胶粉改性沥青的流变特性及改性机理

Rheological characteristics and modified mechanism of crumb rubber modified asphalt

研究了胶粉改性沥青(CRMA)母料的流变特性,考察了混合时间及混合温度对CRMA母料流变特性的影响,提出并验证了胶粉对沥青改性的"力化学"机理。结果表明,与基质沥青相比,CRMA母料的表观黏度较高,黏流活化能与非牛顿指数较低,加入胶粉显著降低了沥青流变特性对剪切速率和温度变化的敏感性;提高混合温度与延长混合时间对CRMA母料流变特性的影响较大,最佳的混合时间为2h;胶粉与沥青混合过程中,混合体系的温度和胶粉的降解度随着混合时间的延长而增大,且在混合时间为2h时,80%以上的胶粉已发生降解;改性机理符合"力化学"原理。

The rheological characteristics of master batches of crumb rubber modified asphalt （CRMA） was studied. The effects of the preparing time and temperature on the rheological characteristics of CRMA master batches were investigated. The ＂Mechanochemical Process＂ mechanism was suggested and examined. The results showed that CRMA master batches had higher apparent viscosity, lower flow-activation energy and non-Newtonian index than that of base asphalt. The addition of the crumb rubber significantly reduced shearing rate and temperature susceptibility of CRMA to rheological characteristics. Increasing temperature and preparing time had great effect on rheological properties of CRMA master batches, the best preparing time was 2 h. The systems could yield a high amount of heat in the blending process with increasing the preparing time. The temperature and the degradation degree of the crumb rubber showed a significant increase corre- spondingly. Moreover, when the preparing time was 2 h, the system degradation ratio could attain about 80%. As a consequence, the modified mechanism of CRMA could be considered as a ＂Mechanochemical Process＂.