骨料–砂浆界面预弱化水泥稳定碎石路用性能研究

Study on the Road Performance of Cement Stabilised Gravel with Emulsified Asphalt Pre-Weakened Aggregate-Mortar Interface

摘要: 内生微裂技术能够抑制水泥稳定碎石基层产生长、宽裂纹，在大温差、高蒸发量地区有广阔的应用前景，但骨料–砂浆界面弱化程度对水泥稳定碎石路用性能的影响规律还不甚明确。采用乳化沥青对水泥稳定碎石所用粗骨料表面进行涂层处理，实现骨料–砂浆界面的预弱化，系统研究了弱化骨料替换率对混合料抗压强度、回弹模量、收缩性能、抗冻性能、阻尼性能、抗剥落性能的影响。结果表明：界面弱化水泥稳定碎石(以下简称IWCTA)试件无侧限抗压强度与回弹模量均随弱化骨料替换率增加而降低，但干缩系数和温缩系数均随替换率增加而减小，表现出更好的抗收缩性能；经历冻融循环后，IWCTA试件表现出更好的抗冻性能，其电化学阻抗谱表征为阻抗变化率明显较小，Nyquist曲线的左偏程度不明显；IWCTA试件阻尼比随替换率的增加而增加，IWCTA基层抗车辆冲击性能更好；IWCTA试件磨耗剥落率随替换率增加略有增加。工程应用中可根据所在地年温差、蒸发率、道路等级等因素综合确定弱化骨料最佳替换率，推荐替换率为50%~100%。

Abstract: The endogenous micro-cracking technology has the potential to mitigate the formation of longitudinal and transverse cracks in cement-stabilized gravel bases, especially in regions characterized by large temperature variations and high evaporation rates. However, the influence of the degree of weakening at the aggregate-mortar interface on the performance of cement-stabilized gravel remains unclear. This study employs emulsified asphalt to coat the surface of coarse aggregates used in cement-stabilized gravel, achieving a pre-weakening of the aggregate-mortar interface. A systematic investigation is conducted on the effects of different weakening aggregate replacement rates on the compressive strength, rebound modulus, shrinkage characteristics, freeze-thaw resistance, damping performance, and spalling resistance of the mixtures. The results indicate that the unconfined compressive strength and rebound modulus of interface-weakening cement-stabilized gravel (referred to as IWCTA) specimens decrease with increasing replacement rates of weakened aggregates. Conversely, both the dry shrinkage coefficient and temperature shrinkage coefficient decrease with higher replacement rates, demonstrating improved anti-shrinkage performance. After undergoing freeze-thaw cycles, IWCTA specimens exhibit enhanced freeze resistance, indicated by significantly less variation in their electrochemical impedance spectra, with a less pronounced left shift in the Nyquist plot. The damping ratio of IWCTA specimens increases with the replacement rate, contributing to better performance against vehicular impact. Furthermore, the wear spalling rate of IWCTA specimens shows a slight increase with higher replacement rates. In practical applications, the optimal replacement rate of weakened aggregates can be determined based on annual temperature differences, evaporation rates, and road classification, with a recommended range of 50% to 100%.