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Home > Publications > 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:
SP112-09
Date:
January 1, 1989
Author(s):
C. J. Turkstra, P. Zoltanetzky, Jr., H. P. Lim, and C. Gordon
Publication:
Symposium Papers
Volume:
112
Abstract:
Presents a comparison of 28 day concrete strength as measured by field probe penetration tests and standard laboratory cylinders. Over a period of 11 months, 318 matched sets of tests were performed on 4000-psi concrete at four major projects. Primary field variables include the project location, operators, test guns, and the element type on which the field tests were made. Corrections to account for temperature variations are considered. Results include statistical analysis of the effects of test parameters and the correlation between field and laboratory results. Based on standard statistical tests, it is concluded that the variability of field probe results is similar to that of the corresponding laboratory cylinder tests. Results did not depend significantly on operators or the particular equipment used. However, results did depend significantly on the type of structural element tested and on the range setting of the firing gun. It is concluded that the calibration charts provided with the equipment should be reviewed.
DOI:
10.14359/3736
SP112-11
R. L. Dilly and W. L. Vogt
Pullout testing and maturity have practical construction applications. Maturity is used to determine curing duration. The pullout test is used to determine in-place strength and to verify the adequacy of cure. Personal computers with spreadsheet software are tools that can benefit concrete construction. Templates developed using spreadsheet software can be used to acquire and analyze relationships between in-place strength and compressive strength, and maturity. Experimental investigations using pullout testing and maturity were undertaken and are reported using graphic features of spreadsheet software. The results of these experimental investigations show that curing environment can affect in-place strength relationships. Also, the results show that top to bottom strength differences can exist and should be considered when determining in-place strength. The results obtained using the compressible disk pullout assemblies indicate that this test method can be used to determine in-place strength without formwork removal, and the method should be further researched.
10.14359/3742
SP112-01
M. Sansalone and N. J. Carino
A nondestructive test method has been developed for locating defects in concrete. The technique is referred to as the impact-echo method and is based on monitoring surface displacements resulting from the interactions of transient stress waves with internal discontinuities. Paper describes the technique and presents results of laboratory studies designed to evaluate the capabilities of the method. These laboratory studies were carried out on 500 mm thick slabs that contained a variety of artificial flaws embedded at known locations. Frequency analysis of recorded time-domain waveforms is explained and shown to be a quick and simple signal processing technique. Finally, results are presented from a field study in which the impact-echo method was used to investigate a 150 mm thick slab believed to contain voids.
10.14359/3688
SP112
Editor: H.S. Lew
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.
10.14359/14145
SP112-05
A. K. Maji and S.P. Shah
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.
10.14359/2846
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