree and the texture in roller compaction process in situ are monitored and they are compared with laboratory test results.

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 Polymer-modified asphalt binder is applied for the heavy trafficked pavement because the asphalt is superior in terms of plastic flow and abrasion resistance. Recently, the development of warm-mix polymer modified asphalt has proceeded. Then, it is necessary to evaluate the characteristics of these asphalt binders. In general, we have estimated the physical behavior of polymer-modified asphalt by DSR test. However, it seems to difficult for DSR test to estimate the nonlinear viscoelastic behavior such as warm-mix polymer-modified asphalt. In this study, we validated the availability of MSCR test for the characteristics of the widely distributed warm-mix polymer-modified asphalts.

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 High-performance Stone Mastic Asphalt (SMA) is an asphalt mixture that achieves a rough surface texture and high durability. To satisfy the quality required of the surface, it is necessary to fully examine the materials, mix design, and construction methods. Rolling compaction during construction is the main factor in obtaining the required quality of the finished surface. However, the relationship between the method of rolling compaction and the finished surface texture depth, density and degree of compaction remains unclear. In this study, as a part of studies regarding appropriate construction methods for high-performance SMA, construction experiments were done with a focus on rolling compaction during construction. The experiments clarified three points. First, when the required surface texture depth is met, then the required density and degree of compaction cannot be met, and vice versa. Second, the use of a horizontal vibration roller for rolling compaction was found to be effective in improving the durability of the surface. Third, surface quality degradation was found in some edges of the paving.

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 In this study, the new road surface survey method using three-dimensional point group date by MMS which was improved for the pavement survey, was applied to the new pavement section in the test course. From the results of application, it was confirmed to be able to evaluate the deformation of road surface even in case of using short range of evaluation unit. However, it was not confirmed the correlation between pavement durability and deformation caught by using improved MMS at the early stage of road pavement.

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 In this paper, simple evaluation method of cavity below the road surface considering soundness of pavement was proposed by applying results of FWD test and sinkhole detection at national highways. Firstly, the influence on FWD deflection by the difference of scale and position for the cavity was analyzed. Then we used the simple method with the isotropic circular analysis and carried out the evaluation for risk of the cavity in consideration of soundness of the pavement. As a result, the classified cavity confirmed that it was evaluated the risk by nondestructive tests in the cavity on the heavy traffic road. Furthermore, from depth and signal width of the cavity and soundness of the pavement, we suggested an evaluation method of the priority of the repair.

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 FWD applies an impact load at the surface of pavement and measures surface deflections at several locations. When the layer modulus of pavement was estimated by backcalculation from the FWD test data, it is desirable to apply dynamic backcalculation procedure. In this study, the analysis engine of existing dynamic backcalculation software “Wave BALM” is revised by new dynamic analysis program which can consider the non-liner contact pressure distribution. The effect of contact pressure distribution on layer modulus estimated by dynamic backcalculation was demonstrated.

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 Contact pressure distribution is one of the key influence factors for dynamic back-calculation program of portable FWD. Since it was limited in a prototype of device to investigate the contact pressure using small pressure gauges, a pressure measurement film offered commercially was introduced so as to observe a full scope of contact pressure of loading plate. A method based on this observation was developed by utilization of a common expression using formula for a typical pattern of the contact pressure distributions. A part of the computer program in Wave BALM was improved that was based on findings of investigations by the method. It was confirmed there was significant difference between before and after the trials.

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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 changing the condition of the groundwater level without any rainwater on the pavement surface. From the results of measurements, it was confirmed loading stress to the pavement and reacting force from the pavement would be balanced in the long term in case of no groundwater, and also it was re-confirmed that not only the water intrusion but also the high groundwater level significantly affects fatigue damage development.

