Study on Cold Recycled Asphalt Mixtures with Emulsified/Foamed Asphalt in the Laboratory and On-Site

Millions of tons of reclaimed asphalt pavement (RAP) and reclaimed aggregate or reclaimed inorganic binder stabilized aggregate (RAI) is produced every year in China. The cold recycled mixture (CRM) technology reduces fuel consumption, emissions, and cost and utilizes the high content of RAP. In this paper, six types of CRM with varying RAP/RAI composition and asphalt binders were investigated. The laboratory tests included strength indicators, high temperature stability, low temperature crack resistance, water stability, and dynamic modulus. A full-scale trial section was constructed after the laboratory tests. Except for low temperature failure strain without secondary compaction in the mixture design, test results illustrated that the performances of different CRMs met the specifications. The cement addition limited the thermo-viscoelastic behavior of the CRM. The RAI contents had reduced the water sensitivity of CRM, and the emulsified asphalt CRM had better performance than the foamed asphalt CRM. The performances of samples cored from the test section in the field met the specifications and were lower than that in the laboratory. The curing conditions in the field were not as effective as in the laboratory. The curing conditions and compaction method should simulate the conditions in the field to guide the CRM selection and mixture design.