Theses and dissertations

This collection includes both ASU Theses and Dissertations, submitted by graduate students, and the Barrett, Honors College theses submitted by undergraduate students. 

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Mechanical and Thermal Properties of Copper Slag Concrete

Description
In this investigation, copper slag was used as a coarse aggregate in four different mixes of concrete, consisting of 0%, 25%, 50%, and 100% copper slag by volume. Locally available Salt river aggregate was used as a control, and mixes were tested for density, strength, thermal conductivity, specific heat capacity,…

In this investigation, copper slag was used as a coarse aggregate in four different mixes of concrete, consisting of 0%, 25%, 50%, and 100% copper slag by volume. Locally available Salt river aggregate was used as a control, and mixes were tested for density, strength, thermal conductivity, specific heat capacity, and thermal diffusivity. Density was shown to increase with increasing copper slag content, increasing an average of 2298 kg/m^3, 2522 kg/m^3, and 2652 kg/m^3 in the 25%, 50%, and 100% mixes. This represents a 15% increase in density from 0% to 100%. Compressive strength testing indicated that the presence of copper slag in concrete provides no definitive strength benefit over Salt River aggregate. This result was expected, as concrete's strength is primarily derived from the cement matrix and not the aggregate. Thermal conductivity showed a decreasing trend with increasing copper slag content. Th control mix had an average conductivity of 0.660 W/m*K, and the 25%, 50%, and 100% mixes had conductivities of 0.649 W/m*K, 0.647 W/m*K, and 0.519 W/m*K, respectively. This represents 21% drop in thermal conductivity over the control. This result was also expected, as materials formed at higher temperatures, like copper slag, tend to have lower thermal conductivities. Specific heat capacity testing yielded results that were statistically indeterminate, though unlike strength testing this arose from inaccurate assumptions made during testing. This also prevented accurate thermal diffusivity results, as diffusivity is a function of density, thermal conductivity, and specific heat capacity. However, given the trends of the first two parameters, it is plausible to say that diffusivity in copper slag concrete would be lower than that of the control ix. All of these results were plugged into ASU's Pavement Temperature Model to see what effect they had in mitigating the UHI effect.
ContributorsLaughlin, Colin (Author) / Kaloush, Kamil (Thesis director) / Phelan, Patrick (Committee member) / Witczak, Kenneth (Committee member) / Barrett, The Honors College (Contributor)
Created2012-05
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Triply Periodic Minimal Surface Structure Porosity Effect on the Power Conversion Performance of a Thermogalvanic Brick

Description
humans are currently facing issues with the high level of carbon emissions that will cause global warming and climate change, which worsens the earth’s environment. Buildings generate nearly 40% of annual global CO2 emissions, of which 28% is from building operations, and 11% from materials and construction. These emissions must…

humans are currently facing issues with the high level of carbon emissions that will cause global warming and climate change, which worsens the earth’s environment. Buildings generate nearly 40% of annual global CO2 emissions, of which 28% is from building operations, and 11% from materials and construction. These emissions must be decreased to protect from further environmental harm. The good news is there is a way that carbon emissions can be decreased. The use of thermogalvanic bricks enables electricity generation by the temperature difference between the enclosure above the ceiling (i.e., the attic in a single-family home) and the living space below. A ceiling tile prototype was constructed that can make use of this temperature difference to generate electricity using an electrochemical system called a thermogalvanic cell. Furthermore, the application of triply periodic minimal surfaces (TPMS) can increase the thermal resistance of the ceiling tile, which is important for practical applications. Here, Schwarz P TPMS structures were 3D-printed from polyvinylidene fluoride (PVDF), and inserted into the electrolyte solution between the electrodes. Graphite was used as electrodes on the positive and negative sides of the tile, and Iron (II) and Iron (III) perchlorate salts were used as electrolytes. The maximum generated power was measured with different porosities of TPMS structure, and one experiment without a TPMS structure. The results indicated that as the porosity of the TPMS structure increases, the maximum power decreases. The experiment with no TPMS structure had the largest maximum power.
ContributorsWen, Chonghan (Author) / Phelan, Patrick (Thesis advisor) / Chen, Candace (Committee member) / Li, Xiangjia (Committee member) / Arizona State University (Publisher)
Created2022