Industry Reports
| Report No. | IP13(jot this number down to order) |
| Title | Tire Chips as Subgrade Insulation Field Trial |
| Author(s) | Humphrey, Dana N., Univ. of Maine, & Eaton, Robert, U.S. Army corps of Engineers |
| Publisher | |
| Pub. Date | October 19-22, 1993 |
| Pages | 15 pages |
| Keywords | |
| Description | A test project that uses tire chips as an insulating layer to limit frost penetration beneath a gravel-surfaced road is described. Tire chips, which are waste tires that have been cut into 50 mm (2 in.) to 300 mm (12 in.) pieces, are an attractive alternative to conventional insulation boards because they have a high thermal resistivity and are durable, free draining and low-cost. Furthermore, this application has the potential to make an important contribution to disposing of the more than 2 billion waste tires that are currently sitting in huge open piles across the United States. The project was constructed in Richmond, Maine, in August, 1992. It is 230-mm (750-ft) long and consists of five sections with different thicknesses of tire chips and overlying soil cover. In addition, there are two control sections. Over 20,000 waste tires were used on this project. The primary goals were to determine the thickness of tire chips needed to provide effective insulation and the minimum thickness of overlying soil cover needed to produce a stable riding surface. The thickness of the tire chop layer ranges from 152 mm (6 in.) to 305 mm (12 in.) while the thickness of the granular soil cover ranges from 305 mm (12 in.) to 610 mm (24 in.). The project is instrumented with thermocouples, resistivity gages, groundwater monitoring wells, and a weather station. In addition, the strength of the road surface is periodically measured with a heavy weight deflectometer. Results from the first year in service have shown that a 152-mm (6-in.) thick tire chip layer can reduce frost penetration by up to 40%. The gravel cover over the tire chips should be 305 to 457 mm (12 to 18 in.) thick to provide a stable riding surface. |
| Postage | $ 2.00 : U.S. $ 2.20 : Canada/Mexico $ 2.40 : Rest of the World |
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