Analysis of pavement structure is modeled by FEM. Results of analysis may be affected by the size of domain of analysis because FEM analysis is conducted in a limited domain instead of half-space domain. This paper investigates the proper size of analysis of FEM analysis. Backcalculating pavement layer moduli from FWD tests is based on a static analysis of impulse-type pavement response. This paper also investigates how factors such as loading time and loading pattern affect surface deflections.

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Tokyo International Airport assigned a technical task of recycling the pavement waste for construction of New B-Runway. Accordingly, an investigation was carried out on the test pavement containing recycled materials to explore the possibility. In the investigation a running load equivalent to the weight of an airplane was applied repeatedly to the test pavement. Outlining the result of the investigation, this report presents estimation of the elastic modulus of the cross section based on the multi-layer elasticity theory and evaluation of the pavement after the application of repeated loads. As a result, it was shown that characteristics of pavement damage can be illustrated by combining such factors as changes in layer thickness and reduction in apparent elastic modulus.

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FWD testing and backcalculation have been conducted on pavement evaluation for many years. However, none of the existing backcalculation procedure is guaranteed to give reasonable moduli values for every deflection basin measured. To increase the precision of the backcalculation moduli, a new backcalculation procedure based on Extended Bayesian Method (EBM) was described in this paper. The advantage of EBM is to utilize prior information of pavement layers, as well as deflection for backcalculation of pavement. The practical backcalculation of FWD common test measurements indicates that the layer moduli of pavement can be estimated properly by this procedure, and the results are stable and reasonable. Finally, the influence of prior information on backcalculated results is also discussed.

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In this paper, simulation approach based on distinct element method (DEM) was applied to deformation analysis of asphalt mixture, and the applicability and mechanical property of the distinct element assembly were probed. Since a mechanical element model used in ordinary DEM was not suitable for simulating a deformation of asphalt mixture, different element model was reconsidered in accordance with real material property. The applicability was evaluated in comparing simulation results with real behavior of asphalt mixture. As a result of comparisons, it was found out that the proposed element model could represent viscoelastic behavior of asphalt mixture on the whole and this simulation method was applicable to deformation analysis of asphalt layer. In addition, mechanical relations between element model and the assembly were also studied by the parametric simulations in which physical properties of mechanical element were changed.

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FWD (Falling Weight Deflectometer) is a nondestructive testing equipment used worldwidely for pavement structural evaluation. Many manufacturers developed various types of FWD equipment which have almost identical peak loads. However, diversity can be found in the other specifications, and this may cause difference in measured deflections and pavement layer moduli backcalculated based on them.
Pavement surface deflections are measured in this study, varying weight and height of falling mass and type of rubber buffer of an FWD (manufactured by Phoenix Road International Co., Ltd.), so that various loading waveforms can be obtained, keeping the peak load almost identical. And influence of loading waveform of FWD on backcalculated pavement layer moduli is examined.

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This paper develops a method to backcalculate layer moduli from a time dependent data measured by FWD in site. The following three basic items are examined: 1) Set an origin in time domain load data. 2) Select sensor locations of which deflection data are used for backcalculation. 3) Determine an interval of the deflection data used for backcalculation. By using both dynamic and static backcalculation methods, layer moduli are estimated from sets of data measured every two hours at pavement whose profile is known and the results are compared in this paper. Validity of the backcalculation based on the dynamic analysis is confirmed.

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When layer moduli are backcalculated from a set of surface deflections measured by FWD, it has been known that the backcalculated moduli are affected by measurement errors as well as model link error. This paper presents a genetic algorithm based method that minimize the effect of measurement errors on the moduli.
To confirm the validity of the method presented herein, layer moduli are backcalculated by using Monte Carlo simulation and a set of measurement locations which is different from the optimal set. Finally, this paper examines how sensor locations affect to backcalculated layer moduli using FWD data measured on test road.

