It is indicated that the field permeability test used in order to measure the permeability of drainage pavement has a problem in the testing method or the testing machine itself. Therefore, the cause which a measurement error generates was clarified in the field permeability test. Moreover, the method of measuring the permeability coefficient of the horizontal permeability which flows parallel with a road surface was developed, and the result and comparison of an field permeability test were performed. Consequently, it confirmed that a permeability coefficient could not be measured by the field permeability test. And it was able to propose about the testing machine and the method for measuring ermeability by an amount of permeability.

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Recently drainage pavement construction is increasing in Japan, cause of the improvement of view in case of the rainy weather and the noise reduction effect. However, in cold snowy areas, compacted snow on its surface remains long time. We have been studied and developed various types of asphalt mixture using rubber particles for the anti-icing asphalt pavement. From these experiments, we try to develop the porous asphalt pavement using rubber particles. In this report, it reports on the influence and the effect of rubber particle and it proposes the drainage pavement using new rubber particles.

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In the previous study on the effect on improving water permeability and restraint of voids blocking of topcoat for porous asphalt, it was found that depend on the condition for the spray application of resin, there are oppositely some possibility to lead to accelerate voids blocking. In this study, in addition to wetting properties between the resin applied and water (surface tension against water, γsl), adhesional wetting properties (work load of water, Wa, etc.) between the resin and asphalt mixes surface during application were discussed, and the mechanism of the voids blocking during application and its recovery performance were investigated, and appropriate application methods were suggested.

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Asphalt concrete pavement can easily absorb solar radiation heat because it is generally black in color and in summer, pavement surface temperature increases easily. In the urban region, development of a pavement that is able to control the rise of road surface temperature is expected as the city environment measure including heat island phenomenon, and also as a measure to improve heat environment in the pedestrian sidewalk space. In this research, the efficiency of the pavement to control the increase of pavement surface temperature was evaluated by taking measurements in periods with different daylight times and amount of rainfall on water supplied permeable pavement and solar radiation reflective pavement, which can control energy absorption of solar radiation.

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There have been various contrived methods in use for preventing the pavement surface from freezing in cold snowy areas. Road heating systems are certainly effective. But it is very expensive for construction and maintenance. Another methods adopted, for example, are an asphalt mix incorporated with a salt, ( i. e ., salt-like material such as calcium chloride ) and with an elastomer such as rubber. The salt-containing pavement becomes ineffective after one to two years because of leaching out of the salt. The elastomer in the pavement tends to come out in summer on account of its low combined strength in general. And the pavement tends to be rutted in summer. It is important that the pavement maintains the freeze-preventing effect over a long period of time and can restore when its effect has been lost.
The newly developed freeze-preventing surface course is a thin layer of open graded asphalt mixture whose voids are grouted with cement slurry comprising portland cement, specific salt, and superabsorbent polymer.

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This paper is concerned with a non-skid pavement method to prevent the road-surface from freezing in cold districts, which may materialize a non-skid road partially with low cost and short time. On the road surface with the rubber-chip board including spikes, non-skid effect and breaking ice layers can be expected by the spikes sticking out of the rubber surface crushed by the vehicle loads.
In this study, the non-skid effect of the rubber-chip board with spikes in this pavement method was experimentally verificated. The boards were laid in the open air and the experiment were carried out by means of fast braking of cars and trucks.

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Recycled asphalts were evaluated based on SHRP binder specification. DSR (Dynamic Shear Rheometer) and BBR (Bending Beam Rheometer) tests were carried out on samples of the recycled asphalts under three conditions : original binder, RTFOT (Rolling Thin Film Oven Test) residue and RTFOT+PAV (Pressurized Aging Vessel) residue. PG (Performance-Graded) classification was conducted. New straight asphalts at which the recycled asphalts are aimed with a same penetration were also tested as control samples. It is indicated that there is no significant difference between the recycled and the controlled samples for the obtained results. It is suggested the agent for asphalt recycling is effective with respect to the SHRP specification.

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Improvement of high viscosity polymer modified asphalt (HVPMA) has been tried for higher durability binder and multiple applications. The present evaluation methods of HVPMA are the same methods as polymer modifiedasphalt type II. However, they aren't necessarily suitable to the improved HVPMA. Then, we tried to evaluate the binder properties of HVPMA by SHRP methods, and examined the influence of the binder properties on the mixture properties. There is a high correlation between the G*/sinδ of HVPMA and the Dynamic Stability of the mixture, and between the G* sinδ of HVPMA and the Cantabro loss of the mixture. Therefore, the mixture properties could be predicted from the DSR tests of the binders.

