Economic Impacts of Fines in the Unbound Pavement Layers

AUTC project number: 510012

PI(s):

Juanyu (Jenny) Liu

Funding:
  • AUTC
  • ADOT&PF
  • Start Date: Aug 1, 2011
  • End Date: Dec 31, 2012

Project Summary

In Alaska's spring months, excess water thawing underneath road pavement wakens roads and other transportation infrastructure, causing great expense and inconvenience for travelers, commercial drivers and the state of Alaska. University of Alaska Fairbanks (UAF) researcher Juanyu Liu is examining how the fines (P200) in base materials effect frost susceptibility and support for vehicular loads during spring thaw. Realizing the variation in critical excess fines content, Liu's team is evaluating the financial impact of using allowable fines in the unbound pavement layers and will identify critical excess fines contents (i.e. threshold fines content) allowed in the typical Alaska unbound base courses. Expanding upon a recent UAF study, Liu is further investigating the impact of fines content on resilient modulus reduction base courses during thawing when frozen under different temperature gradients and with limited water access. To do this, Liu and her team simulate a closed water system by collecting soil specimens with different initial moisture and fines contents and freeze them in the frost heave cell with no access to water. Her team then tests resilient moduli of soil specimens under different and drained conditions. The testing will provide recommendations to determine the situations when ADOT&PF can relax stabilized base policies and/or reduce costs by allowing more fines in the base layers for highway construction.