| abstract |
An accelerator composition for use with sprayed cementitious compositions, which is an aqueous solution or dispersion of a blend of the essential Components 1-3 Component 1 - aluminium sulphate Component 2 - at least one of an alkanolamine and an alkylene diamine or triamine Component 3 - hydrofluoric acid optionally with at least one of Components 4-7, with the proviso that at least one of Component 4 or Component 5 be present: Component 4 - at least one of sodium hydroxide, potassium hydroxide, lithium hydroxide, magnesium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, magnesium carbonate, sodium sulphate, potassium sulphate, magnesium sulphate and lithium sulphate; Component 5 - C 1 - C 10 aliphatic mono- and dicarboxylic acids and their metal salts; Component 6 - aluminium hydroxide; Component 7 - at least one of phosphoric acid and phosphorous acid. The accelerators have excellent long-term stability and work well with "difficult" cements, such as some Japanese OPCs. |