Civil & Environmental Engineering
Senior Thesis Project: Preventing Salt Scaling
Hi! My name is Jen Kim, and I’m in the Structural Engineering program in the Civil and Environmental Engineering department. My chief interests lie in sustainable building and development, in particular focusing on improving infrastructural works. I am passionate about finding sustainable solutions to problems in post-conflict countries that are economically, environmentally, and culturally sustainable.
I previously conducted independent work with Professor Scherer and Professor Stefan Jacobsen from the Norwegian University of Science and Technology on addressing the problem of salt scaling by treating concrete with a solution of diammonium hydrogen phosphate (DAP). Salt scaling is commonly noted on sidewalk concrete, in which the difference in thermal coefficients of the concrete and of the ice that forms from the mixture of salt and water (from de-icing salts) causes cracks in the ice to propagate through the surface of the concrete, chipping out pieces of the concrete surface in scales. This problem makes the concrete susceptible to dangers such as damage due to internal frost action or corrosion of reinforcement steel.
In order to address this problem, I extrapolated the research work of a PhD student, Sonia Naidu, on the application of DAP on carbonate stones, to its application on concrete. Sonia’s work showed that a protective coating of hydroxyapatite (HAP) was produced that provided resistance to dissolution due to acid rain. My hope is to see whether a protective coating of HAP might be produced on concrete surfaces that will provide a layer between the ice and the concrete that will buffer the damaging effects of scaling. For my senior thesis, I am examining the effects of applying a solution of triammonium phosphate (TAP) in place of DAP over concrete in the hopes that this will produce a more efficient reaction for producing HAP.
An example of salt-scaling damage on a cement paste sample: