RE:RE:Anonymous again the killerKing, I would assume that they would add the CO2 (gas?) during the on site mixing process, They would have to find an optimal amount without it affecting the product. CVX should have access to silica fume cement powder through their supply aggreement with Lafarge, who have made this product for several years. As it was explained to me, silica fume is a processed silica and is a fine powder that we interground with clinker and gypsum. It could be blended in with portland cement powder. Not sure what the relationship or similarity between CO2 and silica fume is. Silica fume concrete has a higher compressive strength, and has a higher resistance to the effects of moisture and chemicals. They used it in the construction of the Confederation Bridge that goes to PEI. Happy boating!