泡沫温拌沥青的玻璃态转变温度及低温性能

Glass transition temperature and low temperature performance for foam warm mix asphalt

为研究泡沫温拌沥青的玻璃态转变温度及低温性能,采用不同的沥青类型和不同的发泡用水量,制备泡沫温拌沥青.利用动态热力学分析仪(dynamic thermomechanical analysis,DMA)和差示扫描量热法(differential scanning calorimetry,DSC),确定不同发泡水量下泡沫温拌沥青玻璃态转变温度,采用低温弯曲流变梁(bending beam rheometer,BBR)分析不同发泡水量下泡沫温拌沥青的低温性能.结果表明,分别通过DMA和DSC确定的玻璃态转变温度有所区别,但对于不同的沥青和发泡用水量,两者的变化趋势一致;随着发泡水增多,沥青玻璃态转变温度逐渐增高;加入发泡水会在一定程度降低沥青的低温抗裂性能,采用质量分数为6%的发泡水制备的泡沫温拌沥青不能满足-12℃时的低温环境要求,也无法满足原有未发泡沥青的低温环境适用范围.为保证泡沫温拌沥青良好的路用性能,泡沫温拌沥青制备时,最佳发泡用水量选择应重点考虑其低温抗裂能力.

In order to study the glass transition temperature and low temperature performance of foam warm mix asphalt( FWMA),we have prepared the FWMA samples with different asphalt types and different foaming water contents( FWC). Glass transition temperatures of the samples are determined by using dynamic mechanical analyzer( DMA) and differential scanning calorimetry( DSC) methods,and their low temperature performancesare evaluated by using bending beam rheometer( BBR) method. Results show that for different asphalt types and FWC,the behaviors of glass transition temperatures determined by DMA and DSC are different,but their changing trends are similar. With the increase of FWC,the glass transition temperature of asphalt increases gradually. The addition of foam water damages the low temperature cracking resistance of asphalt to a certain extent. Foaming water with a mass fraction of 6% could not meet the low temperature requirement below-12 °C,and could not satisfy the application scope of the non-foaming asphalt at low temperature. In order to ensure good pavement performance of FWMA,the low temperature cracking resistance must be taken as the priority consideration for choosing the optimal FWC.