A high performance lightweight aggregate which has been recently developed has higher strength and lower absorption than conventional artificial lightweight aggregates. The purpose of this study is to investigate the fracture mechanism of concrete made with the high performance lightweight aggregate. We mainly focused on the combination of matrix strength and aggregate strength. As the result, it was clarified that the fracture energy of the high performance lightweight concrete depends on the strength of matrix and aggregate and the combination of their strengths as well as unit volume, shape and size of aggregate.

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To investigate the applicability of flexibility method that is based on strict force distribution to concrete structures, analyses of RC elements under various cyclic loading were carried out and numerical simulations of concrete structures which reach large deformation states were performed by the method. As results of these analyses, it was shown that flexibility method can estimate the accurate moment and curvature distribution by just one element so long as force distribution is linear, which is an usual case in real elements, and that it is possible to estimate the post-peak behavior by consistent algorithm. Further, it was shown that flexibility method is applicable for both static and dynamic analyses.

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Reinforced concrete structures such as a containment vessel, a support structure of the reactor, piping systems and facilities for storing high level radioactive waste in a nuclear power plant are designed under the conditions that those structures are exposed to high temperature conditions. In the previous paper the author elucidated the temperature dependence of properties of concrete and reinforcement, the influence of the difference of thermal expansion coefficients between concrete and reinforcement on the behaviors of reinforced concrete beams to contribute to the rationalization of the design method. In this paper the influence of high temperature conditions on the flexural behavior and strength capacities of reinforced concrete flexural members were made clear and those estimation methods were suggested.

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To assess analytically and properly the impact resistance and safety of RC structures against impact loads, it should be required to employ the dynamic constitutive model of concrete that involves tri-axial stress states for computer codes. This study is to present the dynamic and tri-axial constitutive model of concrete with strain softening behavior. Thus, the tri-axial and rapid loading tests for cylindrical concrete specimens are executed. In tests, the number of confining aluminum rings and the loading rates are chosen as test parameters. Based on test results, the effects of these parameters on the strain localization and the strain softening behaviors of concrete are examined and the orthogonal anisotropic constitutive model is proposed.

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In this study, the effects of processes, in which the repeatedly recycled coarse aggregate absorbed the colloidal silica solution as pozzolanic liquid, on properties of concrete were investigated. The absorbed colloidal silica solution is considered to fill the micro cracks of aggregate and to change to C-S-H by pozzolanic reaction. With this technique, the strength of repeatedly recycled aggregate concrete was enough to construct ordinary concrete structures, and the capacity of shear transfer at interface along diagonal tension cracks was improved.

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This study makes clear the way of calculation for the shear strength of an RC member with a large angle, which is used in Reinforced Concrete (RC) rigid-frame viaducts and box-culverts.
According to the current Specifications by the Japan Society of Civil Engineers, only one-thud of the horizontal part of the haunch is to be included as effective for calculating the strength. However, this way of calculation is not well-founded, and is felt to be unrealistic based on the authors' experience in railway constriction. In order to establish the actual shear strength, experiments were carried out by using forty-three RC member models with haunches that have various sizes and shapes.
From the results, a proposal was derived for the calculation of the shear strength of RC members with various effective depths.

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After Hyogo-ken Nanbu Earthquake, level II earthquake motions were considered for the current design code of prestressed concrete tanks. In this study, seismic performance for the side wall of the prestressed concrete tank which was design based on the current code was evaluated using the elasto-plastic seismic response analysis in consideration of the interaction effect between the fluid and the side wall. Then, to devise the simple analytical methods for seismic performance evaluation for the side wall, the accuracy of the responses based on the dynamic analysis in which the effect of the dynamic water pressure was converted to mass element and the equal-energy assumption provided in the current code were verified. Finally, seismic design method of the side wall subjected to level II earthquake motions was examined based on the results obtained by dynamic analysis for tanks with several sectional parameters.

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The purpose of this study is to investigate the effect or rheology of mortal that contains limestone powder. already known its chemical and physical properties, place of production and manufacturing process. The flowability of mortal with limestone powder is influenced by CaO content ratio, impurities of raw ore of limestone powder, impurities mixed with limestone powder on manufacturing process, Blaine surface area of limestone powder, replacement ratio of limestone powder. These factors change the restrained water of powder and absorption value of AE high-range water-reducing agent, and effected plastic viscosity and yield value of mortal. And the crystal size of raw ore affects fresh properties of mortal slightly. For flowability of mortal, limestone powder with small crystal size is better.

