This standard is issued under the fixed designation C42/C42M; the number . of core test results.2 and that is free of is the individual responsible for analysis or. ASTM C42/C42M () Standard Test Method for Obtaining and Testing Drilled ASTM International, West Conshohocken. Free SCIRP Newsletters>> . ASTM C Potential Resistance to Degradation. In-situ Tests . Determine time from start until no free water is on ASTM C42, Coring, 3 cores/5, sf.
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Parte 1 de 2 Designation: Additionally, this method may be used to provide strength information on older structures. When grinding frree capping of the bearing surfaces is. A number in parentheses indicates the year of last reapproval. It is the responsibility of the user of this standard to establish awtm safety and health practices and determine the applicability of regulatory limitations prior to use. If time permits, the concrete should not be removed before it is 14 days old.
Therefore, results of two properly fres tests on cores sampled from the same hardened concrete where a single test is defined as the average of two observations coreseach made on separate adjacent drilled 4 in. A specimen taken perpendicular to a vertical surface, or perpendicular to a surface with a batter, shall be taken from near the middle of asym unit of deposit when possible and not near formed joints or obvious edges of a unit of deposit.
If the ratio of the length to the diameter of the core specimen exceeds 2. ACI provides core strength acceptance criteria for new construction. Core specimens with length-to-diameter ratios less than 1. If this is not practical, removal of concrete can proceed if the cut surfaces do not display erosion of the mortar and the exposed coarse aggregate particles are embedded firmly in the mortar.
C42-Obtaining and Testing Drilled Cores and Sawed Beams of Concrete
When the line of contact is not straight or contains projections or depressions having heights or depths greater than 0. Core diameters less than 3. The acceptance criteria for core strength is to be established by the specifying authority. Cores for Compressive Strength 7. SI units are shown in brackets.
The relationship is affected by many factors such as the strength level of the concrete, the in-place temperature and moisture history, and the strength gain characteristics of the concrete. A superscript epsilon e indicates an editorial change since the last asgm or reapproval. In-place test methods may be used to estimate the level of strength development prior to attempting removal of concrete samples.
NOTE 2—Prior to capping, the density of a core may be determined by weighing it and dividing it by the volume calculated from the average diameter and length, or by any other standard method for determining density. Length of Drilled Cores 6. Determine the average diameter by averaging two measurements fee at right angles to each other about the midheight of c2 specimen. Current edition approved Feb. Ends are not to be capped. The values stated may not be exact equivalents, therefore each system must be used independently of the other.
When ftee is employed the caps shall be as thin as practicable and shall be formed of high-strength gypsum plaster. Thus, these factors should be applied to high-strength concrete with caution.
For strengths above psi [70 MPa], test data on cores show that the correction factors may be larger than the values listed above.
Last previous edition C 42 — Significance and Use 3. C 39 with the addition of the following information: Sampling and sample preparation requirements are given to ensure that dimensional requirements are met and that the specimens are comprised of intact sound concrete as free of flaws as the particular structure will allow.
ASTM CC42M – 04 – Free Download PDF
Measure the lengths of such cores in accordance with Test Method C Originally published as C 42 — 21 T. Do not use specimens with projections or depressions greater than 0.
The ends shall be sawed or ground to tolerance or capped in accordance with capping procedures freee hardened concrete specimens of Practice C The preferred length of the capped specimen is between 1.
Measure core diameters to the nearest 0. Average values are given in the table. Combining values of the two units may result in nonconformance.
CObtaining and Testing Drilled Cores and Sawed Beams of Concrete
If necessary, saw the ends of the specimens until the following requirements are met: NOTE 1—It is not possible to specify a minimum age when concrete is strong enough to withstand damage during removal, because the strength at any age depends on the curing history and strength grade of the concrete.
NOTE 3—Correction factors depend on various conditions such as moisture condition, strength level, and elastic modulus. This standard has been approved for use by agencies of the Department of Defense. When preparing strength test specimens from samples of hardened concrete, samples that show defects or samples that have been damaged in the process of removal shall not be used.
The saw shall have a diamond or silicon-carbide cutting edge and shall be capable of cutting specimens which conform to the prescribed dimensions, without excessive heating or shock.