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Within the pavement industry, there exists a continually growing sustainability emphasis. Cold in-place recycling (CIR) of flexible pavements has some potential sustainability implications but has yet to be soundly established on a large scale or fully characterized in terms of performance. Currently-established design and testing procedures for traditional asphalt provide a logical starting point but should be evaluated and possibly modified to accommodate differences within CIR relative to traditional asphalt (e.g. use of mixing water). This paper's objective is to evaluate CIR using several available performance tests originally developed for asphalt concrete and assess their ability to characterize CIR, specifically for a diverse array of binding agents. Tests evaluated are the Cantabro durability test, the bending beam rheometer (BBR) mixture beam test, wheel tracking in the Asphalt Pavement Analyzer (APA) and Hamburg Loaded Wheel Tester (HLWT), a loaded wheel fatigue test, and an indirect tensile (IDT) crack characterization test. Based on results of this paper, Cantabro and BBR tests are not recommended, HLWT and loaded wheel fatigue do not appear promising, APA appears promising, and IDT appears promising and should be studied further. INTRODUCTION AND BACKGROUND Within the pavement industry, there exists a continually growing sustainability emphasis. Cold in-place recycling (CIR) of flexible pavements is one pavement rehabilitation technique with potential sustainability benefits. However, CIR processes have yet to be soundly established on a large scale. Further, CIR is not fully distinguished in terms of performance relative to other recycling options such as traditional asphalt mixtures incorporating high percentages of reclaimed asphalt pavement (RAP). Traditional plant recycling aligns more closely with that of traditional asphalt and, consequently, is reasonably established. Conversely, CIR introduces factors not present in plant recycling or traditional asphalt such as binders with vastly differing properties (e.g. portland cement and asphalt emulsion), cold mixing temperatures, use of mixing water, and similar. Therefore, while currently established design and testing procedures for traditional asphalt mixtures provide a

This paper evaluates cold in-place recycling (CIR) moisture-density relationships. Phase 1 describes the Mississippi Department of Transportation (MDOT) US-49 CIR project and performs complementary Proctor compaction testing, a key component of MDOT’s US-49 design/construction protocols. Phase 2 evaluates the Superpave Gyratory Compactor (SGC) in place of Proctor compaction as MDOT is interested in its future use. Over 300 SGC specimens were compacted using different materials, gradations, binders, and moisture contents. The key finding is that moisture content had no meaningful effect on dry density in the range where Proctor compaction would detect an optimum moisture content (OMC). Because SGC-compacted dry density appears unrelated to moisture content (within reason), Proctor OMC does not seem as informative for CIR as for soil or crushed stone. Therefore, SGC compaction is recommended, likely at a fixed moisture content, for CIR mixture design.