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The method of ductility evaluation of reinforced concrete piers and concrete encased steel piers is examined. The ultimate displacement is defined as the buckling of longitudinal bars inside the cross section. Thus, the ultimate displacement can be calculated with the ultimate curvature based on buckling of bars and the plastic hinge length. Comparison with previous experimental results indicated that the proposed method enables fairly accurate calculation of the ultimate displacement for both of reinforced concrete columns and concrete encased steel columns.

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This paper has been conducted to develop a model to estimate ion diffusion coefficients in cementitious materials. The model is considered with temperature, humidity, hydration as a change of porosity, mixture proportions, kind of target ions, an electrochemical theory and so on. From the comparison of the estimated values and experimental values from immersing tests, exposure tests and diffusion cell tests, it was concluded that the diffusion coefficient from the developed model are equivalent to those from experiments. And it was found that the effect on the diffusion coefficients is larger in order of the effect of time dependence by hydration, water saturation, and temperature.

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The purpose of this study is to develop a method for non-destructively detecting shape and distribution of fine cracks in concrete using X-ray radiography with contrast medium. Firstly, the conditions under which a radioparency dosage penetrates into the concrete structure, and makes a shadow of moderate concentration on X-ray film, were obtained. Next, experiments on an optimum combination between film and intensifying screen and detection condition of the crack were carried out in order to detect the crack in the concrete structure. In order to be applicable for existing structures, the contrast medium was injected into a reinforced concrete specimen in which bending cracks were generated, and the inside crack location was detected using the X-ray technique.

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In aging society's progressing, in addition to thinking of the environment which can go out to outdoors with the aged people and the disabled person firstly, the improvement of the walkway environment must be attempted without delay. In this research, we measure the driving force which acts on the hand limb of the wheelchair when it runs by the aged people, and we examin the influence which “Cross fall of the walkway”, “Gradient of the walkway” and “Depth of the step between the roadway and the walkway” exert on the running by the wheel chair. And adding up those results and the evaluation result by the aged people who use a wheelchair, we considered about the structure of the walkway which fitted in with the walkway environment which is necessary for the aged people.

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The elastic deflection of steel-concrete mixed girders with corrugated steel web is insufficient by the beam theory disregarding an usual shear deformation and it is clear that it should be analyzed in consideration of the shear deformation. It suggests that it is necessary to analyze the creep deflection in consideration of the shear deformation as well.
This study proposes the stiffness equation in considevaton of the influence of the shear deformation, added to the deep analysis method by which the effect of the restraint of the reinforcing bar and the prestressing steel, previously proposed, is considered.
Moreover, the influence considering the shear deformation, exerted on the creep deflection was considered

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Whitetopping is a rehabilitation method which constructs thin concrete slabs over an existing asphalt pavement. The advantage of the method is that the concrete slab and asphalt layer are combined and carry traffic loads togather. The mechanical contribution of the asphalt layer is relatively large in this structure. Therefore, a rational structural model that is able to account for the mechanical behavior of the asphalt layer is required in its structural design. In this study, a structural model based on 3 dimensional finite element method was developed. The model uses the generalized Voigt model to consider the vico-elastic nature of asphalt materials. The model was verified by comparing computed results with experimental ones. Furthermore, the mechanical behaviors of the whitetopping structure were examined in terms of structural design.

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When a concrete specimen is subjected to uniaxial compression, the failure is often localized. Therefore, the identical stress-strain relationship is not adequate to express the softening behaviors of concrete structures. In this study, a series of uniaxial compression tests of concrete specimens has been conducted. A failed specimen was divided into three zones by the local strain obtained from strain gauges attached to an embedded acrylic bar. Subsequently, the stress-strain relationships of concrete at each zone have been formulated. By combining these stress-strain relationships, the average stress-strain relationship of a whole specimen considering the localization of failure in compression can be proposed.

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In this study, we investigate the influence of powders on the fluidity and bleeding of two types of concretes. One is the influence of powders on the fluidity of high fluidity concrete. The other is the influence of powders on the bleeding of concrete. In our investigation, the three types of mineral powders, each of them has two finess, are used in different replacement ratio to make different particle size distribution of powders and to make different surface nature against water. Within the limits of our investigation, the surface nature of every powder is quantitatively represented based on the surface area of cement particles, also the apparent properties of every concrete are explained by the idea based on the properties of corresponding powders.

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Focusing on concrete surface quality, examination of the scaling property of concrete was conducted after the surface had been exposed to long-term freeze and thaw action of a chloride solution in compliance with ASTM-C-672, and quality requirements for obtaining high scaling resistance were studied. As a result, it was clarified that scaling behavior varied by mix proportion and location of the test surface. The optimum W/C (water-cement ratio) was found to range from approximately 35 to 50% for normal portland cement and 35 to 40% for blast-furnace slag cement (Type B). There were also some new findings, including the necessity of further examination concerning surface collapse due to flaking of large masses of mortar in cases with extremely small W/C.

