Compressive strength testing of HPC cylinders utilizing confined caps
OwnerClaude Derrell Johnson, S. Ali Mirza +2inventors
InventorsClaude Derrell Johnson, S. Ali Mirza, Eric Powell, Edith Ramanathan
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Abstract
A confined capping system provides a simple approach for compressive strength testing of high performance concrete specimens. The test specimen ends are capped with a conventional capping compound confined in steel rings larger in diameter than the specimen. The capped rings are compression tested in a conventional way. This method thus employs standard concrete laboratory testing equipment. An inexpensive customized capping apparatus may be used for preparing the specimen ends. The method ensures that confinement is provided to the cap without having to place tight controls on specimen end roughness prior to capping and on the cap thickness itself.
Claims15
A method of preparing for compressive strength testing an end of a high performance concrete specimen having an anticipated minimum compressive strength of at least 70 MPa, the method comprising:
- providing a test specimen of the high performance concrete;
- providing a confining ring;
- capping one end of the test specimen with a capping compound in direct engagement with the end of the specimen, the capping compound having a compressive strength substantially less than said anticipated minimum compressive strength, comprising:
- (i) melting the capping compound;
- (ii) filling the ring with liquid capping compound;
- (iii) placing the end of the test specimen into the capping compound within the ring;
- and
- (iv) allowing the capping compound to solidify.
A test specimen of high performance concrete having a minimum compressive strength of at least 70 MPa, said specimen comprising:
- an elongate member of the concrete, the member having opposite ends;
- two caps covering respective ones of the opposite ends of the member, each cap comprising a sulphur capping material covering the end of the member, in direct contact therewith and a ring surrounding the cap circumferentially, the ring having a tensile strength greater than that of the capping material.
Apparatus for preparing a test specimen of high performance concrete, said apparatus comprising:
- a base plate having a smooth upper surface;
- ring confining means on the base plate for holding a confining ring at a predetermined position on the base plate;
- and
- specimen centering means for engaging a specimen of the concrete and centering the specimen on the ring.
Dependencies are inferred from the claim text.