The environments surrounding the cement industry and the consumer needs for cement have greatly changed since 1979 when the issue No.101 of this journal(ONODA KENKYU HOKOKU) was published. The main topics that have been studied relating to cement during the last 27years are listed below:
(1) The performance enhancement of cement and concrete with water reducing agents, (2) The acceleration of use of industrial wastes and by-products with growing interests in environmental issues, (3) The durability issues of concrete such as alkali aggregate reaction and chloride attack on reinforced concrete, (4) The international standardization of Japan Industrial Standard of cement. In this article, the contribution of cement chemistry through the investigations on these topics and the future prospects of cement chemistry are mentioned.

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 The core technologies for cement manufacturing， which have been developed by TAIHEIYO CEMENT CORPORATION and its predecessor companies for these 35years, are introduced. The technologies introduced here are limited to published ones by the Journals or major conferences related to cement manufacturing technology. They also cover pyro-process technology, grinding process technology, process control technology and operations research for cement manufacturing field.

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 The cement industry can recycle various kinds of waste materials, for use as raw material or fuel, through the following characteristics in manufacturing: (1) High temperature in the cement kiln can decompose the toxic compounds such as dioxins or chlorofluorocarbons, (2) Elements contained in the ash generated by incinerating most waste material is usable as raw material for cement, (3) Other minor elements in ash can be absorbed into the cement clinker and neutralized.
　In this report, research and development on the utilization of used tire, waste plastics and coal ash, recycling sewage sludge, the recycling process of incinerator ash from urban waste (fly ash washing process and ecocement), the recycling process of urban waste (AK process), recovery of heavy metals, decomposition of chlorofluorocarbons and CO₂ fixation is discussed. The research and development of Environmental technologies will become increasingly important, because the demand that cement plant utilize waste that is difficult to recycle by ordinary process, is growing.

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 Concrete does the contribution that greatly becomes construction of all today's social infrastructures as a material indispensable to construct, and this contribution should continue in the future. Then, I pick up the key word concerning a concrete technology from the title in the research paper of academic society such as JSCE (Japan Society of Civil Engineers) and AIJ (Architectural Institute of Japan) after 1975, understand the situation and the background at that time, and look back on the transition of the content of the research concerning a concrete technology. Moreover, I examine an ideal way of a concrete technology in the future and advanced directionality.
　As a result, the research and development of a current concrete technology is promoted being influenced from an each occasion environment, that is, social trend (needs) and a technological trend (seeds). Though a concrete field, which is called one of the maturity industries, the room for the research and development has been still left. I think that a concrete field can keep doing the deepen development, especially by the combination with a state-of-the-art technology of a different field.

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 Recently, as developing of society, economy, and technology, the application fields of concrete and the demand of high performance concrete has being increased. Producing high performance concrete, the performance of cement should be drastically improved. To meet this demand, the research of concrete admixture has been carried out so far, and the many kinds of admixtures have been developed. The concrete admixtures become to be very important and indispensable materials now.
　TAIHEIYO CEMENT CORPORATION started to develop the concrete admixtures from the 1950's, and succeeded to commercialize many useful admixture. Especially, the expansive additive, shotcrete additive, shrinkage inhibitor and high strength additive are the strategic products of TAIHEIYO CEMENT groups and contribute for development of construction field.
　This report describes the definition, the history, present situation and issue in future of above mentioned admixtures.

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 Around 1980, new technical ceramics such as Silicon nitride and SiAlON with excellent mechanical properties at high temperatures were developed, and properties of electronic ceramics were dramatically improved by controlling chemical composition of raw powder or microstructures of ceramics, etc. Against this background, we started the research and development of ceramics with the aim of entering the advanced ceramics business.
　In the beginning, our R&D was focused on the development of both technical ceramics for gas turbine engine and piezo-based electronic ceramics for electronic components. In early 1990', we recognized the limitation in regard to the application of technical ceramics to gas turbine engine and our R&D target drastically changed to precision components for semiconductor manufacturing equipment. Around the same time, we newly started ceramic-matrix and metal-matrix composites for the development of the new field that was completely different from those of advanced ceramics.
　About 25years have passed since R&D of ceramics in our company was started. Technical ceramics, piezo-ceramics and metal-matrix composites have been growing up into the core of ceramics business. As of now, the sales of ceramics business that started over from nothing are over 100 million dollars. R&D Center has been developing the new products and technologies of ceramics for the business expansion and supporting the ceramics business. The history of the R&D of ceramics was looked back over and some of their outlines were introduced.

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