Optimizing on-site compaction processes for enhanced performance in cold recycling mixtures

Emulsified Asphalt Cold Recycled Mixture (EACRM) is commonly used in the upper base of heavy-duty asphalt pavement in the reconstruction and expansion project. This study aims at improving the road performance of EACRM layer by improving on-site construction technology. Firstly, the rolling technology of EACRM base was studied based on the upgrading and expansion engineering of Nanchang City to Zhangshu City Expressway. Furtherly, the optimum thickness of the EACRM layer was determined through layered cutting test of on-site core samples. Finally, the secondary hot compaction effect of EACRM on the compaction effect of the HMA overlay was studied. The results show that the EACRM base can achieve good flatness and compaction degree by using a combination of large tonnage rollers (with rubber wheels of over 30 t and double steel wheels of over 18 t). The optimal thickness of the single-layer EACRM is suggested as 8 cm-12 cm. When the thickness exceeds 12 cm, the compaction degree can be ensured by increasing the compaction work of EACRM layer. The secondary hot compaction of the EACRM layer will affect the compaction degree of the HMA overlay, which can be solved by increasing the rolling times. The experimental results of this study provide a solid foundation for further improving the construction quality and road performance of EACRM.