Recently, due to demands for higher strength and retention of flowability in concrete, polycarboxylate-based superplasticizers (SP) have attracted much attention. Polycarboxylate-based SP above all, have been recognized to show superior water reducing ability and ability to retain workable consistence. SP have also been an indispensable material for various kinds of high performance concrete, especially for making extremely low water-cement ratios (W/C) possible.
　Because of a shortage of quality aggregate in Japan and a need to adhere to the maximum water content regulation for concrete durability in which the upper value is limited to quantities lower than 185kg/m³, the use of SP for water reduction has been increasing.
　The significance of cracks control on the durability of concrete has been pointed out in many studies. For the one of methods to reduce the risk of cracks, it is important to reduce the autogenous and drying shrinkage of hardened concrete. In order to reduce these shrinkages, using organic shrinkage reducing agents and reducing unit water content are effective. However, the use of a shrinkage reducing agent has problem in cost and in increase of number of admixtures. Therefore, it is important to develop to new chemical admixture with multifunction.
　In light of such concerns, a new multi-function and multi-purpose SP has been invented. The performance of the new SP, incorporating both shrinkage and water reducing effects in wide range of W/C, is described in this study. This new SP can be applied to numerous scenarios ranging from high W/C to very low W/C requirements. It's multi purpose makes it a candidate of for a new generation of SP.

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 As a result of investigating factors causing radio-activation of component materials with regard to the phenomenon of activation of shielding concrete, it was ascertained that the contents of sodium and other activation-inducing constituents were extremely low compared with non-limestone aggregates. It was also learned that there was a trend for long-lived radionuclide-producing elements like europium and cobalt to be contained to a high degree in coal fly ash, blast-furnace slag, etc. On performing activation of concrete is reduced in accordance with the quantity of limestone aggregate used due to less ²⁴Na produced. The amount of ²⁴Na production originating from magnesium was also studied.

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 In recent years, self-compacting (SC) concretes have been used for the concrete products and concrete constructions. The SC concrete is high performance special concrete that shows high filling ability without any segregation in fresh state. In Japan, with regard to the SC concretes using fly ash, it has been stipulated as upper limit of 30% of cement replaced by fly ash in the outline of recommendation for design and the Japan Society of Civil Engineers (JSCE) and the Architectural Institute of Japan (AIJ). But fly ash as to by product from coal fired power plants increases with increasing these plants at present. It is desired to apply high volume fly ash to cement in concrete as a partial replacement for cement, from the point of view of effective uses of resources.
　This study is conducted to propose the mix design method for SC concretes containing high volume fly ash, and to evaluate effects of various percentages of cement replaced by fly ash on the strength and durability of the SC concretes compiled with the self-compactability rank 2, and the ability of construction according to practical construction work.
　The results obtained are as follows:
(1) The properties of the SC concretes containing high volume fly ash, such as the strength and durability are dependent on the percentage of cement replaced by fly ash.
(2) The SC concrete at 50% replacement cement of by weight is excellent workability and filling ability at the site of construction.

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 Tensile, bending and shear properties of Reactive Powder Concrete (RPC) which is fiber reinforced cementitious composite with 200N/mm² in compressive strength were investigated experimentally by direct tensile test with cylindrical specimen and Ohno bending shear test with actual size RC beam. RPC (FM) containing 2% of steel fiber maintained tensile strength after cracking in tensile test. The enhancement effect of RPC (FM) on tensile-ductility achieved to support twice higher load than that of high strength concrete in Ohno test. Moreover, its equivalent viscous damping factor much increased. The effect of 2% steel fiber in RPC was equal to increasing of 3.6～4.6N/mm² in shear reinforcing bar.

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 Concrete structures are being protected from fire by using fireproofing. Its cause is the serious damages by fires in tunnels in Europe.
　A performance of the wet spraying vermiculite light-weight mortar fireproofing for protecting concrete from fire as RABT and RWS is studied experimentally and also an applicability of the numerical analysis on the temperature distribution in concrete under fire is studied.
　These studies result in the followings.
(1)The 20mm thick fireproofing performs keeping under 350℃ in concrete temperature under RABT and RWS fire endurance test.
(2)The performance of fireproofing is not damaged until crack width opens to 3mm.
(3)The numerical analysis achieves practically to estimate the temperature distribution in concrete under fire. The accuracy of the numerical analysis is improved by adopting the virtual thermal disconnection boundary between fireproofing and concrete.

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 Piezoelectric transformers of Nihon Ceratec Corp. are mainly commercialized for an LCD back light inverter module. With regard to laptop computers, the required output power for a piezoelectric transformer is around 5W at present, and higher power will be needed for wider displays in the near future. In addition, modules such as AC-DC adaptors or fluorescent lamps may require a higher output power of more than 30W. If we succeed in creating this kind of piezoelectric transformers for high power, and succeed in showing the possibilities of miniaturizing for these modules, we will obtain a wider market in these fields. Here, in order to obtain compact and high-power AC-DC adaptors, we explored suitable designs for a multi-layered piezoelectric transformer, by taking into account the effect of the mechanical quality factor and the electromechanical coupling factor in the samples.

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 We have developed the environmental load evaluation program for concrete structures. This program achieves to evaluate the quantitative degree of the environmental load in the life of a concrete structure from the material manufacture, through the concrete mixing, construction and demolition, to disposal and recycling. The items are the inventories such as the consumption amount of energy resources, CO₂ and NOx, etc. emission, the impacts such as air pollution and global warming, etc., then these items are integrated into the integrated index non-dimensionally.
　This integration method is our original including the appropriate weighting factors and the integration factors from consideration of domestic uniqueness. Moreover, this program also has the function to quantify the degree of environmental load by other methods for comparison.

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