基于pH值优化的改性乳化沥青制备与性能试验研究

Study on Preparation and Performance Experiment of Modified Emulsified Asphalt Based on pH Value Optimization

摘要:

改性乳化沥青是高速公路沥青路面养护的关键材料，其性能受原材料、制备工艺及环境参数等多重因素影响。为明确 pH 值对产品性能的作用规律，确定最优制备参数，以90#基质沥青、SBS?A改性剂、RHJ?A乳化剂为原料，采用高剪切乳化工艺，在固定其他试验条件不变的前提下，系统研究不同 pH 值对改性乳化沥青乳化状态、储存稳定性、筛上剩余量及蒸发残留物软化点、延度、弹性恢复、针入度等指标的影响规律。结果表明：pH值直接决定乳化剂活性与沥青分散效果，pH过高会降低乳化能力、增大筛余并引发分层沉淀；pH过低则会损伤低温延度等关键路用性能。本次试验条件下，体系最优pH值为2.5，此时乳化充分、性能均衡，可满足高速公路养护工程应用要求。

Abstract:

Modified emulsified asphalt is a key material for the maintenance of expressway asphalt pavement. Its performance is affected by many factors such as raw materials, preparation process and environmental parameters. To clarify the influence law of pH value on product performance and determine the optimal preparation parameters, and using 90# base asphalt, SBS-A modifier and RHJ-A emulsifier as raw materials, the high-shear emulsification process is adopted. Under the premise of keeping other test conditions unchanged, the influence laws of different pH values on the emulsification state, storage stability, sieve residue, and softening point, ductility, elastic recovery and penetration of evaporation residues of the modified emulsified asphalt are systematically studied. The results show that pH value directly determines the emulsifier activity and asphalt dispersion effect. Excessively high pH will reduce the emulsification capacity, increase the sieve residue and cause the stratified sedimentation. Excessively low pH will damage the key pavement performance such as low-temperature ductility. Under the test conditions, the optimal pH value of the system is 2.5. At this time, the emulsification is sufficient and the performance is balanced, which can meet the application requirements of expressway maintenance engineering.