Cementitious slurries, methods, and assemblies for electrically grounding and corrosion-protecting a metallic structure

Abstract

A method for electrically grounding and corrosion-protecting a metallic structure includes combining a cementitious powder with water to form a cementitious slurry, applying the cementitious slurry to at least a section of the metallic structure, and curing the cementitious slurry to form a water impermeable and electrically conductive cementitious surround on the section. The cementitious powder includes a cement and a particulate carbonaceous material. The cementitious powder is combined with the water in a ratio of less than or equal to about 2.5 US gallons of water per 55 lb of cementitious powder.

We claim: 
     
         1 . A method for electrically grounding and corrosion-protecting a metallic structure, comprising:
 a) combining a cementitious powder with water to form a cementitious slurry, wherein the cementitious powder comprises a cement and a particulate carbonaceous material, and wherein the cementitious powder is combined with the water in a ratio of less than or equal to about 2.5 US gallons of water per 55 lb of cementitious powder;   b) applying the cementitious slurry to at least a section of the metallic structure; and   c) curing the cementitious slurry to form a water impermeable and electrically conductive cementitious surround on the section.   
     
     
         2 . The method of  claim 1 , wherein the ratio is between about 2.5 US gallons of water and 1.5 US gallons of water per 55 lb of cementitious powder. 
     
     
         3 . The method of  claim 1 , wherein the ratio is about 2.5 US gallons of water per 55 lb of cementitious powder. 
     
     
         4 . The assembly of  claim 1 , wherein the ratio is about 2.0 US gallons of water per 55 lb of cementitious powder. 
     
     
         5 . The assembly of  claim 1 , wherein the ratio is about 1.8 US gallons of water per 55 lb of cementitious powder. 
     
     
         6 . The method of  claim 1 , wherein the surround has a compressive strength of greater than or equal to about 50 psi. 
     
     
         7 . The method of  claim 1 , wherein the surround has a compressive strength of greater than or equal to about 2000 psi after 28 days of curing. 
     
     
         8 . The method of  claim 1 , further comprising, prior to step a):
 digging a hole in the earth for the metallic structure, wherein the hole is sized to leave a gap between the metallic structure and the earth; and   lowering at least a bottom portion of the metallic structure into the hole.   
     
     
         9 . The method of  claim 8 , further comprising pouring the cementitious slurry in to the gap, to apply the cementitious slurry to the bottom portion of the metallic structure. 
     
     
         10 . The method of  claim 1 , wherein the cement comprises Portland cement. 
     
     
         11 . The method of  claim 1 , wherein the particulate carbonaceous material comprises calcined petroleum coke. 
     
     
         12 . The method of  claim 1 , wherein the cementitious powder comprises between about 20 wt % and about 80 wt % Portland cement, and between about 30 wt % and about 80 wt % calcined petroleum coke. 
     
     
         13 . An intermediate assembly that is curable to yield an electrically grounded and corrosion-protected assembly, comprising:
 a metallic structure, wherein at least a portion of the metallic structure is buried in the earth; and   a cementitious slurry applied to at least a section of the portion that is buried in the earth, wherein the cementitious slurry comprises a cementitious product and water, wherein the cementitious product comprises a cement and a particulate carbonaceous material, and wherein the cementitious slurry comprises less than or equal to about 2.5 US gallons of water per 55 lb of cementitious product.   
     
     
         14 . The intermediate assembly of  claim 13 , wherein the cementitious slurry comprises between about 2.5 US gallons of water and 1.5 US gallons of water per 55 lb of cementitious product. 
     
     
         15 . The intermediate assembly of  claim 13 , wherein the cementitious slurry comprises about 2.5 US gallons of water per 55 lb of cementitious product. 
     
     
         16 . The intermediate assembly of  claim 13 , wherein the cementitious slurry comprises about 2.0 US gallons of water per 55 lb of cementitious product. 
     
     
         17 . The intermediate assembly of  claim 13 , wherein the metallic structure is a pole. 
     
     
         18 . The intermediate assembly of  claim 13 , wherein the cement comprises Portland cement. 
     
     
         19 . The intermediate assembly of  claim 13 , wherein the particulate carbonaceous material comprises calcined petroleum coke. 
     
     
         20 . The intermediate assembly of  claim 13 , wherein the cementitious product comprises between about 20 wt % and about 80 wt % Portland cement, and between about 30 wt % and about 80 wt % calcined petroleum coke. 
     
     
         21 . A cementitious slurry curable to form a water impermeable and electrically conductive cementitious surround on a metallic structure, the cementitious slurry comprising:
 a cementitious product comprising between about 5 wt % and about 70 wt % Portland cement, and between about 30 wt % and about 90 wt % calcined petroleum coke; and   water;   wherein the cementitious slurry comprises less than or equal to about 2.5 US gallons of water per 55 lb of cementitious product.