Thesis - University Access Only
Master of Science (MS)
Department / School
The goal of this project was to determine the feasibility of using class F flowable fill to backfill horizontal heat exchanger trenches. Crushed quartzite was added in varying degrees to enhance the thermal properties of the mixture. Three phases of testing were conducted to determine the overall performance. Thermal conductivity tests were run to obtain the thermal properties of the mixtures. Shrinkage tests were performed to determine how well the grouts maintained their initial volume. Finally, long term thermal performance tests were run to evaluate how well the mixtures performed under actual thermal loading. The results of the testing show that the thermal conductivity of these mixtures can easily be enhanced with the addition of quartzite. Low shrinkage values were observed in all of the flowable fill mixtures tested. The thermal performance tests indicated that all but one of the mixtures tested held more than fifty percent of their initial water content under the imposed thermal loading. A final mixture of 35 percent fly ash 35 percent quartzite, 25 percent water, and 5 percent portland cement by weight was recommended for backfilling horizontal heat exchanger loops.
Library of Congress Subject Headings
Fills (Earthwork) -- Thermal properties
Heat -- Transmission
South Dakota State University
Lucht, Douglas A., "Thermal Performance of Flowable Fill Mixtures for Horizontal GSHP Systems" (1995). Electronic Theses and Dissertations. 142.