Chloride binding behaviors of cement, which is important for estimating the chloride penetration into concrete, are investigated. Firstly chloride binding isotherms of major cement hydrates are examined and then a chloride binding isotherm of cements is estimated from the binding isotherms of these hydrates. The results show that the monosulfate hydrate and C-S-H phases have significant chloride binding capacities, whereas ettringite and portlandite have no capacity to bind chlorides. However, there is a possibility that ettringite in cement paste dissolves at high chloride concentration to produce Friedel's salt. The chloride binding by monosulfate hydrate is attributed to the formation of Friedel's salt and the binding isotherm shows a good fit to a Freundlich-type adsorption. The chloride-binding isotherm of C-S-H shows a good fit to a Langmuir-type adsorption. The binding capacity of C-S-H is saturated at about 0.6mmol/g at high chloride concentration over than 2M. Based on the chloride binding isotherm of monosulfate hydrate and C-S-H, the chloride binding isotherms of cements are shown to be realistically predicted.

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 As a long-term durability evaluation of a concrete building, a study about dissolution behavior of hardened cement in the concrete has been carried out. On the other hand, a calculation by a model has been carried out to evaluate the alteration behavior of hardened cement of an extremely long period. In such a model calculation, it is necessary that the dissolution behavior of each hydrate is clarified.
　In the present research, representative cement hydrates were synthesized and leaching test on each hydrates were conducted by changing the ratio of mass of leaching water to mass of hydrates. In addition, the equilibrium composition of the water which contacted with hydrates was calculated by a geochemistry calculation cord PHREEQC and RAIDEN3. The propriety of the conditions to calculate chemical equilibrium was examined by comparing a calculation result with an experiment result. From a result of liquid and solid phase analysis, a crystal phase of the AFm varied with the dissolution, but other hydrates did not have the change. It was recognized that second mineral setting was necessary in the calculation of dissolution of AFm. As the calculation result accorded with an experiment result of liquid composition, it was recognized little difference in result between geochemistry calculation cords which we have used. And it was recognized that the appropriate choice of the thermodynamic equilibrium constant was important.

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 Development of reliable non-destructive methods is needed to assess the damage induced by alkali-silica reaction (ASR) in concrete structures. The aim of this study is to examine the applicability of impact elastic-wave methods for evaluating the degree of deterioration of concrete due to ASR, particularly ASR expansion and ASR cracks occurred on the surface.
　First impact elastic-wave tests using concrete specimens subject to accelerated ASR were conducted. And changes in the parameters such as maximum amplitude and root mean square value of the received wave and P-wave velocity during the progress of ASR were investigated.
　It was found that the P-wave velocity calculated by using frequency peak decreased almost linearly with exposure time and ASR expansion. So the P-wave velocity measured by impact elastic-wave is available for estimating ASR expansion.
　In order to investigate the application of impact elastic-wave method to the real structures such as a large circular column and 3 abutments suffering from the serious damages by ASR, the impact elastic-wave test was carried out together with a visual survey, a compressive strength test using cores and so on.
　The velocity of elastic-wave measured directly in situ test scatters in the positions of ASR damaged RC abutments. On the other hand, maximum amplitude and root mean square value of the received wave obtained from the impact elastic-wave testing are relatively in accord with the degree of deterioration based on ASR cracks occurred on the surface. These parameters could be utilized to evaluate roughly the whole deterioration of concrete structures and to monitor the ASR progresses in future.

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 Static loading test was carried out to investigate the effect of seismic retrofit of RC building frame using shear wall and sidewall made of Ductal^Ⓡ (ultra high strength fiber reinforced concrete;UFC) panel. UFC wall without openings and UFC sidewall were fractured at the joint between the panel and RC frame and the panels were scarcely damaged. UFC wall with lattice openings was fractured within the UFC panel, however it did not show large fallings of UFC. UFC wall and sidewall showed higher strength than nonstructural wall or single column. The maximum shear force of UFC wall was 1.5times the nonstructural wall and that of UFC sidewall was twice the single column. Moreover, UFC wall showed almost 90% in the maximum shear force against RC shear wall that was twice in thickness. Capability of thin, lightweight seismic retrofit method using UFC was shown from the result and further improvement of it will be expected by modifying the joint between panel and existing frame.

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 This thesis describes the performance of snow melting panel made of Ductal^Ⓡ and compares the performance of the same to a snow melting panel made of normal concrete. The results obtained shows that the snow melting panel made of Ductal^Ⓡ has superior thermal efficiency to the latter. Based upon the thermal conductivity theory, numerical formulas expressing the performance are established and are compared with the theoretical formulas and the results obtained were correct. The relation between thermal conductivity to cover of pipe is analyzed and it is concluded that the pipe shall be arranged at a shallow depth for better thermal conductivity.

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 The Li-Mg-N-H system that is synthesized by the mechanical milling of Mg(NH₂)₂ and LiH is a material as the promising hydrogen media, because it is expected that it has the hydrogen capacity of about 5.5mass% in the operation temperature around 150～200℃. In this paper, we examined hydrogen absorption properties and cycling test for the mechanically milled mixture of 3Mg(NH₂)₂ and 8LiH, where the hydrogen desorption and absorption are performed at 200℃ under vacuum and 10MPa hydrogen respectively. As a result, it has been understood to be able to almost completely reabsorb the hydrogen in a condition of above absorption pressure, and to show an excellent reversibility after ten cycles. Moreover, even if the mixtures of MgH₂ or Mg₃N₂ together with LiNH₂ are used as raw materials, the same system as the Li-Mg-N-H hydrogen can be synthesized by heat-treatment for the mixtures at the temperature around 250～350℃ after a mechanical milling.

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 In recent years, incidences of tunnel fire have occurred frequently. Therefore, the effectiveness of enhancing the fireproofing property of the tunnel lining as a measure to secure safety is examined. To investigate this matter, fire resistance test is performed on model specimens that simulate the tunnel lining structure. And, safety evaluation of the tunnel lining structure during a fire is executed by measuring the temperature of each component of the composite material.
　In this report, result of the fire resistance test is obtained for material that is used in tunnels, such as shield segment and immersed tube of steel shell type. After applying wet spray fireproofing to the material, the fire resistance efficiency and the thermal conductivity of the composite are evaluated. However, in the temperature measurement result, the thermal conductivity characteristic at the boundary side of the composite material showed the same thermal property as a uniform material. Therefore, the virtual boundary layer that existed at the boundary side of the material is examined by measuring the temperature of model specimens of steel-concrete composite structure.
　As a result, it is proven that applying wet spray fireproofing can improve the fireproof performance of tunnel composite material. And, the use of model specimens of steel-concrete composite structure for the fire resistance test yields promising result that indicates it is an ideal test method.

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