Blast furnance slag cement

It is a cement manufactued by grinding specifically proportioned amounts of ordinary cement clinkers , with granulated blast furnance slag of selected quality . When Portland cement and slag are ground together , the resulting cement is known by the name Portland -sLAG CEMENT . When lime and slag are ground together it is called lime -slag cement . The percentage of slag in Portland slag cement varies from 40 to 70 percent whereas it varies from 70 to 90 percent in the case of lime slag cement . Lime slag cement is not very good resistat of air and frost and hence its use is restricted to only damp situation . Portland slag cement offers goof rsistance to corrosion and good bond with steel reinforcement . This cement is extensively used in the manufacture of pre-fabricated reinforced concreete units . There is one more cement in which slag is used . it is a sulphate-slag cement . in this cement slag varies from 80 to 90 percent . It also contains about 5 percent Portland cement clinkers . This cement is highly resistant to sulphate action and hence recommendd to be used in martine works and other underground works .