Durability of stabilized base courses subjected to wet–dry cycles

Abstract

A laboratory study was undertaken to evaluate the durability of cementitiously stabilized aggregate specimens subjected to wet–dry (W-D) cycles, representing a base course in a pavement structure. Specifically, cylindrical specimens of aggregates stabilized with 15% cement kiln dust (CKD), 10% class C fly ash, or 10% fluidized bed ash were prepared, cured for 28 days, and then subjected to W-D cycles prior to testing for resilient modulus (M r). Four aggregates were selected in this experimental study: (1) Meridian, (2) Richard Spur, (3) Sawyer and (4) Hanson. Results showed that the M r values decreased as W-D cycles increased up to 30, except for Sawyer specimens stabilized with 15% CKD. These specimens exhibited an increase in M r values with W-D cycles up to 8, beyond which a reduction occurred. The performance of the stabilized specimens is believed to depend upon SAF (Silica, Alumina and Ferric Oxide compounds) and free lime of the stabilizing agents. Also, the optimum moisture content (OMC) and maximum dry density (MDD), were found to be a good indicator of performance pertaining to stabilization and W-D action. A regression model correlating M r with W-D cycles, SAF, free lime, OMC and MDD offered statistically promising results.