Process for using sludge from geothermal brine to make concrete and concrete composition

A process for using siliceous sludge precipitated from a silica-rich geothermal brine to produce a structural concrete material, the process comprising:

• a. disposing a layer consisting essentially of siliceous sludge precipitated from silica-rich geothermal brine onto ground soil;
• b. disposing a layer of cementitious material onto said ground soil, said cementitious material consisting essentially of Portland type cement and flyash;
• c. mixing said layers of siliceous sludge and cementitious material and adding a sufficient amount of activating media to cause the cementitious material to be activated;
• d compacting the mixed layers of siliceous sludge and activated cementitious material;
• and
• e. permitting the mixed, compacted layers of siliceous sludge and activated cementitious material to cure into a structural concrete material.

A process for using siliceous sludge precipitated from a silica-rich geothermal brine to produce a structural concrete material, the process comprising:

• a. combining siliceous sludge precipitated from silica-rich geothermal brine with a cementitious material and a sufficient amount of activating media to cause the cementitious material to activate, said cementitious material consisting essentially of Portland type cement and flyash;
• b compacting the combined geothermal sludge, cementitious material and activating media;
• and
• c. permitting the combined, compacted geothermal sludge, cementitious material and activating media to cure into a structural concrete material.

A process for using siliceous sludge precipitated from silica-rich geothermal brine to produce a concrete material, the process consisting essentially of:

• a. dewatering the siliceous sludge so that the weight percent of water in the sludge is
• b. combining the dewatered siliceous sludge with a hydraulic cementitious material to provide a dry weight ratio of the sludge to the cementitious material of between about 3 and about 12, said hydraulic cementitious material consisting essentially of Portland type cement and flyash;
• c. combining with the siliceous sludge and hydraulic cementitious material a sufficient amount of water, including any remaining in the siliceous sludge, to cause activating of the hydraulic cementitious material;
• and,
• d. permitting the mixture of the siliceous sludge, cementitious material and the water to cure so as to form a structural concrete material with a compression strength of at least about 2500 psig.

A structural concrete material consisting essentially of:

• a. a siliceous sludge precipitated from silica-rich geothermal brine;
• b. a cementitious material capable of being activated by an activating media, said cementitious material consisting essentially of Portland type cement and flyash, said cementitious material being present in an amount such that the dry weight ratio of siliceous sludge and cementitious material is greater than about 3;
• and
• c. a sufficient amount of activating media to cause the cementitious material to activate and enable the siliceous sludge and cementitious material to cure into a structural concrete.