Laboratory evaluation and field demonstration of cold in-place recycling asphalt mixture in Michigan low-volume road

Cold-in place recycling (CIR) is a promising technology for the rehabilitation of asphalt pavements. However, the CIR asphalt pavement constructed in the field often has high air voids due to the presence of moisture during construction, and the moisture susceptibility of the pavement is crucial in determining its service life. Therefore, the objective of this research was to assess the laboratory performance of CIR asphalt mixes under freeze-thaw conditions (The mix prior to being subjected to freezing and thawing is labeled as "dry condition", while the mix that was placed in a refrigerator at -18°C for 16 hours and then transferred to a distilled water bath at 60°C for 24 hours is referred to as "post-freeze-thaw") and forecast in-situ pavement performance through pavement mechanistic-empirical design (PMED). Moisture susceptibility was evaluated by preparing CIR asphalt mixtures under dry condition and freeze-thaw conditions. The Disk-Shaped Compact Tension (DCT) test was utilized to approximate the low-temperature characteristics of the CIR mixture, while the rutting resistance properties were assessed using the Hamburg wheel tracking device (HWDT). The dynamic modulus test was used to assess the elastic deformation characteristics. The asphalt was extracted from the loose material, and the viscoelasticity properties were analyzed using the Dynamic Shear Rheometer (DSR) test and Asphalt Binder Cracking Device (ABCD) test, respectively. Based on the M-E inputs, the projected pavement deterioration was determined through calculations. The outcomes indicated that the dynamic modulus of the asphalt mixture after the freeze-thaw cycle dropped by 11-42% under varying temperatures and frequencies. The number of wheel passes for the dry condition CIR asphalt mixture was 8.4% higher than that of the post-freeze-thaw CIR asphalt mixture. The fracture energy dropped by 6% after freeze-thaw conditions. The emulsion asphalt used in the RAP (reclaimed asphalt pavement) made the binder softer, the fatigue and low-temperature cracking resistance of the material was enhanced, and decreased its resistance to rutting. the results of the M-E pavement design demonstrated that the freeze-thaw condition increased rutting, cracking, and IRI (International Roughness Index) distress. In conclusion, the application of CIR technology in the project enhanced the performance of the asphalt pavement with regard to its resistance to cracking and fatigue. As a result, CIR pavement may be suitable for use in low-traffic road.