Phase-II would be done if test sections are needed as noted below. This would require funding for construction and monitoring. First Tire would like to propose a two test section located on the MnROAD driveway while comparing surcharge load thicknesses of 18-24 inches compared to 48 inches or more over 3 feet of compacted TDA. There are some varying experiences from different successful installations across the industry regarding how much (soil weight) material is required to successfully surcharge the TDA before the soil embankment can be successfully surfaced.
If these test results show a thinner volume of surcharge is required to construct a quality road, TDA may become a more easily designed material for use in conventional roadway construction practices. Additional testing can be done to this installation to document the effective capillary break TDA provides for road subgrades.