A premixed cement paste for use in medical or dental applications. The premixed cement paste remains fluid when stored in a hermetically sealed condition, but hydrates and hardens to set when placed in a physiological environment. The cement paste includes at least one calcium silicate compound and at least one substantially water-free liquid carrier mixed with the at least one calcium silicate compound; the substantially water-free liquid carrier avoids hydration of the mixture during storage, but undergoes exchange with aqueous physiological solutions so that the cement past hydrates and hardens to set when placed in a physiological environment. The paste may be placed in the physiological environment by injection, for example. The at least one calcium silicate compound may be, for example, calcium silicate, dicalcium silicate, tricalcium silicate, or mixtures thereof. The substantially water-free liquid may be, for example, ethylene glycol, polyethylene glycol, liquid glycerol, glycerin, ethyl alcohol, vegetable oil, animal oil, silicon oil, hydroxypropyl methylcellulose, or mixtures thereof. The substantially water-free liquid carrier preferably includes water in an amount less than about 20% by weight percent of the paste. The paste may include a secondary phase for enhanced properties, such as, for example, a fibrous or particulate material for enhanced mechanical properties, biodegradable or soluble materials that provide room for bone in-growth, bioactive materials such as antibiotics that elute into the physiological environment from the set cement, and radio-opaque materials that enhance X-ray imaging of the cement.