Influence on Compaction of Cold Recycled Mixes with Emulsions Using the Superpave Gyratory Compaction: Fid-Bau Portal

Influence on Compaction of Cold Recycled Mixes with Emulsions Using the Superpave Gyratory Compaction

Gao, Lei / Ni, Fujian / Charmot, Stephane / Luo, Hailong

Cold in-place recycling (CIR) has been increasingly applied in many areas of China, but there is no widely accepted method for the mix design of CIR. The compaction of cold recycled mixtures in the field varies significantly in different working conditions. It is therefore necessary to study the compaction characteristics of cold recycled mixtures. In this study, the primary compactibility energy index (PCEI) and secondary compactibility energy index (SCEI) of CIR were defined from the gyration compaction curve to evaluate the effect of compaction temperature, asphalt emulsion content, moisture content, aggregate gradation, and initial cure time. The control variable method was adopted to conduct the CIR compaction tests. The compaction parameters of CIR were obtained and analyzed statistically. The results from this study indicate that the SCEI of cold recycled mixtures is significantly affected by all variables and the regression of $N_{des}$ is linear relative to the compaction temperature and asphalt emulsion content. The effect of compaction temperature is much more significant than the other factors. Based on the effect of moisture content on PCEI and SCEI, a new method to determine the optimum moisture content of CIR is provided. The effect of initial cure time actually represents the effect of moisture content to some extent.