基于能量耗散理论的纳米改性沥青多次损伤愈合性能研究

Study on Multiple Damage Self Healing Properties of Nano-modified Asphalt Based on Energy Dissipation Principle

为了分析纳米改性沥青多次损伤愈合规律,以愈合前后累积耗散能比作为愈合指标,基于能量耗散理论研究了沥青的损伤愈合过程,采用动态剪切流变仪以时间扫描模式进行损伤-愈合加载试验,对影响纳米改性沥青多次损伤愈合性能的因素进行单因素和灰关联分析。研究结果表明:纳米蒙脱土(MMT)可以促进沥青内部微裂纹的愈合,经过3次损伤后MMT/SBS复合改性沥青相比SBS改性沥青的愈合性能提升效果最为显著。单因素分析显示,适当提高愈合温度、延长愈合时间对纳米改性沥青的多次损伤愈合性能有促进作用;随着损伤度的增大、老化时间的增长,纳米改性沥青的愈合性能呈下降趋势。灰关联分析显示影响纳米改性沥青多次损伤愈合性能最关键的影响因素是老化时间;损伤度的影响仅次于老化时间,同愈合性能关联显著;愈合时间的影响则不明显;单次损伤下愈合温度同愈合性能关联显著,但随着损伤次数的增加,愈合温度的影响不再显著。

In order to study the law of multiple self healing of nano-modified asphalt,the dynamic shear rheometer was used to perform damage-healing loading test in time scanning mode.The accumulated dissipation energy was selected as the healing index,while the damage healing process is studied based on energy dissipation theory.Using single factor method and gray relational analysis to study the factors affecting the healing performance of nano-modified asphalt under multiple damage.Results showed that MMT could promote the healing of micro-cracks inside the asphalt.After three times of damage,MMT/SBS composite modified asphalt has the most significant improvement in healing performance compared to SBS modified asphalt.Single factor method showed that appropriately increasing the healing temperature and prolonging the healing time could promote the multiple damage healing performance of nano-modified asphalt;with the increase of damage degree and aging time,the healing performance of nano-modified asphalt showed a downward trend.Gray relational analysis showed that the most critical factor affecting the healing performance of nano-modified asphalt under multiple damage was the aging time;the influence of the damage degree was second only to the aging time,which was significantly correlated with the healing performance;the influence of healing time was not obvious;the healing temperature was significantly correlated with healing performance under single injury,but with the increase of damage times,the influence of healing temperature was no longer significant.