AASHTO T260
Full Name
AASHTO T260 – Standard Method of Test for Sampling and Testing for Chloride Ion in Concrete and Concrete Raw Materials
Scope
AASHTO T260 is a standard test method used to determine the chloride ion content in concrete, aggregates, Portland cement, mortar, and other concrete raw materials. Chloride ions, when present in excessive amounts, can cause corrosion of steel reinforcement in concrete, leading to structural deterioration and reduced service life. Therefore, monitoring the chloride ion content is crucial for ensuring the durability and longevity of concrete structures.
Key aspects of AASHTO T260:
- Purpose: the primary objective of this test method is to quantify the amount of acid-soluble chloride ions or water-soluble chloride ions present in concrete and its raw materials. The total amount of chloride is usually equivalent to the acid-soluble chloride, but in some cases, organic additives or minerals might contain acid-insoluble chloride that could become acid soluble over time due to the alkaline environment in concrete.
- Test procedures: AASHTO T260 outlines two procedures for determining chloride ion content:
- Procedure A: determination of acid-soluble and water-soluble chloride ion content by potentiometric titration or ion-selective electrode.
- Procedure B: determination of acid-soluble chloride ion by atomic absorption.
- Sample preparation: the standard provides guidelines on obtaining representative samples from concrete structures and raw materials. It also describes the procedures for preparing the samples for analysis, including crushing, grinding, and dissolving the samples in acid or water.
- Analysis: the chloride ion content is determined using either potentiometric titration, ion-selective electrode, or atomic absorption spectroscopy. The choice of method depends on the desired precision and the availability of equipment.
Significance of AASHTO T260:
- Durability assessment: the chloride ion content is a critical parameter for assessing the durability of concrete structures, especially in environments exposed to chloride ions, such as marine environments or deicing salts.
- Quality control: the test is used by concrete producers and construction contractors to ensure that the materials used in their projects meet the specified chloride ion content limits.
- Corrosion prevention: by monitoring the chloride ion content, engineers can implement appropriate corrosion prevention measures, such as using corrosion-resistant reinforcement or applying protective coatings.
- Research and development: AASHTO T260 provides a standardized test method for chloride ion analysis, facilitating research and development of new materials and techniques for improving the durability of concrete.
AASHTO T260 Accredited Laboratory
Applied Testing & Geosciences, LLC is accredited for performing tests using the AASHTO T260 standard.
Our laboratory offers comprehensive testing services for chloride ion content in concrete and concrete raw materials according to AASHTO T260. Our experienced technicians utilize modern equipment and adhere to strict quality control procedures to provide accurate and reliable results.
Contact us for more information.
Resources
Keywords
chloride ion; concrete; sampling; testing; potentiometric titration; ion-selective electrode; atomic absorption spectroscopy; acid-soluble chloride; water-soluble chloride; aggregate; Portland cement; mortar