The invention relates to a composition for injectable cement, comprising a mineral sold phase, a separate liquid phase and, optionally, microparticles of a biocompatible and biodegradable polymer. The mineral solid phase comprises a mixture of powders with the molar composition: (CP)6 (CaO)y (SrCO3)z, [CP being CaHPO42H2O, CaHPO4, Ca1-xSrxHPO4, an equimolar mixture of bis(Ca(H2PO4)2, H2O and CaO, or a mixture of two or three of said compounds] and y+z=4?1. The liquid phase comprises pure apyrogeneic water or a saline aqueous solution with pH 4 to 9. The ratio L/P [volume of liquid phase/mass of solid mineral phase] is at least 0.4 ml/g. The above is of application as bone replacement.