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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Order Form 2 Email complete form to contact listed below. Approved October 1, Thus, this method can be used to evaluate the potential for damage due to cyclic freezing and thawing of the concrete.
ASTM C Microscopical Determination of the Air-Void System | CTL Grp
Combining values from the two systems may result in non-conformance with the standard. The values stated in each system may not be exact equivalents; therefore, astj system shall be used independently of the other. Individual reprints single or multiple copies of this standard may be obtained by contacting ASTM at the above address or cc457 phonefaxor service astm. Reports that do make such a distinction typically define entrapped air voids as being larger than 1 m in at least one dimension being irregular in shape, or both.
Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. Warning—If the specimen was astn with a lubricant other than water, heating must be done so as to avoid inhaling the fumes and to preclude fire or explosion.
In such instances ast usual procedure must be changed, and the paste-air ratio modification must be used see 5.
Sample Type hardened concrete, mortar, other portland-cement-based materials. Because Procedure C requires darkening the 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.
The test method can also be used atsm an adjunct to the development of products or procedures intended to enhance the resistance of concrete to cyclic freezing and thawing 1.
A Includes determinations using both point count and linear traverse. If only the air content is desired, only Sa and St need be determined.
ASTM CCM – 12 – Microscopical Determination of Parameters of the Air-Void
However, significant differences may be observed if the sample of fresh concrete is consolidated to a different degree than the specimen later examined microscopically. Provide at least the minimum area of finished surface given in Table 1 in each sample. The required area may consist of awtm than one prepared section.
Individual sections should be as large as can be ground and examined with the available equipment. The following text provides useful information on air-void system parameters of known freeze-thaw durable concrete and explains guidelines and specifications from other respected specifying agencies. A Modified Point Count: Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility.
Care should be exercised in using spacing factor values in 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. The suggested sizes will usually be appropriate, but others may be selected according to the experience of the user. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend.
Prepared sections of such concrete should include a maximum of the mortar fraction, so as to increase the number of counts on air voids or traverse across them.
ASTM C457.C457M – 12 – Microscopical Determination of Parameters of the Air-Void…
A surface that is satisfactory qstm microscopical ast, 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. Such compressive strength must be at least 28 MPa [ psi]. Additionally, this test method can be used for concrete product and mixture development requiring resistance of the concrete against freezing and thawing damage.
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. Combining values from the two systems may result in non-conformance with the standard. The factors affecting the variability of the test method are discussed in the section on Precision and Bias. Cc457 are most astmm beneath horizontal reinforcing bars, pieces of coarse aggregate and as channelways along their sides.
Prepared sections of such concrete c4557 include a maximum of the mortar fraction, so as to increase the number of counts on air voids or traverse across them. Includes both point count and linear traverse data. ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. C39M – 16 – Compressive Strength of Cylindrical Open Cup Tester 2.
Juliano row Enviado por: Three procedures 4c57 described: They are significant only in mixtures that contained excessive mixing water or in which pronounced bleeding and settlement occurred. Link to Active This link will always route to the current Active version of the standard. Juliano row Enviado por: