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|Title:||Effect of method of preparation of ends of concrete cylinders for testing|
|Authors:||United States. Army. Office of the Chief of Engineers.|
Saucier, K. L.
Concrete test specimens
|Publisher:||Concrete Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||Miscellaneous paper (U.S. Army Engineer Waterways Experiment Station) ; C-72-12.|
Abstract: The purpose of this program was to investigate the effects of (a) the strength and surface condition of the several materials commonly used for capping concrete cylinders and (b) various degrees of restraint of the capping material on the apparent strength of concretes of different strength levels. The program was divided into four phases. Phase I incorporated an experimental method of preparing specimens utilizing light steel rings to confine a gypsum plaster cap on the end of the specimen during testing. Variables included strength of concrete, use of rings, strength of capping material, and cleanliness of the cap surface. Phase II extended the investigation to very high-strength concrete and utilized medium-thick rings and a sulfur-silica capping compound. Unexpected results with the medium-thick rings dictated additional work with very thick rings, Phase III. In Phase IV, a high-strength sulfur capping compound was evaluated. Test results indicate that lubricant on the cap of a compressive test specimen has no effect on the compressive strength if there is only a slight film of oil. Low-strength capping material (<3000 psi) was suitable for capping only low-strength concrete specimens. It was not possible to practically confine a weak capping material sufficiently to produce a state of high stress resistance in the material and allow a high-strength concrete to demonstrate its maximum strength. High-strength gypsum and sulfur compounds (7500 psi) were found to be satisfactory for capping test specimens in the range of 10,000-psi compressive strength. If very thin caps are used, sulfur compounds with compressive strengths of 7000 psi or greater be used for capping concrete cylinders the ultimate strength of which approaches 16,000 psi.
|Rights:||Approved for public release; distribution is unlimited.|
|Appears in Collections:||Miscellaneous Paper|
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