Modeling and empirical formulas for chemical corrosion and stress corrosion of cementitious materials

The behavior of mortar, ordinary concrete and high strength concrete under chemical corrosion and stress corrosion attacks is studied in the presented work. The specimens were immersed into a variety of chemical solutions, namely, 5% and 0.5% ammonium sulfate solutions, 10% and 1% ammonium nitrate solutions, and under different flexural loads with load levels of 30%, 40% and 50% of their initial flexural strengths, respectively. The strength development of the specimens was studied. The depth of penetration of the attacking ammonium nitrate ions was also determined. A synergy effect factor which describes the simultaneous actions of mechanical stresses and chemical attacks is defined in this paper. Consequently, a strength model for cementitious materials was developed, and new equations describing chemical corrosion and stress corrosion of cementitious materials,i.e. strength-time-curves, are proposed.