Masters Theses

Abstract

"The ASTM standard slump test as set forth in ASTM Designation: C143-52, has been used for many years in concrete construction tor measuring the consistency of plastic concrete. Slump tests taken in the laboratory are considered reasonably accurate; however, there are numerous disadvantages in performing these tests in the field; the most serious being the time required to make a test on pavement work. The standard slump cone method is also subject to personal differences in sampling, rigidity and smoothness of base, dampening the apparatus, filling the cone, rodding, raising the cone, freedom from jarring and selection of point to which slump is measured.

To alleviate the difficulties encountered in the standard slump cone test, the Kelly ball apparatus was developed. This apparatus provides a means of measuring the consistency by penetration of a standard ball into fresh concrete.

The purpose of this study is two fold. The first is to correlate the Kelly ball penetration readings with the standard slump cone for different mixes of concrete, using local Missouri aggregate, and develop curves, plotting Kelly ball penetration readings versus slump, for each mix. The second purpose of this study is to develop the proper technique tor the operation of the Kelly Ball Penetrator.

The principle possible source of error in the ball test is the rate of releasing the ball and this can be quickly detected if an assistant observer also makes the test. Grieb and Marr made the following comments on the Kelly ball test as a replacement for the slump test to measure the consistency and uniformity of concrete in the field:

1. The concrete may be tested in place, therefore, the selection or preparation of a sample is eliminated.

2. Three or more Kelly ball tests can be made at a selected location in less time and with less effort than is required for one slump test. Due to the speed with which the test can be made, the operator can work where the concrete is being discharged from the mixer without delaying paving or finishing operations.

3. Making the consistency test easier and faster, should encourage more frequent testing and should be helpful in the control of the uniformity of the concrete.

4. The apparatus can be maintained in usable conditions between tests by merely wiping with an oily rag.

5. The slump test is not practical tor use in testing concrete with a maximum size of coarse aggregate over two inches. The Kelly ball penetration test may be used on concrete containing larger aggregate if a sufficient volume is available to provide adequate depth.

The ball test can be performed so quickly and so easily that perhaps its potentialities have not always been appreciated. It is visualized that after a concrete mix has been adjusted in trial batches from the initial design to meet job requirements, a standard penetration could be recorded. Throughout the remainder of the job, tor that given mix, the penetration would remain the same (with a tolerance usually set at ± 1/4 inch penetration). This would be particularly helpful in enabling the inspector to reject improper batches as they come from the mixer and before they have been used. A satisfactory correlation between the slump test and the Kelly ball penetration test, using local Missouri aggregate, will provide a much simpler field method tor determining the consistency of plastic concrete in the field"--Introduction, pages 1-3.

Advisor(s)

Carlton, E. W.

Department(s)

Civil, Architectural and Environmental Engineering

Degree Name

M.S. in Civil Engineering

Publisher

Missouri School of Mines and Metallurgy

Publication Date

1957

Pagination

v, 61 pages

Note about bibliography

Includes bibliographical references (page 60).

Rights

© 1957 James Claude Rives, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Subject Headings

Aggregates (Building materials) -- TestingPavements, Flexible -- TestingConcrete -- Additives -- Testing

Thesis Number

T 1136

Print OCLC #

5153761

Electronic OCLC #

944122309

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