All the Controls products ASTM C standard. Enter now!. ASTM C Standard Practice for Capping Cylindrical Specimens. P. F NA. Procedure. 1. Prepare sulfur mortar by heating to a temperature. Note: Also recommended but not part of basic set—Exhaust fume hood and suitable alignment device(s). For V/60Hz applications, substitute: H with.
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Retarders may be used to extend working time, but their effects on required water-cement ratio and strength must be determined. Current edition approved April 1, It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
No further reproductions authorized. Make caps as thin as practicable. NOTE 6—The required consistency of the paste is determined by the appearance of the cap when it is stripped. Carefully cover the capping plate and mold with a double layer of damp astmm and a polyethylene sheet to prevent drying. After solidification is complete, remove the cubes from the mold without breaking atsm the knob formed by the filling hole in the cover plate.
C39M – 16 – Compressive Strength of Cylindrical The surface roughness of newly finished metal plates shall not exceed that set forth in Table 4 of American National Standard B Allow sufficient time awtm maximum shrinkage, due to cooling, and solidification to occur approximately 15 min and refill each hole with molten material Note The same requirement is applicable to the relationship between the axis of the alignment device and the surface of a capping plate when guide bars are used.
During the molding of the cylinder, strike off the upper end even with or slightly below the plane of the rim of the mold.
In addition, the location of each bar with respect to its plate must be such that no cap will be off-centered on a test. A superscript epsilon indicates an editorial change since the last revision or reapproval.
A very slight twisting motion may be required to extrude excess paste and minimize air voids in the paste. Remix as necessary to maintain acceptable consistency Note 6. Originally approved in Some retempering of the paste is acceptable if the required water-cement ratio is not exceeded. Form the cap by placing a conical mound of paste on the specimen and then gently pressing a freshly oiled capping plate on the conical mound until the plate contacts the rim of the mold.
The 2 to 4 h period is generally appropriate for portland cements. Note 7 Qualification tests shall be made to determine the effects of water-cement ratio and age on compressive strength of 50 m [2 in. The surface, when new, shall be free of gouges, grooves, or indentations beyond those caused by the finishing operation.
C61 7—Low-strength molding plaster, plaster of paris, or mixtures of plaster of paris and portland cement are unsuitable for capping.
The capping plate must not rock during this operation. The manufacturer must requalify lots of material manufactured on an annual basis or whenever there is a change in the formulation or the raw materials.
In all cases, plates shall be at least 25 m [1 in. If a given lot of the capping material fails to conform to the strength requirements, it shall not be used, and strength tests of the replacement material shall be made weekly until four consecutive determinations conform to specification requirements.
Higher water-gypsum cement ratios extend working time, but reduce strength. Metal plates that have been in use shall be free of gouges, grooves, and indentations greater than 0. The user of the material c671 retain a copy of the qualification results, and the dates of manufacture of material qualified and of the material currently being used.
Do not apply the neat paste to the exposed end until the concrete has ceased settling in the molds, generally from 2 to 4 h after molding. The rod should be of sufficient size to conduct enough heat to the top on reheating to melt a ring around the rod first and thus avoid the development of pressure.
A number in parentheses indicates the year of last reapproval. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. See Test Methods C for alternative compaction procedures. NOTE 8—The water-gypsum cement ratio should be between 0. Recharge the pot with fresh material after the flame has been extinguished. For concrete strengths of 35 MPa [ psi] or greater, sulfur mortar caps must be allowed to harden at least 16 h before testing, unless a shorter time has been shown to be suitable as specified in 5.
NOTE 10—The second filling helps to prevent the formation of a large void or shrinkage pipe in the body of a cube. NOTE 5—Freshly mixed pastes tend to bleed, shrink, and make unacceptable caps.
When using melting pots not so equipped, a build-up of pressure under the hardened surface crust on subsequent reheating may be avoided by use of a metal rod that contacts the bottom of the pot and projects above the surface of the fluid sulfur mix as it cools. Types I, I or II; however, Specification C blended cements, calcium aluminate or other hydraulic cements producing acceptable strength may be used.
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