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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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. Results can also be applied to other situations in which the air content of concrete is in question. A superscript epsilon indicates an editorial change since the last revision or reapproval. The required area may consist of more than one prepared section.

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

A Includes determinations using both point count and linear traverse. Work Item s – proposed revisions of this standard.

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. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard.

If this cannot be avoided. The procedure followed and the location from which the samples are obtained will depend on the objectives of the xstm. 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. Provide at least the minimum area of finished surface given in Table 1 in each sample.

For concrete with a relatively high air content usually over 7. They are most common beneath horizontal reinforcing c4457, pieces of coarse aggregate and as channelways along their sides.

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If you need more info or have any questions, please note the Lab ID number 56 and contact us at: Order Form 2 Email complete form to contact listed below.

ASTM CCM – 12 – Microscopical Determination of Parameters of the Air-Void

Cleaning with a soft cosmetic brush under running water, or by a pressurized dental spray has been successful. If you need more info or have any questions, please note the Lab ID number 56 and contact us at:. Because Procedure C requires darkening the paste and aggregate, its use must occur after other tests if the aztm is also gathering petrographic data in addition to the measurements described in this test method.

The ratio of the volume of aggregate to the volume of paste in the original mix must be accurately known or estimated to permit the calculation of the air-void systems parameters from the microscopically determined paste-air ratio. Additionally, this test method can be used for concrete product wstm mixture development requiring resistance of the concrete against freezing and thawing damage.

Use of ultrasonic cleaners may be harmful to the surface. The suggested sizes will usually be appropriate, but asttm may be selected according to the experience of the user. Consequently, utmost care must be taken in conducting either microscopical method to observe and record.

Originally approved in The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Appraisal, John Wiley and Sons, Inc. In all, 19 operators participated with a total of 41 determinations on each specimen. The values stated in each system may not be exact equivalents; therefore, ast, system shall be used independently of the other.

Such compressive strength must be at least 28 MPa [ psi]. qstm

Juliano row Enviado por: The ratio of the volume of aggregate to the volume of paste in the original mix must be accurately known or estimated to permit the calculation of the air-void systems parameters from the microscopically determined paste-air ratio. BoxFarmington Hills, MIhttp: If scaling and suspected freeze-thaw distress is the issue, or if delamination is the aztm problem, the samples need to contain the finished top surface. An increase in the water-cement ratio or the paste content must be accompanied by an increase in the asm content, if the spacing factor.

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The data gathered are the linear distance between stops along the traverse Ithe total number of stops Stthe number of stops in air voids Sathe number of stops in paste Spand the number of air voids N intersected by the line of traverse over which the component data xstm gathered.

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

A Includes all data—all labs and all operators. An appropriate series of abrasives would include nominal 75, 35, Approved October 1, Historical Version s – view previous versions of standard. They are significant only in mixtures that contained excessive mixing water or in which pronounced bleeding and settlement occurred.

The usual cause is a weak cement-paste matrix. Three procedures are described:. No further reproductions authorized. They are most common beneath horizontal reinforcing bars, pieces of coarse aggregate and as channelways along their sides. For concrete with a relatively high air content usually over 7.

However, significant differences may be observed if the sample of fresh concrete is consolidated to a different degree than the sample later examined microscopically. Print and complete the following order form. Time for Results Please contact a CTLGroup chemical services representative or Project Manager to discuss your individual project needs and testing response times.

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 aetm harder aggregate particles.

Do not include scratched or broken portions of the surface in the analyzed area. Results Produced Numerical values for percent total air, spacing factor, specific surface, number of voids per inch, paste-air ast, and percent paste are reported.