The results of an experimental research on the factors responsible to a greater extent for the action of simulated acid precipitations on cement concrete works, both in static and in dynamic conditions, are discussed. The influence of the cement type, the role of calcium hydroxide, the influence of water-cement ratio, and the retard effect on assault, owing to a surface treatment with a water repellent agent, are emphasized. (C) 1998 Elsevier Science Ltd.