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In dynamic compaction test of zero-slump concrete, pore pressure and acceleration are measured in order to investigate the dynamic compaction precess. Trasition from the unsteady state to the steady during compaction is examined by acoustic emission (AE) measurement. Such mechanical properties as permeability coefficient, phase velocity and attenuation coefficient (Q value) of concrete are measured in the early age. Based on the two-phase model, the boundary element method (BEM) is applied, taking into account the viscosity and inhomogeneous distribution of permeability coefficients. An applicability of BEM analysis is comfirmed in both elastic and visco-elastic solutions.

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To establish a numerical analysis method for appropriate evaluation of the failure behavior of flexural strengthened RC beams with FRP sheet bonding on tensile surface, three-dimensional elasto-plastic finite element analysis was performed proposing a new interface model to better simulate debonding behavior of FRP sheet. From this study, following results were obtained: 1) by applying the proposed interface model, debonding behavior of FRP sheet can be rationally analyzed in spite of material properties of FRP sheet and/or magnitude of sheet volume; and 2) the debonding behavior of FRP sheet due to a peeling action of the concrete block formed in lower cover concrete near loading points can be numerically confirmed.

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Due to heavier aircraft loading conditions, the durability of airport asphalt pavements must be increased. In addition, the fast and efficient construction method of asphalt concrete is required, especially in overlay works. As the measure to accomplish these requirements, the thick lift construction method using conventional asphalt concrete for airport pavement surface course is considered herein. Through a series of researches, mechanical properties of the thick lift-constructed asphalt concrete, and the bearing capacity and surface characteristics of the resultant pavement are found to satisfy the specification even when 10cm thick layer is constructed in one lift. In conclusion, the applicability of thick lift construction method in actual projects was verified.

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This report presents the development process of silica-resin grout that is diffused as the supplementation method of tunnel excavation. The purpose of this material development was to obtain the grouting material in place of urethane grout that has problem in economic or safety. The present research intended to indicate the fundamental properties of silica-resin grout with showing the applicability of some chemical materials for the development. Furthermore, this paper presents an example of the estimation theory for material development in order to give a contribution for civil engineering in the future.

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Robust and engineering oriented three-dimensional concrete constitutive laws are formulated from equivalent continuum of lattice system. Two approaches are taken to develop these constitutive laws: one from known strain field i. e. kinematic constraint and other from known stress field i. e. static constraint; later one to incorporate poisson's ratio in the rigidity matrix. Methods are also proposed to establish the stress-strain behavior of individual concrete lattices. Finally, the developed constitutive laws are applied to analyze biaxial and triaxial test results of various researchers. Analysis results show close approximation of test data, which indicates the effectiveness of these proposed constitutive laws.

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This paper presents the results of tests of four reinforced concrete beams with web reinforcement in order to measure the significance of shear deformation of the beams after diagonal cracking. The parameters affecting shear behavior, i. e. reinforcement ratio, shear span-to-depth ratio, and web reinforcement ratio were considered here. In addition, parametric study is performed by using the results of nonlinear finite element analysis and analytical model for predicting shear deflection is derived. The validity of the proposed model is made through the comparison with the above experimental results. It was found that the additional shear deflection computed using the present model agrees well with the experimental measurement.

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Thirteen reinforced concrete beams with square and rectangular sections were tested to investigate ultimate capacity under bi-axial shear loading and the ultimate bi-axial shear capacities of concrete and shear reinforcement are defined separately. The test results show that the ellipse formula underestimates bi-axial shear capacity of concrete and overestimates bi-axial shear capacity of shear reinforcement of specimens with rectangular section in which a model to calculate shear reinforcement capacity is formulated based on diagonal crack configuration. It is found that the estimations of bi-axial shear capacity of shear reinforcement of rectangular reinforced concrete beams give the values in the range of 0.88-1.27 of the tests.

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It is usually observed that RC deep beams, where the entire member becomes D-region, fail by the localized compressive failure of concrete. In this study, the utilization of the concept on localized compressive failure in formulation of the material model of concrete, based on the parameters such as the localized compressive failure length, L_p, and the compressive fracture energy, G_Fc, is performed. By incorporating the proposed compressive stress-strain relationship to the 2 simplified analytical models, the lattice model and Mander's truss model, the satisfactory predictions on the shear behavior of RC deep beams with and without transverse reinforcement are obtained.

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