Water permeable concrete is required to have the given coefficient of permeability and compressive strength depending on environmental and structural conditions. Their requirements should be controlled with mix proportion, compaction, curing conditions and so on. The purpose in this study is to frame the mix design method of water permeable concrete satisfying the requirements. We carried out to classify void in the concrete into the three types of void of permeable, non permeable and entrained air, and to define the ratio of absolute volume of aggregate, cement paste-aggregate volume ratio. Thus, it is found that new mix design method for water permeable concrete by vibrating compaction could be proposed and be available for the practical mix.

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The authors presented an integrated computational system of 3D FE structural analysis program, and 3D FE thermo-hygro physical analysis which can deal with the development and deterioration process of concrete materials performance. The thermo-dynamic oriented system can give the solutions of temperature, pore pressure, pore distributions and other material properties in both 3-D space and time. By provided these information to the structural mechanics oriented system, the stress and the damage of RC member caused by temperature change and shrinkage can be obtained. The generation of crack will change the material properties in mass transport feature controlled by the thermo-physics. This proposed integrated system can be used for simultaneous evaluation of the total structural and material performances without distinguishing between structural and durability, respectively.

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This report discusses the reprocessing of waste asphalt concrete and concrete dust into reusable materials. A new reprocessing technique is proposed first, then important factors of the technique are identified such as the mixing temperature and the appropriate amounts of additives. Next, the fundamental properties of asphalt compounds consisting of the reclaimed materials are examined. Consequently, the proposed technique has been found to be capable of producing reusable recycled fine or coarse aggregate easily from waste asphalt concrete. As films of asphalt remain on the surface of reclaimed coarse aggregate, the development of a method to remove the films was studied. It was found that the proposed technique restores the reclaimed coarse aggregate to its original as-new condition with no asphalt adhering to its surface.

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The results of compressive rapid loading tests and many studies related on the dynamic compressive properties of concrete have been reported. However, the strain softening behaviors of concrete material under uniaxial compressive rapid loading has been left unsolved. This may be the reason that it is difficult to measure the post-peak behaviors of plain concrete since the fracture of the test specimen will happen suddenly and instantaneously under rapid loading. Thus, the methods of measuring overall deformation of the specimen is presented in this study. Also, this study is to investigate the strain softening behaviors of concrete material in compression under rapid loadings. The length of specimen, the constriction of both ends of specimen and the loading-rate are chosen as test parameters. From tests results, the effects of these parameters on the peak stress, the strain at the maximum stress, the stress softening behaviors and the strain localization are examined. Furthermore, based on the concept of the fracture energy, a set of formulations of the uniaxial compressive stress-strain relationship in the fracture zone is proposed.

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Fly-Ash-Cement mixtures mixed with optimum water content are only moist powder immediately after mixing. However by vibrating with higher energy these mixtures change into fluid state in few minutes and can be sufficiently compacted. In this study we investigated the influence of vibration level, mixture proportion and properties of materials on the fluidized phenomenon and compactability of Fly-Ash-Cement mixtures.
From the test results it was clarified that fluidized phenomenon of the Fly-Ash-Cement mixtures are influenced by the amplitude of vibrating acceleration and consolidation behavior can be estimated by the vibrating energy.

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This study has been executed to find a pavement structure on which elderly people do not meet an accident owing to stumble. In this study, an experiment on walking properties of elderly people has been carried out, and faults at joints of block pavements have been measured. These results have been analyzed and an allowable height of faults over which elderly people can walk safely has been proposed.
We found that the standard deviation of faults at joints of block pavements should be less than 2.4mm when the locus of the tip of a toe is approximated by a cubic equation.

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It is of utmost importance to hold the FRP rods/strands when they are to be used as prestressing tendon or in tension tests. The authors have developed a new anchoring method, using Highly Expansive Material (HEM) in which the expansive pressure can be attained up to more than 50MPa and the pressure is transmitted in a manner similar to that of the fluid pressure, In this paper, the relationship between the anchorage length and the expansive pressure for post-tensioning type anchors, along with long term stability and fatigue characteristics and some others are investigated. Also supplemented with experimental studies on performance of multi-cable type anchorage.

