蓖麻油基生物沥青与集料界面黏附性研究

Study on Interfacial Adhesion Between Castor Oil-based Bio-asphalt and Aggregate

为研究生物沥青-集料的黏附性及老化作用对其黏附性的影响,以70号石油沥青和蓖麻油基生物油为原料混合制备生物沥青,采用旋转薄膜烘箱(RTFOT)模拟沥青的短期老化,并采用水煮法和接触角试验对不同生物油掺量(0%、5%、10%、15%)的原样沥青、RTFOT后的沥青与集料(石灰岩、废钢渣)的黏附性进行评价。结果表明:总体上生物沥青与废钢渣的黏附性优于石灰岩,且在生产运输阶段短期老化对黏附性影响较小;水煮法下,生物沥青与石灰岩、废钢渣的黏附性等级均为4级,仅老化后在生物油掺量为15%时,生物沥青-集料黏附性等级降为3级;表面自由能理论下,生物沥青的表面自由能以及其与集料的黏附功、配伍率均随生物油掺量的增加呈现先增大后减小的趋势,而剥落功相反;相较于高掺量生物沥青,掺加5%生物油的生物沥青-集料黏附性最佳,集料表面沥青剥落率最小,且生物油掺量越高,负面效果越大;此外,水煮法与表面自由能理论的规律契合度好,即用黏附功和剥落功表征老化前后生物沥青-集料黏附性与水煮法评定具有一致性。

In order to study the adhesion of bio-asphalt and aggregate and the influence of aging effect, the bio-asphalt was prepared by mixing the 70# petroleum asphalt and castor oil-based bio-oil. The short-term aging of bioasphalt was simulated by the Rolling thin film oven test(RTFOT). The adhesion of original with different bio-oil dosages(0%, 5%, 10%, and 15%) and bio-asphalt and aggregates(limestone and scrap steel slag) by RTFOT were evaluated by boiling method and contact angle test. The result shows that the adhesion of bio-asphalt and steel slags were better than that of limestone, and short-term aging had little effect on the adhesion during the production and transportation stage;By boiling method, all of the adhesion grade of bio-asphalt, limestone and steel slag were grade 4.However, after aged, the adhesion grade of bio-asphalt with 15% bio-oil and aggregate dropped to grade 3;Under surface free energy, surface free energy of bio-asphalt and the adhesion work and the compatibility rate of bio-asphalt and aggregate increased at first and then decreased with increase of the bio-oil content. But the change trend of peeling work was opposite;Compared with bio-asphalt with high content, the bio-asphalt with 5% bio-oil and aggregate had the best adhesion and the minimum asphalt spalling rate on the aggregate surface. The higher the content, the greater the negative effect;In addition, the boiling method fit well the surface free energy theory. That is,characterization of the adhesion between bio-asphalt and aggregate before and after aging by adhesion work and peeling work is consistent with the water boiling method.