High quality shotcrete (HQSC) has been applied to construction of the New Bullet Train Projects tunnel since 1997. The number of applied sites at the present time (July, 2008), which are distributed from Kyushu to Hokkaido in the whole country, is almost 130. Therefore, a material procured in the locale to the shotcrete is various. Especially, the difference of the fine aggregate characteristics is large, as for the method of mix proportion of HQSC, the change in the construction performance between the regions and sites is feared. In this report, the correspondence method to the problem is discussed by clarifying the realities to arrange the construction results of HQSC, and objectively analyzing the results data to use a statistical analytical technique, in addition to the content of three volumes announced to Journal of tunnel engineering (JSCE) from 2004 to 2006.

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  It is important for satisfying the required performance of concrete structure, such as the strength and durability, by sufficient curing of concrete. Researchers focused mainly on only compressive strength, not durability. Besides, in most of their research, they used Ordinary Portland Cement (OPC), not blended cement. It is necessary to define the relationship between curing condition and concrete durability using OPC and blended cement. In this research, the effect on concrete durability of different curing conditions and periods of concrete using OPC and Blast-furnace slag cement type B (BB) identified JIS R 5211 were investigated. As a result, BB concrete durability is more sensitive to curing condition than OPC. However BB concrete has necessary for extended curing period of 2 days by OPC concrete for keeping enough durability.

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  The shape optimization method of reinforcement corrosion in concrete is developed on the basis of temperature history of concrete surface, which is changing due to the heat conduction from the reinforcement stored by an electromagnetic induction heating.
  In this paper, the conventional method was extended so that the control of two boundary surfaces might be possible simultaneously, in which one surface is between concrete region and corrosive region in reinforcement, and the other is between corrosive region and non-corrosive region in reinforcement. Then, the applicability of the presented 2-dimensional analytical method was estimated due to the comparison with the experimental results.

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  Vertical and horizontal mechanical properties of pavement layers are expected to differ, because pavements are constructed by road rollers by compacting in the same direction. It has been experimentally confirmed there exist anisotropic characteristics in granular materials and their characteristics have been measured in a laboratories. The objective of this study is to develop the theoretical solutions for transversely isotropic layered half space. Pavement structure is modeled by a multilayer structure with Voigt type viscosity. The solution is derived by directly applying Hankel transforms to the Navier's equations for transversely isotropic layer when impulsive force is applied at its surface. By comparing responses of isotropic system, the characteristics of the system are investigated.

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  When mechanistic methodology is used for pavement design, static analysis is generally conducted. However it is important to make it clear how much static responses differ from the responses due to a moving load with constant speed. Therefore, governing equations are derived assuming that a load moves at constant speed over the surface of pavement composed of voigt model type layers. Theoretical solution is derived by applying Fourier transform in a space domain and FFT in a time domain. From the theoretical results, it becomes clear that the responses reduce with increasing speed of moving load and with increasing damping, but they are affected little with or without densities.

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  It is important to estimate the cracking tendency or the time of cracking due to restraint of drying shrinkage in design and construction of concrete structures. For this estimation, it is necessary to clarify the tensile stress-strain relationship of concrete at early age under restrained shrinkage conditions. The tensile stress is relieved by creep. In this research, the tensile creep of early age concrete under the restrained conditions was measured by use of a ring-shaped concrete specimen restrained by a inner steel ring. This type of specimen can restrain the shrinkage from just after casting of concrete. The tensile stress-strain relationship under the restrained conditions can be obtained by measurements of free shrinkage strain and strain of the steel ring in ring specimen. Test results gave the tensile creep coefficient ranging from one to two regardless of the degree of restraint and the time at which drying begins.

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  In this paper, we studied the evaluation methods of deformation capacity related to damage degree for repaired reinforced concrete (RC) members. Based on experimental and analytical investigations, we clarified the deformation capacity of repaired RC members is affected by buckling of axial reinforcement :Firstly, in the case of the damage without buckling of axial reinforcement before the repair, the deformation capacity of repaired RC members is more than or equal to that of no-damage RC members. Secondly, in the case of damage with buckling of axial reinforcement before the repair, the deformation capacity of repaired RC members is inferior to that of no-damage RC members. In addition, we proposed the calculation methods of rigidity and maximum load of repaired RC members.