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The experimental and analytical study on the detailed estimation of the pore water pressure occurring in concrete subjected to the cyclic load as a porous permeable material, which is partially saturated with water, was performed. In the experimental estimation, at first, the measurement of pore water pressure was performed due to the pore water pressure cell which is assumed to be one dimensional consolidation and then the characteristic of pore water pressure under cyclic load was examined. In the analytical estimation, the coupled model with water and concrete solid which is expanded such as able to apply to the time dependent behavior was developed and then the effect of pore water pressure on concrete stress under cyclic load was examined analytically.

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An analytical model for predicting mechanical behavior of asphalt pavement on steel deck plate has been developed being based on the Finite Strip Method (FSM) using overlaid strip element. Overlaid strip elements which are connected to underneath strip elements by link elements represent the pavement on the deck plate. This model is also able to acommodate longitudinal joint in the pavement. Comaprisons of the computed starins with the ones measured on an actual pavement on deck plate showed the validity of the model.

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The composite bridge column aiming high-speed construction time, has significant features that several steel tubes are placed inside the section and high strength strand are set spirally. The cyclic loading test has focused on the moment capacity, composite action and placing effect of steel tubes using beam-type model, and the effect of lateral reinforcing ratio and width/depth ratio of cross section for ductility, and shear strength using column-type model.
The following result were obtained that the maximum moment capacity coincides with the calculated value assuming perfect bond action between steel tube and concrete, and the ductility was better. On the other hand, the behavior of shear failure was ductile due to the existence of steel tube.

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The applicability of new in-situ testing method for permeability of surface layer of concrete, whose original concept has been proposed by authors using water pressure originated from rubber tube, is examined.
In order to make clear a basic concept of this “rapid water permeability rest” method, the water permeation from the test hole was presented by a basic equation concerning pressure diffusion. The effects of factors relating to the water permeation were summarized using the diffusivity estimated from the basic diffusion equation, and the mutual relationship between the diffusivity in the estimation and that obtained in conventional in-door water permeability test, was examined.
In conclusion, this method was judged promising for the in-situ test to assess the water permeability and the simplified in-door test to assess the diffusivity in the surface layer of concrete.

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In this study, the progress of steel corrosion in model specimens with chloride induced corrosion and then patched with self-compacting concrete were investigated. The formation of corrosion on steel bar in concrete was discussed with the aid of electrochemical methods.
Self-compacting concrete is superior in protecting steel bar from chloride induced corrosion to normal concrete with the same strength with self-compacting concrete. Also the formation of macro-cell corrosion on steel bar in self-compacting concrete and the re-deterioration of repaired member were impeded.
On the other hand, steel corrosion in chloride contaminated concrete with self-compacting concrete patching was more severe than the one with ordinary concrete patching.

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In this study, the chloride induced corrosion mechanism and the rate were experimentally investigated on reinforced concrete beams with bending cracks. Special features of this study include: crack formation through application of bending load, consideration of main rebars and stirrups separately and as a whole, and measurements of both macro-cell and micro-cell currents. Indoor experiments were conducted to investigate local corrosion of main rebars and stirrups. Then, the corrosion of main rebars and stirrups was studied on model beams. To clarify the indoor test results, larger scale beams exposed to outdoor environment were investigated. Results of the importance of stirrups near cracks on corrosion and the influence of existence of cracks on the corrosion mechanism and rate are reported.

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Firstly, a simple apparatus for evaluating the self-consolidating property of concrete was introduced, and the results of tests conducted to confirm the suitability of the apparatus were shown. Then, applying the test results on concrete mixtures of various mix proportions and various properties, an effort was made to convert two measured values using the apparatus into two indices with which both the passing ability through closely spaced obstacles and segregating property of fresh concrete could be quantitatively evaluated, and it was confirmed that the indices were quite adequate for their evaluation. Simple means for judging the self-consolidating property of field concrete using the apparatus were also shown.

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The characteristics of residual displacement developed at earthquake-damaged piers were analyzed. Residual displacement in the transverse direction was found to have a good correlation with the eccentricity between the center of the pier and the center of the girder. The analyses utilizing aerial photographs showed that ground, buildings, girders and piers all had same residual direction to the west (Kobe side).

