The recent polycarboxylate type superplasticizer (PC) shows high dispersibility for cement and it is possible to make highly fluid concrete with good slump retention at 20℃. However, at higher temperatures, tile slump loss tends to increase. At lower temperatures, the fluidity is low just after mixing, and the fluidity tends to increase with time.
　In this paper, the mechanism of the temperature dependence of PC as mentioned above was investigated. In the experiments using normal Portland cement paste, the time variations of BET specific surface of cement paste and sulfate ion concentrations in liquid phase of cement paste were evaluated. The time variation of the dispersibility is thought to be explained by the combination of surface area change of cement paste and sulfate ion concentration change in solution phase. The low dispersibility at lower temperature just after mixing was attributed to the high sulfate ion concentration in solution phase. The fluidity gain at lower temperatures was attributed to the slower hydration speed and the larger decrease of sulfate ion concentration. The larger fluidity loss at high temperatures was attributed to the higher reaction rate of cement.

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 The high performance lightweight aggregate which was developed recently in Japan has a water absorption ratio of under 5% and a specific gravity of between 0.8 and 1.2. These characteristics are superior to conventional lightweight aggregates. However it is known that the shear capacity of concrete beams using conventional lightweight aggregates is lower than that of normal aggregate concrete beams having a same compressive strength. The authors prepared prestressed concrete beam specimens using the high performance lightweight aggregates with a prestress of 3.0N/mm². and verified the effect of the prestressing in improving the shear capacity. The test results demonstrated that the shear capacity of the prestressed concrete beams using the high performance lightweight aggregates was improved significantly by prestressing.

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 The new artificial lightweight aggregate, whose properties have both higher strength and lower water absorption ratio than ordinary lightweight aggregates, has been developed recently.
　It was studied on seismic performance and deformation capacity of reinforced concrete column, which were made by high-strength concrete used by varied high performance aggregates with different specific gravity in the case of the column received under axial and shear force combined with bending force.
　As a result, maximum stress of specimen were the same stress under the same compressive strength of concrete, but deformation capacity and failure pattern of concrete indicated different failure behaviors as specific gravity (strength) of aggregate were different, so it affected behaviors of concrete after maximum stress.
　Axial strain of lightweight concrete specimen were decreased, because young’s modulus of concrete increased as specific gravity of aggregate were weighted, and the strain were bigger than which of normal concrete.

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 The authors have developed producing techniques on artificial lightweight aggregates using perlite from a mine, which belongs to Taiheiyo Cement Corporation, and an aggregate which has specific gravity of 0.85 ± 0.1. is in market. This aggregate (trade name: Asano Super Light, ASL) has remarkably low water absorption and high strength, comparing to traditional artificial lightweight aggregates produced from expanding shale as a main raw material.
　Because ASL belongs to a granulated type of artificial aggregate, appropriate grinding and granulation are important to produce an aggregate of high quality, finally.
　As results, the authors succeeded to increase a grinding amount from 0.45t/h to 1.4t/h and strength of green pellet by checking up of grinding and granulating processes.

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 Burner diffuser cones (hereinafter referred to as "diffuser") are components attached to the tip of burners in boilers used for thermal power generation. Although conventional diffusers were made of stainless steel and other metals, metal diffusers must frequently be repaired and replaced due to low corrosion resistance. Ceramic diffusers made of SRBSN (Sintered reaction bonded silicon nitride) was therefore newly developed because of its excellent strength, oxidation resistance, and hot corrosion resistance by joint development between Taiheiyo Cement Corp. and Chugoku Electric Power Co., Inc.. SRBSN is produced by the reaction of silicon powder compact added sintering aid in nitrogen gas.
　The results of laboratory test (thermal resistance test, thermal shock resistance test, and vibration resistance test) show that SRBSN can be applied in diffuser. To evaluate the material's practical usage, SRBSN diffusers are field-testing with two boilers operated by Chugoku Electric for thermal power generation.

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 The fracture probability of the multilayered piezoelectric transformer under the high mechanical vibration was investigated. In this work, the fracture stress measured with a mechanical method and the generated stress under driving measured with a electrical method were compared. The tensile strength was calculated from the 3-point bending strength. The fracture stress of the piezoelectric transformer was obtained as 43MPa. The piezoelectric transformers were driven under a loading condition postulated the cold cathode tube and the liquid crystal display panel. The generated stress under driving was obtained from the measurement of vibration velocity. Driving at λ/2 mode (output: 4.2VA), the generated stress would be 26 MPa and the probability of fracture was 8.6×10^-3. On the other hand, driving at λ mode (output: 5.3VA), the generated stress would be 16 MPa and the probability of fracture was 1.2×10^-4. It is lower than the fracture probability at λ/2 mode.

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 The method for extracting pore solution in hardened cement mixture by high pressure force was developed in the 1970's.
　Chemical components in the pore solution are in equilibrium with the solid phase around them. Composition of the liquid phase is influenced by the properties of hydrate materials, which consist of hardened cement mixture. Liquid phase composition also changes with curing conditions and hydration. Therefore, since deterioration in concrete advances through the pore solution, the mechanisms of deterioration can be identified by examining pore solution.
　We summarized the investigation of this extraction method, analytical method and application, and give some suggestions for future researches.

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 Recently, the problem of exogenous endocrine-disrupting chemicals is recognized to be one of the most important environmental problem all over the world. The aims of this research are to have a proper understanding of EDCs, to get hold on the steps in the country and in foreign countries and to clarify the relation of the problem to our business.
　EDCs act on the function of hormones or inhibit the activity of hormones. Even a very small amount of EDCs can have disruptive effects. They particularly have serious effects on fetuses and infants, and the effects of exposure to such chemicals during the development of fetuses are likely to appear after they grow up. Some EDCs that are nondegradable or toxic have been already imposed legal controls. In the future, the steps to noncontroled EDCs will be more important. In the world, a screening program for chemicals having estrogenic or other endocrine disrupting properties prepare is now preparing. For our business it is necessary to pay attention to some air-entraining admixture, waste plastics, swage sludge, incinerated ash and sludge of fresh concrete.

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 Recently, several new types of cement aiming at the reduction of environmental load have been developed and published. In this paper, a brief introduction of these cements is made, and the evaluation methods and criteria of the environmentally consciousness generally used are reviewed. Based on these, the problems in the evaluation procedure of environmentally consciousness of these types of cement are discussed, and some suggestions to solve the problem are made. In relation to this, the application of the check-list on environmentally conscious materials or products to cement and related materials is discussed.

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