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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Measure core diameters to the nearest 0. If time permits, the concrete should not be removed before it is 14 days old.

Do not use specimens with projections or depressions greater than 0. SI units are shown in brackets. If fre 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.

The values stated may not be exact equivalents, therefore each system must be used independently of the other. When grinding or capping of the bearing x42 is.

Average values are given in the table. If necessary, saw the ends of the specimens until the following requirements are met: In-place test methods may be used to estimate the level of strength development prior to attempting removal of concrete samples.

Core specimens with length-to-diameter ratios less than 1. ACI provides core strength acceptance criteria for new construction. When capping is employed the caps shall be as thin as practicable and shall be formed of high-strength gypsum plaster. 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. Parte 1 de 2 Designation: Measure the lengths of such cores in accordance with Test Method C 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 f42 of flaws as the particular structure will allow.


The ends shall be sawed or ground to tolerance or capped in accordance with capping procedures for hardened concrete specimens of Practice C Current edition approved Feb.

Additionally, this method may be used to provide strength information on older structures.

CObtaining and Testing Drilled Cores and Sawed Beams of Concrete

Thus, these factors frew be applied to high-strength concrete with caution. 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.

Core diameters less than 3. The preferred length of the capped specimen is between 1. They are applicable to both dry and wet concrete for strengths between and psi [14 to 42 MPa]. Determine the average diameter by averaging two measurements taken at right angles to each other about the midheight of the specimen.

The acceptance criteria for core strength is to be established by the specifying authority. Significance and Use 3.

C42-Obtaining and Testing Drilled Cores and Sawed Beams of Concrete

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. A specimen taken perpendicular to a vertical surface, or perpendicular to a surface with a batter, shall be taken from near fere middle of a unit of deposit when possible and not near formed joints or obvious edges c4 a unit of deposit.


The relationship is affected by many factors such as the strength level of frew concrete, the in-place temperature and moisture history, and the strength gain characteristics of the concrete.

Cores for Compressive Strength 7. It is the responsibility of the user of this standard asfm establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Last previous edition C 42 — Length of Drilled Cores 6.

If the ratio of the length to the diameter of the core specimen exceeds 2. 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.

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. This standard has been approved for use by agencies of the Department of Defense.