The mortar expansion by delayed ettringite formation (DEF) in high slag cement (ECM) in accordance with blast furnace cement class C was examined. The effects of cement composition, SO₃ content, type of sand, water to binder ratio (W/B), pre-curing time, curing conditions, and the addition of an air entrained (AE) agent were studied through experimental approaches. SO₃ was added in the form of anhydrite and potassium sulfate at 0.92 to 3.0mass%. Type of sand was selected from ISO standard or limestone. The W/B was varied from 22% to 60%. Pre-curing times before high temperatures varied from 1.0 to 13.5 hours. After pre-curing, three curing conditions were studied; sealing, moisture curing, and water curing. Expansion was measured by JIS A 1146. Morphological observation of expanded mortar was conducted by scanning electron microscopy (SEM). As a result, the expansion by DEF increased at high SO₃ content, lower pre-curing time, greater water supply by curing condition, and non-AE condition in high early strength cement. Microcracks were observed in only high early strength cement. Expansion was not observed at any experimental condition on ECM.

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 It is expected that an increase in belite in Portland cement causes not only a reduction in the manufacturing energy of the clinker, but also a decrease in the early strength of the cement. To address this, it is necessary to improve the early hydration reactivity of belite, but detailed analyses of the relationships between manufacturing conditions and hydration reactivity of belite have not been studied. In this study, we synthesized C₂S solid solutions under various conditions to evaluate their hydration reactivity in high belite cement. As a result, it was found that the hydration reactivity of C₂S solid solution was strongly affected by the chemical composition, the crystal phase composition, and the fineness. In addition, the hydration reactivity was greatly improved by adding barium and increasing the fineness.

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 In this study, new manufacturing methods have been investigated for cementitious materials containing novel cement systems. The purpose of this work was to achieve the highest level of compressive strength in hardened mortar. The grain size and proportions of ternary blended cement systems were calculated using the closest packing theory of Furnas. The cast specimens were prepared by mixing the constituents with an extremely small amount of water. After removal from the mold, the hardened products with the densest packing cement systems were subjected to water absorption from the outside surface, followed by two-stage heat curing. As a result, the densest packing design and pre-soaking treatment enable the production of hardened cement having ultra high compressive strength of more than 460N/mm².

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 For containing 45% to 60% of ground granulated blast-furnace slag ( equivalent to type B blast furnace slag cement) based on moderate-heat portland cement, the effect of specific surface area and mixture ratio of granulated blast-furnace slag on properties such as adiabatic temperature rise, chemical properties, autogenous shrinkage, etc., were determined by comparison with the properties of slag cement concrete based on ordinary portland cement. In Addition, property values were obtained from the temperature history in tests on mass concrete members, and the thermal cracking resistance was evaluated by 3-dementional FEM temperature stress analysis using these property values. From the results it was found that the strength of slag cement concrete based on moderate-heat Portland cement was reduced compared with the strength of slag cement concrete based on ordinary portland cement, but superior results were obtained for the adiabatic temperature rise and autogenous shrinkage properties. The temperature cracking resistance from the analysis results suggest the possibility of obtaining superior properties from slag cement concrete based on moderate-heat portland cement than slag cement concrete based on ordinary portland cement.

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 Lithium-ion batteries having high energy density are required for applications such as electric vehicles and hybrid electric vehicles. Cathode materials have attracted considerable attention to improve the energy density of lithium-ion batteries in recent years. The Li2MSiO4 family of compounds, where M is typically Fe, Mn, Co, or Ni, is considered as a promising class of cathode material for next-generation lithium-ion batteries. In this study, the crystallographical and morphological data, as well as galvanostatic cycling and the rate performance of Li₂Fe_0.27Mn_0.63Co_0.10SiO₄/C synthesized by a solvothermal method were reported and compared with samples prepared using a hydrothermal process. Li₂Fe_0.27Mn_0.63Co_0.10SiO₄/C comprising uniform nanosized primary particles and no impurities was successfully synthesized using a solvothermal method, followed by carbon coating. The solvothermal products were all indexed on the basis of the orthorhombic unit cell to the space group Pmn2₁. The crystallite size of the solvothermal products was smaller than that of the hydrothermal samples. Moreover, the discharge capacity and rate capability of the solvothermal products were better than those of the hydrothermal products. The solvothermal products synthesized using the optimum solvent mixture exhibited the best electrochemical performance with first discharge capacities of 223.5mAhg⁻¹ at a current rate of 33mAg⁻¹. The enhanced electrochemical performance of Li₂Fe_0.27Mn_0.63Co_0.10SiO₄/C is attributed to the smaller crystallite size of the solvothermal products compared to the hydrothermal ones and the uniformity of the primary particle size.

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 Mixtures of sewage sludge incineration ash and calcium carbonate were fired at different temperatures and the different CaO content. To evaluate the fired products as phosphate fertilizer, citric solubility of P₂O₅, 0.5M HCl solubility of SiO₂, and mineral composition were analyzed. The results showed that the temperature and mineral compositions to maximize the P₂O₅ solubility and the SiO₂ solubility were different for each ash. The fired products from low-P₂O₅ ash, middle-P₂O₅ ash and high-P₂O₅ ash mainly consisted of gehlenite and nagelschmidtite, gehlenite and silicocarnotite and calcium silicate and silicocarnotite, respectably.
　Phosphate fertilizer with excellent solubility of P₂O₅ and SiO₂ regardless of P₂O₅ content of raw ash was obtained by firing raw materials adjusted to 50% CaO concentration in the temperature range 1,200 and 1,450℃.

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 Ultrafine cement grout has been used to increase strength and cut-off performance when injected and permeated into sandy ground or rock mass with fine cracks. For this application, the use of general purpose cement has been difficult.
　However, there is a limitation in the permeability of ultrafine cement grout with respect to sandy ground with low water permeability and containing a large fine fraction. In this report, a prototype ultrafine cement with a particle size that is even smaller than that of conventional ultrafine cement was prepared, a new method for preparing three- dimensional artificial ground with uniform low water permeability was devised, and the prototype cement and method were used to evaluate the permeability. From the results, it was confirmed that permeability is significantly improved compared with conventional ultrafine cement, and that the prototype ultrafine cement exhibits the same level of performance as chemical solution grouts. It was also confirmed that the improved strength significantly exceeded that of chemical solution grouts.

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