Ground granulated blast furnace slag (GGBS) blended cement (slag cement) is a promising material presenting less environmental impact and showing superior durability than Portland cement when used in producing concrete. However, slag cement presents some disadvantages compared to normal Portland cement: lower early strength, faster carbonation, and unstable sulfate resistance because of its chemical composition. A new type of GGBS has been developed to improve its sulfate resistance. In this study, superior sulfate resistance of this GGBS was demonstrated and the mechanism of improvement was discussed. Addition of a novel GGBS suppressed further ettringite formation after immersion in sulfate solution. Considering advantages of novel GGBS such as comparable strength to that of common cement in hot climates such as Southeast Asia, slag cement of two types were proposed and their respective performances in concrete were demonstrated. One type showed similar strength development to that of PCB40, which is a commonly used cement in Vietnam, in addition to better performance in sulfate resistance and chloride penetration resistance. The other type showed lower strength, but excellent sulfate resistance and higher fluidity at a low water-to-cement ratio with the superplasticizer.

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 Considering durability of reinforced concrete structures, we have specifically examined the change of properties of cover concrete. Generally, it has resistance against chloride and carbon dioxide gas penetration. Thereby, it protects the embedded reinforcing bars. Consequently, it is important to practice initial curing to produce durable concrete structures.
　Nevertheless, it is common to decide the timing of demolding formwork according to the cylinder compressive strength. The surface properties of concrete are not considered. This paper presents discussion of effects of the difference of the timing of demolding formwork on development of strength and pore structure of the concrete.
　In the experiments, a general water-cement ratio of concrete was set and several types of cement were used: Normal, Blast-furnace slag, Low heat, and High-early strength.
　Results show that the surface properties of the cover concrete can be improved by lengthening the curing time; the effect depends on the cement type.

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 Demand for highly volatile lower-cost coals, such as sub-bituminous coal, is increasing because of the skyrocketing costs of coal. However, highly volatile coal tends to combust spontaneously during storage.
　Because spontaneous combustion results from low-temperature oxidization of coal, it can be evaluated through oxygen absorption measurements. Although the BOD OxiTop method is used to measure the oxygen consumption of microorganisms, the applicability of this method to evaluation of the oxygen absorption of coal has been proven.
　Measurements of the oxygen absorption rate for coals of several common types with different ranks using the OxiTop method revealed that the respective oxygen absorption rates for bituminous coal and sub-bituminous coal are 1.0×10^-4–2.5×10^-4 and 4.0×10^-4–5.0×10^-4 [m・mol-O₂/g-coal/hr].
　Furthermore, a positive correlation between the O₂ absorption rate and atmospheric O₂ contents was confirmed experimentally.

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 In July of 2006, the CODEX Alimentarius Commission of the United Nations Food and Agriculture Organization (FAO) and the World Health Organization (WHO) adopted the new international standard for Cd concentration in polished rice; this level is at 0.4 mg/kg. In the Japan’s Agricultural Land-Soil Pollution Prevention Law, the Cd concentration of brown rice is at 1.0 mg/k. It is forecasted that the Japan’s standard may be amended to 0.4mg/kg. Therefore increasing attention has recently been paid to remediation technologies for Cd contaminated paddy soils.
　From 2003, Taiheiyo Cement Corporation and National Institute for Agro-Environmental Science have carried out the joint research about the remediation of Cd-contaminated paddy soils by washing with chemicals. We have already developed the basic method using iron (Ⅲ) chloride¹⁾²⁾³⁾. We have newly developed the advanced method aimed at enhancing remediation effect and reducing construction period.
　The advanced chemical-washing method was applied on a paddy field. The remediation effect of this method is two times of that of the basic method and it successfully reduced the Cd content in soil to 0.07mg/kg. The Cd concentration of the brown rice cultivated in the chemical-washied field was also reduced to 0.2mg/kg. It also shortened the time required for washing process to 2/3 of that of the basic method that would most likely help reduce cost as well.

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 Recently, supplies of high-quality natural aggregates used to produce concrete poles have become exhausted. Therefore, we studied application of limestone aggregate to a concrete pole, which would present advantages of stable supply and quality control. Additionally, we assessed the reduction of the environmental load: concrete created using limestone aggregate is recyclable as a cement material.
　Results show that concrete produced using limestone aggregate has equivalent performance to that produced using natural aggregate; it meets the standard values of concrete pole products. Furthermore, LCCO₂ can be reduced about 14% using concrete materials for cement, which engenders efficient reduction of the environmental load.

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 The Li-N-H system hydrogen storage materials are materials constituting the lithium amide and lithium hydride composition. These materials can transfer hydrogen of 6.5 mass% in and out at 150℃. The uniform mixture and composition of raw materials are indispensable for improvement with hydrogen release characteristics of Li-N-H system hydrogen storage materials. Using a planetary mill, a reasonable condition was determined according to the rotary speed and milling time. The reasonable milling condition was related to the acceleration of gravity, the sample weight, and the milling time. The DTA peak temperature shows a hydrogen release character by lengthening the milling time. Furthermore, the peak temperature of DTA deteriorated by the increase of rotary speed. However, the hydrogen release character worsens when the milling time is too long and the rotary speed is too high. The GT/w parameter expressed a reasonable condition. It is necessary to find a milling condition to improve hydrogen release characteristics with a GT/w parameter.

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