Sulfate
corrosion of cement in concrete analyzed by improved mathematical model
Saša Miletić
Marina Ilić
Radomir Folić
Mirjana Đurić
Slobodan Otović
The
paper gives a critical analysis of the equation that predicts and estimates the
progress of degradation for various building materials, recently proposed by
Matsufuji et al. After the analysis, the paper suggests an improved mathematical
model, particularly oriented to modelling of sulfate corrosion. The experiments
on two Portland cement samples and two Portland cement samples with 30 % of coal
ash were performed. The samples were immersed into the 10%
(NH4)2SO4
solution and the concentrations of the
ions in both systems, the solution
and the material, were measured. As a parameter that quantifies cement
degradation, a quantity of bonded
ions was suggested. By using the
obtained data, mathematical models for description of sulfate corrosion of four
examined samples were defined. The models were applied for an analysis of ash
and non ash samples behaviour. They allowed not only better explanations of
degradation during the investigated period of time but also showed a significant
resistance of ash systems to the sulfate corrosion.
Ključne reči: Concrete corrosion, sulphate corrosion, mathematical modelling.