Table 1.

Physical and chemical characteristics of Portland cement and silica fume.

Constituent (%)	PC	SF
CaO	57.87	0.45
SiO2	17.99	90.36
Al2O3	3.88	0.71
Fe2O3	3.36	1.31
MgO	1.49	-
SO3	2.47	0.41
K2O	-	1.52
Na2O	-	0.45
Cl	0.005	-
Loss of Ignition	3.37	3.11
Insoluble Residue	0.34	-
Free CaO	2.18	-
Specific surface (m2/kg)	394 a	21,080 b
Specific gravity	3.15	2.2

^a Blaine specific surface area. ^b BET specific surface area.