Gravel Road Test Sections Insulated with Scrap Tire Chips: Construction and theFirst Year's Results

摘要

A test project that uses tire chips as an insulating layer to limit frostpenetration beneath a gravel-surfaced road is described. Tire chips, which are waste tires that have been cut into 2-in. pieces, are an attractive alternative to conventional insulation boards because they have moderate thermal resistance 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 U.S. The project was constructed in Richmond, Maine, in August 1992. It is 750 ft long, consisting of five sections with different thicknesses of tire chips and overlying soil cover and two control sections. Over 20,000 waste tires were used on this project. The primary goals were to determine the necessary thickness of tire chips to provide effective insulation and the minimum thickness of overlying soil cover needed to produce a stable riding surface. The thickness of the tire chip layers ranges from 6 to 12 in., while the thickness of the granular soil cover ranges from 12 to 24 in. The project is instrumented with thermocouples, resistivity gauges, 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 of service have shown that a 6-in. tire chip layer can reduce frost penetration by up to 25% and the gravel cover should be 12 to 18 in. thick to provide a stable riding surface. Cold regions, Gravel roads, Rubber chips in roads, Frost heave, Insulated gravel roads, Scrap tire chips in roads.