Certification of SRM 114q :

Abstract

The standard reference material (SRM) for fineness of cement, SRM 114, is an integral part of the calibration material routinely used in the cement industry to qualify cements. Being a powder, the main physical properties of cement, prior to hydration, are its surface area and particle size distribution (PSD). Since 1934, NIST has provided SRM 114 for cement fineness and it will continue to do so as long as the industry requires it. Different lots of SRM 114 are designated by a unique letter suffix to the SRM number, e.g., 114a, 114b, …. ,114q. A certificate that gives the values obtained using ASTM C204 (Blaine), C115 (Wagner) and C430 (45 µm sieve residue) is included with each lot of the material. The supply of SRM 114p, which was released in 1994, was depleted in 2004. Therefore, a new batch of SRM 114 needed to be developed. This process included selection of the cement, packaging the cement in small vials, and determination of the values for the ASTM tests reported. In this case, the Blaine, Wagner and 45 µm sieve residue were the tests used. Later the particle size distribution (PSD) will be added. The purpose of this report is to provide a detailed description of the process used to package and certify SRM 114q. All measurements used for the certifications are provided along with descriptions of the statistical analyses.

Identifying Improved Standardized Tests for Measuring Cement Particle Size and Surface Area

“…From the beginning, it was stated that this is a relative test as it depends on the shape of the particles and the compaction level or porosity of the bed. For this reason, ASTM C204 Section 4.1 states that the calibration of the instrument must be done by using a standard reference material (SRM), such as SRM 114 (5,6).…”

Certification fo SRM 46H

“…From those numeric results, the 2.5 % and 97.5 % quantiles of the distribution for mr45, can be seen to be 6.64 % and 8.14 %. [3],df [3]) y58=c ( 3.39592489013184,3.4889533140058 , NA,3.42349535881825, 3.29703267059646,3.4255467891740 7, 3.22355289421158,3.4613845538215 3, 3.87116134840452,3.7307461492298 5, 3.52070414082817,3.5831919353228 9, 3.68815592203898,3.6681659170414 8, 3.52647352647353,3.7732082251946 5, 3.71368673255466,3 The particle size distribution (PSD) is given in Table 5 and Figure 9. …”

“…Seventeen vials were blended together to obtain the material needed for the tests. Two measurements were done: 3.27 g/cm 3 and 3.30 g/cm 3 . These values are given for information only and are not certified values.…”

“…Blaine: Analyses for specific surface area using ASTM Standard Test Methods C 204-00 were performed on four samples at NIST. SRM 114q Portland Cement Fineness Standard was used for calibration and the density was assumed to be 3.15 g/cm 3 as recommended in the SRM 114q certificate. The Blaine value was determined as 3720 cm 2 /g ± 36 cm 2 /g (372.0 m 2 /kg ± 3.6 m 2 /kg).…”

“…Different lots of SRM 114 are designated by a unique letter suffix to the SRM number. A certificate that gives the values obtained using ASTM C 204 (Blaine) [1], C 115 (Wagner) [2] and C 430 (45 μm residue) [3] is included with each lot of the material.…”