International Concrete Abstracts Portal

ABOUT THE INTERNATIONAL CONCRETE ABSTRACTS PORTAL

  • The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.

International Concrete Abstracts Portal

Showing 1-10 of 40 Abstracts search results

Document: 

SP82-39

Date: 

September 1, 1984

Author(s):

N.G. Zoldners and J.A. Soles

Publication:

Special Publication

Volume:

82

Abstract:

Non-destructive concrete testing methods provide construction engineers and concrete technologists with useful tools for quality control of concrete and for evaluating the strength and durability of existing structures. This annotated bibliography, chronologically arranged, compiles literature published from 1975 to 1983 on innovations and modifications of non-destructive methods used for the testing of concrete. Attention was focused on the new methods used for monitoring concrete deterioration, crack development and corrosion of reinforcement. The journals, symposia and books selected for review have international stature, and contain state-of-art experimental works from diverse laboratories. Authors' abstracts or their translations are included when possible, to assist the. Concrete engineer in determining the applicability of a method to provide needed data. The study was made possible with a Canadian government contract awarded to the senior author.

10.14359/6584


Document: 

SP82-38

Date: 

September 1, 1984

Author(s):

Makoto Kagaya, Hiroshi Tokuda, Makoto Kawakami, and Masami Shoya

Publication:

Special Publication

Volume:

82

Abstract:

The variation in the mechanical properties in the vertical direction can be assessed by the ratio of the difference between the measured value in top layer and that in the bottom layer over standard value obtained from cylinder concrete. The variation in internal composition can be estimated from that of unit coarse aggregate content. Good relationship existed between the degree of variation of unit coarse aggregate content in vertical direction and the ratio of unit aggregate content in the top layer to the specified value. Good relationship between the variation in the mechanical properties in vertical direction and that of internal composition represented by a ratio relative to the coarse aggregate content was also recognized. The variation in the degree of mechanical properties in the vertical direction could be assessed with good accuracy by measuring only the unit coarse aggregate content in the top layer. The simple and quick procedure developed in this work can be used to study the effect of segregation due to vibration-compaction on the mechanical properties in concrete structures and also to control the quality of concrete placed.

10.14359/6583


Document: 

SP82-37

Date: 

September 1, 1984

Author(s):

M.P. Rebic

Publication:

Special Publication

Volume:

82

Abstract:

During the compressive loading of 20 cm and 10 cm concrete cubes, acoustic emission (AE) and the ultrasonic pulse transit time were measured. The critical load ( 6 ) at which the internal structure of the concrete the AE- 6 and 6 and 6 the factor F =6/6. i d e a l l y ductile completely brittle begins to be damaged is determined from transit-time/ 6 diagrams. The ratio between rupture load, is defined as the crackability This factor increases from zero (f o r materials) towards a value o f 1 .0 (f o r materials). From the tests described it follows that the factor has practically the same value whether from A E or ultrasonic measurements. Itit also is determined follows that the statistical distribution of the factor F is wider than the distribution of the rupture loads, which means that the start of the irreversible changes lies in a wider range of loading than the rupture load.

10.14359/6582


Document: 

SP82-36

Date: 

September 1, 1984

Author(s):

Kiyoshi Okada, Kazuo Kobayashi and Toyoaki Miyagawa

Publication:

Special Publication

Volume:

82

Abstract:

chlorides; corrosion; maintenance; measurement; nondestructive tests; offshore structures; polarization; reinforcing steels; repair.

10.14359/6581


Document: 

SP82-35

Date: 

September 1, 1984

Author(s):

H. Tamura and M. Yoshida

Publication:

Special Publication

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.

10.14359/6580


Document: 

SP82-34

Date: 

September 1, 1984

Author(s):

Taketo Uomoto and Kazusuke Kobayashi

Publication:

Special Publication

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.

10.14359/6579


Document: 

SP82-33

Date: 

September 1, 1984

Author(s):

Toshiaki Takabayashi and Hiroshi lshida

Publication:

Special Publication

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.

10.14359/6578


Document: 

SP82-32

Date: 

September 1, 1984

Author(s):

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

Publication:

Special Publication

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.

10.14359/6577


Document: 

SP82-31

Date: 

September 1, 1984

Author(s):

P.F. Mlakar, R.E. Walker, B.R. Sullivan, and V.P. Chiarito

Publication:

Special Publication

Volume:

82

Abstract:

The acoustic emissions of various concrete specimens under different loadings are studied. First, six monotonic and six cyclic load compression tests on 6- by 12-in. cylindrical concrete specimens were monitored for acoustic emission. Fundamental data were collected and analyzed and the Kaiser effect was observed. The data are presented as counts versus events to aid in the identification of source characteristics. Next, one multiaxial load (compression and tension) test was monitored. The slope of the counts- versus-events curve for this primarily tension test differed from those of the curves for the compression test. This difference suggests that the source characteristics of concrete acoustic emissions can be empirically separated and identified. Finally, the emissions detected in a model of a reinforced concrete circular conduit

10.14359/6576


Document: 

SP82-30

Date: 

September 1, 1984

Author(s):

A. Honig

Publication:

Special Publication

Volume:

82

Abstract:

Radiometric determination of density and moisture of soils and building materials has been carrie jout successfully. Many types of instruments are available. However, instruments are not available for measurement on fresh concrete so that it is not possible to repair inhomogeneities, if any even before hardening. The paper describes an analog and a digital radiation density meter and their application in the inspection of concrete walls against radiation. By repairing defective concrete in the course of concrete placement it is possible to attain a laboratory quality of concrete placed on site. Long-term and temperature stability, the measuring procedure, calibration of the instruments, biological shielding tests and the evaluation of the results are described.

10.14359/6575


1234

Results Per Page