DURABILITY OF SOME PORTLAND-CEMENT PASTES IN VARIOUS CHLORIDE SOLUTIONS

Hardened pastes of ordinary Portland cements, Portland pozzolanic and sulfate resisting cements have been stored for up to one year in solut ions with 5% MgCl2, CaCl2, NH4Cl and NaCl. The penetration. of chlorid e ions into the pastes is influenced by the type of cement and by the attached to the chloride ion. The investigation has shown, that the pe netration of chloride into Portland pozzolanic cement is the lowest, f ollowed by ordinary Portland cement, whereas sulfate resisting cement has the highest depth of penetration. The penetration of chloride was related to great extent to the amount of free lime. Pozzolanic Portlan d cement pastes therefore have the highest resistance to chloride atta ck.