Performance evaluation of Cold In-Place Recycling mixtures using emulsified asphalt based on dynamic modulus, flow number, flow time, and raveling loss

Abstract

The need for a Cold In-place Recycling using emulsified asphalt (CIR-emulsion) mixture with specific engineering properties calls for the use of a mix design and, recently, a new mix design procedure was developed for CIR-emulsion. As a part of CIR-emulsion mix design process, dynamic modulus, flow number, flow time and raveling tests were conducted to evaluate short- and long-term performance of CIR-emulsion mixtures at various testing temperatures and loading conditions. Based on the test results, the optimum emulsified asphalt content for CIR was determined. Dynamic modulus, flow number and flow time of CIR-emulsion mixtures using CSS-1h (cationic slow setting emulsion) were higher than those of HFMS-2P (high-float medium-setting emulsion modified with a polymer). Flow number and flow time of CIR-emulsion mixtures using RAP materials with softer residual asphalt was higher than those of CIR-emulsion mixtures using RAP materials with harder residual asphalt. The dynamic modulus, flow number and flow time were affected by both emulsion type and residual asphalt stiffness of RAP materials. Raveling loss of CIR-emulsion mixtures with 1.5% emulsified asphalt was significantly less than those with 0.5% and 1.0%.