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 13 Abstracts search results

Document: 

SP141-01

Date: 

December 1, 1993

Author(s):

Bryant Mather

Publication:

Symposium Papers

Volume:

141

Abstract:

The customary criterion for establishing grades of structural concrete is the crushing strength measured in an arbitrary manner on a standardized specimen stored in a stipulated fashion for approximately a month after making. In some parts of the world, the specimen is a cube, and in other parts of the world, the specimen is a cylinder. There have been debates as to how the strength at 28 days can be predicted from procedures performed at early ages, especially 24 hr, on the grounds that a month is not soon enough. The intent of this paper is to suggest that the only time that really is "soon enough" to know that the grade of the concrete in any batch is correct is before the concrete is discharged from the concrete mixer into the forms. It is suggested, therefore, that effort would preferably be expended upon insuring that the materials used are those intended and the proportions in which they are used are those that were intended. If this is the case, the grade of concrete will be proper at all ages, and testing at any age is merely confirmation.

DOI:

10.14359/3987


Document: 

SP141-02

Date: 

December 1, 1993

Author(s):

G. M. Idorn

Publication:

Symposium Papers

Volume:

141

Abstract:

The three power centers in the world today must support the tremendous concrete construction and building investments that are needed in the developing regions where 90 percent of the world's population lives. Concurrently, renovations and renewals are required in industrial countries. Profound updating of conventional concrete technology is necessary, recognizing the differences between the behavior of test samples of concrete under laboratory conditions and of field concrete. For example, the historic development of curing concrete is reviewed with emphasis on the methods for monitoring heat development during curing of modern concrete. Proposals for wider transfer of this technology are also presented.

DOI:

10.14359/3988


Document: 

SP141-03

Date: 

December 1, 1993

Author(s):

Nicholas J. Carino

Publication:

Symposium Papers

Volume:

141

Abstract:

In-place testing is used to estimate the compressive strength of concrete in a structure by measuring another related property. A strength relationship is used to convert the in-place test results to an estimate of the compressive strength. Statistical methods are needed for reliable estimates of in-place strength. Such methods should account for the uncertainties in the measured property, the uncertainty of the strength relationship, and the variability of the in-place concrete. Standard statistical procedures for dealing with these uncertainties have not yet been adopted in North American practice. Recommendations are provided for developing the strength relationship, and a reliable, easy-to-use approach is presented to estimate in-place characteristic strength.

DOI:

10.14359/3989


Document: 

SP141

Date: 

December 1, 1993

Author(s):

Editors: Tony C. Liu and George C. Hoff / Sponsored by: ACI Committee 214

Publication:

Symposium Papers

Volume:

141

Abstract:

This Special Publication of 12 papers contains a wide range of subjects related to concrete materials and technology. Topics include statistical methods for evaluations of core strength and in-place concrete test results, roller compacted concrete dams, concrete bridge pavements, reliability of models for precast concrete slabs, quality assurance and quality control, plus numerous other topics. Note: The individual papers are also available as .pdf downloads.. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP141

DOI:

10.14359/14181


Document: 

SP141-09

Date: 

December 1, 1993

Author(s):

Sami W. Tabsh and Alex Aswad

Publication:

Symposium Papers

Volume:

141

Abstract:

A reliability-based approach is used to recommend allowable edge loads for precast hollow core slabs. Full-scale test results are used to predict the statistical parameters of the resistance at the edge. The study indicated that the allowable load is a function of dead-to-live load ratio and concrete strength. The analysis is extended to include system reliability of the whole slab due to different failure modes. The failure modes include flexure at midspan and total shear at the ends, in addition to local failure at the edge. The system modeling is composed of a series system made up of three partially correlated elements. A numerical example is also included for illustration. The approach will help engineers make a rational selection of allowable edge loads that occur around large floor openings.

DOI:

10.14359/3965


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