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Pavement layer moduli are estimated from surface deflections measured by FWD in order to diagonize a pavement structure. It is shown that strong similarity exists between a generalized inverse matrix method employed he and the Gauss-Newton method Sensitivity equation with respect to error is derived. By using the sensitivity with respect to error, optimal sensor locations winch minimize the effect of measurement and model parameter errors are obtained by exaustive sank

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Results of structural evaluation analysis of pavement using FWD data from route 219 at Saito in Miyazaki Prefecture, Japan are presented. FWD is a dynamic loading device. DSGT, a dynamic analysis method and AASHTO and NIPPO which are static analysis methods, are used for the analysis. Subgrade modulus and effective pavament full depth AC thickness are backcalculated. A potential problem of whether static analysis (mostly used method) or dynamic analysis should be performed on the data is discussed in this paper by looking at the difference of results these two methods give in the analysis of FWD data.

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In the structural design of continuously reinforced concrete pavement (CRCP), load transfer across transverse cracks should be properly taken into account. Plate FEM based on the elastic plate theory can be a good tool for stress analysis of concrete pavement slab with cracks and joints. Though load transfer at crack could be modeled by three elastic springs, coefficients of the springs have never been exactly specified. In this study, the coefficients were identified from the results of loading experiments conducted on test pavements. It was found that the coefficients depend on the average temperature in the concrete slab.

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The thin reinforced concrete precast slab overlay method is the new effective rehabilitation method for asphalt concrete pavements. In this method, the small thin RC slabs are made at a yard, and then they are carryed and set on the asphalt concrete pavement. But the mechanistic properties of thin RC slabs are not clear enough. In this study, we investigate the mechanistic properties of slabs by the loading test of the real size slabs. From the results of the test, the RC slab have a enough ability for heavy loads. Then we constructed this thin RC precasted pavement for the heavy truffic road and examined the serveciability of this pavement.

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The prestressed concrete pavement planned in Tokyo International Airport Offshore Expansion Project has cuttings for taxiway lighting wiring. Aiming at learning whether there is a problem in using pavement with such cuttings as apron and whether “Prestressed Concrete Lift-Up Method” needs to be modified, the authors carried out a laboratory fatigue test, flexural test, two-dimensional analysis using an elastic beam model and three-dimensional analysis of a plate on prestressed concrete. Proposed as a result are revised specifications for lift-up mechanism of prestressed concrete pavement with surface cuttings.

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By comparatively analyzing the FWD measurements with plate-on-liquid model and plate-on-elastic solid assumption, some frequently concerned questions associated with back-calculation results of concrete pavement were described in this paper. The results of the analysis presented indicate that:(a) the concrete slab modulus values back-calculated on the basis of the liquid model are unreasonably higher than what would normally be expected.(b) temperature gradient has a significant effect on FWD deflections and back-calculation results.(c) ratios of foundation moduli derived from different load locations are considerably dependent on foundation models and temperature gradient.

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In case the pavement foundation soils is dispersed in characteristics, a uniform bearing capacity cannot be expected, and the foundation itself is not suited to be used as subgrade. Accordingly, the subgrade is made up by excavating and replacing the foundation soil with sand. In that, if the reduction of the subgrade thickness is made possible, the problem of removal of surplus soil will be possibly reduced. With this objective in mind, the geo-textile was inserted into the subgrade to gain the reinforcement effect and the subsequent reduction in replacement thickness. Such a possibility was examined by conducting in-situ tests, laboratory tests and analyses of the test results. The test results reveal that the reduction in thickness is structurally difficult.

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In recent years, the destructive force acting on the ballasted track is on the increase with the speed-up of trains and the increase in the number of trains, requiring more labor and expenditure to maintain the track in good condition. On the other hand, it is increasingly difficult to obtain maintenance manpower, because Japan is quickly shifting to a society of elders, and people tend to hate tough works such as manual track maintenance work. Under these circumstances, the Paved Track which is to be laid during the midnight interval on existing line has been developed and improved in order to reduce the maintenance work of the ballasted track on subgrade. This paper describes the track structure and the results of the performance tests of this track.

