Date of Graduation

5-2013

Document Type

Thesis

Degree Name

Bachelor of Science in Civil Engineering

Degree Level

Undergraduate

Department

Civil Engineering

Advisor

Braham, Andrew

Reader

Coffman, Richard A.

Second Reader

Hall, Kevin D

Abstract

Often, a direct correlation is observed between a country’s transportation network and economic development. Evidence of this is observed all over the world. Full Depth Reclamation (FDR) is a roadway recycling technique that mills and mixes the existing roadway with a stabilizing agent and then re-compacts the mixture to create a thicker, stabilized pavement layer. This method is both cost effective and environmentally friendly, making it a very appealing option as the need to rehabilitate or increase the structural capacity of existing roads grows. In this study, the material characterization of FDR was examined as a composite material of both asphalt concrete pavement and some soil. This was accomplished by comparing different compaction methods utilized for both soil and Hot Mix Asphalt (HMA) compaction. The effects of different compaction methods on the strength of the FDR mixtures were evaluated. The Superpave Gyratory Compactor is typically used for the compaction of HMA samples in the lab, and the Proctor hammer is the most common method of compaction for soil samples. In addition to these two methods, different sized compaction molds and varying amounts of compaction effort were compared as well. Optimum moisture contents for each compaction method were developed by compacting FDR samples at 2, 4, 6, and 8 percent water content and determining the dry density of the samples at each water content. With the exception of two, the slotted mold SGC compaction method and the modified Proctor method, the compaction curves displayed similar trends and could be used to easily identify an optimum moisture content. Two strength tests, the Marshall Stability and Flow test and the Indirect Tensile Strength Test (ITS), were then used to evaluate the effectiveness of FDR samples compacted by each of the methods. For both the Marshall Stability test and the Indirect Tensile test, the SGC samples had higher strengths. The slotted SGC samples had a slightly higher stability and tensile strength than the unslotted SGC samples. The tensile strength ratios, which compare tensile strength of moisture conditioned samples to the tensile strength of unconditioned samples, showed that the strength of the FDR samples was decreased by at least 30% when moisture conditioned. Overall, samples compacted in the gyratory compactor seemed to be stronger and more durable. Future research should be done to observe the effect of optimum moisture content on the strength of an FDR mixture.

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