ACI Global Home Middle East Region Portal Western Europe Region Portal
Email Address is required Invalid Email Address
In today’s market, it is imperative to be knowledgeable and have an edge over the competition. ACI members have it…they are engaged, informed, and stay up to date by taking advantage of benefits that ACI membership provides them.
Read more about membership
Learn More
Become an ACI Member
Topics In Concrete
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:
SP112-01
Date:
January 1, 1989
Author(s):
M. Sansalone and N. J. Carino
Publication:
Symposium Papers
Volume:
112
Abstract:
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.
DOI:
10.14359/3688
SP112-06
C. H. Yun, K. R. Choi, S. Y. Kim, and Y. C. Song
Presents an investigation to determine the within-test variability of various nondestructive test methods (NDT) and the correlation between NDT test results and the corresponding compressive strength of cores. The size effects of coarse aggregate on the variability and correlation were also evaluated. The NDT test methods evaluated in the test series include rebound hammer, pulse velocity, probe penetration, pullout, and CAPO (cut and pullout). Companion tests of field-cured standard cylinders and cores were also made at the ages when the NDT tests were made. Results show that the within-test variability of the in situ tests reported (except the pulse velocity test) is two to five times higher than that of the corresponding standard compression test and is affected significantly by the amount of coarse aggregate and its size. There is a good relationship between the results of in situ tests and the compressive strength. In general, the highest degree of correlation is for the pullout test followed by that for the CAPO (cut and pullout) test and rebound test, probe penetration test, and pulse velocity test.
10.14359/3706
SP112-07
G. V. Teodoru
Aim is to analyze the correlations between several nondestructive measured values (ultrasonic velocity and attenuation, rebound number) and the compressive strength of concrete. A computational program performs a step-by-step analysis. First, isolated linear correlations are established for each one of the three nondestructive tests. Then the results are compared with each other in the sense of a general multiple correlation of the values. Since the results obtained from the nondestructive tests are equally scattered, the program determines interactively, in a second step, the multiple coefficients of correlation and restarts the analysis several times by tentatively disregarding the presumably bad experimental results. Since the measured values also comprise a large spectrum of magnitude, limits of validity of the assumed correlations are investigated concomitantly with the process of analysis. A last step is performed to identify a tendency of deviation of the single and multiple correlations from the basic linear ones.
10.14359/3715
SP112-08
T. R. Harrell
A case history of methods used to evaluate the allowable form removal time for a large diameter tunnel concrete lining is presented. To meet schedule requirements, a concrete placement was to be made every alternate day. A triad of testing was done to evaluate the time at which the reusable, self-propelled, steel-skinned form could be stripped from an existing placement. This testing consisted of field-cured cylinders and nondestructive testing that included embedded thermocouples in the concrete placements and penetration-resistance testing. Reference curves and tables were developed for use in the form removal evaluation. Statistical methods were used on test data obtained from results of testing done with the actual concrete mix to be used in the placements. Control curves were then developed. Target values were selected to be used in determining when the concrete was of sufficient strength to allow for the form removal.
10.14359/3726
SP112-03
M. A. Taylor
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.
10.14359/2362
Results Per Page 5 10 15 20 25 50 100
Edit Module Settings to define Page Content Reviewer