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  The electrochemical inspection is useful for the assumption of the reinforcing bar corrosion, as a non-destructive test. But the accuracy of results between non-destructive tests and exposure tests, are not discussed enough among researchers. In this paper, the results are compared with exposure tests, marine and inland circumstance, by the results of the half cell potential, the concrete resistance and the polarization resistance. There are good agreements in these results when the electrochemical method is used in severe conditions for example marine environment. And the residual life for the repair concrete structures are shown by the results, it is useful for the administrator when they plan the life cycle costs.

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  In order to investigate each critical chloride ion concentration of JIS standard reinforcing bar (SUS304SD, SUS316-SD, SUS410-SD), corrosion tests in concrete environment were performed. One test was constant potential electrochemical corrosion test of intrinsic chloride ion mortar specimen, the other test was infiltration and diffusion of exotic chloride ion in concrete accelerated test by contacting 10%NaCl solution and controlling constant temperature and moisture in a chamber for investigating corrosion initiation chloride ion concentration of reinforced concrete. And it turned out that the critical chloride ion concentration of each stainless steel type was considerably higher than that of the carbon steel reinforcing bar (1.2-2.5kg/m³) in each test, and critical chloride ion concentrations of stainless steels are introduced with past researches.

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  The hazardous property and physical properties of the slag which was dumped illegally in the area bording Iwate and Aomori Prefectures were investigated. Some problems were seen such as survival of metal aluminum and elution of fluoride. However, it becomes clear that they are solvable by suitable post-treatment, and so on. Moreover, some character of concrete in which fine aggregate was replaced by the slag was investigated. To use of slow cooled slag does not have an exceptional problem. In the case of water cooled slag, delay of setting time, strength reduction and deterioration of freeze-thaw resistance of concrete were seen. These problems can solve by setting up the material and the mix proportion suitably.

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  Concrete-filled circular spiral steel tubes were tested under concentric compression. The welded part of this steel tube form a spiral and the seam-welded part is thicker than the steel tube wall. The test results showed that filling in steel tube with concrete enhanced the loading capacity and ductility, and the spiral-welded part had no influence on the tube's behavior. A formalized stress-strain model for concrete confined by steel tube was also developed, based on the test results in this study and other previous studies. Regardless of the difference between the production methods of steel tube, the ratio of tube diameter to steel thickness, tube length and concrete compressive strength, it can be used more extensively than the previous models.

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  The purpose of this study is to estimate of carbonation process of underground concrete structure as an example of the communication infrastructure facilities. Underground concrete structure is received on a gradual dry and wet cycle by the seasonal variation, and the speed of carbonation is changed on the boundary of some value on the surface water content of underground structure. An underground structure that exists in a dry environment, is carbonated more easily than usual structure. It was confirmed that this event was examined in the concrete permeability by the test piece, and it changed greatly on the boundary of some value on the surface water content.

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  Flexural cracks adversely affect mass transfer in cover concrete of reinforced concrete members. However, the internal structure of flexural cracks including crack width near a reinforcing bar and bond degradation area has not been figured out sufficiently except for surface crack width. The effects of internal structure of flexural cracks on mass transfer and on corrosion of reinforcing bars have not also been clarified. It is also unclear whether increasing cover thickness to improve durability affects the internal structure of flexural cracks or not.
  In this research, focusing on cyclic loading and cover thickness, the effects of internal structure of flexural cracks on steel corrosion were examined by accelerated corrosion tests and visualization of cracks.
  As results, it became clarified that the crack width near reinforcing bar and bond degradation area were increased and the initiation of steel corrosion was made earlier by increasing the number of cyclic loading, and that the crack width near reinforcing bar was increased in some cases with the increase of cover thickness due to the localization of damages around a reinforcing bar near the main crack.

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  The paper discussed characteristic change of following items after applying cathodic protection of impressed current method: that is a) electro-chemical properties of both PC strand and anode materials, b) material properties of both anode and concrete in the vicinity of PC strand, and c) mechanical properties of PC strand and flectural properties of PC members. Experimental work includes the indoors tests and the long-term PC beams tests. Follwing results were made clear based on the testing results,
1) It is inclined that larger the embedded bars corrodes, larger the electro-chemical properties change. It might be reasoned that the interface between concrete and PC strand is improved.
2) It is notieced that concrete surrounding PC strand severely deteriorates providing that electric current is impressed excessively.
3) When the effective protection method is applied, the material properties of PC strand and the flexural behavior of beams showed as same as those of non-corroded one.

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