ASTM C349
ASTM C349 Standard Test Method for Compressive Strength of Hydraulic-Cement Mortars
Introduction to ASTM C349
ASTM C349 Standard Test Method is a specific procedure designed to measure the compressive strength of hydraulic-cement mortars. This test is unique in that it uses portions of prisms previously broken in flexure under Test Method C348. The method is integral for assessing the structural capabilities of cement used in construction.
Overview of the Test Method
Purpose: ASTM C349 provides a way to determine the compressive strength of hydraulic-cement mortars using the remaining portions of prisms that were initially used for flexural strength testing (C 348).
Scope: It covers the methods for preparing and testing these specimens to obtain compressive strength values.
Key Aspects of the Test Method
Apparatus:
Bearing Plates: Made of hard metal with specific thickness and hardness requirements.
Aligning Device: Ensures the proper positioning of bearing plates during testing.
Testing Machine: A hydraulic testing machine conforming to the requirements of Test Method C 109/C 109M.
Test Specimens:
Utilize both halves of each prism broken in flexure.
Selected specimens should be free of defects and meet minimum length criteria.
Procedure:
Specimen Preparation: Maintain specimens in specific conditions between flexure and compressive testing.
Testing: Carefully align specimens in the testing machine and apply load according to Test Method C 109/C109M.
Timing: Testing of modified cubes must follow the flexure test within a prescribed time limit.
Calculation and Reporting:
Calculate compressive strength in megapascals using the provided formula.
Discard results from faulty specimens and retest if necessary.
Report the average compressive strength of the tested specimens.
Significance of the Test Method
This test method allows for the efficient use of materials by obtaining two different strength values (flexural and compressive) from the same specimens.
It provides valuable data for reference purposes, contributing to the understanding of the material properties of hydraulic cement.
Precision and Bias
Precision: Defined limits on how much test results can vary within a single laboratory and between different laboratories.
Bias: The test method itself has no inherent bias, as the compressive strength value is directly defined by the test.
Application in the Construction Industry
ASTM C349 is widely used in cement manufacturing and quality control laboratories to assess the structural integrity and reliability of cement-based materials.
The method supports the construction industry's need for materials that meet strict quality and strength standards.
Conclusion
ASTM Standard Test Method C 349 plays a crucial role in the quality assessment of hydraulic-cement mortars. By reusing prism portions from flexural tests, this method not only promotes material efficiency but also provides comprehensive data on the material strength, ensuring the production and use of reliable and robust cement in construction projects.