Browsing University of Alaska Fairbanks by Subject "Calcium Chloride"
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Evaluation of Deicer Impacts on Pervious Concrete Specimens (Phase II)This research examined the chemical degradation of pervious concrete due to calcium chloride or magnesium chloride deicers. The project consisted of Phase I, Phase IIa, and Phase IIb. Phase I was previous work where a testing protocol was developed to mimic deicer applications. Phases IIa and IIb are parts of this project. Phase IIa used split tensile testing on Phase I specimens and further evaluated the chemical data from Phase I magnesium chloride applications. Phase IIb repeated the Phase I protocol for a larger number of new ordinary Portland cement specimens and evaluated the impact on strength using the unconfined compressive strength test. The hypotheses were based on complexation and precipitation chemistry. Specimens subjected to calcium chloride showed visible degradation. Specimens exposed to magnesium chloride deicer showed a large increase in loss of calcium ions in Phase I. Both deicers showed a loss in strength compared with a water control in Phase IIb. Results from the split tensile testing were inconclusive. The protocol from Phase I with the unconfined compression test may be an effective testing procedure to determine if different designs might be more resistant to chemical degradation by these two deicing chemicals.
Managing Dust on Unpaved Roads and AirportsFugitive dust emanating from vehicle traffic on unpaved roads and runways can have significant impacts on safety, health, quality of life, and the cost of maintenance. Managing dust provides a means of reducing these impacts. Shearing forces created at the interface between the surface and vehicle tires produce dust on unpaved surfaces. The dust produced becomes airborne as a result of turbulence created by moving vehicles. Once airborne, different monitoring techniques can be used to assess the amount of fugitive dust produced and to measure the effectiveness of dust management strategies. Communities can manage dust by properly constructing and maintaining the unpaved surface, reducing vehicle speed on roads, and with the proper use of dust palliatives. The proper gradation of aggregate, the right profile, and good drainage are all necessary for reducing fugitive dust from unpaved roads and runways. Moreover, reducing vehicle speed on unpaved roads can dramatically reduce the amount of fugitive dust and result in longer periods between maintenance events. Several different types of palliatives are available for both managing dust on unpaved roads and runways. The choice of palliative is dependent on aggregate gradation, traffic amounts, climate, and location (remote or accessible).