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The body of data about the reaction kinetics of cement has greatly grown in recent years, and in terms of techniques for the prediction of the resulting hydrate formation phases, databases contributing to thermodynamic equilibrium calculations have been developed and are growing increasingly sophisticated. On the other hand, though many studies on cement aim to contribute to concrete engineering and numerical model researchers have pointed out the necessity of shedding light on the relationship between the microstructures generated by hydration and physical properties, such data remains scarce. This study investigated Portland cements using two commonly used water-cement ratios and three types of mineral compositions in the material age range of up to one year. The phase composition in relation to cement hydration was determined by X-ray powder diffraction and Rietveld analysis. In terms of physical properties, compressive strength and Young's modulus were measured through loading tests, and Young's modulus and Poisson's ratio were also obtained from the ultrasonic pulse propagation velocity of longitudinal and transverse waves. Further, water vapor adsorption tests to shed light on moisture behavior were conducted, yielding the BET specific surface area. Thermal conductivity, an important determinant of thermal behavior, was measured using the transient hot wire method. On the premise of the application of these physical properties to numerical calculations, their correlation with the information obtained from the phase composition was considered, leading to the proposal of simple and relatively high-accuracy empirical formulas. Further, background information about raising the correlation of these empirical formulas was also discussed.

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Methods for assessing the soundness of concrete exposed to irradiation are being developed within the framework of a project of the Nuclear Regulation Authority (NRA) “Japan Ageing Management Program for System Safety”. This paper presents the background of this project and recent research works. The major reason for deterioration of concrete under irradiation conditions is expansion of aggregate due to neutron and gamma-ray irradiation. Dislocation of atoms in covalent structures of aggregate minerals, and resultant lattice constant change and alteration to amorphous phase are produced by fast neutrons. In addition, through electronic exertion, some energy deposition is accumulated as permanent distortion/strain in atomic structures. Other effects are also summarized. We plan to conduct a neutron irradiation test from May 2013. In selecting mix proportions and concrete components for the irradiation test program, sample size as a function of capsule size and gamma-heating, cement type, and aggregate size and type are determined based on preliminary experiments.

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During sorption, the microstructural evolutions of two different cement pastes (with water-to-cement ratios of 0.40 and 0.55) are studied via proton-nuclear-magnetic-resonance relaxometry. The water uptake test is performed for samples dried at 105°C under three different temperatures of 20°C, 40°C, and 60°C for the first twenty-six days of sorption. It is observed that the water went first to the larger pores before migrating to the finest ones. This behavior is accelerated with increasing temperature. The rate of water exchange between fine and large pores is estimated and found to increase with temperature for both studied mixtures. The activation energy corresponding to this water movement is calculated and found to be higher for the lowest water-to-cement ratio, owing its finer microstructure. Finally, the activation energy related to the local water transport in re-distribution from large pores to fine pores is calculated and found to be inferior to the experimental results, which can be explained by the dynamic microstructure not being considered in the classical theories. Recently, based on the proton nuclear magnetic resonance ( 1 H-NMR) relaxometry technique, the dynamic