ASTM C457 PDF

Baixe grátis o arquivo ASTM CCM – 12 _ Microscopical Determination of Parameters of the Air-Void System in Hardened Concrete (2).pdf enviado por. This standard is issued under the fixed designation C ; the number concrete. 1 This practice is under the jurisdiction of ASTM Committee C-9 on Concrete. Humboldt’s Linear Traverse Machine for concrete air void testing facilitates the counting of microscopic voids in concrete. Meets or exceeds ASTM C

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If you feel that your comments have not received a fair hearing ast, should make your views known to the ASTM Committee on Standards, at the address shown adtm.

They are significant only in mixtures that contained excessive mixing water or in which pronounced bleeding and settlement occurred. A Includes determinations using both point count and linear traverse. Use The test is a quantitative method that measures the air-void content and other air-void system parameters in hardened concrete.

Air Void Testing for Concrete, ASTM C

Because Procedure C requires darkening adtm paste and aggregate, its use must occur after other tests if the analyst is also gathering petrographic data in addition to the measurements described in this test method. Results can also be applied to other situations in which the air content of concrete is in question. The required area may consist of more than one prepared section.

For specific hazard statements see 8.

ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. For concrete with a relatively high air content usually over 7. NOTE 2—Apparatus for measurement of prepared samples is described in the two following procedures. The selection of which one of the three methods to be used shall be subject to agreement of the user and provider of the determination.

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Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. If you need more info or have any questions, please note the Lab ID number 56 and contact us at:.

A surface that is satisfactory for microscopical examination will show an excellent reflection of a distant light source when viewed at a low incident angle and there shall be no noticeable relief between the paste and the aggregate surfaces.

Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend.

The ratio of the volume of aggregate to the volume of paste in the original mix must be accurately known or xstm to permit the calculation of the air-void systems parameters from the microscopically determined paste-air ratio.

The suggested sizes will usually be appropriate, but others may be selected according to the experience of the user.

A Modified Point Count: Individual reprints single or multiple copies of this standard may be obtained by contacting ASTM at the above address or at phonefaxor service astm. Hence, this test method can be used to develop data to estimate the likelihood of damage due to cyclic freezing and thawing or to explain why it has occurred.

ASTM C457.C457M – 12 – Microscopical Determination of Parameters of the Air-Void…

Current edition approved Dec. A Includes all data—all labs and all operators. Combining values from the two systems may result in non-conformance with the standard.

The procedure followed and the location from which the samples are obtained will depend on the objectives of the program. The problem is manifested by the plucking of sand grains from the surface during the lapping, with consequent scratching of the surface, and by undercutting of the paste around the aetm aggregate particles. Originally approved in Privacy Policy Sensors Sitemap. Friable particles of aggregate can also cause difficulty.

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For specific hazard statements see Note 9 and Note Reviews in Engineering Geology, Geol.

ASTM C Microscopical Determination of the Air-Void System | CTL Grp

Three procedures are described:. For voids per in.: Use of ultrasonic cleaners may be harmful to the surface. C39M – 16 – Compressive Strength of Cylindrical The test results can also be used to explain the reason why such damage has occurred in concrete.

Three procedures are described: Approved October 1, They are significant only in mixtures that contained excessive mixing water or in which pronounced bleeding and settlement occurred.

Do not include scratched or broken portions of the surface in the analyzed area. The most common examples are concrete with large coarse aggregate and samples from the finished surface region, for both of which the examined sample consists of a disproportionately large amount of the mortar fraction.

Appraisal, John Wiley and Sons, Inc. Somewhat larger values may be adequate for mild exposure, and smaller ones may be required for severe exposure, especially if the concrete is in contact with deicing chemicals.

Care should be exercised in using spacing factor values 4c57 specifications since the standard deviation of that property has been found to approach one-fifth of the average when determinations are made in different laboratories. They are most common beneath horizontal reinforcing bars, pieces of coarse aggregate and as channelways along their sides. The honey-combing that asttm a consequence of the failure to compact the concrete properly is one type of entrapped air void.

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