DEVELOPMENT OF A RATIONAL AND PRACTICAL MIX DESIGN SYSTEM FOR FULL DEPTH RECLAMATION (FDR)

In full depth reclamation (FDR), there is a need for a proper mix design procedure for selection of type and amount of additive. This research sought to develop a rational mix design system for FDR and to evaluate different additives used in FDR. Findings from the first phase of the study are presented in this paper. The first phase included initial mix design, construction of test sections and data acquisition immediately after construction of the test sections. Results showed that by compacting samples with the gyratory compactor, an optimum total fluid content for FDR mixes can be determined by using the total fluid content versus dry density criteria. Sealing compacted specimens with the CoreLok (Trademark) device is suggested for determination of bulk density. The number of gyrations (N sub design) recommended for use in mix design is 75. When using just water or asphalt emulsion, a bulk density equal to or more than 97% of the density obtained at N sub design should be obtained at the end of construction. For FDR with cement, a density equal to at least 91% of the density obtained at N sub design should be obtained at the end of construction. Falling weight deflectometer testing and testing of in-place cores after nine months are planned for the next phase of the study. These results will help in determination of the relative advantages of using one additive over the other.