再生沥青混凝土之使用分析

陈建旭¹、林桂仪²

Chen, Jian-Shiuh, Lin, Kuei-Yi

                       (成功大学土木工程学系)

摘要：道路工程所使用的沥青混凝土回收料（RAP）具有可回收再利用的特性，可以直接达到砂石减量及环保资源再利用等多项有利条件。但是，对于适当的RAP添加范围目前仍无明确的学理定义，公路相关单位也没有适当的方法检验再生沥青混凝土混合料（RAC）中RAP的添加量，使得承包商过量添加及使用更软软化剂的情形时有所闻。本研究收集分别代表国道、省道、县道的回收料，将其老化沥青萃取及回收，考量施工单位现场的时效性、经济性及简易性，发展一套黏度预测模式，研究结果显示此黏度预测模式能较ASTM黏度拌合图表更准确的预测拌合后的再生沥青胶浆（RAB）黏度，且能合理的预测RAP的适合用量，并提供RAP材料黏度的容许范围，检验RAC中是否有添加比AC-10更软的软化剂。混凝土的工程性质试验结果显示，AC-5虽能提高RAC的抗水侵害能力，但由于黑石头效应而无法提供足够的强度；重油因缺乏黏结力，其RAC试体松散且无工程强度，因此建议仅能使用比目标黏度降一等级的软化剂。

关键词：再生沥青混凝土；黏度预测模式；软化剂

Analysis of Recycled Asaphalt Concrete

Chen, Jian-Shiuh  Lin, Kuei-Yi

Abstract: Economic and environmental considerations have prompted the recycling of hot-mix asphalt mixture.  Decreasing supplies of locally available quality aggregate in many regions around the world, growing concern over waste disposal, and the rising cost of asphalt binder have resulted in greater use of reclaimed asphalt pavement (RAP) for road construction.  The purpose of this study was to understand the effect of different softening agents on the properties of reclaimed asphalt pavements (RAP) according to the binder and mixture properties.  Asphalt was extracted from RAP for using in blending with binder and mixture.  The recovered binders were blended with virgin asphalt (AC-10) at ten different concentrations.  Tests including penetration, ductility, viscosity, dynamic shear rheometer and moisture sensitivity were conducted to characterize the viscoelastic properties of RAP blends and the mechanical behavior of recycled asphalt concrete (RAC).  Results indicated that the rheological parameters of RAP blends correlated well with field observations.  The energy loss was found to be directly related to RAC’s resistance to moisture induced-damage.  A noticeable increase in energy loss with as much as 50 percent RAP was observed.  At 20 percent RAP, there was not enough RAP to change binder or mixture properties.  The predicted performance of mixtures containing up to 40 percent RAP by weight was shown to be similar to that of virgin material mixtures.  A model was developed to estimate the RAP content in terms of penetration, viscosity and energy loss.

Keywords: recycled asphalt concrete, prediction model for viscosity, softening agent