Low-Temperature Performance Improvement Measures for Emulsified Asphalt Cold Recycled Mixture: A Comparative Study

Abstract

With the application of cold recycling technology in cold seasons or northern regions, suitable low-temperature performance evaluation methods and low-temperature performance improvement measures of a cold recycled mixture (CRM) became very topical. This study attempts to clarify the manufacturing process of low-temperature beam specimens by simulating the secondary thermal compaction of the overlying hot mix asphalt mixture layer. Next, the applicability of indirect tensile tests, low-temperature bend tests, and SCB tests to low-temperature performance evaluation of CRM is evaluated. The low-temperature improvement measures of emulsified asphalt CRM are analyzed, showing that “primary rolling for 24 times + secondary rolling for 12 times” of the low-temperature beam specimens conforms to the field compaction state of the CRM layer. The low-temperature performance of CRM under different design schemes can be characterized by the fracture work in the indirect tensile tests and fracture energy in the SCB tests. Compared with the ordinary emulsified asphalt CRM, the mixture design scheme of “3% latex +5% regenerant” can significantly improve the low-temperature performance of CRM. The lower the temperature, the more pronounced the improvement effect. Considering that the low-temperature performance of CRM meets the road requirements, the design scheme of “3% latex +5% regenerant” is recommended, while the “3% latex” scheme is the most cost-effective.