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Fatigue tests were carried out on the fretting of prestressing strands S15.2 given a small radius of curvature, in external tendons of a prestressed concrete bridge. It was confirmed that the fretting associated with high bearing stress and relative slipping at the contact points between prestressing strands causes the ruptures of strands, and fretting mark and crack were found at the point of origin of rupture. It was learned that the lifetime under these conditions is shorter than the usual fatigue lifetime in which fretting effects are negligible. From the test results, we propose a design fatigue strength formula of prestressing strands that takes fretting in small radius of curvature into account and show that a cable grouted with cement mortar is effective in suppressing fretting fatigue.

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In this study, the propagation behaviors of elastic waves in concrete were investigated through both experimental and theoretical approach. As a result, the size and the amount of aggregate in concrete were key factors for the propagation behaviors of elastic waves. Furthermore, it was clarified that the pulse velocity was also related to the characteristics of cement-paste matrix. In addition, the condition of the aggregate-matrix interface and the existence of microcracks resulted in the changes in the frequency characteristics of the elastic waves propagated through the concrete.

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The purpose of this study is to find the governing factor of deterioration of lightweight concrete due to repeated freezing and thawing. The tested lightweight concrete was made with artificial lightweight coarse aggregate and normal sand, and nominal air content was 5.0%. This study is conducted rapid freezing and thawing in water.
Void system of artificial lightweight aggregate is determined, and the effects of moisture content on freeze-thaw durability is discussed in this paper. It is resulted that the durability factor depends on the percentage of moisture content in lightweight coarse aggregate at mixing and/or in hardend concrete spesimen at freez-thaw test.

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Applicability of acoustic emission (AE) technique for evaluation of fatigue damage was examined in reinforced concrete (RC) slabs under cyclic loadings in both laboratory and real structure in service. The fundamental test performed in laboratory showed that cracking process can be practically monitored by the measurement of AE signals. The analysis of the relationship between loading phase and AE activity indicated that the final stages of the fracture process can be evaluated by detecting AE signals generated near the minimum loading phase. The comparison of the result from the real structure and that from the laboratory specimen demonstrated that AE energy can be an effective parameter for evaluation of fatigue damage in RC slabs in service.

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High fluidity concrete was apllied for sandwich composite structure of immersed tunnel elements. This works requires reliable concrete filling techniques into the steel-shells of shutting sandwich composite structure, for difficulty to confirm filling state and finished concrete filling form. Still more, although we use two ready mixed concrete plants anxious about changes of aggregate qualities and so on, this works requires for techniques of stable making of high fluidity concrete satisfied needed properties.
The object of this study is to investigate the influence on properties of fresh high fluidtiy concrete, caused by changes of concrete materials state, such as fine aggregate grading, fine aggregate surface moisture, temparature and so on. And some concernings were making on reliable concrete filling method.

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It is a part of the performance-based evaluation to examine the flexural crack width of a reinforced concrete structure. For the purpose of comparing the flexural crack width measured for a reinforced concrete beam with that calculated according to the Concrete Standard Specifications (Design Part I) of JSCE, the flexural strength tests were carried out with a number of reinforced concrete beams of the same shape and the same mix proportion. The testing beams were 27 in number.
It was shown that the maximum flexural crack width measured at the position of tensile reinforcing bars of side face in the beam was smaller than one calculated by the JSCE specification. However, the mean flexural crack width measured at low face in the beam was longer than the calculated value by about 20% in mean value, by about 50% in widest value.

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Economic design scheme of durable concrete structures is proposed in this paper based on the publication in 1995 by JSCE research working group on durability design for concrete structures. According to the publication, the durability format is given that the durability index should be greater than the environmental index. The durability index is taken to be 100 in normal design condition. If the index is less than 100, some technology points are improved to ensure the index greater than or equal to 100. In order to improve that, the value evaluation is developed here. The scheme proposed here is modeled and solved as the combinatorial optimum design problem.

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Computer modelings are one of the most suitable and promising approaches for comprehensively understanding the mechanisms of failure in concrete. This paper presents a practical, computationally efficient procedure for analyzing fracture of reinforced concrete structures. Concrete material is represented by a rigid-body-spring model with random geometry. Rather than averaging the effects of reinforcing over a regional material volume, reinforcing material is explicitly modeled using a beam- and linkage-spring. The spring network gives reasonable predictions of fracture behavior in reinforced concrete structures. Numerical predictions are compared with experimental results of reinforced concrete piers and beams.

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