Injectable, ready-to-use two-paste cement-forming compositions comprise a first paste and a second paste. The first paste comprises a non-aqueous oil-based suspension of monocalcium phosphate monohydrate (MCPM) powder, at least one surfactant effective to improve compatibility of the oil and the MCPM, and an organic acid, with an oil to MCMP powder weight ratio of about 0.2 to about 0.5. The second paste comprises an aqueous suspension of β-tricakium phosphate (β-TCP) powder and a gel-forming polymer, with a water to β-TCP powder weight ratio of about 0.3 to about 0.5. The molar ratio of β-TCP powder to MCPM powder is greater than 1. An article of manufacture comprises a first compartment in which the first paste is contained, and a second compartment in which the second paste is contained. The compositions are useful for bone repair or replacement.