The author has been proposing a new philosophy of design concept for concrete structures named performance-creative design method. Recently, various structural performances should be verified according to the specific design code. This trend has invited the design attitude of the verification of structural performance, say, performance-verification design method. However, the author has felt that the philosophy of design should be more active and creative in manner rather than the verification for a given structural system. Here, the author pointed out the contradiction of the terminology in the coined Japanese words of “subjective” and “objective” which are essential concept to express creativity. Construction of structures in the society is the construction of artificial environment. Therefore, creativity in the design of structural concrete is inevitable to construct and maintain an attractive society. Japan Prestressed Concrete Engineering Association stipulated an entirely new rule for concrete structures based on the performance-creative design concept and has published it in September 2011. In this rule necessary function of the structure is first determined as a subject and then the structure is realized creatively to get the object.

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The research committee on shrinkage cracks of concrete organized in ASCoT (NPO) has addressed the following two subjects, which are the proposal of the method to estimate drying shrinkage strain of concrete and the arrangement of shrinkage crack control measures. With regard to the first subject, the collaborative experiment was carried out in the committee, and then the estimation method focusing on considering the effect of aggregate was proposed. In this method, the drying shrinkage strain of aggregate is estimated from specific surface area, air-dried moisture content of aggregate or direct measurements of that for coarse aggregate, and the drying shrinkage strain of concrete is calculated based on the composite theory using the obtained value. With regard to the second subject, effectiveness, cost advantage and versatility of various crack control measures were evaluated.

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Three kinds of recycled aggregate and the recycled concrete were established as Japanese Industrial Standards from 2006 through 2007. However, the supply in the market of the normal ready-mixed concrete can afford to be enough under the present conditions, and therefore recycled concrete does not come to spread. Therefore this study compared the influence that the use of the recycled concrete gave to economy, quantity of CO₂ outbreak, energy consumption by a case study based on a model of the reconstruction project of the apartment complex. In addition, this study used the recycled aggregate of the M class for recycled concrete. The reason depends on there being little disposal amount of resources to occur secondarily in production of the recycled aggregate.

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According to the reason for such as close bar arrangement and the use of fat diameter bar, it is necessary to consider it more than the past for securing cover thickness. Then, authors executed the questionnaire survey to understand the actual situation of construction and to examine the effective countermeasures and the note in design for securing cover thickness in the reinforced concrete work. As a result of the questionnaire survey, the constructer's consideration concerning the securing cover thickness, and the actual situation in the method of the example of the problem concerning storing in the design and the measures and construction and management, etc. were clarified.

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[in Japanese]

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[in Japanese]

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