International Concrete Abstracts Portal

International Concrete Abstracts Portal

Showing 1-5 of 40 Abstracts search results

Document: 

SP82

Date: 

September 1, 1984

Author(s):

Editor: V.M. Malhotra

Publication:

Symposium Papers

Volume:

82

Abstract:

SP82 Contains 38 papers covering the following in situ/nondestructive testing methods: surface hardness and penetration resistance tests; pullout; ultrasonic pulse velocity; break-off; combined methods; maturity techniques. For tests of concrete other than strength: magnetic; electrical; radioactive; pulse echo; radar; microwave absorption; acoustic emission; nuclear; infrared thermography; and permeability methods. A global review of in situ/nondestructive testing is also included.

DOI:

10.14359/14039


Document: 

SP82-32

Date: 

September 1, 1984

Author(s):

H. Roper, D. Baweja, and G. Kirkby

Publication:

Symposium Papers

Volume:

82

Abstract:

Brief consideration is given to the uses of a quantitative measure of durability of concrete structural members. A classification scheme of structures, elements, and causes and effects is reviewed by the use of examples. Any quantitative measure of durability of in-situ structural members must be based on data gathered using non-destructive test methods. For any phenomenon such as cracking, corrosion or spalling which influences durability, three factors must be considered, viz. a method of measurement of the phenomenon, the intensity of the phenomenon, and its distribution over the observed area.

DOI:

10.14359/6577


Document: 

SP82-33

Date: 

September 1, 1984

Author(s):

Toshiaki Takabayashi and Hiroshi lshida

Publication:

Symposium Papers

Volume:

82

Abstract:

This paper describes a method of measuring the thickness of pavement concrete and other concrete structural members. A particular feature of this method involves the combined usage of the ultra-sonic pulse and resonance methods to compute the thickness of concrete by measuring the sonic velocity and resonance frequency of concrete.

DOI:

10.14359/6578


Document: 

SP82-34

Date: 

September 1, 1984

Author(s):

Taketo Uomoto and Kazusuke Kobayashi

Publication:

Symposium Papers

Volume:

82

Abstract:

To control the quality of steel fiber reinforced con-determination of fiber content is one of the most important matters in practice. Although SFRC is often assumed to be satisfactorily mixed by any concrete mixer, uniform fiber content can not always be obtained if mix proportions and mixer design are unsuitable. To deal with the problem of nonuniform fiber a simple in-situ test is needed to check the quality of SFRC before it is cast. Determination of the fiber content of SFRC can be accomplished by using techniques such as X-ray image analysis, separation by washout analysis, and an electro-magnetic method. However, some of these techniques are too troublesome to be used as in-situ The special electro-magnetic method described herein is not only applicable to hardened concrete but also to fresh concrete. Measurement of fiber content can be done within a few minutes whether the test is performed in the laboratory or on the job. The proposed method of measuring fiber content is discussed from the point of view of practical problems such as the effects of distribution and orientation of fibers, etc.. This method has been introduced as a standard test of SFRC in Japan.

DOI:

10.14359/6579


Document: 

SP82-35

Date: 

September 1, 1984

Author(s):

H. Tamura and M. Yoshida

Publication:

Symposium Papers

Volume:

82

Abstract:

This paper presents a new non-destructive detecting method of corrosion of reinforcing steel in concrete. The state of corrosion of steel can be electrochemically estimated by using not only natural potential, but also polarization and electrolyte resistance. These three kinds of electrochemical values can be measured with a polarization resistance meter and a two-electrode probe set on the surface of concrete above any measuring point of steel. These values obtained from the surface of concrete are only apparent, being composed of the values in both anodic and cathodic sites. The authors therefore analysed the relationship between the measured apparent values and real values in an equivalent electric circuit reflecting the corrosion phenomenon in concrete, Furthermore, the relationship among the various kinds of electro-chemical characteristics was evaluated by a numerical study. In-situ application of the new non-destructive method is also presented.

DOI:

10.14359/6580


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