Natural silica-containing cement and concrete composition

A method of producing a concrete composition, comprising mixing together a cement which releases lime upon hydration, an aggregate material, water and a mineralogic silica source material which reacts with the lime to form calcium silicate hydrate, which binds as a strengthener in the concrete composition, so as to reduce the amount of lime in the concrete composition

• wherein the silica source material consists of feldspathic quartzite which is at least 50% by weight silica, said method including grinding said silica source material to produce a generally uniform comminuted material having a maximum particle size of about 45 microns, an average particle size of about 1 to 10 microns, and a specific surface area of from 4680 to 10,000 square centimeters/gram.

A method of producing a blended cement, comprising mixing together gypsum, portland cement clinker and a mineralogic silica source material which reacts with lime released from the gypsum and portland cement upon hydration,

• wherein said silica source material consists of feldspathic quartzite which is at least 50% by weight silica, and said method including grinding said silica source material to produce a generally uniform comminuted material having a maximum particle size of about 45 microns, an average particle size of about 1 to 10 microns, and a specific surface area of from 4680 to 10,000 square centimeters/gram.

A method of producing a concrete composition, comprising mixing together a cement which releases lime upon hydration, an aggregate material, water and a mineralogic silica source material which reacts with the lime to form calcium silicate hydrate, which binds as a strengthener in the concrete composition, so as to reduce the amount of lime in the concrete composition

• wherein the silica source material consists of feldspathic quartzite which is at least 50% by weight silica, said method including grinding said silica source material to produce a generally uniform comminuted material having a maximum particle size of about 45 microns, an average particle size of about 1 to 10 microns, and a specific surface area of from 4680 to 10,000 square centimeters/gram.

A method of producing a blended cement, comprising mixing together gypsum, portland cement clinker and a mineralogic silica source material which reacts with lime released from the gypsum and portland cement upon hydration,

• wherein said silica source material consists of feldspathic quartzite which is at least 50% by weight silica, and said method including grinding said silica source material to produce a generally uniform comminuted material having a maximum particle size of about 45 microns, an average particle size of about 1 to 10 microns, and a specific surface area of from 4680 to 10,000 square centimeters/gram.