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Experimental investigations were carried out for polymer modified binder (PMB) thin film and microtexture of the coarse aggregate's surface, which are microstructure at an intermediate level considered to connect chemical phenomena and physical phenomena in modified asphalt mixtures. It was shown that measuring the viscoelasticity with the thick film is not appropriate and that The G*/sind measurement result of film thickness of 20mm has a high correlation with the flow deformation resistance of the porous asphalt mixture. This is because the morphology varies depending on the Colloidal Index (Ci) of the base asphalt and the Melt Index (Mi) that is related to the molecular weight of SBS. Also, the microtexture of the coarse aggregate's surface was expressed in a form of Fractal Dimension. It was shown that the fractal dimension had a high correlation with the flow deformation and the compaction properties of the porous mixtures.

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As introducing porous asphalt pavement onto bridge sections, water proofing of the bridge decks is becoming very important. Besides applying a water-proof layer, stone mastic asphalt (SMA) is studied here to increase water-tightness of levelling course mix, based on both lab and field tests. The result indicates that the water-tightness of SMA mix depends on its porosity and layer thickness, however giving enough compaction on the mix to provide less than the required porosity is comparatively difficult in the fields. Hence, the water-proof layer is indispensable regardless SMA application on bridge decks.

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Recycling of asphalt concrete is increasingly used as a major rehabilitation method in Japan because it can conserve natural resources, reduce costs and save energy. In this study, reclaimed asphalt concrete from Tokyo International Airport was evaluated for use in four types of base materials : recycled granular material, recycled cement stabilized material, recycled cement-emulsified asphalt stabilized material and recycled hot-asphalt stabilized material. The results of laboratory tests indicated : 1) These materials can satisfy base course and subbase requirements, and 2) they are sensitive to temperature and water.

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Decision on the use of recycled aggregates depends on the aging measured by penetration of the recovered asphalt. However, it is difficult to make correct evaluation of aging of asphalt recovered from waste porous pavement materials because properties of high viscosity modified asphalt change during extraction / recovery process. In this research, a method on the use of Cantabro test to measure aging of waste porous pavement mixture to determine the usability as well as amount of rejuvenator is presented. Furthermore, properties and durability of porous pavement mixtures prepared using materials obtained by this method and virgin materials were well compared.

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[in Japanese]

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There are two approaches to back-calculate layer moduli from FWD data. One is called a static method which uses only peak values of both loading and surface deflections, and the other called a dynamic method utilizes time histories of loading and surface deflections. However, if time dependent data is used, velocities and/or 116 accelerations can also be served for this purpose. In order to measure surface deflections, a stationary point has to be selected. Velocities and accelerations can be easily measured. Furthermore, since the magnitude of those responses are much greater than that of deflections, it is easy to maintain accuracy. Thus, presuming velocities or accelerations are measured, a method to identify layer moduli from those data are presented and the results are discussed in this study.

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The whole system of a portable FWD equipment and ground was made to be the spring mass mode as the kinetic energy of the falling weight became impulsive force and it was produced a deflection of the ground. Simultaneous differential equations were deduced. At the next stage, it was introduced the model of the ground using rubber board. And, the loading was made to be the rubber board by the portable FWD equipment which installed the accelerometer in and the prediction of the displacement of the falling weight by double integral and deflection of the ground were compared with the calculation result from the measurement in respect of the acceleration. The calculation using the ballast of roadbed was similarly compared with the observation in the ground. The validity of the solution deduced from this model was confirmed.

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Research on SASW (Spectral analysis of surface wave) has been well known as one of nondestructive testing methods for pavements, which has been extensively conducted at University of Texas since 1980. This method makes use of the dispersion characteristics to estimate pavement structure. However, the area of research in our country is almost nothing. Fundamental research on the surface wave test is presented in this paper.
The objective of this research is to compare four numerical methods to compute phase velocity of layer systems, to examine dispersion characteristics of two layer systems exchanging the layer stiffnesses. and to find the effects of the layer thickness and the stiffness ratio of two layers on dispersion curves.

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This paper is according to estimation of the elastic coefficient using a very small elastic wave in which the distortion in the roadbed is very small in the loading condition. The ballast generally used is set as a target. In advance, a roadbed test pit was used for the generating method and the detection method of an elastic wave by indoor examination. The validity of the elastic coefficient for which it asked was judged from the result of loading and bending using a portable FWD.The elastic coefficient obtained by in-site examination based on these was almost as the same tendency as the in-door test results. As mentioned above, the usefulness of this research has been checked.

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This paper is to study on discriminant methods based on image processing, which can be recognized pavement conditions as an area, by using digital camera. This criminant method is focused on the texture analysis of intensity distribution depending on pavement conditions, which is composed of statistical parameters analysis and Fouriel transform. The criminant results of various pavement conditions are proved by the true prediction ratio based on Fuzzy theory. Furthermore, Wavelet analysis is tried as the method to recognize the spatial allocation of complex surface conditions by a time-frequency analysis.

