The durability of the materials based on hydraulic binders represents their basic characteristic and the behavior of the cement in acid corrosive environments represents a nowadays concern, due to the increasing aggressiveness of the more and more various environments in which the civil and industrial constructions are exploited.

The paper presents the results obtained by studying the corrosive effect of 4 acids, inorganic and organic – hydrochloric acid, nitric acid, formic acid and acetic acid – on a type III/B cement, with a content of portland cement and ~70% blast furnace slag. The samples tested were cement pastes and plasters. Their behavior has been studied up to 180days of curing in acid solutions of 0.1mol/l concentration. The analyses carried-out were: mechanical strength measurements, chemical analyses of the core of the samples and of the corroded layers and X-ray diffraction analysis. The results of the analyses pointed-out the advanced degradation of the samples in all the corrosive solutions employed, with losses of the compressive strength between 68-73% of the etalon samples cured in water the same time and a good correlation of the results of the chemical analyses with those of the X-ray diffraction measurements.