The surface energy of hardened cement pastes, before and after treatment by organic coating, and two individual cement paste components (CSH and ettringite) have been characterized by inverse gas chromatography (IGC) at 35 degreesC, using n-alkanes, 1-alkenes, benzene, chloroform and CCl4 molecular probes. The cement pastes were prepared by mixing an ordinary Portland cement (OPC) with water at a water/cement ratio (W/C) equal to 0.3 and 0.5. They were further coated with an epoxy resin (R) and triethylenetetramine hardener (H), separately, at a mass loading of 1 and 10 wt.%, respectively. Changes in the dispersive contribution to the surface energy (gamma(s)(d)) and Lewis acid-base interaction energies were found to be significantly dependent on the W/C parameter on the one hand, and the adsorption of H and R, on the other hand. (C) 2004 Elsevier B.V. All rights reserved.