New technical committees
It is required to extend the remaining life of existing structures in order to reduce the life cycle costs of the structures. For this purpose, intensive researches are on-going to develop useful techniques of inspection, diagnosis, assessment and prediction of performance, countermeasures for concrete structures. Recently, inspection techiniques of concrete structures are advanced, not only nondestructive testing methods but also locally destructive testing methods such as drilling and coring with samaller diameters are now used in practice, realizing accurate evaluation of deterioration occurred in structural components. However, it is difficult so far to quantitatively assess and predict structural soundness and remaining life of the target structure by utilizing such inspection data. This committee will investigate how to evaluate the state of deterioration in structural components by using inspection results of nondestructive testing, locally destructive testing, and their combination. Finally, we will propose diagnosis methodoligies to rationally and accurately assess structural soundness of existing concrete structures by utilizing the advanced inspection techniques. .
Concrete cracks due to large drying-shrinkage become the big problem in Japan recently. In orfer to control those cracks, the regulation on drying-shrinkage of ready-mixed concrete is examined to be settled. Because the preparation of the industry for this are not set, they have much confusion now. JCI had carried out a special technical committee from 2008 to 2010 to solve the confusion, and the TC analyzed the present situations and suggested some technical proposes. However, many problems were left. Jci-TC-102A, therefore, is going to study on following items;
The decrease in construction investiment and deteriorating reputation of the construction industry, among other factors, are causing unease for those who work in the construction industry. The popularity of the construction/concrete industry is sluggish, and industry energy and motivation have decreased remarkably as a result. The purpose of this techniccal committee is to propose the future straregy for the construction/concrete industry considering the young eingineers and researchers who have to carry the industry into future, as well as disseminate the results of such investigations to society and the world. The relationship between social environment and the construction/concrete industrial systemu will be investigated and compared to the systemus in other foreign countries, the systemd of other industries, and the proposals of intellectuals outside the construction/concrete induatry. The main topics for discussion are as follows: (1) Industrial system: it is believed that the current concrete industry system is a hold-over from the social environment during the period of high economic growth. An industrial system which can flexibly meet diverse needs is necessary and will be investigated. (2) Technology management: The directionality of technology will be disucussed considering the future environment, society, and economic situation. (3) Education: The future education system in both university and the industry will be discussed considering the output of both(1) and (2).
In the past decade, a wide variety of fiber reinforced cementitious composites has been developed, and many applications such as joint systems, energy absorption members, repair and strengthening for concrete structures have been proposed. Although performance based design for fiber reinforced cementitious composites might be useful to construct an advanced and durable application, the design scheme for the materials is not established yet. <WG1: Application methods> <WG2: Evaluation methods> <WG3: Environmental aspects>
The drying shrinkage of the aggregate itself increase the shrinkage of concrete. In fact, the recent report indicates that the aggregate caused severe damage of an existing concrete structure through cracks in Japan. Based on such report, some design codes regulate the drying shrinkage of concrete, while the effect of shrinkage on the durability as well as mechannical behavior of concrete structures is not cleared. For solving the problem caused by the shrinkage of concrete, it is required to clear the relationship between shrinkage of concrete and performance of concrete structures, and establish the evaluation method of them. Technical Committee on Shrinkage Effect Evaluation based on Durability Mechanics (JCI-TC-105A) has been established to study the shrinkage problem based on the durability mechanics. Here, the durability mechanics is a new concept re-defined as one of the academic disciplines of Engineering Mechanics for the systematic prediction and evaluation of time-dependent behavior of concrete materials and structures, by the Working Group on Durability Mechanics (WG3) within Technical Committee on Time Dependent Behavior of Cement-Based Materials (JCI-TC-061A). Firstly, 1) the mechanism of shrinkage of concrete and its physical modeling and 2) shirnkage-induced stress and resultant cracking in concrete structures, as well as their effect on the structural and durability performance will be categorized and discussed. Then, 3) Modeling and coding of structural and durability performance of concrete structures based on the results of 1) and 2) will be discussed and make an proposal for the general design codes for effect of shrinkage.
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JCI-TC-101A Technical Committee on Diagnosis Methodologies of Structural Soundness of Concrete Structures by Utilizing Advanced Inspection Techniques
