Graduation Year
2015
Document Type
Thesis
Degree
M.S.C.E.
Degree Name
MS in Civil Engineering (M.S.C.E.)
Degree Granting Department
Civil and Environmental Engineering
Major Professor
Alberto Sagüés, Ph.D.
Committee Member
Andrés E. Tejada-Martínez, Ph.D.
Committee Member
Qiong Zhang, Ph.D.
Keywords
Free Nitrite, pH, Porosity, Coarse Aggregate, Fine Aggregate
Abstract
Calcium nitrite as a corrosion inhibitor is mainly used to protect steel reinforcement in concrete by reducing its corrosion rate. Hence the effectiveness of calcium nitrite depends on its availability as a free nitrite in the pore solution. The present research work aims to determine the concrete mixture component mostly responsible for nitrite binding in concrete. Firstly, the experimental program included testing of nitrite binding in cement paste. Secondly, the effect of adding the fine aggregate (mortar mix) on nitrite binding was assessed. Finally, the mix with coarse aggregate (concrete mix) was evaluated. In-situ leaching method was used to obtain the pore solution that was needed.
Measurement of pore solution with the In-situ leaching method and after an average of 48 days showed that concrete specimens have the most nitrite binding capacity. Then, the binding of nitrite was less in mortar and paste specimens respectively. Therefore, concrete specimens bind more nitrite compared to the paste and mortar specimens. The binding ratio increased whenever the nitrite addition level increased. Nevertheless, the free nitrite were similar in the case of the lowest nitrite addition for all types of mix. The pH levels for the mixes with nitrite present, were lower than those of the control mixes.
Scholar Commons Citation
Alshehri, Saad, "Binding of Nitrite in Concrete, Cement Mortar and Paste" (2015). USF Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/5899
