For the purpose of establishing a repair design method of asphalt pavements for the Japanese expressways, the nationwide research of pavement structure using FWD was conducted there. As a result, it was considered that strength of asphalt layers' structure contribute reduction of deflection. It was also found that there is a slight relation between deflection difference (D0-D90) and summation of layer's thickness to multiply resilient modulus of the asphalt cores sampled from the loading point in the field..

View full abstract

The D runway in the Tokyo International Airport is planned to be constructed on a reclamation area and the concrete slabs on the pier. The asphalt pavement on the slab for runway is designed with a total thickness of 20cm because it is necessary to accommodate various airport facilities in it like light devices and their pipe conduit. Since the pipe conduit of light devices is installed on the hard slab and it is embedded in comparatively upper part of the pavement, it was feared that fatigue cracks would be generated in the pavement around or on the conduit due to heavy aircraft gear loads. Therefore, authors executed experiment and FEM simulation which modeled the pipe conduit section to examine the safety for the fatigue of the pavement around or on the pipe conduit section for pavement design life. As a result of the experiment and analysis, it was confirmed the safety of the pavement for the fatigue cracking over the design period.

View full abstract

This paper presents the results of field trials and thermal analysis conducted to verify the applicability of infrared thermographic inspection method to airfield pavements. As the results of field trials, it was confirmed that de-bonding can be found by infrared thermography. As the results of thermal analyses, it was clarified that amount of solar radiation, wind velocity and air temperature difference between day and night affected the surface temperature difference due to the existence of de-bonding, and appropriate time for the infrared thermographic inspection was also verified.

View full abstract

Data obtained from a FWD test are time series of loading and surface deflections at several locations, since it is an impulsive test. Thus dynamic backcalculation is more suitable than static one because the former conforms to a nature of the test. The software based on the concept is called DBALM (Dynamic Backcalculation for Layer Moduli). DBALM, which was originally based on MS-DOS command line interface, has been revised and simplified by implementing GUI. The windows version of DBALM is called “Easy DBALM for Windows”. This development has brought simplification of input data and visualization of output.

View full abstract

Back calculation by which pavement layer moduli can be estimated from surface deflections, serves an essential tool for its structural evaluation. However its verification has not been fully conducted. Two methods are available, one is static back calculation which utilizes a set of peak surface deflections and the other dynamic back calculation which employs a set of time series deflection data. FWD tests were conducted at pavement test sites and pavement layer moduli are back calculated by both methods. The result of structural evaluation is verified by comparing the measured strains with computed by utilizing these layer moduli and FWD loadings.

View full abstract

The objective of this study is to develop a method of computing responses of axisymmetric elastic multilayered systems subjected to rigid plate loading by “GAMES”. The software can solve problems of elastic multilayered systems with multiple uniform loads. When a load acts on a rigid plate contacting the system, contact pressure distribution is not uniform. Since the contact pressure on an elastic semi-infinite space has been known, a method to approximate the distributed contact pressure by multiple uniform loads is presented and an elastic multilayered system is analyzed with the loading systems. The multiple loading approach results in a good agreement with theoretical responses of a semi-infinite space, and it becomes apparent the approach can be applied to an elastic multilayered system with good accuracy if a top layer is as thick as or thicker than a diameter of loading plate.

View full abstract

This paper presents a simple method to estimate cyclic plastic deformation of ballasted track subjected to repeated train pas-sages in terms of the strength and deformation characteristics of coarse granular materials. A new analytical procedure with linear elastic FE analysis considering the cumulative strain derived from multi-ring shear test results of poorly-graded crushed stone, namely ballast, was proposed, and it was revealed that the analytical procedure could roughly estimate the residual settlement of railroad ballast under cyclic moving wheel loads, by comparing test results of small scale model tests of ballasted track with the analytical results.

View full abstract

As the fourth runway at Tokyo International Airport (Runway D), the hybrid structures consisting of asphalt pavements on the pier are planned in part. As their behaviors against aircraft loading have been scarcely studied, several aspects on asphalt pavements on the pier (concrete decks) are studied through a variety of laboratory tests. The following results were obtained. 1) The surface course asphalt mixture with type H polymer-modified asphalt has the sufficient durability against both the repeated loading and the segregation between asphalt and aggregates. 2) The bonding between asphalt mixture layer and concrete deck is secured after 20, 000 times of repeated wheel track loading. This is also true in the case of loading test under the submerged conditions. 3) Three kinds of asphalt mixtures composing the surface course on concrete deck have the sufficient fatigue resistance as they have never been failed in 200, 000 times of loadings.

