Graduation Year

2022

Document Type

Thesis

Degree

M.S.E.V.

Degree Name

MS in Environmental Engr. (M.S.E.V.)

Degree Granting Department

Engineering

Major Professor

Christopher L. Alexander, Ph.D.

Committee Member

Katherine Alfredo, Ph.D.

Committee Member

Ryan Toomey, Ph.D.

Keywords

Durability, Half-Cell Potential, Impedance, Ordinary Portland Cement

Abstract

The concrete manufacturing industry has faced challenges with reducing carbon dioxide emissions as it currently produces about 8% of the world’s anthropogenic carbon dioxide emissions. With global atmospheric carbon dioxide concentrations being higher than ever, the solution is urgent. Due to this, a more sustainable type of concrete has been proposed.Calcium silicate cement (CSC) composed of essentially the same raw materials as ordinary portland cement (OPC) cures through the consumption of carbon dioxide rather than hydration like OPC. CSC is being explored as a potential alternative to OPC, however, there is little to no information on its corrosion related durability.

The investigation presented in this thesis considers two CSC formulations meanwhile also comparing different steel performances in the formulations. Previous work [23] assessed corrosion performance of CSC considering carbon steel, however, due to the belief that galvanized steel may offer superior corrosion protection, it is being explored. The corrosionof steel reinforcement for OPC based structures has been previously researched and documented thus service life forecasting models currently exist. The investigation presented aims to provide service life forecasting of the proposed cement technology CSC. Laboratory specimens consisted of specimens in compliance with ASTM G-109 standard [4]. Testing performed on specimens included half-cell potential (HCP), macro-cell current density, and electrochemical impedance spectroscopy (EIS). The results this investigation provides includes corrosion steel penetration, chloride profiles, and pore solution composition. Time to cracking of the concrete cover for all cement and steel type combinations will be presented.

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