Corrosion inhibiting hydraulic additives and compositions containing same

An additive for hydraulic cement compositions is provided which advantageously provides corrosion inhibition and set acceleration, in combination with a high level of fluidity and retention of fluidity over a desired period of time. The cement additive comprises an accelerator selected from the group consisting of alkali or alkaline earth metal nitrates, alkali or alkaline earth metal nitrites, and mixtures thereof, and a plasticizer comprising copolymers of an ether comonomer and an ethylenically-unsaturated comonomer. Fluid hydraulic cement compositions and a method of preparing them are further provided comprising these additive combinations.