基于表面自由能理论研究改性沥青-集料复合材料黏附性能

基于表面自由能理论,首先测定不同沥青、集料与已知试剂的接触角,然后通过相关公式计算得到沥青-集料复合材料的黏附功、剥落功及水稳定性指标ER,并分析老化前后沥青-集料复合材料的黏附性变化。研究结果表明:沥青-集料复合材料的黏附过程和剥落过程均对外放热且自发进行;同种沥青不同集料的复合材料黏附性和抵抗水损害能力排序为沥青-石灰岩沥青-玄武岩沥青-花岗岩,不同沥青同种集料复合材料黏附性强弱和抵抗水损害能力排序为复合改性沥青(CM)-集料胶粉改性沥青(CRM)-集料苯乙烯-丁二烯-苯乙烯改性沥青(SBSM)-集料复合材料;老化后沥青-集料复合材料的黏附性能和抵抗水损害能力均呈现下降趋势,且压力老化(PAV)比旋转薄膜烘箱老化(RTFOT)更为明显,但老化过程并未改变沥青与集料间的配伍性;对三种改性沥青的SEM图像进行分析,发现老化后沥青与集料界面黏结特性发生变化,导致沥青-集料复合材料黏附能力下降。

Study on the adhesion performance of modified asphalt-aggregate composite based on the surface free energy theory

Based on the surface free energy theory, firstly, the contact angel between asphalt, aggregate and known reagent was measured, then the adhesion and peeling work and water stability index ER of asphalt-aggregate composites were calculated according to relative formulas, followed by the analyse of the change of adhesion abilities of asphalt and aggregate before and after aging. The results show that the adhesion and peeling process of asphalt-aggregate composite release heat energy to external and are spontaneous. For the composite of same asphalt and different aggregate, the rank of adhesion and resist water damage ability from strong to weak is asphalt-limestone > asphalt-basalt > asphalt-granite, and for the composite of different asphalt and same aggregate, the rank is composite modified asphalt(CM)-aggregate > rubber crumb modified asphalt(CRM)-aggregate > styrene-butadiene-styrene modified asphalt(SBSM)-aggregate. After aging, the adhesion and resist water damage ability of asphalt-aggregate composite present a decline trend and the pressure aging vessel(PAV) is more clear than rolling thin-film oven test(RTFOT), but aging process does not change the compatibility of asphalt-aggregate composite; By analyzing the SEM image of three modified asphalt after aging, it can be discovered that the interface adhesion properties between asphalt and aggregate has been changed, which results in adhesion ability decreases of asphalt and aggregate.