Concrete Journal

Updated Review on Nondestructive Testings in Concrete Engineering

Masayasu Ohtsu

1993 Volume 31 Issue 12 Pages 5-14
Published: December 01, 1993
Released on J-STAGE: April 26, 2013

DOIhttps://doi.org/10.3151/coj1975.31.12_5

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Nondestructive testings (NDT) of concrete are in extensive demand for deterioration evaluation and diagnostic application of concrete structures. An updated review on NDT techniques is reported, on the basis of stimulated activities in world-wide organizations and societies. NDT techniques are conventionally known as testings for strength property, while material properties other than strength are new targets of NDT for the evaluation of the structural integrity. These are testing methods for deterioration and defects, mechanical and chemical properties, and rebar location and corrosion. In particular, NDT techniques for deterioration and defects in concrete, such as impact-echo, pitch-catch, acoustic emission, X-ray, radar, and infrared wave are discussed and updated. As human body, concrete structures have to be properly inspected for maintenance. In this respect, NDT techniques could provide base-line information for repair and rehabilitation.

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State-of-the-Art Report on Polymer-Modified Mortars as Repairing Materials for Reinforced Concrete Structures Damaged by Chloride Corrosion

T. Moriwaki, Y. Tsuji

1993 Volume 31 Issue 12 Pages 15-21
Published: December 01, 1993
Released on J-STAGE: April 26, 2013

DOIhttps://doi.org/10.3151/coj1975.31.12_15

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Polymer-modified mortars are widely used as finishing materials because of their excellent adhesion and waterproofness. Recently, as various excellent performances of polymer-modified mortars such as freeze-thaw resistance, resistance to carbonation, resistance to diffusion of chloride ion and oxygen and so on are found, polymer-modified mortars get much attention as repairing materials for deterioration of reinforced concrete structures. This paper will describe the states of polymer-modified mortars as repairing materials for reinforced concrete structures damaged by chloride corrosion.

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Bottom-Up Concreting into Steel Tube Column Filled with Ultra High-Strength Concrete Using Silica Fume

T. Yonezawa, T. Okuno, K. Mitsui, N. Numakura, T. Ôura, M. Sato

1993 Volume 31 Issue 12 Pages 22-33
Published: December 01, 1993
Released on J-STAGE: April 26, 2013

DOIhttps://doi.org/10.3151/coj1975.31.12_22

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In this technical report outline of the first application, in Japan, of the ultra highstrength concrete with design strength of 600 kgf/cm² using silica fume to a super high-rise building is presented.The structure of the 39 story building is a steel frame with steel tube colums filled with the ultra high-strength concrete. The concrete was pumped into the columns from the bottom up to 61.9 m at a time. For the production of the silica fume concrete, a ready mixed concrete plant that enables the use of as-produced silica fume was developed. Trial mixing tests, pumping tests and bottom-up concreting tests were carried out before construction. The outline of the plant and the results of the actual construction are presented along with the preliminary tests.

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Prestressed Concrete Rigid Frame Bridge Utilizing Carbon Fiber Reinforced Plastics for Cantilever Tendons

F. Seki, S. Tanaka, T. Hamada, T. Enomoto

1993 Volume 31 Issue 12 Pages 34-42
Published: December 01, 1993
Released on J-STAGE: April 26, 2013

DOIhttps://doi.org/10.3151/coj1975.31.12_34

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A prestressed concrete bridge utilizing new material for all main tendons, located within a golf course in Tsukude Village, Minami Shitara County, Aichi Prefecture has been completed. It is a rigid frame bridge with center hinge. The bridge length is 111.0 m (span=75.0 m). Carbon Fiber Reinforced Plastics (CFRP) were used as tendons for cantilever erection as well as external tendons.The scale of the bridge and the quantity of new material used are the among the largest so far. In order to overcome the problems faced in the application of multi-cable in the bridge, various experiments were conducted.This paper introduces particularly on the design method of the bridge and report of experiments related to anchorage system, design and construction.

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Huge Construction Work Using Precast Prestressed Concrete

R. Okamoto, K. Hattori, T. Takasaki

1993 Volume 31 Issue 12 Pages 43-51
Published: December 01, 1993
Released on J-STAGE: April 26, 2013

DOIhttps://doi.org/10.3151/coj1975.31.12_43

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The WORLD RYUTSU CENTER is one of the largest trading facilities in the world, situated in the AOUMI area of the TOKYO BAY where TOKYO TELEPORT TOWN has been planned. The required period for construction was so short that some industrialized methods, mainly precast-prestressed concrete, were adopted. The weight of almost precast members was more than 20 ton, so it could be possible to lift up the precast members by using the 650 ton crawler tower crane. And the working area was divided effectively in order to decrease the construction period with considering the workability of crane and the equality of the number of the labors. As a result, the period for construction was shortened about one year.

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[title in Japanese]

[in Japanese], [in Japanese]

1993 Volume 31 Issue 12 Pages 52-57
Published: December 01, 1993
Released on J-STAGE: April 26, 2013

DOIhttps://doi.org/10.3151/coj1975.31.12_52

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[title in Japanese]

[in Japanese]

1993 Volume 31 Issue 12 Pages 88-93
Published: December 01, 1993
Released on J-STAGE: April 26, 2013

DOIhttps://doi.org/10.3151/coj1975.31.12_88

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