ASTM C265
Full Name
ASTM C265 – Standard Test Method for Water-Extractable Sulfate in Hydrated Hydraulic Cement Mortar
Scope
ASTM C265 covers the determination of water-extractable sulfate (SO3) in hardened hydraulic cement mortar. This measurement is used to estimate the unreacted, available sulfate remaining in the mortar, which can be an indicator of the potential for sulfate attack or delayed ettringite formation.
Specifically, the standard addresses:
- Sample preparation: the method requires preparing mortar cubes or prisms according to specified procedures.
- Extraction process: it outlines the extraction of water-soluble sulfate from the hardened mortar samples using distilled water.
- Sulfate determination: it describes the determination of sulfate (SO3) concentration in the extracted solution using appropriate analytical techniques.
- Calculation: It provides formulas for calculating the water-extractable sulfate content in the mortar.
ASTM C265 is important for:
- Assessing sulfate resistance: the test helps evaluate the potential for sulfate attack in concrete made with a particular cement-aggregate combination.
- Quality control: it can be used for quality control purposes to monitor the sulfate content in cement during production.
- Investigating field problems: the test can be helpful in diagnosing field problems related to sulfate attack or delayed ettringite formation in concrete structures.
It is important to note that this standard focuses on water-extractable sulfate and may not represent the total sulfate content in the mortar. Additionally, the test results should be interpreted in conjunction with other relevant factors, such as the type of cement, aggregate characteristics, and environmental conditions, to assess the overall risk of sulfate-related problems in concrete.
Keywords
hydraulic cement; optimum sulfate content; sulfate; sulfate content
ASTM C265 Accredited Laboratory
Applied Testing & Geosciences, LLC is accredited for performing tests using the ASTM C265 standard.
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Resources
Keywords
water-extractable sulfate; hydraulic cement mortar; sulfate attack; delayed ettringite formation; mortar cubes; sulfate content; extraction