Portland cement clinker and use thereof

A Portland cement comprising

• a Portland cement clinker, the Portland cement clinker being free of C.sub.4 A.sub.3 S and having the following pro-portions of clinker phases in % by wt.:
• --C.sub.3 S:
• 40 to 80
• --C.sub.4 AF:<20
• --C.sub.2 S<30
• --C.sub.3 A:<20
• and a SO.sub.3 content from 1.0 to 3.0% by wt., based on the clinker, obtained by burning a mixture of raw materials containing CaO, SiO.sub.2 Al.sub.2 O.sub.3, Fe.sub.2 O.sub.3, and an additive containing SO.sub.3 at a temperature from 1200.degree. centigrade to 1350.degree. centigrade,
• the Portland cement further including up to 2% by wt. of SO.sub.3 in the form of gypsum and/or anhydrite,
• the Portland cement having a specific surface area according to Blaine from 2,500 to 4,000 cm.sup.2 /g.

A Portland cement comprising,

• a Portland cement clinker having the following proportions of clinker phases, in percent by wt.:
• --AS:
• 40 to 80
• --C.sub.4 AF:<20
• --C.sub.2 S:<30
• --C.sub.3 A:<20
• and a SO.sub.3 content from 1.0 to 3.0% by wt., based on the clinker, obtained by burning a mixture of raw materials containing CaO, Sio.sub.2, Al.sub.2 O.sub.3, Fe.sub.2 O.sub.3 and an additive containing SO.sub.3 at temperatures from 1200.degree. to 1350.degree. centigrade,
• the SO.sub.3 content being from 1.5 to 2.5% by wt., based on the clinker,
• the additive containing SO.sub.3 being a calcium sulphate carrier selected from gypsum, anhydrite and/or industrial residues
• the Portland cement clinker being free of C.sub.4 A.sub.3 S,
• wherein the proportions of the C.sub.2 S and C.sub.3 A clinker phases add up to less than 5% by wt.,
• the Portland cement clinker having a content of free CaO from 0.5 to 5.0% by wt., and
• the Portland cement clinker having a total open porosity >8% by vol., and
• up to 2% by wt. of SO.sub.3 in the form of gypsum and/or anhydrite, having, a specific surface area according to Blaine from 2500 to 4000 cm.sup.2 /g.

A method of producing a blended cement, comprising the steps of

• forming a Portland cement clinker having the following proportions of clinker phases, in percent by wt.:
• --C.sub.3 S:
• 40 to 80
• --C.sub.4 AF:<20
• --C.sub.2 S:<30
• --C.sub.3 A:<20
• and a SO.sub.3 content from 1.0 to 3.0% by wt., based on the clinker, obtained by burning a mixture of raw materials containing CaO, SiO.sub.2, Al.sub.2 O.sub.3, Fe.sub.2 O.sub.3 and an additive containing SO.sub.3 at temperatures from 1200.degree. to 1350.degree. centigrade,
• the SO.sub.3 content being from 1.5 to 2.5% by wt., based on the clinker,
• the additive containing SO.sub.3 being a calcium sulphate carrier selected from gypsum, anhydrite and/or industrial residues
• the Portland cement clinker being free of C.sub.4 A.sub.3 S,
• wherein the proportions of the C.sub.2 S and C.sub.3 A clinker phases add up to less than 5% by wt.,
• the Portland cement clinker having a content of free CaO from 0.5 to 5.0% by wt., and
• the Portland cement clinker having a total open porosity >8% by vol., and
• adding to the Portland cement clinker granulated blast-furnace slag, pozzolans or other latent hydraulic materials individually or in blends.