International Concrete Abstracts Portal

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.

Showing 1-5 of 12 Abstracts search results

Document: 

SP112-03

Date: 

January 1, 1989

Author(s):

M. A. Taylor

Publication:

Symposium Papers

Volume:

112

Abstract:

Gamma-ray absorption techniques were used to determine the amounts of each component in a system of mixtures (such as concrete). The technique uses photons of several energies in contrast to previous applications where only one energy was employed. The use of multiple energies provides more information than the single-beam system, and thus more properties can be determined. Several possible models for cementitious materials are discussed and compared. The paper presents the experimental determination of the initial data set needed prior to prediction experiments. One predictive technique is evaluated by comparison with blind tests.

DOI:

10.14359/2362


Document: 

SP112-10

Date: 

January 1, 1989

Author(s):

T. J. Parson

Publication:

Symposium Papers

Volume:

112

Abstract:

Reports results of an investigation into the use of maturity for predicting early-age concrete strengths. Prediction models were developed from cylinder-test results obtained from twelve concrete mixtures cured under three constant curing conditions. A datum temperature of 25 F (-4 C) was used as it appeared to produce the best results. A prediction model based on estimated ultimate concrete strength was used and found to be independent of curing temperature. However, the estimated ultimate concrete strength value appeared to be dependent on curing temperature. The model was verified by using it to predict concrete strengths obtained from cylinders and slabs cured outdoors.

DOI:

10.14359/2372


Document: 

SP112-04

Date: 

January 1, 1989

Author(s):

M. Ohtsu

Publication:

Symposium Papers

Volume:

112

Abstract:

On the basis of the acoustic emission (AE) measuring technique, a diagnostic method for nondestructive evaluation of cracks in concrete is proposed. The diagnostics consist of a mechanical criterion of crack initiation, a quantitative waveform analysis of AE, the evaluation of deterioration by a test of core specimens, and the ultrasonic spectroscopic investigation of cracked members. Results of basic studies on these methods are summarized. Results of basic studies confirm the feasibility and the usefulness of the proposed method as diagnostics of cracks in concrete structures.

DOI:

10.14359/2840


Document: 

SP112-05

Date: 

January 1, 1989

Author(s):

A. K. Maji and S.P. Shah

Publication:

Symposium Papers

Volume:

112

Abstract:

The fracture process of a composite material involves crushing or slippage of adjacent particles, microcracking, etc., resulting in changes in the load-versus-displacement behavior. A study of the fracture process is necessary to develop a rational material model. Laser holographic interferometry was applied to study the whole field deformation pattern. Speckle photography was used to measure quantitatively displacement discontinuities at bond cracks at various stages of loading. Acoustic emission (AE) techniques were applied to monitor microseismic activities resulting from the various fracture phenomena. The rate of microfracture was measured from the AE event rates. A source location algorithm was used to calculate the locations of the AE events. Specimens were made with different aggregate and void sizes to study their effect on crack patterns and load-displacement behaviors.

DOI:

10.14359/2846


Document: 

SP112

Date: 

January 1, 1989

Author(s):

Editor: H.S. Lew

Publication:

Symposium Papers

Volume:

112

Abstract:

SP112 Nondestructive Testing of Concrete has been especially prepared to present, examine, and promote the use of nondestructive testing techniques in concrete construction. Providing the latest information on the development and applications of nondestructive testing techniques, this collection of 11 papers will be of interest to anyone working in the field of concrete.

DOI:

10.14359/14145


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