Practical Approach to Criteria for the Use of Lime-Fly Ash Stabilization in Base Courses (05-2435)
William F. Barstis, Mississippi Department of Transportation
John B. Metcalf, " "
In October of 2000 MDOT initiated a study to evaluate the long-term performance of LFA stabilized soil as a base course material. This study entailed: (1) FWD tests on both newer and older pavements; (2) Coring pavement at each FWD location to visually observe the condition of the layers, to obtain pavement thicknesses and for unconfined compressive strength (UCS) testing; Visual observation, backcalculated modulus, and in-situ structural layer coefficient values, showed that MDOT LFA stabilized soil base courses possess highly variable material properties and thicknesses. Recommendations were made to increase the average LFA material property values and reduce the spread in these values, by: (1) increasing in the required compaction of the LFA stabilized soil base layer to 96 percent modified Proctor effort and, (2) reducing variability by either improving the current method of field-mixed-in-place stabilization, or requiring plant-mixed material with placement of the blended material via a paver.