泡沫温拌沥青胶浆的流变特性及微观机制分析

Analysis of Rheological Properties and Micromechanism of Foamed Warm Mix Asphalt Mastic

为了全面探究泡沫温拌沥青(以下简称泡沫沥青)胶浆的流变特性,分别针对不同粉胶比的泡沫沥青胶浆进行温度和频率两种扫描模式下的动态剪切流变(DSR)和弯曲梁流变(BBR)试验,分析了粉胶比对泡沫沥青胶浆高、低温性能的影响,利用van Gurp Palmen(vGP)图分析了泡沫沥青胶浆时温等效原理的有效性,基于此建立了泡沫沥青胶浆在频率扫描模式下的主曲线,并运用此主曲线分析了其在较宽的温度和频域下的流变特性。此外,通过扫描电子显微镜(SEM)的微观结构识别和差示扫描量热(DSC)的热特性测试分析了泡沫沥青胶浆的微观机制。结果表明:矿粉的添加对泡沫沥青的高、低温性能均有显著影响,随着粉胶比的增大,泡沫沥青胶浆的高温性能逐渐增强,低温性能逐渐降低;泡沫沥青胶浆适用于时温等效原理,在较宽的温度域及频率域内,泡沫沥青胶浆较基质沥青胶浆具有更优的高温性能。此外,泡沫沥青胶浆与基质沥青胶浆的低温等级温度基本一致;泡沫沥青胶浆中矿粉的分散性优于基质沥青胶浆中矿粉的分散性,且泡沫沥青胶浆中含有更多的微孔洞;基质沥青较泡沫沥青具有更好的热稳定性,但在相同的粉胶比下,泡沫沥青胶浆较基质沥青胶浆具有更好的热稳定性;粉胶比不大于1.0时,泡沫沥青胶浆较基质沥青胶浆具有更高的玻璃化转变温度。综合流变特性及微观机制分析得到泡沫沥青胶浆的粉胶比不宜大于1.0。

The objective of this study is to explore the rheological properties of foamed warm mix asphalt( foamed asphalt) mastic with different fillerbinder ratios completely,by using the dynamic shear rheometer( DSR) with temperature and frequency sweep,and bending beam rheometer( BBR) tests,respectively. Also,the influence of filler-asphalt ratio on the high and low temperature performance of the foamed asphalt mastic was analyzed,and the effectiveness of time-temperature superposition principle was discussed for the foamed asphalt mastic by the v GP graph.The master curve of foamed asphalt mastic was established,and then the master curve was used to perform a rheological analysis in a wide temperature and frequency domain. In addition,this study investigated the micromechanism of the foamed asphalt mastic by using direct microstructure observations and thermal property testing,including scanning electron microscope( SEM) and differential scanning calorimeter( DSC). The results show that the addition of mineral filler exhibits a significant influence on the high and low temperature performance of the foamed asphalt.Then,with the increase of filler-binder ratio,the high temperature performance of the foamed asphalt mastic increases,and the low temperature performance decreases. The time-temperature superposition principle can be employed in the foamed asphalt mastic investigated. The foamed asphalt mastic shows high temperature performance better than the base asphalt mastic in a wide temperature and frequency domain. The low temperature grading temperature of the foamed asphalt mastic exhibits a favorable consistency with that of the base asphalt mastic in this study. The distribution of filler in the base asphalt mastic is inferior to that in the foamed asphalt mastic. The base asphalt mastic with larger amount of microhole is found compared with foamed asphalt mastic. The foamed asphalt indicates a thermal stability lower than base asphalt,however,the thermal stability of foamed asphalt mastic displays an obvious increase as compare to that of base asphalt mastic. The foamed asphalt mastic performs glass transition temperature higher than the base asphalt mastic when the filler-binder ratio is less than 1. 0. The filler-binder ratio in the foamed asphalt mastic is proposed to be less than 1. 0 through the rheological properties and micromechanism investigation.