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The intensity of compaction in railway embankment is controlled by K₃₀-value in the plate loading test for road. However, the plate loading test takes much time and needs a large reaction equipment. Thus, it is necessary to work out a simple and easy method for compaction control in railway embankment work. The present paper gives an outline of the rolling compaction test to applying FWD to compaction control in railway embankment work. The result from rolling compaction test shows that K-value by FWD correlates with several values indicating the compaction level (degree of compaction, air void ratio, K₃₀-value), leading to the conclusion that it is possible to apply FWD to compaction control in railway embankment work.

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Hot asphalt mixtures are widely used as road pavement materials. But they require the optimun working temperature and consume the large quantities of energy. This paperpresents a method to reduse heating temperature of hot asphalt mixtures keeping the required conditions. This consists of produing micro-bubbles in binder using additives, and then improve the fluidity and compressibility. As the results, it is confirmed that the degree of compaction and mechanical properties of the asphalt mixtures of reduced heating are equal to generally used hot asphalt mixtures.

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The surface of a rapidly urbanized city has been covered by asphalt pavements, concrete buildings, and other heat retaining structures. This coverage causes its higher temperatures even in the evening and so-called a heat island phenomenum can be found. The accumulated heat makes ambient air warmer and causes an updraft of the air, being followed by a localized torrential downpour. The materials used for these structures are usually unpearmeable and help the rain water run off quickly into sewer pipe through their surfaces.
This study places an emphases on porous asphalt mixtures that can keep the water in themselves and discharge it gradually. The effect of porous asphalt pavements preventing the flood is examined by a case study in Meguro area where an actual flood took place and wide area was covered by water.
It was found that it is very effective to employ the porous asphalt pavements to prevent this kind of flood. The void is recommended to be larger than 20%.

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The microtexture and macrotexture are said to have close relation to the skid resistance. Traditional measurement method gives indirect information and approximate value of texture. Therefore, prototype stationary laser profilometer was used to measure and analyze profile. To analyze the profile, frequency of amplitude was applied and the way shows the characteristics of profile on each asphalt mixture type very well. The index called PDI that is weighted arithmetic mean depth of amplitude has high correlation with skid resistance at high speed range.

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To produce comfort sidewalk, it is necessary to evaluate unevenness of sidewalk pavement. We used wheel chair with acceleration meter on its flame as a apparatus for unevenness evaluation. In laboratory test with the apparatus, we have done frequency and integral analysis of measured vibration wave. As the results of vibration analysis, the apparatus was able to evaluate unevenness of pavement in comparative assessment.
In field test with the apparatus, the integral values of the area needing repair were higher than those of normal area. From this result, we found out that we could also evaluate unevenness of pavement by the apparatus.

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This study examines skid resistance of grooved airport runways in wet condition. It deals with these factors influencing the measurement such as adhered rubber, water film thickness, temperature and texture by the field measurements and laboratory tests. The following conclusions are obtained.
1) The friction coefficient in the touch-down area is smaller by 30-50% than that in mid-runway.
2) The friction coefficient in summer is smaller by 10-20% than that in winter.
3) As a remedy for obtaining the sufficient skid resistance, the removal of the tire rubber is effective.
4) The friction coefficient measured by vehicle type equipment can be estimated by the use of handy type equipment.

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A fundamental investigation was made on void structures of porous and coarse graded asphalt mixtures to combine their geometrical and physical characteristics. The voids in the mixture were visualized by filling them up with colored epoxy resin. The mixture was then cut after hardening and the sections were carefully imaged by a scanner connected to a personal computer system.
Every pixel of the scanned image of each section was digitized into three values and geometrical distributions of void, mineral aggregate, and binder are characterized as well as each content is quantified. It was found that each mixture has its own specific characteristics in images in cross sections, which is presumably related to its mixture properties.

