Magnesium phosphate cement systems

Abstract

A mixture capable of forming a hard, bonded cement composition when admixed with water comprising magnesium oxide; a water soluble phosphate; a retarder selected from the group consisting of polycarboxylic acids, polyphosphonic acids, and salts of such acids; and an essentially inert aggregate filler. The retarder is preferably selected from the group consisting of citric acid, sodium citrate (monobasic), sodium citrate (dibasic), tartaric acid, trimellitic acid, nitrilotriacetic acid trisodium salt monohydrate, Dequest 2000 and Dequest 2006. The phosphate is preferably monoammonium phosphate and the filler is preferably silica sand and fly ash which are essentially free of calcium oxide and calcium carbonate. The mixture is admixed with water at a job site and used to fill holes in roads and other structures and is capable of being worked for at least seven minutes before initial set.

Dependencies are inferred from the claim text.