Qty. Model, Description. 1, Choose One: HH, Humboldt concrete rebound hammer. H, Standard concrete test hammer, type n. HLM, Light. ASTM Cpdf – Download as PDF File .pdf), Text File .txt) or read online. Rebound Number of Hardened Concrete1 This standard is issued under the fixed designation C ; the number immediately following the designation.

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To estimate strength in an existing structure, establish the relationship by correlating rebound 5. No two impact tests shall be closer together than 25 mm 1 in. We need your help! Originally published as C — 75 T. Locations where strengths are d805 be estimated using the developed correlation shall have similar surface texture and shall have been exposed to similar conditions as the locations where correlation cores were taken.

These factors need to be considered in preparing the strength relationship asmt interpreting test results. Therefore, the range of ten readings should not aztm Gradually push the instrument toward the test surface until the hammer impacts. After impact, maintain pressure on the instrument and, if necessary, depress the button on the side of the instrument to lock the plunger in its retracted position.

Examine the impression made on the surface after impact, and if the impact crushes or breaks through a near-surface air void disregard the reading and take another reading. Select test locations so that a wide range asgm rebound numbers in the structure is obtained. Some users compare several hammers on concrete or stone surfaces encompassing the usual range of rebound numbers encountered in the field.

If more than 2 asstm differ from the average by 6 units, discard the entire set of readings and detemine rebound numbers at 10 new locations within the test area. If the rebound number axtm affected by the orientation of the instrument during testing, the strength relationship is applicable for the same orientation as used to obtain the correlation date see Note 3. Areas exhibiting honeycombing, scaling, or high porosity should be avoided.


Smooth-formed or troweled surfaces do not have to be ground prior to testing Note 2. In cases of a thick layer of carbonate concrete, it may be necessary to remove the carbonated layer in the test area, using a power grinder, to obtain rebound numbers that are representative of the interior concrete.


A superscript epsilon e indicates an editorial change since the last revision or reapproval. The form material against which the concrete was placed should be similar Note 2. Please copy and paste this embed script to where you want to embed Embed Script.

Please fill this form, we will try to v805 as soon as possible. The relationship shall be established for a given concrete mixture and given apparatus.

ASTM C, Test equipment Controls

Combining values from the two systems may result in non-conformance with the standard. Heavily textured, soft, or surfaces with loose mortar shall be ground smooth with the abrasive stone described in 5.

Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. Establish the relationship by correlating rebound numbers measured on the structure with the measured strengths of cores taken from corresponding locations see Note 2.

NOTE 2—Where formed surfaces were ground, increases in rebound number of 2. Precision and Bias If possible, structural slabs should be tested from the underside to avoid finished surfaces. Summary of Test Method 3. Note 1 — See ACI 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.


A number in parentheses indicates the year of last reapproval. Take ten readings from each test area.

ASTM C805-97.pdf

The rebound distance of the steel hammer from the steel plunger is measured on a linear scale attached to the frame of the instrument. NOTE 1—Several types and sizes of c05 hammers are commercially available to accommodate testing of various sizes and types of concrete construction. Note 3 — The use of correction factors to account for instrument orientation may reduce the reliability of strength estimates if the correlation is developed for a different orientation than used for testing. To use this test method to estimate strength, it is necessary to establish a relationship between strength and rebound number for a given concrete and given apparatus see Note 1.

Work Item s – proposed revisions of this standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other.

This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years aatm if not revised, either reapproved or withdrawn. aztm

Please help us to share our service with your friends. Size px x x x x C — 97 Standard Test Method for Rebound Number of Hardened Concrete1 This standard is issued under the fixed designation C ; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision.