According to the enhanced performance of concrete and the generalization of high strength concrete, the model code is improved to cope with them. The prediction equations of creep and shrinkage for high strength concrete are also indispensable to the present model code.
In this study, the precision of the present prediction equations was examined by using some data bases. The reliable knowledge of the effect of concrete strength on creep and shrinkage was also derived from the data included in these data bases. New prediction equations proposed in this paper are very simple and available for wide-ranged strength concrete creep and shrinkage.

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Analyzing and understanding dam concrete temperature is significant for design and construction method of gravity dam. The Adiabatic Temperature Rise Model which is used conventionally and is specified hydration heat property of dam concrete is, however, generally considered to underestimate the temperature rises than its actual movement.
The purpose of this study is to improve the accuracy of dam concrete temperature analysis. We apply the Hydration Heat Model to describe the long-term hydration heat process of dam concrete. We inspect the specification of long-term hydration heat property of dam concrete by comparing measurements of concrete dam temperature with the results of temperature analysis considering the total hydration heat quantity of dam concrete.

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The effects of the surface condition on the shear bond properties of concrete joints were investigated through compression tests. The bond properties of concrete joints at 60 degrees to the horizontal axis, which were treated in different ways, were able to be characterized with the peak load and the area under the load-displacement curves. The shape of the load-displacement curve of the post peak load was more sensitive to the joint surface treatment than the peak load. The acoustic emission (AE) technique was applied to the shear bond properties of the concrete joints. The results of the location of AE event sources depended on surface conditions. The AE technique gave us detailed informlation about fracture properties of concrete joints.

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In this paper, the interrelationship between hydration and moisture equilibrium was theoretically discussed based on the experimental fact that the hydration process of low W/C concrete differs from that of concrete which has sufficient water for hydration. Free water available for hydration was defined based on the thermodynamics, and was obtained by moisture isotherm/transport and pore-structure development models. By coupling of the hydration heat model with the obtained free water in porous medium. we aimed to predict the hydration process of low W/C concrete. Through several numerical sensitivity analyses and verifications with experimental data. the authors showed that the interaction of hydration with moisture equilibrium in porous medium should be considered in low W/C concrete.

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The polyester type concrete retarder (coated on polyethyleneterephtalate film) shows some good retarding effects; the effects are stable and last for a long time, a high waterproof against rain and sprinkling. In this study, we examine the relation between the chemical structure of the polyester and the retarding effects, and we find that the retarding effects can be controlled by the chemical structure concerning with the hydrolysis rate of the polyester. We also examine the treatment properties of vertical construction joint with polyester type retarder, and it shows that the treatment with polyester has almost the same effect as the conventional method, such as tipping.

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This paper proposes an estimating method of the coarse aggregate volume used for self-compacting concrete. This method employs a probability model derived by the Monte-Carlo simulation, which regards the critical state of self-compactability as a bridge structure of the coarse aggregate covered with adherent mortar films. The probability model was compared to the published results of previous experiments for examination and validation of its applicability. The comparison clarified that the application of the model would enable to estimate the coarse aggregate volume for self-compacting concrete and facilitate its mix design.

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The objective was to clear comprehensively the corrosion cell formation pattern (macro-cell and micro-cell) and the rate induced by chloride or carbonation in mortar with defects. Therefore, the corrosion cell formation pattern and the rate were analyzed using the model defects simulated cold joints and cracks. Herein three parameters were set: 1) supply of Cl^- or CO₂, 2) supply of H₂O and O₂, 3) W/C. As a results; with presence of defects, A) in the case of chloride-induced corrosion, the decreasing W/C increased the activity of macro-cell corrosion, while the increasing W/C prevailed the micro-cell corrosion, and there was the case in which the corrosion rate became high at the low W/C, B) in the case of carbonation-induced contusion, macro-cell corrosion was formed regardless of W/C, also the corrosion rate decreased at the low W/C, C) the chloride induced corrosion rate was higher than that induced by carbonation.

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Silane treatments which are typical hydrophobic treatment have been focused to be better performance in reducing alkali-silica expansion. However, the influence of water content of concrete on the effectiveness in reducing alkali-silica expansion by silane treatment system have not been investigated enough. In this study, silane treatments were applied on various water content of concrete and the effect of silane treatments to reduce alkali-silica expansion was discussed. Furthermore, quasi-actual size specimens were placed outdoors to take account of moisture transfer of concrete in the state of quasi-actual condition. The effect of silane treatment system to reduce alkali-silica expansion on quasi-actual specimens was investigated.

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The present study aimed at evaluating autogenous and drying shrinkage of high strength concrete quantitatively. For this purpose, bound water content of concrete sealed as well as exposed to drying at different ages was measured and the relationship between autogenous shrinkage strain and bound water content of sealed concrete was obtained. Assuming that autogenous shrinkage strain depends only on bound water content even under drying, autogenous shrinkage strain under drying was estimated and then drying shrinkage was calculated. The present method showed that the conventional method based on the superposition principle overestimated autogenous shrinkage strain under drying, which also gave the percentages of autogenous shrinkage strain for total strain.

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In order to rationalize the hammering test and to eliminate the dangerous works for inspecting in concrete structures, an application of remote measurement by the laser doppler vibrometer (LDV) is investigated. The relationship between impact echo and surface vibration of structures measured by LDV is clarified. For a concrete specimen with a void, energy ratio of the power spectrum density is employed to extract local frequencies at void parts, and their location is identified from mode shapes at the frequencies. The identification method is based on the frequency domain analysis of measured surface vibrations. Furthermore, a non-contact input excitation method using sound pressure is also proposed. These results indicate that the LDV has potential applicability to defect identification of concrete structures.

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The demand for shield driven tumels of rectangular cross section is increasing in recent years, and the development of an economical segmental lining structure has become necessary.
In order to be able to employ in segmental linings an open sandwich structure constructed by first erecting a steel segments and then placing reinforced within this segments, development activity was performed with respect to joint structure selection and tightening control method, high fluidity concrete mix design and placing method, and structural analysis models.
The results of this development were applied to a rectangular shield driven tumel that is one of the largest in the world. Their effectiveness was verified through this construction.

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In this paper, a unified plastic model for concrete, in which only one criterion is considered to describe the behavior of concrete under different stress states, is used. This model can treat a major nonlinear phenomenon of concrete such as cracking; shear transfer degradation, tension stiffening and compressive strength reduction. The objective of this paper is to follow mentioned method together with presented formulation based on complementary matrix to analyze localized failure of RC panels as well as post-peak behavior while shear band is formed. This phenomenon occurs when the material acoustic tensor A(n) looses its positive definiteness and usually takes place when RC element fails in shear.

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The effect of loading path on the behavior of RC members is investigated. The shear capacity of RC members under coupled axial tension-shear is discussed. Three main effects of axial tension are (1) early yielding of main bar due to initial stress; (2) axial tensile stress accelerates the formation of diagonal crack and (3) pre-cracks caused by axial tension blunt the localization of diagonal cracks. The increase or decrease in shear capacity is possible depending on the relative effect of these three factors. JSCE design code seems to recognize only the first factor without explicit coverage of the second and the third ones. Comparative study of experimental results, JSCE and FEM predictions is conducted.

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Water can cause increasingly severe damage to airport pavements as the magnitude and number of aircraft loads increase. A water drainage system can extend pavement life and is recommended for heavyduty airport pavements. Characteristics of permeable asphalt base mixtures and porous asphalt surface mixtures, which are used to remove rainwater from pavement, were studied in laboratory tests. As a result, the applicability of both materials for airport pavements was fully confirmed.

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