**1. Introduction**

One of the growing areas of research interest is the development of eco-friendly alternatives to the OPC system. These low-lime calcium silicate cements harden and gain strength by carbonation (carbon mineralization), and thus store CO2 permanently. The objective of the study presented in this paper was to evaluate the sulfate resistance of lowlime carbonated calcium silicate (CCS) pastes. The experimental plan involved exposing paste powders made out of different carbonated CCSs (wollastonite, amorphous CS, and two types of commercially produced low-calcium binders (SolidiaTM cements)) to sodium sulfate and magnesium sulfate solutions for a period of up to 120 days. At various times during the exposure period (0.5, 1, 5, 10, 20, 60, 90 and 120 days), the paste + sulfate solution slurries were filtrated and separated into solids and leachates. The solids were subjected to thermogravimetric analysis (TGA) in order to quantify the amount of gypsum formed. The leachates were analyzed by the ion-chromatography (IC) and by the inductively coupled plasma optical emission spectroscopy (ICP-OES) techniques, to determine changes in the concentrations of the Ca, Mg, Na, Si and sulfate species.
