Life-Cycle Assessment-based Feasibility Study of Spall Damage Rehabilitation using 3D Printing Technology
Spall damage to concrete pavement is often caused by heavy vehicles or low-quality construction materials. Spall damage occurs when loads from heavy vehicles are repeatedly applied to the joints between concrete plates, or from internal pressure caused by vapor evaporating from wet aggregates in hardened concrete. Since the damage worsens if it is not promptly addressed, the repairs must be made soon after the damage occurs. The most common existing spall repair method involves placing and curing fresh concrete. According to the unified facilities criteria published by the US Department of Defense, to properly cure a high-quality concrete patch, vehicles must be detoured around the job site for at least seven days. This could cause indirect losses of up to $140,000, based on information provided by the US DoD. This study proposes an alternative means of rehabilitating spall damage that uses the advantages of 3D-printing technology. This proposed method involves prefabricating a 3D concrete patch that can be inserted into a spall; the result is that the gap from the spall damage is filled faster than it would be if the existing spall repair method (partial-depth repair) were employed. This research also presents results from the Economic Input-Output Life Cycle Assessment (EIO-LCA) that compares the existing and proposed spall repair methods and investigates the feasibility of the more rapid spall repair method.
Measurement Comparison of City Roadway Intersection Models Obtained via Laser-scanning and Photogrammetry
This project compares and contrasts the suitability of certain measurements for a city roadway intersection of two point-cloud models obtained via a laser scanner and a UAV-borne camera via a photogrammetry workflow. The two methods are employed and a total of 21 measurements are collected and compared from their respective models. The selected site is prone to many accidents, and thus city engineers are considering how to redesign it for a more efficient traffic flow. Regarding accurate dimensioning, certain features in both models are compared for smaller- and larger-scale distances, considering a central point location and the benchmarks used for this relatively simple four-way intersection. A basic analysis of discrepancies was also completed, and the photogrammetric workflow was found suitable for use in this surveying application, and it can be used for fast analysis and measuring between closer-range points. Being richer in points and therefore containing more topographic information, the laser-scanning model is recommended for larger-scale measurements between features which are not in close vicinity.
Quantifying the Cache: The Premium for Solar Homes is Not Explained by Reduced Energy Costs
South Carolina has a tax policy that is very favorable to those wishing to install photovoltaic (PV) panels on their homes. A local resident contacted Clemson University for guidance on investing in PV. This paper uses the homeowner’s situation as a framework to investigate the value of solar energy from a financial perspective. By modeling multiple PV arrays, this paper demonstrates that solar panels are a good investment overall, largely due to favorable tax policies and rebates. Further, this study shows that the size of the system and the timing of the sale of the home (after installing solar panels) significantly influences the investment choice. Building on prior research, which shows that homebuyers depreciate solar faster than straight-line depreciation, this study finds that a 9kW array will add a $28,000 premium to a home sold one year after installing solar panels but only $14,000 to a home sold eight years after installing panels. Finally, this paper shows that the premium paid for solar homes is only partial explained by reduced energy costs. While homebuyers will pay a $28,000 premium for a 9kW array, only $11,000, or 39 percent, can be attributed to future energy savings. The remaining 61% is driven by nonfinancial benefits to solar.