View full abstract

The Wheel Tracking Test (WTT) is already established as a standard test method to evaluate the plastic deformation resistance of the asphalt mixture and its effectiveness has been generally accepted, in Japan. Obtained data from recoverable deformation measurement using the WTT will provide very useful information for the permanent deformation predication of the asphalt mixture.
In this paper, a measurement method of recoverable deformation behavior using the WTT is described and obtained data of several asphalt mixtures are shown. Next, a permanent deformation analysis method based on stiffness of binder and the mixture shown in “Standard specification for pavenents-2007” is applied to these obtained data. The calculated results are compared with the measured results. Then, compatibility and issues on the analysis model are described.

View full abstract

Fatigue characteristics of hot mix asphalt (HMA) mixtures are influenced from the kind of asphalt binder and aging effects on the fields. It is understandable that the fatigue characteristics of HMA mixtures can be evaluated from physical properties of the asphalt binders. The study investigates a correlation between viscoelastic property of asphalt binders and the fatigue life of the HMA mixtures. Based on the results, this study finds the appropriate viscoelastic parameter and testing conditions, and confirms that the parameter has a high correlation with the fatigue life.

View full abstract

The four point bending fatigue tests were carried out for dense graded asphalt mixtures under various wave patterns in repeated loading: sinusoidal, triangular, twin peaks, sinusoidal with one second rest period, sinusoidal with ten second rest period. Analyzing the results using classical fatigue analysis, energy approach and ENTPE fatigue damage approach, it was found 1) that the fatigue damage subjected in asphalt mixtures differs significantly depending on the wave patterns of repeated loading, giving much difference in the number of load applications to failure, 2) that the number of load applications to failure is depending considerably on the rest period 3) that there are linear relations between the rate of stiffness change and the number of load applications to failure, showing approximately constant relations even if loading wave pattern and rest period are different.

View full abstract

Development of permeable pavement, which has durability and sufficient permeability even under the condition of heavy traffic and/or soil sub-grade, has been necessary in recent years to prevent river flood in urban region. Laboratory tests, full-scale accelerated loading test and 3 years' test pavements constructed all over the Japan have clarified: 1) Permeable pavement on sand layer has the same durability as the ordinary pavement. 2) When the pavement need to be constructed on a soil layer, drainage from sub base-course could be an effective countermeasure to improve its durability. 3) Its permeability has not been deteriorated after 2-3 years service. 4) Permeable pavement could be effective for preventing river flood by reducing and delaying run-off.

View full abstract

The rainfall storage and infiltration facilities of permeable pavements have been attracted attention as an improvement measure of urban environment. In this paper, experimental study makes clear that rainfall infiltration facilities of permeable pavements are strongly dependant on rainfall intensity and unsaturated zones prevent rainfall from infiltrate into the pavement. We develop the simulation method that analyze the air and seepage flow simultaneously and we demonstrate that the dependence of rainfall infiltration facilities on rainfall intensity is mainly caused by the behavior of air flow in the pavement. It is shown that the effects of permeable pavements on flood control can be evaluated accurately by using this simulation method.

View full abstract

The permeable pavements are mainly constructed for the purpose of cultivating ground water and mainly applied on the sidewalk. It was admitted that permeability was effective for flood which increases rapidly in the city. And application on a heavy traffic road is also considered now in regarding to a recent law about control runoff. Therefore, test constructions are tried in various places. However, it is necessary to solve problems, such as durability, to apply permeable pavements to the roadway. Especially, aggregates of granular materials moves by infiltration of rain water and the quality have been changed. This paper verified the quality change of granular materials by the infiltration of rain water.

