Cement for mining
It belongs to the group of CEM III cements (pozzolanic). In mining, cement can be used for concretes operating in the most difficult conditions. Therefore, the cement used for it must have high-quality properties, and above all, it must provide concrete with resistance to chemically aggressive environments, high water resistance and durability, little shrinkage and little creep.
SG special cements 42,5 i SG 32,5 for the mining industry, they meet these conditions. The essence of getting them is this. that active microsilica is added when grinding Portland clinker, in the amount of approx. 10% mass. Micro silica by binding with calcium hydroxide Ca(OH)2, leads to its reduction by approx 40-60%.
This direction of development of cements is observed in countries with high construction technology. Mining cement can be usefully used for structural repairs by spraying and for high-strength concretes (B > 60 MPa). The fineness of this cement is quite high and amounts to approx. 4800 cm²/g.
A special mining blast cement is also produced in two types: HSG -22.5 i HSG – 32.5. Both bind no sooner than after 1 hour, have a specific surface area after 3600 cm²/g. The content of granular blast furnace slag can be varied within limits as required 30-70% the whole mass of cement.
HSG cements of both varieties also contain microsilica and can be widely used in marine construction due to increased resistance to chloride corrosion. The fact is important from the investors' point of view. that mining cements do not travel more than 0 10% from their counterparts without microsilica.