Effects of Compaction Temperature on the Volumetric Properties and Compaction Energy Efforts of Polymer-Modified Asphalt Mixtures

In order to determine a proper compaction temperature that affects the workability and compactibility of the polymer-modified asphalt（PMA）, the effect of compaction temperature was examined on the volumetric properties and the compaction energy indices. Change in compaction temperature shows an important influence on the maximum specific gravity of mixture（G_（mm）） by internal volume change of PMA. The change in G_（mm） mainly affects the effective volume of the aggregate（V_（Eff））. Reduction in V_（Eff） from Zero shear viscosity（ZSV） to superpave temperature allows 0.1%-0.15% of the asphalt binder to occupy highly the external voids of aggregates. The volumetric properties for all compaction specimens meet superpave criteria, but the energy efforts were the lowest at ZSV temperature. Lower energy efforts at the ZSV temperature reflect easier compaction than those at excessively high temperature. Clearly, excessive compaction temperature may not be necessary to improve the compactibility and to reduce the compaction efforts.

Influence of Adding Compatibilizer to SBS Polymer-Modified Asphalt on Compatibility and Rheological Behavior

Adding compatibilizer to polymer-modified asphalt(PMA)is an effective method to improve compatibility and performance.However,only few studies have systematically focused on how compatibilizer can affect the performance of styrene-butadiene-styrene(SBS)polymer-modified asphalt(PMA).In this study,six compatibilizers with different compositions were used to prepare SBS PMA samples.Conventional performance,viscosity-temperature characteristics,viscoelastic behavior,creep properties,and morphology were investigated.The results show that adding compatibilizer to SBS PMA has a great effect on its performance.High aromatics content in compatibilizers can improve the high-temperature performance of SBS PMA,while a high saturates content can enhance the low-temperature performance.Additionally,high aromatics content in compatibilizer can increase the temperature sensitivity.While the aromatics content does improve the compatibility of SBS PMA to some extent,adding compatibilizer to SBS PMA has few effects on the microstructure.Judging from our test results,we can conclude that the optimum aromatics content for adding compatibilizer to SBS PMA ranges from 33.21%to 54.22%.

聚合物改性沥青显微结构及量化研究

荧光显微照相技术不会破坏聚合物相在沥青中的形态 ,是评价改性沥青机理的有效手段。本文介绍用荧光显微照相观测到聚合物相在沥青中真实的相态结构及如何利用改进的方法获得大量重现性很好的显微图像 ,本文还对目前改性沥青显微结构的研究现状及存在的问题进行了评价与分析 ,并提出改进的方法 ,配备了数字化处理所需的硬件设备及功能完善的图像处理软件 ,可以对聚合物改性沥青的显微结构进行量化分析。