View full abstract

This paper presents use of nonferrous metal slag as fine aggregate of the asphalt mixture. The nonferrous metal slag, which is produced in the process to smelt copper or ferronickel, was used at the experiment. Evaluations about the environment safety and the quality of the several slags were carried out in the experiment. As the results, the quality of the slag satisfied the standard of fine aggregate of the asphalt mixture, and the performance of a mixture satisfied using as the surface material fully. And, relationship between the quality of the slag and performance of the asphalt mixture became definite. In particularly, there was a slag that the content of several toxic substances exceeded its standard, but it was confirmed that is no problem by the environmental soil quality examinations at the field test.

View full abstract

Materials for paving on the pedestrians-friendly pavements, which are constructed as the pavements and the promenade in parks, attracts attention, because it is welcomed as eco friendly method considered recent global warming. On the other hand, under the recent influence of rising crude oil price, the demand of thermal power generated by coal has been growing, causing a large amount of coal fly ash. However as securing the large scale of disposal site has been getting more difficult, widening effective utilization of coal ash has become a fairly critical theme. Considering those conditions, this study concludes the properties of the strength of materials using two types of coal ash, PFBC and FA. And then we tried to improve the vulnerability by adding the wasted bamboo crashed to the chip state as a step against the crack. The main conclusions are summarized as follows: 1) Materials added PFBC ash has prominent congealment effect, compared with material added FA ash. 2) In case of using of FA ash, it is possible for the material to gain the higher strength than the PFBC's at the same level, by mixing cement. 3) Destruction due to vulnerability is restrained by mixing 10 percent bamboo chips.

View full abstract

The occurrence of the pot holl causes a trouble with low noise pavement of the trunk road. A cold mixture is used for the repair of the pot holl. As for the cold mixture, high-quality things with the fixed period durability are necessary. But, performance appraisal method doesn't establish a cold mixture. The performance which was necessary for the high-performance pattern cold mixture was put in order by this thesis. Then, how to evaluate each performance suitably was examined. It was examined about seven kinds of typical high-performance patterns cold mixture. And, it was evaluated synthetically including the questionnaire survey to the field technician.

View full abstract

Since the porous asphalt pavement which has drainage function has constructed for 20years. The time to repair the porous pavement will come soon at a burst. Therefore, it is necessary to establish the recycling technology for porous pavement in hurried. Also, the technology is desired to reuse milled pavement in large quantity at once. For the purpose that raising the rate of using recycled aggregates, we applied superheat steam crushing technology for manufacturing recycled aggregates, and could confirmed that mixing rate of recycled aggregates for the mixture up to 90% on our calculation. However, it is difficult to re-modify the old asphalt with sufficient quality for porous asphalt pavement if the large quantity of recycled aggregate put into the mixture. In order to solve this problem, special binder was developed to be re-modify the old asphalt in the range of 20% to 80% of mixing rate of recycled aggregate, and we confirmed that good recycled porous asphalt mixture is produced from this method.

View full abstract

High-temperature and high-pressure water, which has solvent performance, is supercritical and subcritical water. This paper presents method to separate aggregate from asphalt mixture by using these water. Then, applying the method, the quality of separated aggregate was firstly evaluated by the several tests. And then, the performance of drainage asphalt mixture using it was evaluated by the several tests. As the results, it was confirmed that the subcritical water can remove the asphalt from asphalt mixture as same as the supercritical water, and separated fine aggregate and coarse aggregate were the same as the former quality. And, for the performance of the mixture, it was compared with the mixture that the waste material was mixed, and the result was confirmed that the performance is well.

View full abstract

It is needed to consider both loading stress due to aircraft load on concrete slab and thermal stress due to temperature change of concrete slab in design of airport concrete pavements. However, thermal stress is just considered by safety factor in present empirical concrete design method. For the purpose of clarifying thermal stress of airport concrete pavements, experimental pavement was constructed, and then, strain and temperature in concrete pavement were measured. As a result, it was clarified that thermal stress of airport concrete pavement was smaller than that of road concrete pavement, and thermal stress formula for airport concrete pavement was proposed

View full abstract

To prevent a pumping phenomenon at joint of airport PC pavement, we developed structure that reduces deflection difference between joint sleeper slab and both PC slab and buffer slab by connecting these slabs by the bolts. In this study, Static Load Test and Wheel Running Test were carried out to verify the space between bolts and the connection force by the bolts, and Slide Test was also carried out to confirm the effect of connecting slabs by the bolts on axial displacement of slabs due to variation of temperature. As a result, we confirmed experimentally that connecting joint sleeper slab with PC slab by the bolts reduced the opening between these slabs, and a pumping phenomenon was hard to occur.