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In this paper, applications of Markovian transition probability model to decision of optimal maintenance strategy of flexible pavements on network basis are discussed.
The optimal maintenance strategy at the project level is formulated based on both dynamic progrmming and the equivalent annual maintenance cost. These two methods give the exactly same optimal maintenance level for the minimum long-run expected average cost.
Introducing the concept of repaired ratio, the optimal strategy at the network level is formulated as budget allocation problem by expansion of the equivalent annual maintenance cost model at the project level.

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We reported a method of the neural network performance modeling using a pavement design equation and few pavement data obtained in Tohoku. However, the pavement data had the influence of abrasion by studded tires. In this study, we used the pavement data obtained in Kyushu, and confirmed the general use of the neuro performance modeling using few pavement data.

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It is of great importance to predict performance curve from a viewpoint of life cycle cost analysis in a pavement management system. Although the pavement performance depends on many factors shch as a pavement profile, traffic and environmental conditions, it is ofen represented by a simple model with a few key factors of cumulative traffic volume and a number of years in service.
This paper demonstrates gradual deterioration of pavement structurs using elastic multi-layer analysis along with environmental and loading conditions at each passage of vehicle. From the deterioration, cracking ratio, ruting depth and a performance curve of MCI are predicted.

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The Bibi Test Road is located on National Route 36 on the way from Tomakomai to Sapporo. The Civil Engineering Research Institute constructed 8 types of layer structures in July 1990. This study describes performances of pavements by researching changes observed in 4 types of sections.
It was proved that rutting significantly affects MCI, and these factors are correlated to the number of equivalent 5 t (49 kN) wheel load. The studded tire regulations were promulgated during the research period and their influence was observed. It was found that the thicker the layer, the larger the rutting of pavement surfaces, and the smaller the design traffic volume, the greater clibgidence of the subbase course.

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A method to calculate the interval of cross-sectional cracks or the thermal cracking rate in asphalt pavements after a fall in temperature is proposed considering the energy balance in an asphalt layer at the occurrence of a thermal crack. Using this method, an analysis of factors influencing on the thermal cracking rate of asphalt pavements is attempted. When the result of this research is applied to the cold area special asphalt mix pavements, the thermal cracking rate can be reduced.

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Much volume of pavement waste will be generated from the old airport area in Tokyo international airport. We have done laboratory and field tests to make sure of applicability of these pavement waste to runway pavement. The rate of recycled aggregate is 70%, which is fixed by the balance of generated and using volume of pavement.
There are three purposes in these tests; to make sure of performance, resistance for fracture, and durability of recycled asphalt mixtures. And we proved that pavement waste is applicable to airport pavement.

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This report is about accelerate-aging tests which are simulating the heat aging (process) during mixing at an asphalt plant and the oxidativeaging (process) occuring in asphalt binders during service. The accelerate-hardening test methods were TFOT, RTFOT, and PAV. A new test method for the accelerate-oxidative aging using an oxygen filled oven at 60°C.
From these test methods we can conclude that 1) TFOT which modified testing time, was the same hardening as during mixing at an asphalt plant, 2) PAV and the accelerate-oxidative aging using an oxygen filled oven at 60°C were similar as far as oxidative aging of asphalt in field.

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We noted the shear rate of the viscosity test to calculate viscosity of asphalt on mixing. We measured viscosity of one straight asphalt and three modified asphalts with cone-and-plate viscometer changing shear rate. It is compared with the behavior of the liquid and the viscosity-temperature relation. The optimum mixing temperature of asphalt under the high shear rate is lower 20 or 30 degrees than one measured by the capillary tube viscometer.

