Education
This seminar discussed lab and field tests that were conducted to evaluate the stiffness properties and quantify the contributions of FDR to overall pavement performance. For stabilized FDR, there is no guideline for GE. Some local engineers believe that the GE of FDR material should be greater than 1, especially for stabilized FDR. In addition, little information is available on how seasonal changes affect pavements with a stabilized FDR base. Because stabilized FDR contains less moisture and has higher stiffness than aggregate base, it is believed that stabilized FDR should be less susceptible to spring thawing. This seminar reviewed how lab and field tests were conducted to evaluate the stiffness properties and quantify the contributions of FDR to overall pavement performance. Falling weight deflectometer tests were also used to study the effects of seasonal changes on FDR, especially stabilized FDR. The presentation also highlighted test results, including the finding that all materials had lower stiffness in spring than in summer and fall. Most of the stabilized FDR materials tested, but not all, showed improved seasonal stiffness.