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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CObtaining and Testing Drilled Cores and Sawed Beams of Concrete
A number in parentheses indicates the year of last reapproval. A superscript epsilon e indicates an frwe change since the last revision or reapproval. SI units are shown in brackets. The values stated may not be exact equivalents, therefore each system must be used independently of the other.
Combining values of the two units may result in nonconformance. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine freee applicability of regulatory limitations prior to use.
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.
Additionally, this method may be used to provide strength information on older structures. 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. The acceptance criteria for core strength is to be established by the specifying authority.
ACI provides core strength acceptance criteria for new construction.
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.
Current edition approved Feb. Originally published as C 42 — 21 T.
Last previous edition C 42 — BoxFarmington Hills, MI 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.
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.
If time permits, the concrete should not be removed before it is 14 days old. 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. In-place test methods may be used to estimate the level of strength development prior to attempting removal of concrete samples.
A specimen taken perpendicular to a vertical surface, or perpendicular to a surface with a batter, shall be taken from near the middle of a unit of deposit fref possible and not near formed joints or obvious edges of a unit of deposit.
Measure the lengths of such cores in accordance with Test Method C Core diameters less than 3. The preferred length of the d42 specimen is between 1. If the ratio of the length to the diameter of the core specimen exceeds 2.
Core specimens with length-to-diameter ratios less than 1. If necessary, saw the ends of the specimens until the following requirements are dree Cap or grind the cores, and test them within 48 h of receipt. The ends shall be sawed or ground to tolerance or capped in accordance with capping procedures for hardened concrete specimens of Practice C 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.
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Determine the c24 diameter by averaging two measurements taken at right angles to each other about the midheight of the specimen. Measure core diameters to the nearest 0. NOTE 3—Correction factors depend on various conditions such as moisture condition, strength level, and elastic modulus. Average values are given in the table. They are applicable to both dry and wet concrete for fre between and psi [14 to 42 MPa].
For strengths above psi [70 MPa], test data on cores show that the correction factors may be larger than the values listed above.
Thus, these factors should be applied to high-strength concrete with caution. C 39 with the addition of the following information: Therefore, results of two properly conducted 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.
Ends are not to be capped. When the line of contact is not straight or contains projections or depressions having heights or depths greater than 0. Do not use specimens with projections or depressions greater than 0.
When capping is employed the caps shall be as thin aatm practicable and shall be formed of high-strength gypsum plaster. When grinding or capping of the bearing surfaces is.
Parte 1 de 2 Designation: This standard has been approved for use by agencies of the Department of Defense. Significance and Use 3. Length of Drilled Cores 6. Cores for Compressive Strength 7. Livro sobre Cimento Portland e Concreto.