Low-Cost Rural Surface Alternatives Phase III: Demonstration Project TR-721

The objectives of the proposed Phase III project are to construct and monitor several more test sections around Iowa using additional stabilization methods employing different types of virgin and recycled materials. The economic and initial versus life-cycle maintenance costs for the different methods will be studied as was done in the Phase II project (TR-664). It is proposed that four to five additional demonstration sections be constructed in Hamilton County, including one control section. Similar demonstration sections will then be built in three additional counties distributed around Iowa (a total of 16 to 20 test sections over four counties), to cover a range of different aggregate sources, subgrade soil types, and weather conditions. All demonstration sections will then be tested and monitored through two winter freeze-thaw cycles, and the construction and maintenance costs will be tracked and analyzed as was done in the Phase II project. The most effective and economical stabilization methods will be identified, and a "How-To" guide will be written for county and district engineers to implement the stabilization methods. Additionally, tests will be performed at several existing macadam-based granular roadways around Iowa, to try to identify the surface-course material properties and subgrade conditions that lead to good long-term performance of non-bitumen macadam bases under granular-surfaced roads.