水泥对乳化沥青混合料路用性能的影响

Effects of Cement on Road Performances of Emulsified Asphalt Mixtures

针对乳化沥青混合料路用性能特点,研究不同水泥剂量时,乳化沥青混合料在7 d和28 d龄期的路用性能变化规律.采用SEM,EDAX和Zeta电位仪等分析其机理.结果表明:乳化沥青混合料马歇尔稳定度、静压强度、回弹模量、动稳定度及冻融劈裂比等随水泥剂量增加而增大;在一定范围内,水泥剂量增加,混合料低温劈裂强度增大,但脆性增加,较合理水泥剂量为混合料重量的3.0%.水泥水化硅酸钙(C─S─H)等水化产物能够提高混合料Zeta电位,增加Ca,Si元素数量,减少自由沥青比例,从而增强浆体致密性,减小浆体与集料界面距离,改善混合料路用性能.

Aiming at the characters of road performance of emulsified asphalt mixtures, the rules of road performance of the mixtures with different cement dosages at 7 days and 28 days were studied and its mechanisms were analyzed with some micro-test apparatuses, such as SEM, EDAX and Zeta potential apparatus. The results indicate that marshall stability, static compression strength, compression bound module, dynamic stability and frost-thaw splitting strength ratio are all enhanced with increase of cement dosage. Within a dosage limitation, splitting strength at low temperature of the mixtures increases with increase of cement, but its brittleness begins to increase. The optimal cement dosage is 3.0% of the mixtures mass. The micro-tests find that there is much C--S--H gel in the mixtures, a cement hydration product, which can enhance Zeta potential value, increase quantity of Ca and Si elements, decrease proportion of free asphalt, make mortar in the mixtures dense and reduce instance from mortar to aggregate. So road performance of the mixtures is improved.