Towards the development of cement for next-generation's long-term durable concrete, extensive studies were conducted on the fundamental properties of concrete using belite-based cement in which grading of cement particles and mineral composition were modified. The test results showed that the strength development of concrete is dependent on the grading of cement particles and water cement ratio, these properties are influenced by hydration change of C₃S and C₂S and the corresponding porosity and the amount and forms of Ca(OH)₂, and the hydration of C₂S in the concrete with low water-cement ratio last for four years.

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To predict the long-term degradation of cementitious materials, we have studied the leaching behavior of Ca. In this study, the Ca-leaching model from alite hydrates was proposed. The shift of the degrading front of Ca(OH)₂ derived by the modeling result agreed with that by experimental result, so the proposed model was considered to be appropriate. In this model, the porosity of starting sample and the increase of porosity by the leaching of Ca(OH)₂ were reflected to the Ca diffusion coefficient. High relationship was suggested between Ca diffusion coefficient and porosity.

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As a part of the sequential study to evaluate the cracking resistance at low temperature of asphalt mixture for hydraulic structures, the ring-type asphalt mixture specimens restrained by an inner steel ring are exposed to low temperature. Influences of material types, mix proportion, degree of restraint and history of temperature upon the temperature on the occurrence of cracks are examined. The corresponding strain and stress of the mixture at the cracking time and the transition temperature at which the mixture changes from viscoelastic stage to elastic stage are discussed. The temperature at which micro cracks occur in the asphalt mixture is measured utilizing the acoustic emission method.

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In this paper, the ion-diffusivity through hardened cement mortar, and the chemical deterioration of mortar due to the attack of various electrolyte solution, were investigated from the viewpoint of concrete durability. As the source electrolyte, NaCl, CaCl₂, H₂SO₄, Na₂SO₄, NaNO₃ and HNO₃ were prepared and dissolved into de-ionized water. For testing the ion diffusivity and degradation of cement hydrations, the ion diffusion cell, which was modified by AASHTO-T 277, was set up. And Ca(OH)₂, CSH and AFm were mainly measured as the cement hydration products. Through these test results, the deterioration mechanisms of cement mortar were experimentally investigated.

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When the application of the waterproof material is attempted with the purpose of durability maintenance of concrete slab in the pavement structure, it is required not only the waterproof function of the material but also the properties for the dynamic load which the waterproof material is applied on structure. Especially, it is important performance in pavement structure that is adhesive properties between the waterproof material and concrete slab. In this study, it was proposed an evaluation method of adhesive property on dynamics loading condition, and the effectiveness of proposed method was showed by testing some cases.

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The paper discusses neutralization of concrete which causes corrosion of reinforcing bars based on the experimental work and the analytical approach. Acceleration that applied consists of the promoting neutralization and the alternate wet and dry conditions. The equation between the reinforcing neutralization depth of concrete and the electrical potential are experimentally obtained. Then, corrosion model of bars is analytically constructed mainly based on the equation which included the factor of passing time. Finally, the equation is proposed, which is able to estimate the corrosion amount of reinforcing bar exposed to simultaneous neutralization and wet and dry condition.

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As to the data processing of road profile, discrete wavelet transform (DWT), which enables the data to be divided and downsampled by operating a localized basis function, has drawn unprecedented attention. However, the DWT has a disadvantage that its output results depend on the basis function. In this paper, we study influence of the basis functions on output characteristics of the profile data obtained by the PIARC Evenness Experiment. As findings of this study, it is cleared that the basis function which has linear phase characteristics is optimum for stabilizing the outputs after decomposition of the data.

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Portland cement concretes with high flexural strength by using ordinary materials are applied to airport pavement constructions in accordance with the social requirements on savings of both resources and construction costs. The main conclusions are as follows: 1) Concrete slabs with high strength concretes can be constructed in the same way as that of conventional concretes. However, both timing and method of curing must be carefully minded. 2) The behaviors against the environmental actions, load carrying capacities and fatigue characteristics of high strength concretes are almost same as those of conventional concretes. Therefore, the current structural design methods can be adopted.

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We investigated the structural characteristics of concrete curved chord truss bridges consisting of a roadway slab deck, steel diagonals and a bottom slab which is prestressed by tendons. The bridge can be erected in the same method as used for stress ribbon bridges. After the roadway slab is completed, the structural system changes to a self-anchored system. The Ganmon Bridge is the first bridge constructed as a concrete curved chord truss bridge in Japan. We carried out the vibration test, and the validity of our analytical model was shown. Moreover, we showed the interesting comparison results of the structural and vibration characteristics using analytical models with diagonal members or vertical members. Finally, we could estimate the the serviceability of this bridge applied by dynamic responses analysis under moving vehicles. Furthermore, we showed the structural behavior in ultimate loading applied by non-linear analytical method using the fiber model.

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The fundamental properties of rejuvenating agents for reclaimed asphalt, which play a vital role in the design of recycled asphalt concrete, are investigated as for both asphalt binders and asphalt concretes. Commonly used three agents with highly variable ingredients are evaluated in this study. In comparison with new asphalt, recycled asphalt shows the more aged properties before aging process is applied, whereas the differences between them become smaller as the aging proceeds. The difference in an effect of rejuvenating agent on the performance of recycled asphalt concretes also becomes smaller as the aging proceeds, while that of recycled asphalt still remains even after aging.

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Firstly, this paper presents a concentric loading test of reinforced concrete columns confined by rectangular ties. Test variables are concrete compressive strength ranging from 45 to 130MPa and tie yield strength ranging from 320 to 1300MPa. It was confirmed that the yield stress of transverse reinforcement was not reached for reinforced concrete columns using high-strength concrete or tie, and previous stress-strain models computing the lateral pressure with tie yield strength overestimate the maximum strength of confined concrete. A method is proposed to compute the stress in the transverse reinforcement at the maximum strength of confined concrete and a new stress-strain model has been developed. The model has been verified extensively against experimental data included columns with a wide range confinement parameters and shows good correlation with stress-strain relationships established experimentally.

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Numerical analysis of electric potentials and currents inside reinforced concrete is performed to study nondestructive evaluation of corrosion by the half-cell potential measurement and polarization resistance method. Electric fields around reinforcing steels are analyzed by using the Boundary Element Method (BEM). 3-dimensional analysis is conducted to compare with 2-dimensional analysis. Distributions of potentials inside concrete and current flows around rebars are clarified three-dimensionally.

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A pavement deterioration model (PDM) applying Radial Basis Function Neural Networks (RBFNN) is presented in this paper. The RBFNN architectures are designed to be used to develop PDM based on the database that has at least two point history condition data, and are also designed as sequential PDM where the future pavement condition can be predicted using only information about present MCI value and age of pavements. The pavement condition prediction results are compared with actual measured MCI value and other existing methods. The results indicate that proposed RBFNN architectures have good capability to be used to predict future performance of pavements, and its application is very flexible and less time consuming.

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