View full abstract

Grout materials were sometimes injected beneath the airport PC slabs to reinforce pavement subgrade. Its strength and deformation at the traffic opening should be precisely designed. However, a few of them were severely damaged in several years. To investigate the cause of failure, the authors conducted a series of model tests, while the grout failure similar to that found in-situ were observed in several test cases. Based on the observations in the tests, new grout materials were developed to assure the sufficient strength, even though they are injected into the water remained beneath the PC slabs.

View full abstract

This study looks into methods to improve bonding strength between UFC panel and grout that is very important to ensure good performance of Ultra-thin White Topping with High Strength Concrete (HSC-WT). For that, several methods with combinations of forming macro textures on the panel surface and special surface treatment with chemical ingredients on the interface were examined by shear tests and direct tension tests in a laboratory. After the examinations, some of candidate methods were selected and applied to full scale pavement loading tests and their effects on the pavement behavior were investigated. Positive effects of the methods were confirmed from the test. Also, possibility of early opening to traffic of the pavement was examined by increasing early age of strength of grout.

View full abstract

This paper deals with a development of a new rutting evaluation index based on the vehicle dynamics taking into account mt shape, the mtting/vehicle interaction, and driver sensitivity. The result of lane change at the proving ground shows that the mtting affects the vehicle rolling behavior consisted by the frequency band above 0.8Hz. The Half-Car model which is the conventional vehicle simulation model is effective to represent the roll response induced by the rutting. Then, we develop two indices which are accumulation value of roll angle/roll rate obtained from Half-Car simulation to evaluate the rutting. From result of the subjective assessment survey by a driving simulator, we conclude that the accumulation value of the roll rate as the index has the strong relationship with road usefs senses.

View full abstract

In this research, biosignals, heart rate and skin conductance response, were discussed as indices for the evaluation of ride comfort. A driving simulator that reproduces the behavior of vehicles traveling on uneven road surfaces was used for subjective evaluation of the road profile. At the same time, the fluctuations in the heart rate and skin conductance response were measured. From the results, it was found that the test subject's heart rate increased when driving on the uneven roads, and as the vertical acceleration R.M.S. value increased, the variability of heart rate increased. Moreover, it was also confirmed that the test subject's skin conductance response increased when driving on the uneven roads, but there was no significant relations between the vertical acceleration R.M.S. value and variability of skin conductance response.

View full abstract

Kansai International Airport is a key airport with multiple runway and 24-hour operation service. In order to improve international competitiveness and customer satisfaction it is necessary to provide safe and satisfactory pavement at low cost. Kansai International Airport diverted its policy from breakdown maintenance to preventive maintenance considering the minimization of life cycle cost. It developed pavement management system as a tool to achieve this policy objective. Besides verification and evaluation of present condition, this system consists of predicting and evaluating the future performance of the pavement. This paper reports about the introduction of performance curve of surface characteristics, structural evaluation technique etc in the pavement management system. It also covers the outline of the practical application of the pavement management system.

View full abstract

In this research, a pavement management methodology based on fatigue analysis was discussed. The feature points of this research are as follows. 1) The fatigue analysis of pavement design takes into consideration of ground unequal settlement. 2) The concrete pavement is designed by fatigue analysis in consideration of material fatigue reliability. 3) Aging analysis of crack index, which is derived from fatigue analysis, helps to make a strategy of pavement maintenance. 4) As for tactics for maintenance methodology of individual pavement, maintenance risk tree, which is developed by event and fault tree analysis, is useful in assessing deterioration.

View full abstract

City of Yokohama needs to manage more than 7, 400km long roads among more than 7, 600km long road network around the city. City of Yokohama has intended to introduce the asset management system (AMS) for pavement aiming effective implementation of the limited budget and establishing accountability to citizens because it is expected that those roads will be reached to the update period all together near future. It is important to create appropriate pavement performance prediction models to establish the useful AMS, so a model was created. Life-cycle costs of road network were calculated based on the established model and it is proposed that an evaluation method for pavement rehabilitation strategies in terms of cost-effectiveness.

View full abstract