Portland cement is calcium silicates for the most part. The lime that most people refer to is hydrated lime, calcium hydroxide. These are two very different products. You can produce either from limestone, one of the most common minerals on earth. I say again, I do not use lime in my pc. I do use a product that was produced mostly from limestone.
From the Federal Highway Administration - a definition of portland cement.
"ASTM C 150 defines portland cement as "hydraulic cement (cement that not only hardens by reacting with water but also forms a water-resistant product) produced by pulverizing clinkers consisting essentially of hydraulic calcium silicates, usually containing one or more of the forms of calcium sulfate as an inter ground addition." Clinkers are nodules (diameters, 0.2-1.0 inch [5-25 mm]) of a sintered material that is produced when a raw mixture of predetermined composition is heated to high temperature. The low cost and widespread availability of the limestone, shales, and other naturally occurring materials make portland cement one of the lowest-cost materials widely used over the last century throughout the world. Concrete becomes one of the most versatile construction materials available in the world."
Cement contains lime, so all pc contains lime. Its what gives pc its high pH, protecting it against rot. --- In papercreters@yahoogroups.com, spaceman <Spaceman@...> wrote:IF you use lime, maybe. Lime has advantages and disadvantages. I don't use it in my pc.
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