Portland Blast Furnance Slag Cement | PBFSC 32.5

Slag cement, has been incorporated into concrete projects for over a century to improve durability and reduce life cycle costs. Among its measurable benefits in concrete are better workability and finish ability, higher compressive and flexural strengths, and improved resistance to aggressive chemicals.

Portland Blast Furnace Slag Cement (PBFSC)
Complies with Pakistan Standard PS – 1631/1984; British Standard BS –146 – 1973 ; and American Standard ASTM C-150 TypeIV

PBFSC is used in coastal areas due to resistance to Sulphates and Alkalies.
PBFSC is used in massive constructions like Dams/Canals due to its inherent quality of low heat of hydration and expansion factor. Furthermore, lighter colour of the cement ensures decorative use in paints and due to higher fineness greater area can be covered.

PBFSC is manufactured from Portland Cement Clinker, Blast Furnace Slag and Gypsum.

Slag Cement is recycling of blast furnace slag has been used for a long time in the cement industry. It is often used in composite cement. Slag is not hydraulic by it self, but if an activator (e. g. lime) is present, it takes part of the hydration reactions and makes a substantial contribution to the hydration product. Blast furnace slag can also be used as a raw material for the manufacture of Portland cement clinker. In general slag contains 30-50 % lime, 30-40 % silica, 10-25 % aluminia, 0-20 % magnesia and minor elements, e. g. Sulfur, iron, manganese, titanium, sodium, potassium etc.

S.no	Constituents	BS 146:2002 Req:	Results
Chemical Composition % %
1	Loss on ignition (LOI)	5.00	1.37
2	Insoluble residue (IR)	5.00	0.30
3	Silicon Dioxide(SiO2)	--	27.71
4	Aluminum Oxide (AL2O3)	--	9.28
5	Iron Oxide (Fe2O3)	--	2.52
6	Calcium Oxide(CaO)	--	52.42
7	Magnesium Oxide (MgO)	--	3.48
8	Sulfate (SO3)	4.00	1.89
9	Chloride (Cl)	0.10	0.01
10	Sodium Oxide (Na2O)	--	0.22
11	Potassium Oxide (K2O)	--	0.54
12	Total Alkalies as (Na2O)	--	0.58
13	Titanium dioxide (TiO2)	--	--
14	Magnese Oxide (MnO2)	--	--
15	CaO – MgO/SiO2	--	2.02
Physical Properties
1	Specific Surface (Blaine)(m2/kg)	--	341
2	Standard Consistency %	28	28
3	Setting time (Vicat method)
	Initial (Minutes)	Min -50	180
	Final (Minutes)		280
4	Soundness (mm)	--	0.7
5	Compressive Strength (N/mm2)
	a. 2 Days	--	11.4
	b. 7 Days	12 – Min	21.4
	c. 28 Days	32.5 – 42.5	40.4
Remarks: Test Method as per BS EN 196: P 2 : 1995

Slag Cement
This is another variety of low heat cement. Grinding 35% to 65 % of granulated blast furnace slag with ordinary Portland cement clinker produces it. The higher the slag contents, the lower are the 3 and 7 days strengths but better is the resistance to chemical attack. Under German standards as much as 90% slag can be used with type HOZ cement and under Japanese standard up to 70% in the type BSCC. This cement is slower hardening compared to OPC- its strength compared to OPC in ASTM being as follows:

	OPC	B.F SLAG CEMENT
3 days strength	1,800	760
7 days strength	2,800	1,400
28 days strength	4,000	3,000

This cement besides being a low heat cement has also the advantage of being medley sulphate resistant although it cannot replace the highly sulphate resistance cement for marine piles and foundations. This cement has excellent resistance to weak organic acids present in the soil and has also the very desirable quality of protecting reinforcement steel better than any other cement.