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This paper describes a method for structural evaluation of concrete pavements using FWD deflections. The results obtained in the previous studies were reviewed in this paper. Especially, temperature gradient of concrete slabs affects FWD deflections of concrete pavements. Therefore, we examined the influence of the temperature gradient and loading positions on the concrete slab. On basis of these factors, structural evaluation, critical deflections of lower modulus of base course reaction were proposed. Furthermore, structural evaluation methods of concrete pavements were proposed for the network level and the project level.

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In August 1997, the loading test with a concrete pavement was carried out at the Public Works Research Institute (PWRI). From this experimental result, the permanent deformation of the base course surface by cyclic loading was confirmed. In this study, the estimation method of permanent deformation of base course surface was suggested based on the theory of elasticity and the repeated tri-axial compression test result of granular base course material and subgrade material. And then, the analytical result was compared with the experimental result. As the result of comparison, the estimated value and the measured value agreed well, and the adequacy of this estimation method was confirmed in this paper.

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Whitetopping is thin concrete overlay on asphalt pavements. However, the structural design method has not been established, because the bonding between concrete and asphalt layers is the important parameter and has not been cleared. In this study, we constructed the field trial of whitetopping using several types of concrete, conducted loading tests and measured strains in the concrete and asphalt layers. Through comparing the measured strains and the analyzed strains using FEM, we obtained the bonding parameters and elastic moduli of asphalt layers. Furthermore, we conducted the FWD tests and back-calculation of elastic moduli and calculation of transfer efficiency. Results showed that the structural evaluation of whitetopping would be possible by the FWD deflection.

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The basic concept of the design of the white topping is fatigue analysis of concrete slab. The analysis requires not only load stress but also curling stress due to temprerature gradients in the concrete slab. In this tudy, based on the results of temperature measurements and FWD tests conducted on a test pavement, effects of thickness of the concrete slab, stiffness of the asphalt layer, joint spacing and joint stiffness on the curling stress in the concrete slab were investigated with three dimensional finite element method.

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This paper describes an application of curing method using membrane curing compound consistently to airport concrete pavement. First, the laboratory tests were conducted to clarify volume of drying shrinkage, flexural strength and volume of water retention. Then, test pavement was constructed and we measured volume of drying shrinkage and temperature in situ. As the result, following conclusions were obtained : (1) volume of drying shrinkage was lager in the beginning and less in the latter than that of water curing specimens. (2) flexural strength was over 90% as much as that of water curing specimens. (3) Variation of pavement temperature on curing compound area was larger than that on water curing area in the beginning of curing term.

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The presence of water in an asphart pavement on bridge-deck can lead the pavement to failure. For this research, specimens were made in laboratory. The test wheel was tracking and traversed on a specimen under supplying water from its bottom until the pot-hole was occurred, and the mechanism of occurrence and factors of influence on the pot-hole were discussed. The factors selected for the experiment are design of asphalt mixture, binder course material, difference of the boundary, supply of water, variety of aggregate, anti-stripping agent.

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The overlay is popular rehabilitation works for the existing asphalt pavement or the cement concrete pavement. But at the early stage the reflective cracks caused the cracks of the existing asphalt pavement or the joints of the cement concrete pavement. We selected the inhibition process using non-woven fabric for reflective cracking that process was easy way at the overlay rehabilitation works. On this report we mentioned the method of establishment for optimum tack coat content, the inhibition efforts of reflective cracking on the laboratory tests, and the evaluation of inhibition efforts from the follow ups on the field.

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In situ construction test on an overlay with cement treated asphalt mixture (CTAM) for airport asphalt pavements was conducted and then a repeated loading test with a landing gear same as B-747 aircraft was carried out. As a result, the following items were found; an overlay construction up to the thickness of 200mm was fully possible, the overlaid pavement had a sufficient load carrying capacity against 1, 000 times of repeated loading and joints had no influence on the structural condition of pavement. Based on these, the fundamental principle for structural design of overlay construction was developed.

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As the present situation concerning the welfare in my country, domestically, the rapid aging society which has never been experienced is progressing, and also internationally, to build the environment that the disabled person can do social participation aggressively becomes urgent social request.
In this reserch, to service the enviroment to live with the aged people and the disabled person, we verify “the slip resistance in the aspect of the walkway pavement” from the inside of the basic walkway environment, and we verify about these from the viewpoint of two of the general walking and the aged people walking.
(1) The proper range about the slip resistance value which is necessary for the minimum walking
(2) The proper range about the slip resistance value which is easy to walk
(3) The proper range about the slip resistance value which is necessary for the walking of the road inclination part

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The use of coarse aggregates of smaller diameter or twin layers in porous pavement have been found to be effective in reducing tire/surface noise. However, a problem of few researches for establishment of the relation between surface texture and low tire/surface noise till remains. In this research, relations between tire / surface noise measured up to now and the surface texture of porous pavement sections were evaluated. Relationship between a range of coarse aggregate size and variation in power spectral density of the surface texture was also evaluated. Measurement of surface texture can be effective in proper selection of aggregates or mix design for the purpose of reducing tire/surface noise.

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