CommodityGREY PORTLAND CEMENT FOR CONSTRUCTION GRADE 42. 5 according to British standards BS12 / 96 or ASTM C-150. Chemical Composition Silicon Dioxide (SIO2) 21. 00Aluminium Oxide (AL203) 05. 30Ferric (FE203) 03. 30Calcium (CAO) 65. 60Magnesium (MGO) 01. ...