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This paper investigates effects of fine aggregate shapes on characteristics of asphalt mixtures. The internal friction of fine aggregates, the complex modulus of asphalt mortals and the optimum asphalt contents (O. A. C.) of asphalt mixtures were depended on fine aggregate shapes. In case of natural sands, the dynamic stabilities (D. S.) decreased when O. A. C. increased in accordance with viscoelasticity of asphalt mortars. In case of screenings (Scr), D. S. increased in spite of higher O. A. C. The image processing analysis showed that Scr had high degree of needle-like shapes. The degree of needle-like shapes showed difference between natural sands and Scr through cluster analysis. These results are considered that the specific shape of Scr improve the plastic flow resistance of asphalt mixture.

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In this study an excellent non-plastic, wear and wheather resistant gap-type mixture has been developed in creating a skid resistant rugged surface. Mainly the coarse aggregate quantities, as well as the binder were examined in this study considering road revision construction work in cold regions. When small non-plastic elements are contained in the lower layer, cracks will hardly form. The increase of the asphalt layer bending was also examined.

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We studied mix design method of Splitt Mastix Asphalt (SMA) applied for bridge deck pavement in stead of gussasphalt. The mix design procedure we adopted is Gyratory Testing Machine (GTM) which simulates actual rolling. As a result of our study is follows; Gyration number ND in mix design is given by passing percent of 2.36mm sieve size of SMA aggregate gradation. Asphalt content of SMA should be selected both to have air voids of under 3% level for having properties of impermeability and Dynamic Stability (DS) by wheeltracking test of over 3, 000 pass/mm for rutting registance.

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The purpose of the series of our study, including this paper, is to clarify the base structure and the functions of the sand layer and jointing sand in the concrete block pavement and the conditions required of them, and to use the obtained results as the basic data for the design method to apply the concrete block pavement to heavy-load fields. In this paper, the structures of the jointing sand and various bases under moving loads are examined by using a load simulater which can evaluate the pavement under conditions similar to the actual running cars.

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This paper concerns the development of the pavement structural design in railway container yards where weight forklifts are driving for loading works. One important objects in this paper is to estimate the subgrade strength easily. By the economical analysis on the construction cost, the minimum subgrade strength was decided as CBR 6. HFWD was introduced to estimate the subgrade strength which is more conveniently estimate the strength. The other object is to maintain the subgrade strength more inexpensively. The geotexitile was introduced to the subgrade in the yard pavement in the cold area and the construction cost was less than the conventional methods.

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Recently, it is important for us to expand use of coal ash. So we have bean committed to research into the utilization of coal ash (solidified coal ash with a relatively small amount of cement added) as base course material. Performance of base course material is able to judge especially from long-term durability. We have tested base course materials in the construction of a road since 1988. Results of the test road construction show that base course material made of coal ash have a performance similar to conventional base course material both in strength and service performance.

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The decomposed granite soil which is widely distributed over the Abukuma Heights is used in a considerably large amount in a variety of construction work including earthwork materials. However none of extensive study concerning the properties viewed from a standpoint of geotechnical engineering has been made. Keeping such a situation in mind, fundamentals of the physico-chemical and mineralogical properties together with features concerning the compaction, the stabilization of CBR, etc. were examined, and concurrently investigation was made taking up the data obtained in other regions mainly including the ones in Western Japan. As a result, a tendency was noted with the decomposed granite soil of the Abukuma Heights in grain refining, the development of the soil grain structure, or lowering of crystallineness. On the other hand, a feature is pointed out with the fact that CBR is very small even if dry density is the same. Furthermore the evaluation of the quality conducted in accordance with the rules of Japan Highway Public Corporation has revealed that judgement can be made from the ignition loss values.

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In case of lifting up a large scale PC pavement, grout injection is an important factor for construction and economy. In case that it is necessary that shorten closing time of airport facilities as it is possible, high-early-strength materials were hoped, and without that case grout materials that can support with 1 day curing was selected. For a lift-up method construction at PC pavement, we reviewed about a quality of grout materials for a purpose that considers improvement of construction and arranges stress of grout layer to stabilize of structure. This paper reports summary of examinations about grout materials_

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