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 Asphalt interlayer on the subbase is expected to contribute further durability o composite pavement structure. This study was conducted to reveal the degree of structural contribution of above interlayer by mechanical analysis. In a project of expressway construction, a full-scale test section was built to measure the temperature and strain inside of the continuous reinforced concrete slab underneath the asphalt top layers in seasons. A structural model was proposed with 3D-FEM program, for analyzing both thermal and wheel load stresses in the composite pavement. As a result of this analysis, the asphalt interlayer contributes to the reduction of fatigue of composite pavement structure by 10% approximately.

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 In Tokyo International Airport, Private Finance Initiative (PFI) was adopted for the construction projects of facilities including demands of international flights. This was the first large PFI project in Japan. In the project, jointed concrete pavement (JCP) was employed in the international apron, because JCP are supposed to be highly durable and easy to be partially repaired. The JCP on the apron was designed based on FEM stress calculations and fatigue analysis. In this study, loading tests were conducted on the existing JCP and measured strains in the concrete slab. The stresses estimated from the measured strains were compared with the stresses calculation procedure. From the comparisons, it was found that FEM analysis was able to reproduce the responses of the actual JCP under the loading by changing the value of subbase reaction parameter. However, stress measured under traveling airplane were not predicted well with FEM.

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 This paper develops a coupled thermo-hydro-mechanical (THM) FE analysis, which can reproduce frost-heave phenomenon of soils observed in snowy cold regions, and examines the applicability of the proposed coupled THM analysis in terms of the validity of its governing equations and the setting method of input parameters by performing numerical simulations for frost heave tests. In addition, by conducting a series of numerical simulations for pavement structures subjected to freeze-thaw action, the influence of frost heave-thaw on the interaction between soil ground and structures was evaluated. As the result, it was revealed that the frost heave-thaw behavior has a considerable influence on the fatigue life of pavement structure.

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 We carried out laboratory experiments to confirm a compressive strength, a bending strength and a bending fatigue strength of a prepacked concrete which was made by injecting mortar into crushed stones replacing ballasts. Then, we performed a full-scale model cyclic loading test to investigate a strength and subsidence inhibitory effect of the prepacked concrete trackbed. By the full scale test, it was confirmed that the prepacked trackbed has sufficient strength to support the train load after two hours of the injection. Finally, we confirmed the performance of the prepacked concrete trackbed based on a design standard of track structure.

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 Regarding ballasted tracks on soil roadbeds, it is necessary to perform the roadbed improvement at locations where the ballast includes a high mix ratio of fine-particles and the bearing capacities of roadbeds are insufficient. In the roadbed improvement of such locations, the deteriorated ballast is discarded as surplus soils in most cases. Then, we have developed a new method able to be executed simply and in short working time to reuse the deteriorated ballast mixed with grout. In this study, we confirmed a settlement reduction effect of the method by full-scale model tests for soft clay roadbed. In addition, we performed also the field test on an existing line laid on soft roadbed to validate a roadbed improvement effect of this method.

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 Hexavalent chromium is sometimes eluted from cement concrete recycled base course material. Therefore, hexavalent chromium eluted restraint technology is developed. The concentration analysis of hexavalent chromium is difficult, when a reducer coexists. There were not that standard measurement methods. We have already developed the analysis method of hexavalent chromium when a return substance coexists. When using this way, even if there is a return substance, hexavalent chromium is measured right. So hexavalent chromium reduction technologies were studied using accessible materials. As a result, hexavalent chromium eluted restraint technologyreducing sugar has been developed.

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 There is a possibility that the ballasted track occurs in the ballasted track of rail way. However, little is known about change of the elastic shear modulus by cyclic loading and its mechanism of the base course material. In this study, mechanism of change of the elastic shear modulus by cyclic loading and wetting-induced collapse behavior were evaluated by mean of cyclic traxial loading test, bender element test and X-ray CT scan. The test results show that although the volume strain was increased by cyclic loading, the collapse settlement was not observed. In the case of small void ratio, the trend of increasing elastic shear modulus by the cyclic loading can be evaluated by the coordination number from X-ray CT scan.

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