ASTM C1891 is the standard test method for determining the fineness of hydraulic cement by air jet sieving at 45-µm (No. 325). It provides a defined approach for evaluating how finely cement has been ground, which is an important factor in product consistency and quality control. By focusing on a specific sieve size and test technique, this ASTM standard helps support repeatable results when assessing cement fineness for technical and procurement purposes.

Overview of ASTM C1891

The Standard Test Method for Fineness of Hydraulic Cement by Air Jet Sieving at 45-µm (No. 325) is intended to measure cement fineness using an air jet sieving procedure. In practical terms, it gives laboratories and manufacturers a standardized way to assess the fraction of material retained at the 45-µm threshold. ASTM C1891 is useful where consistent particle size characterization is needed to compare cement lots, support specification review, or confirm product uniformity during testing and production.

Common use cases of ASTM C1891

This standard is commonly used in cement testing laboratories, manufacturing quality control, and incoming material evaluation for hydraulic cement. It may also be referenced during product qualification, lot verification, and routine consistency checks where fineness is a relevant property. Because the method centers on air jet sieving, it is especially relevant to workflows that rely on controlled sieve-based measurement and documented test results for cement performance assessment.

Benefits of using ASTM C1891

Using ASTM C1891 helps bring consistency to fineness testing by applying a recognized ASTM method for hydraulic cement. That can improve comparability between test results, support compliance efforts, and reduce ambiguity in procurement or specification review. For producers and labs, the standard also aids quality control by providing a defined procedure for evaluating whether cement fineness aligns with expected product targets and technical requirements.

• Hydraulic cement fineness testing
• Air jet sieving at 45-µm (No. 325)
• Quality control and lot comparison
• Laboratory and production evaluation