Astm C876-09 Pdf Free 26
Astm C876-09 Pdf Free 26
Astm C876-09 is a standard test method for corrosion potentials of uncoated reinforcing steel in concrete. It is used to estimate the electrical corrosion potential of the steel, which indicates the corrosion activity and the likelihood of deterioration of the concrete structure. The test method is suitable for in-service evaluation and for research and development work.
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The test method involves measuring the voltage difference between a reference electrode and the reinforcing steel embedded in concrete. The reference electrode can be a copper-copper sulfate electrode, a silver-silver chloride electrode, or a saturated calomel electrode. The reference electrode is placed on the concrete surface and connected to a voltmeter. The other terminal of the voltmeter is connected to the reinforcing steel through a wire. The voltage reading is recorded as the corrosion potential of the steel at that location.
The corrosion potential values are interpreted according to the criteria given in Table 1 of Astm C876-09. The criteria are based on statistical analysis of experimental data and empirical correlations with other indicators of corrosion activity, such as chloride content, carbonation depth, and rate of corrosion. The criteria are as follows:
Corrosion Potential (mV)
Probability of No Corrosion
More positive than -200
90 % or greater
-200 to -350
Uncertain
More negative than -350
Less than 10 %
The test method has some limitations and assumptions that should be considered when applying it. For example, the test method assumes that the concrete is electrically conductive and that the reference electrode is in direct contact with the concrete surface. However, in some cases, such as dry or coated concrete, the electrical circuit may be interrupted or distorted, resulting in inaccurate or unreliable measurements. Therefore, it is recommended to verify the electrical continuity of the concrete and the reference electrode before conducting the test.
Another limitation of the test method is that it does not provide information on the extent or severity of corrosion, nor on the structural properties of the steel or the concrete. Therefore, it is often necessary to use other methods or data, such as visual inspection, chloride analysis, carbonation depth measurement, delamination survey, rate of corrosion measurement, and environmental exposure conditions, to complement the corrosion potential measurements and to draw conclusions about the corrosion activity and its effect on the service life of the concrete structure .
Astm C876-09 is available as a PDF file for free download from various sources on the internet. However, it should be noted that Astm C876-09 has been superseded by Astm C876-15, which was published in November 2015. Astm C876-15 has some revisions and updates from Astm C876-09, such as adding a new reference electrode (zinc-zinc sulfate), modifying some terminology and definitions, and providing more guidance on interpretation of results and reporting. Therefore, it is advisable to use Astm C876-15 instead of Astm C876-09 for current applications.
: [Astm C876-09 - Standard Test Method for Corrosion Potentials of Uncoated Reinforcing Steel in Concrete] : [Half-Cell Potentials of Uncoated Reinforcing Steel in Concrete] : [Designation: C876 09] : [Astm C876-15 - Standard Test Method for Corrosion Potentials of Uncoated Reinforcing Steel in Concrete](