ASTM C191
Full Name
ASTM C191 – Standard Test Methods for Time of Setting of Hydraulic Cement by Vicat Needle
Scope
ASTM C191 outlines the procedures for determining the time of setting of hydraulic cement using a Vicat needle apparatus. This test is crucial for assessing the suitability of cement for various construction applications.
The scope of ASTM C191 includes:
- Methods: the standard provides two test methods:
- Method A: the reference test method using a manually operated standard Vicat apparatus.
- Method B: allows the use of an automatic Vicat machine that meets the qualification requirements of the standard.
- Time of setting: the test measures two key parameters:
- Initial time of setting: the time elapsed from the initial contact of cement and water to the time when the Vicat needle penetrates 25 mm into the cement paste.
- Final time of setting: the time elapsed from the initial contact of cement and water to the time when the Vicat needle no longer leaves a complete circular impression on the cement paste surface.
- Apparatus: it specifies the apparatus required for the test, including a Vicat apparatus, a mold, a non-absorptive plate, and a Vicat needle with a specific diameter and mass.
- Procedure: it details the step-by-step procedure for conducting the test, including preparing the cement paste, filling the mold, performing penetration tests at regular intervals, and determining the initial and final setting times.
- Precision and bias: it provides information on the precision and bias of the test methods.
ASTM C191 does not cover:
- Factors affecting setting time: the setting time of hydraulic cement can be influenced by various factors, such as temperature, humidity, and the type and amount of admixtures. These factors are not directly addressed in the standard but should be considered when interpreting the results.
- Alternative test methods: other test methods for determining setting time, such as the Gillmore needle test, are not covered in this standard.
Overall, ASTM C191 is essential for assessing the setting behavior of hydraulic cement, which is crucial for ensuring the workability, strength development, and durability of concrete in various construction applications.
ASTM C191 Accredited Laboratory
Applied Testing & Geosciences, LLC is accredited for performing tests using the ASTM C191 standard.
Contact us for more information.
Resources
Keywords
setting time; Vicat needle; hydraulic cement; initial setting time; final setting time; Vicat apparatus; penetration; cement paste