A feasibility study for the use of propane as a subbase drying technique.

Michael Blahut (1)

Dr. Vernon Schaefer (2)

Dr. Chris Williams (3)

The use of propane as a soil drying technique will be studied to determine the economicand technical feasibility for use in transportation related projects. The need originates from the earthwork portion of a construction schedule, which can be severely delayed if the soil is too wet for compaction. The ultimate goal is develop an implement that can be used in the field and can be adapted to work with existing equipment; i.e. pulled by earth moving equipment. The laboratory drying device has provisions to receive the propane fuel, transfer the propane to heat through interchangeable instruments, output the heat onto the soil, and till the soil as it passes over the sample. A laboratory based

technical feasibility analysis is currently under way to determine the amount of propane in BTU's that is required to dry a soil to a desirable level that has an over optimum moisture content. Several types of drying instruments will be implemented with all using propane as their fuel source. Some of these heating instruments include forced air, direct flame and infrared heating. Soils typically used in Iowa for subbase and base courses will be used. The properties of the soils will be measured before and after drying. The properties that will be measured are dry unit weight, moisture content and the Atterberg limits. All soil types could benefit from a drier device but those with percent fines content above 20 will benefit the most. We will also investigate to determine if any chemical changes occur after the application of propane heat.

Key words: propane - compaction - earthwork - soil drying

(1) Graduate Student, Iowa State University, Civil Engineering, 394 Town Engineering, Ames, IA 50011,

Tel: (515) 745-9245, Email: meblahut@iastate.edu

(2) Professor, Iowa State University, Civil Engineering, 488 Town Engineering, Ames, IA 50011, Tel: (515)

294-9540, Fax: (515) 294-8216, Email: vern@iastate.edu

(3) Associate Professor, Iowa State University, Civil Engineering, 482A Town Engineering, Ames, IA 50011,

Tel: (515) 294-4419, Email: rwilliam@iastate.edu