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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Lap the surface with successively finer abrasives until it is suitable for microscopical observation.
ASTM C457.C457M – 12 – Microscopical Determination of Parameters of the Air-Void…
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 Note 1: They occur also immediately c475 surfaces that were compacted by finishing operations before the completion of bleeding.
A These numbers represent, respectively, the 1s and D2s limits as described in Practice C An appropriate series of abrasives would include nominal 75, 35, 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. The maximum value of the spacing factor for moderate exposure of the concrete is usually taken to be 0.
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. The usual cause is a weak cement-paste matrix. Results Produced Numerical values for percent total air, spacing factor, specific surface, number asgm voids per inch, paste-air ratio, and percent paste are reported.
ASTM C Microscopical Determination of the Air-Void System | CTL Grp
The test method can also be used as an adjunct to the development of products or procedures intended to enhance the resistance of concrete to cyclic freezing and thawing. Ashm procedures are described: C39M – 16 – Compressive Strength of Cylindrical Time for Results Please contact a CTLGroup chemical services representative or Project Manager to discuss your individual project needs and testing response times.
The ratio of the volume of aggregate to the volume of paste in the original mix must be accurately known or estimated ast, permit the calculation of the air-void systems parameters from the microscopically determined paste-air ratio. 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.
The following text v457 useful information on air-void system parameters of known freeze-thaw durable concrete and explains guidelines and specifications from other respected specifying agencies.
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.
A Includes all data—all labs and all operators.
Juliano row Enviado por: They are significant only in mixtures that contained excessive mixing water or in which pronounced bleeding and settlement occurred. 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.
A sample may be composed of any aztm of specimens. Historical Version s – view previous versions of standard.
Air Void Testing for Concrete, ASTM C
Friable particles of aggregate can also cause difficulty. Combining values from the two systems may result in non-conformance with the standard.
In such instances the following c4577 is helpful. The procedure followed and the location from which the samples are obtained will depend on the objectives of the program. 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. The flash point of the lubricant may be found by use of Test Method D This standard is subject to revision wstm any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn.
Results can also be applied to other situations in which the air content of concrete is in question. The data gathered are the total length traversed Ttthe length traversed through asfm voids Tathe length traversed through paste Tpand the number of air voids intersected by the traverse line N. Link to Active This link will always route to the current Active version of the standard. Individual sections should be as large as can be ground and examined with the available equipment.