The Certified Reference Material CRM has been developed by National Council for Cement and Building Materials (NCB), India  to calibrate Blaine Air Permeability Apparatus according to Indian Standard ‑ IS 4031 (Part ‑ 2) ‑ 1999. One set of CRM‑1002A9 consists of 4 sealed glass vials and each vial contains approximately 10g of powered Portland Pozzolana Cement.

 

Traceable to SI unit of measurement. The certified value and expanded uncertainty of CRM, estimated with known sources of bias will be given.

 

Instructions for use

• CRM should be used in controlled conditions, using calibrated equipment, by trained personnel.
• The Blaine cell calibrated for bed volume, preferably by and accredited laboratory, must be used.
• Before use, shake the material vigorously for 2 minutes in a suitable jar to break any lump or agglomerate.
• After opening the vial, the material should be protected from atmospheric moisture and used within 4 hours.
• One vial is sufficient for carrying out one time calibration for apparatus constant, taking measurements on three compacted beds, as required in IS 4031 (part 2): 1999. Leftover portion, if any, should not be used for standardization at a later date.
• For standardization, prepare the bed of CRM (standard sample) using 0.5 porosity, Alternatively, make a firm bed by trial method.
• Porosity of the test sample will have to be determined by trial method using the following equation given in IS 4031 (part 2) ‑ 1999, for calculating specific surface of test sample:
• W = p*v*(1‑e)
• Specific gravity of test sample and CRM being almost same (in Indian Cements), the application of above CRM simplifies calculation of apparatus constant for PPC and provides greater degree of accuracy in results.
• The material should be stored under non‑humid conditions to avoid any ingress of moisture/CO2.