Date of Award

12-17-2019

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Systems Engineering

First Advisor

Alexandru Biris

Abstract

Utilized globally in the construction industry, concrete is an integral component of homes, roads, airports, skyscrapers, and tunnels. Traditional concrete components are cement, fine aggregate (sand), coarse aggregate (gravel or crushed stone), and water. When cement and water compound together they will make a paste which binds all the aggregates together to make the concrete. Unfortunately, every one ton of cement manufactured emits 0.9 ton of CO2into the air. The goal of this two-part work was to obtain an environmentally friendly concrete. The first part used supplementary cementitious materials (SCM), fly ash and silica fume, to create concrete with high compressive strength, which reduces the cross-section area of the concrete structure and, in turn, reduces the amount of cement necessary. This would ultimately reduce CO2 emissions from cement production. We compared a traditional concrete mix with SCM mixes to determine the amount of cement that could be saved and the effect this would have on cement demand and production, especially for the highest global users. Trial and error were used to find the mix with the highest compressive strength. Economic feasibility was studied to show the amount of money that could be saved by using SCM concrete. The second part of this work focused on creating environmentally friendly concrete via different sizes (micro-scale and nano-scale) of the following photocatalytic materials: titanium dioxide, zirconium dioxide, and zinc oxide. These materials were tested in different ratios (3%, 6%, 9%, 12%, and 15%) in proportion to the cement to obtain a concrete that can clean itself and the air around it when exposed to sunlight. We used Methylene blue dye and Rhodamine B dye to represent organic pollutants on the concrete samples. Microscopic analysis was conducted using scanning electron microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS) to show the distribution of photocatalytic materials on the surface of concrete. After finding the optimum mix of concrete and amount of photocatalytic materials, we made a combined sample to observe its effect on color removal efficiency.

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