Accelerator admixture

An accelerator composition adapted to be used with sprayed cementitious compositions, comprising an aqueous solution or dispersion of a blend of Components 1-3:

• Component 1—aluminium sulphate
• Component 2—at least one of an alkanolamine, an alkylene diamine or alkylene 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 or lithium sulphate;
• Component 5—at least one of C1-C10 aliphatic mono-carboxylic acids, C1-C10 aliphatic dicarboxylic acids or their metal salts;
• Component 6—aluminium hydroxide;
• or
• Component 7—at least one of phosphoric acid or phosphorous acid.
• The components being present in the following proportions (active ingredients by weight);
• Component 1—from 30% to 60%, calculated on the basis of 17% aluminium sulphate;
• Component 2—from 0.1% to 15%
• Component 3—from 0.2% to 84%
• Component 4—up to 15%
• Component 5—up to 15%
• Component 6—up to 15%
• Component 7—up to 5%.