速溶橡胶粉改性沥青的胶核微观尺寸的宏观效应

To solve the weaknesses of the traditional rubber asphalt such as long time of swelling, rubber powder with uneven degradation degree, segregation of the rubber modified asphalt, as well as large energy consumption and serious pollution during the production process, this project put forward the concept of "instant rubber modified asphalt" with the characteristics of faster swelling and less segregation whose application is full of promise. In this project, twin-screw extruder was adopted using the mechanochemical method and the devulcanization and degradation of traditional asphalt rubber is transferred from asphalt to the process of rubber powder, which can produce instant rubber powder with high devulcanization degree . Fluorescence microscopy, scanning electron microscopy, gel permeation chromatography technology are applied to obtain microstructure characterization indexes such as rubber core size, distribution density, difference of morphology before and after the devulcanization, and interfacial bonding conditions, relative molecular mass, crosslink density, to reveal the mechanism of instant rubber powder in asphalt. Meanwhile the three major indicators, viscoelasticity, anti-rutting factor, hot-storage stability, low temperature crack resistance and other macroeconomic performance test will be conducted to study and establish the relationship model between microstructure and pavement performance, and to determine the preparation process of rubber modified asphalt considering both instant solubility and road performance. The results of the research will provide scientific evidence and theoretical guidance on application and popularization for instant rubber modified asphalt.

为解决传统橡胶沥青降解溶胀时间长、溶胀程度不均匀、易离析，以及其生产能耗大、污染严重等不足,本课题提出“速溶”橡胶改性沥青的概念，其具有溶胀反应快、不易离析等特点，在工程中具有广泛的应用前景。本课题拟采用机械力化学双螺杆挤出法，将传统橡胶沥青脱硫过程从沥青中的降解反应转移到橡胶粉的加工过程中，生产出脱硫程度高的速溶橡胶粉。本课题采用荧光显微技术、扫描电子显微镜、凝胶渗透色谱仪等技术获得胶核尺寸、胶核分布密度、脱硫前后微观形貌变化、界面结合状况、相对分子质量、交联密度等微观表征指标，揭示速溶橡胶粉在沥青中的速溶机理，同时测定三大指标、粘弹性、抗车辙因子、高低温性能等宏观性能指标，研究建立胶核的微观尺寸与路用性能之间的关系模型。本课题的研究成果将为速溶橡胶改性沥青的应用与推广提供科学依据和理论指导。

为解决传统橡胶沥青降解溶胀时间长、溶胀程度不均匀、易离析，以及其生产能耗大、污染严重等问题，本课题提出“速溶”橡胶改性沥青的概念，其具有溶胀反应快、不易离析等特点，在工程中具有广泛的应用前景。本课题将胶粉（轿车车胎胶粉、载重车车胎胶粉）进行活化（活化剂种类、活化温度、活化剂掺拌比）后，制备活化橡胶改性沥青，由红外光谱等微观测试分析活化胶粉的改性机理；并通过常规、流变等试验得到胶粉/助剂最优掺拌比为3:1；胶粉70 ℃活化时，改性沥青综合性能最优；相同掺量下植物油对胶粉活化效率更高。将最佳活化胶粉投入双螺杆挤出机，通过控制挤出温度（轿车车胎胶粉：150℃、180℃、210℃；载重车车胎胶粉：120℃、160℃、200℃、240℃）对胶粉进行剪切脱硫，制得脱硫程度更高的速溶橡胶粉，将胶粉按不同掺量（20%、30%、40%）加入沥青制得速溶橡胶改性沥青，采用荧光显微等技术获得胶核尺寸等微观表征指标，揭示速溶橡胶粉速溶机理；同时测定常规、流变等宏观性能，建立胶核的微观尺寸与宏观性能之间的关系模型，并得到胶粉在180℃挤出、掺量在30%以内时改性沥青性能最佳，由双因素方差分析得到胶粉挤出温度对改性沥青性能的影响更为显著。将300℃挤出的胶粉以质量分数20%、30%、40%、50%制备橡胶改性沥青，得到深度降解橡胶粉能更快分散于沥青中，在不显著增加改性沥青黏度情况下，胶粉掺量可达50%以上。制备不同级配（干法间断级配、湿法间断级配、湿法连续级配）速溶橡胶改性沥青混合料，通过高、低温和水稳性能测试，得到湿法工艺优于干法工艺，间断级配优于连续级配，20%胶粉掺量的ARM高温性能较好，30%胶粉掺量的ARM低温和水稳定性能较好，并建立改性沥青胶核的微观尺寸与路用性能之间的关系模型。通过软件对胶粉、沥青和橡胶改性沥青分子建模，进行分子动力学模拟，得到180℃时天然橡胶与沥青的溶解度差最小，沥青与两种胶粉的分子势能均达到最大，两者相容性最好。为速溶橡胶改性沥青的应用与推广提供科学依据和理论指导。